In the United States, twelve major soil texture classifications are defined by the United States Department of Agriculture.[1] The twelve classifications are sand, loamy sand, sandy loam, loam, silt loam, silt, sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, and clay.[5] Soil textures are classified by the fractions of each soil separate (sand, silt, and clay) present in a soil. Classifications are typically named for the primary constituent particle size or a combination of the most abundant particles sizes, e.g. "sandy clay" or "silty clay". A fourth term, loam, is used to describe equal properties of sand, silt, and clay in a soil sample, and lends to the naming of even more classifications, e.g. "clay loam" or "silt loam". Determining soil texture is often aided with the use of a soil texture triangle.[5] An example of a soil triangle is found on the right side of the page. One side of the triangle represents percent sand, the second side represents percent clay, and the ...
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Cation exchange capacity (CEC) and total exchangeable cations (TEC) are two significant concepts in soil fertility. Cations refer to the positively charged nutrients in the soil, e.g. Ca2+ and K+. They are important as they give you an idea of how many cations a soil can potentially hold and how many cations are currently being held. Understanding exactly how these soil properties influence soil fertility and applying soil management systems that enhance these properties can assist in improving pasture quality and yield.. CEC is defined as the degree to which a soil can adsorb (hold/capture) and exchange cations with the soil solution1. This term is often confused with a soils TEC which refers to the number of basic cations that are held on the soil exchange sites (CEC sites) in comparison to the total sites and is usually reported in cmol(+)/kg soil. The ability of the soil to hold nutrients is greatly influenced by the soils organic matter (OM) content, which is mostly made up of carbon, as ...
The aim of this study was to evaluate a measuring technique for determining soil CO2 efflux from large soil samples having undisturbed structure under controlled laboratory conditions. Further objectives were to use the developed measuring method for comparing soil CO2 efflux from samples, collected in three different soil management systems at various soil water content values. The experimental technique was tested and optimised for timing of sampling by taking air samples after 1, 3 and 6 hours of incubation. Based on the results, the incubation time was set to three hours. The CO2 efflux measured for different soil management systems was the highest in the no-till and the lowest in the ploughing treatment, which was in accordance with measurements on accessible organic carbon for microbes. An increase in CO2 efflux with increasing soil water content was found in the studied soil water content range. Our results indicate that soil respiration rates, measured directly after tillage operations, ...
Introduction. The decline of soil organic matter as a result of agricultural land use was identified for review, with the ultimate aim of developing a soil protection strategy and policy for South Africa. Organic matter is of great importance in soil, because it impacts on the physical, chemical and biological properties of soils. Physically, it promotes aggregate stability and therefore water infiltration, percolation and retention. It impacts on soil chemistry by increasing cation exchange capacity, soil buffer capacity and nutrient supply. Biologically, it stimulates the activity and diversity of organisms in soil.1. The organic matter content of soils is determined mainly by climate (rainfall and temperature), vegetation cover and, to a lesser extent, by topography, parent material and time. Changes in land use, however, can significantly impact on the organic matter content of soils. This impact usually results in the reduction of the organic matter content in soils. The largest of these ...
Cation exchange capacity indicates the ability of a soil to hold onto positively charged ions (cations) including plant nutrients such as potassium, calcium, magnesium and ammonium. The CEC is largely determined by clay content and organic matter. Clay has the greatest ability to hold cations, as it has a very large surface area compared to sand or silt (see Soil Texture in the Lab factsheet). Organic matter also has a high cation exchange capacity (up to 30 times greater than clay ...
Soil samples (0-60 cm) were collected from poplar based agro-forestry system varying in age from 2-20 years to study changes in total soil organic C (SOC), available phosphorus (P) and potassium (K). Soil plough layer (0-15 cm) had significantly higher SOC concentration by 34, 61 and 83%, compared with 15-30, 30-45 and 45-60 cm soil depths, respectively. Soil organic C decreased significantly with increasing soil depth, regardless of the age of poplar plantation period. The concentration of available-P and K was significantly higher in the surface soil, and decreased with increasing soil depth. Available-P increased significantly (p|0.05) by 16.3-17.7% and available-K by 36.5-52.4% in soil plough layer (0-15 cm) under agro-forestry for 20-yrs, compared with soils under agro-forestry for 2-yrs. Soils under 20-yrs old agro-forestry system had 39.8% and 50.6% higher SOC in 0-7.5 cm and 7.5-15 cm soil depth, compared with soils under 2-yrs old plantation. These results revealed C and nutrients (P and K)
Conservation tillage is expected to have a positive effect on soil physical properties, soil Carbon (C) storage, while reducing fuel, labour and machinery costs. However, reduced tillage could increase soil nitrous oxide (N2O) emissions and offset the expected gains from increased C sequestration. To date, conservation tillage is barely practiced or studied in Bosnia and Herzegovina (BH). Here, we report a field study on the short-term effects of reduced (RT) and no tillage (NT) on N2O emission dynamics, yield-scaled N2O emissions, soil structure and the economics of cereal production, as compared with conventional tillage (CT). The field experiment was conducted in the Sarajevo region on a clayey loam under typical climatic conditions for humid, continental BH. N2O emissions were monitored in a Maize-Barley rotation over two cropping seasons. Soil structure was studied at the end of the second season. In the much wetter 2014, N2O emission were in the order of CT , RT , NT, while in the drier ...
Crop production requires adequate soil nitrogen; therefore a false conclusion may be made from only measuring carbon dioxide as a soil health indicator. In this study, one might conclude that sod was the most productive soil according to the field respiration test. However, soil nitrogen levels were the lowest in the sod treatment. This would result in poor crop performance. Soil health reports are needed that include nutrient levels, especially soil nitrogen. Soil conservation practices such as reduced tillage and cover crops have the ability to improve soil productivity. If farmers can measure these soil health improvements and the measurements correlate to crop production increases, then soil conservation will be practiced. The effect of soil moisture and temperature on soil nitrate, ammonium, and carbon dioxide can determine the accuracy of prediction for nitrogen availability (Clark, 2007). A soil health test conducted by V6 growth stage would be useful in corn production to allow farmers ...
We characterized soil communities in the Mojave Desert across an elevation gradient. Our goal was to test the hypothesis that as soil quality improved with increasing elevation (due to increased productivity), the diversity of soil prokaryotes and nematodes would also increase. Soil organic matter and soil moisture content increased with elevation as predicted. Soil salinity did not correlate to elevation, but was highest at a mid-gradient, alluvial site. Soil nematode density, community trophic structure, and diversity did not show patterns related to elevation. Similar results were obtained for diversity of bacteria and archaea. Relationships between soil properties, nematode communities, and prokaryotic diversity were site-specific. For example, at the lowest elevation site, nematode communities contained a high proportion of fungal-feeding species and diversity of bacteria was lowest. At a high-salinity site, nematode density was highest, and overall, nematode density showed an unexpected, positive
We characterized soil communities in the Mojave Desert across an elevation gradient. Our goal was to test the hypothesis that as soil quality improved with increasing elevation (due to increased productivity), the diversity of soil prokaryotes and nematodes would also increase. Soil organic matter and soil moisture content increased with elevation as predicted. Soil salinity did not correlate to elevation, but was highest at a mid-gradient, alluvial site. Soil nematode density, community trophic structure, and diversity did not show patterns related to elevation. Similar results were obtained for diversity of bacteria and archaea. Relationships between soil properties, nematode communities, and prokaryotic diversity were site-specific. For example, at the lowest elevation site, nematode communities contained a high proportion of fungal-feeding species and diversity of bacteria was lowest. At a high-salinity site, nematode density was highest, and overall, nematode density showed an unexpected, positive
The decline of soil fertility has been one of the major constraints to low level of agricultural productivity and it primarily referred to the exploitation of soil nitrogen. Nitrogen could be added to or lost from the soil via different natural and human-induced processes. The work area is located in lower bilate river basin within the ethiopian rift valley which was characterized by an arid climatic conditions. The core objectives of this work were modeling of the soil nitrogen balance and the plant available stock soil nitrogen by using GIS and Remote sensing and assessing the uncertainities and source of errors. The widely used methodology of Stoorvogel and Smaling was adapted for soil nutrient balance estimation while the plant available stock soil nitrogen was determined using empirical relations. This book described acomprehensive methodology which is spatially explicit for modelling soil nitrogen balance and is very useful to professionals working in agricultural land management and ...
PREFACE xi. INSTRUMENTAL METHOD ACRONYMS xiv. COMMON HYPHENATED INSTRUMENTAL METHOD ABBREVIATIONS xv. ABBREVIATED PERIODIC TABLE OF THE ELEMENTS xvi. CHAPTER 1 SUMMARY OF THE HISTORY OF SOIL CHEMISTRY 1. 1.1 The 19th Century 3. 1.2 The End of the 19th and the Beginning of the 20th Century 8. 1.3 The 20th Century 11. 1.4 The End of the 20th and the Beginning of the 21st Century 14. 1.5 Conclusion 15. Problems 15. References 16. Bibliography 18. CHAPTER 2 SOIL BASICS PART I: LARGE FEATURES 19. 2.1. Horizonation 28. 2.2 Peds 33. 2.3 Soil Color 36. 2.4 Soil Naming 38. 2.5 The Landscape 39. 2.6 Relationship of Large Features to Soil Chemistry, Soil Analysis, and Instrumentation 40. 2.7 Conclusions 42. Problems 42. References 43. Bibliography 43. CHAPTER 3 SOIL BASICS PART II: MICROSCOPIC TO ATOMIC ORBITAL DESCRIPTION OF SOIL CHEMICAL CHARACTERISTICS 44. Soil Components Independent 45. 3.1 Soil Solids 45. Soil Components Interacting 53. 3.2. Bonding Considerations 53. Soil Components in Combination ...
Tripolyphosphates (TPP) have been commonly used as a phosphorus (P) source in slow release liquid fertilizers [1-3]. To be bioavailable to plant or microbial communities, TPP must first be hydrolyzed to phosphate monomers (ortho-P). Tripolyphosphate is believed to persist in the soil solution until undergoing hydrolysis, when it becomes bioavailable and reactive in the soil environment [4-6]. However, there is significant evidence that suggests TPP and other linear polyphosphates adsorb directly to metal oxide surfaces without having to first be hydrolyzed [7-11]. If TPP adsorbs directly to soil mineral surfaces, this could not only reduce TPP mobility in the soil solution but also reduce calcium phosphate (Ca-P) mineral precipitation. Calcium phosphate mineral formation immobilizes P from the soil solution, reducing the fraction of readily bioavailable P.. Tripolyphosphate or linear polyphosphate applications to calcareous soils may be a novel way to improve P nutrient availability. Since ...
Globally, soil and surface litter store 2 to 3 times more organic carbon than vegetation and 3 times more carbon than the atmosphere. The soil organic stock at a soil depth of 1 m is globally about 1500 to 1600 Pg (Pg = 1015 g). The amount of carbon and nitrogen stored in the soil is influenced by many factors. An important factor affecting soil properties, carbon and nitrogen storage is land use and land cover change (LULCC). Conversion of grasslands into tree plantations is common with the aim of increasing aboveground carbon stocks to mitigate climate change. This study investigated the changes that happened in the soil in the Glendhu catchment (Otago, New Zealand) after conversion of tussock grassland to pine plantation 36 years ago. The objectives of this study were to  Quantify the soil carbon and nitrogen stocks to 1 m soil depth  Determine the physical parameters of soil  Investigate the relationships between soil parameters, soil depths and land use types  Investigate the ...
Plant performance is, at least partly, linked to the location of roots with respect to soil structure features and the micro-environment surrounding roots. Measurements of root distributions from intact samples, using optical microscopy and field tracings have been partially successful but are imprecise and labour-intensive. Theoretically, X-ray computed micro-tomography represents an ideal solution for non-invasive imaging of plant roots and soil structure. However, before it becomes fast enough and affordable or easily accessible, there is still a need for a diagnostic tool to investigate root/soil interplay. Here, a method for detection of undisturbed plant roots and their immediate physical environment is presented. X-ray absorption and phase contrast imaging are combined to produce projection images of soil sections from which root distributions and soil structure can be analyzed. The clarity of roots on the X-ray film is sufficient to allow manual tracing on an acetate sheet fixed over the ...
Composts provide fertility and many other benefits to soil that no other chemical fertilizers can provide. Composts contain both macro- and micro-nutrients in proportions not typically present in most fertilizer inputs. Nutrients in composts are released slowly, thus providing more balanced nutrition throughout the growing season while reducing leaching potential. Composts can also buffer soil acidity or alkalinity so as to develop a more optimal pH for plant growth. In addition to adding nutrients, the main benefit of using composts is the improvement of soil structure. Organic matter provided by compost amendments can promote soil aggregate formation, thus improving soil structure. Improved soil structure can lead to better water infiltration, air penetration, and plant-root establishment. The added organic matter also increases retention of soil nutrients and, if properly incorporated, reduces soil-erosion risk. Composts also foster diverse soil organisms; these bacteria, fungi, insects, and ...
Liu , X , Zheng , J , Zhang , D , Cheng , K , Zhou , H , Zhang , A , Li , L , Joseph , S , Smith , P , Crowley , D , Kuzyakov , Y & Pan , G 2016 , Biochar has no effect on soil respiration across Chinese agricultural soils Science of the Total Environment , vol 554-555 , pp. 259-265 . DOI: 10.1016/j.scitotenv.2016.02. ...
The plan released today lays out a series of goals for its action teams (or committees) to tackle. Beth Mason, NACDs North Central Region representative and Soil Health Champions Network lead, serves as co-chair on the groups Communications and Education Action Team alongside Ron Nichols, soil health communications coordinator for NRCS.. Each of SHIs goals fall under a general category. For instance, under "Research," SHI proposes to enhance agricultural productivity and resilience through improved soil health by optimizing soils water holding capacity, water infiltration, and plant nutrient availability, and suppressing soil-borne diseases through soil health management systems. Its second research goal aims to quantify the environmental and human health benefits that result from improved soil health.. The group has also set out to determine how best to design and conduct large-scale soil health assessments, such as a National Soil Health Assessment. Other goals included quantifying the ...
A soil has a "soil texture" (sand and silt and clay) and it has organic matter mixed in it. But weather changes the soil. It is cold on the Earth near the north and south poles. It is hot near the equator of the Earth. Some places on Earth get a lot of rain and some places get no rain. Hot and wet weather make one kind of soil. Cold and dry weather make another kind of soil. Rain water makes small things in the soil move down with the water. When the things in the water get stuck in the soil those things make a layer in the soil. If you dig down into the soil you may find many layers in the soil. The layers may have different colors. The layers may have different "soil textures". The top part of the soil may have a lot of humus and sand. Below that layer there may be a layer of silt. Below that layer there may be a layer of clay. The sand stays on the top because it is large. The silt goes down a little with the water and makes a layer because it is small. The silt is smaller than some of the ...
A total APAL nutrient analysis enables you or your agronomist to formulate and exact foliar program.. Leaf/Soil analysis: There are significant differences between a soil and plant leaf analysis. LEAF (TISSUE) ANALYSIS. Represents plant nutrient levels and uptake of elements as a result of soil levels and soil imbalances.. A leaf analysis is not always an indication of soil levels.. SOIL ANALYSIS. Shows available soil elements and mineral imbalances.. Plant uptake can be different due to soil imbalances.. UNDERSTANDING THE DIFFERENCE. BETWEEN A LEAF AND A SOIL ANALYSIS and the IMPORTANCE OF BOTH. A leaf analysis can often be seen as a reflection of the soil in that it reflects what nutrients the soils mineral balance is allowing the plant to extract eg. High soil potassium inhibit plant uptake of magnesium, high magnesium soils inhibit plant potassium, high sodium inhibits plant potassium and calcium and high soil calcium inhibits plant uptake of most trace elements, so we often see a mineral ...
First and foremost, we need to disturb soil less. The advent of no-till and reduced tillage methods have allowed us to increase the carbon content of soils.. No-till and direct-seeding methods place the seed directly into the soil, minimizing the disturbance associated with seedbed preparation. The lack of disturbance allows the roots and crop residues from the previous crops to form soil organic matter. It reduces the degradation of the soil organic matter already present in the soil.. In Canada, we are already benefiting from reduced tillage. In the Prairies, no-tillage agriculture has increased from less than five per cent of the land area in the early 1990s to almost 50 per cent in 2006.. The situation is a bit more complex in Eastern Canada. The regions soil type and climate make it less easy to build soil organic matter. At Dalhousies Atlantic Soil Health Lab, we are exploring the potential of various cropping practices to increase soil organic matter content in the soils of Atlantic ...
Soils can vary on the same property. An easy way to identify your soil type is to fill a small jar with soil from your yard, shake it, and let the soil settle overnight. The following day you should notice distinct soil layers. Sandy soil tends to settle at the bottom, clay at the top, and silt in the middle.. Why Does Soil Matter?. Soil performs five essential functions; using the wrong type of soil or unhealthy soil can impede tree health by constricting roots from accessing the water and nutrients necessary. Soil helps regulate water, supports biodiversity, filters pollutants, provides physical support, and cycles nutrients. You can understand why attempting to plant a tree that requires less soil saturation may not thrive if its planted in silt or clay soil. Trees show signs of stress, possible signs that the soil isnt healthy include leaf discoloration, brittle limbs, and even stunted tree growth.. Its also important to dig a hole deep enough for tree roots to grow. Planting in shallow ...
How soil microbes assimilate carbon-C, nitrogen-N, phosphorus-P, and sulfur-S is fundamental for understanding nutrient cycling in terrestrial ecosystems. We compiled a global database of C, N, P, and S concentrations in soils and microbes and developed relationships between them by using a power function model. The C:N:P:S was estimated to be 287:17:1:0.8 for soils, and 42:6:1:0.4 for microbes. We found a convergence of the relationships between elements in soils and in soil microbial biomass across C, N, P, and S. The element concentrations in soil microbial biomass follow a homeostatic regulation curve with soil element concentrations across C, N, P and S, implying a unifying mechanism of microbial assimilating soil elements. This correlation explains the well-constrained C:N:P:S stoichiometry with a slightly larger variation in soils than in microbial biomass. Meanwhile, it is estimated that the minimum requirements of soil elements for soil microbes are 0.8 mmol C Kg -1 dry soil, 0.1 mmol N ...
The experiment was implemented at Sher-e-Bangla Agricultural University, Bangladesh to assess the effect of variety and vermicompost on the starch and sugar content activity of potato and their performance under ambient storage condition. The experiment consisted of two factors, i.e., factor A:- Potato varieties (V-4): V1: BARI TPS-1, V2: BARI Alu-28 (Lady Rosetta),V3: BARI Alu-25 (Asterix) and V4: BARI Alu-29 (Courage); factor B:-Vermicompost level (M-4): M1: 0 t ha-1 (Control), M2: 2 t ha-1, M3: 4 t ha-1 and M4: 6 t ha-1. Inferior quality is a major problem for potato production in Bangladesh. The application of vermicompost may enhance the processing quality of potato. The research revealed that vermicompost had a remarkable effect on most of the processing quality contributing parameters. Results also exhibited those processing parameters improved with increasing vermicompost level. Among the sixteen treatment combinations, Asterix with vermicompost at 6 t ha-1 showed the highest glucose, sucrose
AbstractSoil Compaction results from compressive forces applied to compressible soil by machinery wheels, combined with tillage operations. Draft animal‐pulled equipment may also cause soil compaction, but a huge gap exists on experimental data to adequately assess their impacts and, actually, animal traction is an option seen with increasing potential to contribute to sustainable agriculture, especially in mountain areas. This study was conducted to assess the impacts on soil compaction of tillage operations with motor tractor and draft animals. In a farm plot (Vale de Frades, NE Portugal) treatments were applied in sub‐plots (30 m × 3 m), consisting in a two way tillage with tractor (T), a pair of cows (C) and a pair of donkeys (D). Undisturbed soil samples (120) were taken before and after operations for bulk density (BD) and saturated hydraulic conductivity (Ks). The relative changes in BD observed after tillage in the 0-0.05 m soil depth increased after operations in all treatments. The
Soil Tests. Soil samples are sent to Hills Laboratories in Hamilton. They take around 10 days to be analysed and show the CEC and mineral reserves in the soil. We require about 3 cups of soil or 15-20 soil cores, sampled to 150mm depth, taken from random places in the garden or paddock. Avoid sampling recently grazed paddocks. If sampling grazed pasture, avoid dung and urine patches, camping areas, water troughs and gateways. Cation Exchange Capacity (CEC) basic soil test (K, Ca, Mg, Na, pH, Olsen P, CEC, Base Saturation) plus S (includes SO4, extractable Organic S and Anion Storage Capacity) and an Organic Soil Profile (for checking soil carbon levels) costs $121 +GST per sample.. The above soil tests, plus Resin P (good for measuring available P in soils with low pH or if you have been using RPR) and total S costs $157 +GST per sample.. Herbage Tests. Herbage tests complement Reams soil tests and allow levels of trace minerals to be analysed. Herbage samplse are sent to Hills Laboratories in ...
Most soil surveys are based on soil geomorphic, physical and chemical properties, while many classifications are based on morphological properties in soil profile. Typically, microbial properties of the soil(e.g. biomass and functional diversity) or soil biological quality indicators (SBQIs) are not directly considered in soil taxonomic keys, yet soil classification schemes are often used to infer soil biological function relating to policy (e.g. soil pollution attenuation, climate change mitigation). To critically address this, our aimwas to assess whether rates of carbon turnover in a diverse range of UK soils (n , 500) could effectively be described and sub-divided according to broadly defined soil groups by conventional soil classification schemes. Carbon turnover in each soil over a 90 d period was assessed by monitoring the mineralisation of either a labile (14C-labelled artificial root exudates) or more recalcitrant C source (14C-labelled plant leaves) in soil held at field capacity at 10 ...
Organo-mineral nutrient sources are promising soil amendments for sustainable crop production in Nigeria. A field experiment was conducted at the Teaching and Research Farm of the Cross River University of Technology Obubra during the 2016 cropping season. The objective of the study was to evaluate the effects of nitrogen (N) and amended rice mill waste (RMW) on some soil chemical properties and yield of maize (Zea mays L.). The treatments consisted of 10 kg ha-1 RMW as control and 10 kg ha-1 of RMW amended with 10, 20, 30, 40 or 50 kg N ha-1. The 6 treatments were replicated 3 times under RCBD with each experimental plot size measuring 4 × 3 m. All the treatments including control increased the chemical properties of the soil over the initial soil properties including total N, available P, SOM, pH and the exch. Cations; Ca2+, K+, Mg2+, Na+. RMW + 40 kg N ha-1 and RMW 50 kg N ha-1 produced tallest plants, highest number of leaves per plant and largest leaf area of maize plants.  RMW + 30
Soil organic matter (SOM) cycling has significant consequences for ecosystem processes and functioning. Studies of SOM have focused traditionally on soil microorganisms that regulate the fundamental biochemical processes of litter mineralization and organic matter formation. However, microbe-mediated processes rarely occur in isolation in natural systems without the involvement of soil fauna. Nevertheless, little attention has been paid to soil fauna - e.g., the direct roles they play in SOM cycling, and indirect roles through changing microbial community composition, activity, and function to influence soil C and N dynamics. We combine traditional morphological characterization of soil invertebrates with microbial functional assays, and modern chemical techniques to identify relationships among soil fauna, microbe, plant residue inputs, and SOM. Our ultimate goal is to investigate whether/how soil fauna contribute to soil organic carbon storage, especially through their impacts on microbial ...
Cover crops can help resolve a host of soil health and environmental concerns, especially nutrient retention, according to research conducted at Agriculture and Agri-Food Canadas (AAFC) Harrow Research and Development Centre in Ontario.. "Cover crops are an amazing tool that producers have available to them," says Dr. Craig Drury, soil management and biochemistry researcher at Harrow. "The cover crop increases soil organic carbon, improves soil structure and overall soil quality, and can also improve the drainage of soil.". Cover crops are planted in the late summer or early fall following the harvest of a cereal crop, or inter-seeded into an annual row crop, such as corn. They can capture the residual nitrogen that remains in the soil at the end of the growing season and effectively tie it up over winter. The nitrogen is then released into the soil when the cover crop decomposes in the following spring. This is important because, as Drury says, farmers "want to hold a nutrient like nitrogen in ...
Loss of soil resource capacity can be defined as points at which one or more of these outcomes are realised. In terms of the first and second outcomes, the most readily quantifiable point for soil resource loss is 1 mg/kg for total soil cadmium. This is both the current recommended limit for cadmium in agricultural soils, and a default human health protection limit for Waikato properties being subdivided to residential or rural-residential land. The recommended agricultural soil cadmium limit is set partly with respect to current and anticipated expectations of New Zealands international trading partners. The third outcome, non-compliance with food standards, relates mainly to particular types of horticultural and arable crops. The exact point at which soil cadmium has become high enough to cause food standards to be exceeded can be difficult to predetermine, as it depends on crop and soil conditions. However, this outcome has been observed to occur at soil cadmium concentrations below the ...
Several physical and chemical reactions take place: dissolution in water, reaction with soil organic matter and clay, and attachment of resulting ammonium ions on the soil cation exchange complex. These reactions all tend to limit the movement of ammonia, with water having the greatest initial effect. The highest concentration of ammonia is at/near the point of injection, with a tapering of the concentration toward the outer edge of the retention zone. Usually the greatest ammonia concentration is within the first inch or two of the injection point, with the overall retention zone being up to 3-4 in. in radius in most soils. The size of the ammonia retention zone, and shape, vary greatly depending upon the rate of application, knife spacing, the soil and soil conditions at injection (soil texture, soil structure, organic matter and moisture status).. Ammonia moves farther at injection in coarse-textured soils and soils low in moisture. Also, if the injection knife causes sidewall smearing (when ...
Healthy soil is more productive, has better drainage, holds on to nutrients, resists erosion, and has better water holding capacity. What does it take to have a healthy soil? Good levels of organic matter support populations of microbes and this combination improves and stabilizes soil structure.. Erosion prevention is crucial to soil health. Scientists estimate that it takes 100 years for one inch of topsoil to form. Learn how to keep your soil on your farm in the Erosion Prevention section. The Improving Soil Health section describes ways to get the most out of your soil, including the use of cover crops.. Soils vary in texture, drainage, susceptibility to erosion, water holding capacity, and other traits. These characteristics and how they affect the potential of a soil are described in the soil survey for each county. Free, printed copies are available at the East Multnomah SWCD office, but we recommend you use the online version at http://websoilsurvey.nrcs.usda.gov. This site allows you ...
The understanding on the contribution of root respiration to total soil respiration is still very limited, especially for sugarcane. In this study, trenching experiments in sugarcane plantations were conducted to separate and investigate soil respiration for this crop. The measurements were performed for the whole growing period of 344 days to quantify root respiration. The obtained monitoring data showed that the respiration rate is increasing with the age of the plant, accounting for up to 29% of the total soil respiration before harvesting. The root to soil respiration ratio increased rapidly during the young seedling stage, i.e. first five months, then declined and finally got stabilized during yield formation and ripening stages, respectively. In addition, the results from the measurements confirmed that soil respiration was positively correlated with soil moisture content.
Actual transpiration decreased with decreasing soil moisture content and increasing potential transpiration. Average soil suction in the root zone when the actual transpiration rate fell below the potential rate varied from 12 bars when the potential transpiration rate was 1.4 mm. per day to 0.3 bar when the potential rate was 6 to 7 mm. per day.. Please view the pdf by using the Full Text (PDF) link under View to the left.. Copyright © . . ...
Relationship of microbial activity and abundance to soil properties in Yucatan SDTF.Due to the lower water supply, SDTFs usually have a lower decomposition rate (25), higher soil C and N concentrations (33), and a more open N cycle (characterized by high N inputs and losses) than their wet counterparts (34). These properties can explain why the organic C contents found in these soils are larger than values reported for any other tropical soil (35). These soils also contain variable amounts of organic matter, which are in the same range as those reported for other Yucatan forest soils (27, 31). Furthermore, the experimental plots are found in nutrient-poor areas because of the regions recent geological origin, where karstic substrate dominates the landscape (30). In particular, recent studies have documented that karst soils contain abundant organic matter, which is mainly stored in the soil surface (36, 37). In addition, the karstic soils of the Yucatan have high potential to form aggregates ...
Recognition of the detrimental influence of accelerated soil erosion on agricultural societies dates back to Plato and Aristotle, and several now-classic studies have attributed the bare rocky slopes of the classical world to ancient soil erosion (1-3). In recent decades, archaeological studies confirmed pronounced episodes of soil erosion associated with the rise and subsequent decline of civilizations in the Middle East, Greece, Rome, and Mesoamerica, as well as other regions around the globe (4-8). Most commentators, however, generally attribute such erosional episodes to the effects of deforestation (9-12) and neglect the role of agriculture in maintaining accelerated erosion in upland environments.. Soil erosion is a complex process that depends on soil properties, ground slope, vegetation, and rainfall amount and intensity (13). Changes in land use are widely recognized as capable of greatly accelerating soil erosion (14-16), and it has long been recognized that erosion in excess of soil ...
This study examined the change of soil carbon affected by the increase of biomass crops and more phenol and organic acid input in soil due to elevated CO_2 concentration.A culture experiment using soil from a field after being cultured one year under FACE platform with two CO_2 levels(ambient CO_2 and elevated CO_2)and two N levels(normal N and low N)was conducted in a greenhouse at the same N treatment with the field.The results indicated that compared to soil from ambient CO_2,turnover of different soil particles in soil from elevated CO_2 was increased and affected by added straw and nitrogen levels.Soil carbon content in particles of size 250 and 53 μm was increased due to input of phenol and organic acid under straw added or not condition.Soil carbon content in each particle per unit of soil was increased and the increase magnitude was larger in particles 53 μm.The change was larger at normal N with no straw and at low N with straw added.The results indicated that straw,phenol and organic acid
Stock farming plays an important role in the agriculture of alpine regions although deleterious effects on the soils are most pronounced here. We investigated the effects of cattle trampling on soil physical, chemical and microbial properties in a Swiss sub-alpine pasture. About 10% of the study site was bare of vegetation as a result of repeated cattle trampling and the bulk density of these bare steps was 20% higher than of the soils unaffected by trampling. In the upper 25 cm, soil organic carbon (SOC) concentrations and total SOC stocks were 35% and 20% respectively lower than on the vegetated slope. As compared with the vegetated slope, topsoils of the bare steps featured narrower C:N-ratios and were more enriched in the 15N isotope, with typical values of deeper soil layers. This indicates that bare soils primarily evolved by erosion and not by a compaction, which might, together with the reduced litter input, explain the lower SOC contents. The abundances of soil microbes, estimated by ...
The uppermost layer of the earths crust is known as soil. It is a mixture of rock fragments and organic matter which has decomposed into constituent nutrients.Soil formation is influenced by the weathering and erosion processes that are defined by a regions climate. Apart from this, the nature of the parent rock, topography, vegetation cover etc., also determine the type of soil that is formed.Pedogenesis is the process of soil formation under the action of various forces of nature such as wind, flowing water etc.Soil can be classified into three types based on the texture of grains found in it.Sandy soils - if the size of soil grain is in the range of 2 to 0.05 mm.Silt - if the size of soil grain is in the range of 0.05 to 0.002 mm. It is usually found on the river bedsClayey soils - if the size of soil grain is less than 0.002 mmSandy soils have enough gaps between their grains to drain water quickly. Hence, these soils tend to be dry, light in weight, and well aerated.Clayey soils are more ...
Waste products from industry have often been disposed in landfills without regard for any beneficial uses of the product in agricultural production. This research was conducted to determine the effect of a refractory metal processing waste product on (a) soil chemical and physical properties, (b) perennial ryegrass forage quality and seed yield, and (c) percolation water quality. Refractory metals processing waste was applied either as a slurry or dried to Dayton silty clay loam (sicl) at rates of 0, 5, 10, 25, and 50 tons/acre. Ammonium nitrate, concentrated superphosphate, muriate of potash, calcium sulfate, and lime were added to optimize plant growth. Lime, gypsum, and phosphorus fertilizer variables were incorporated into the study to investigate specific beneficial or problems areas associated with the waste product. The waste and fertilizers were tilled into the soil, and all plots seeded with perennial ryegrass (var. Linn) and irrigated. Elements found in the waste in excess of one ...
Soil organic carbon (SOC) is an important and manageable property of soils that impacts on multiple ecosystem services through its effect on soil processes such as nitrogen (N) cycling and soil physical properties. There is considerable interest in increasing SOC concentration in agro-ecosystems worldwide. In some agro-ecosystems, increased SOC has been found to enhance the provision of ecosystem services such as the provision of food. However, increased SOC may increase the environmental footprint of some agro-ecosystems, for example by increasing nitrous oxide emissions. Given this uncertainty, progress is needed in quantifying the impact of increased SOC concentration on agro-ecosystems. Increased SOC concentration affects both N cycling and soil physical properties (i.e., water holding capacity). Thus, the aim of this study was to quantify the contribution, both positive and negative, of increased SOC concentration on ecosystem services provided by wheat agro-ecosystems. We used the Agricultural
Soil tillage practices have a profound influence on the physical properties of soil and the greenhouse gas (GHG) balance. However there have been very few integrated studies on the emission of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) and soil biophysical and chemical characteristics under different soil management systems. We recorded a significantly higher net global warming potential under conventional tillage systems (26-31% higher than zero tillage systems). Crucially the 3-D soil pore network, imaged using X-ray Computed Tomography, modified by tillage played a significant role in the flux of CO2 and CH4. In contrast, N2O flux was determined mainly by microbial biomass carbon and soil moisture content. Our work indicates that zero tillage could play a significant role in minimising emissions of GHGs from soils and contribute to efforts to mitigate against climate change.. ...
Second, recognize that when we say healthy soils we are referring not only to oxygenated, aerobic soil structure but also to the abundance of beneficial microorganisms (microbes) that should exist in all productive soils. The famous adage Feed the Soil, Feed the Plant means that whatever we apply to the soil should feed the soil microbes and the plants too. We want our soils to be teaming with beneficial bacteria, fungi, nematodes, protozoans and micro-arthropods. Through the amazing work of Dr. Elaine Ingham, The Soil Foodweb, started in the mid 1990s, we now know of the incredible work that the invisible to the naked eye microbes do to grow and protect plants.. And we now know that plants give up to 80% of their manufactured photosynthesized food through the root system to directly attract and feed the microbes. The plant feeds the soil microbes and the soil microbes help the plants grow and protect them from diseases, pest insects and weeds. So to the soil do no harm. This is easily ...
Soil is a natural resource that is fundamental for all human uses. Soil is primarily used for agriculture and soil erosion plays a major role in causing serious disruption in agricultural activity. Soil erosion occurs mainly due to natural disasters like floods and droughts. Prevention and mitigation are effective ways to manage this problem. GIS in conjunction with the Universal Soil Loss Equation (USLE) can be used to evaluate the risk area of soil erosion. The USLE is the most commonly used estimator of soil loss caused by overland erosion. It is used in most parts of the world including India ...
Agricultural systems rely on healthy soils and their sustainability requires understanding the long-term impacts of agricultural practices on soils, including microbial communities. We examined the impact of 17 years of land management on soil bacterial communities in a New Zealand randomized-block pasture trial. Significant variation in bacterial community structure related to mowing and plant biomass removal, while nitrogen fertilizer had no effect. Changes in soil chemistry and legume abundance described 52% of the observed variation in the bacterial community structure. Legumes (Trifolium species) were absent in unmanaged plots but increased in abundance with management intensity; 11% of the variation in soil bacterial community structure was attributed to this shift in the plant community. Olsen P explained 10% of the observed heterogeneity, which is likely due to persistent biomass removal resulting in P limitation; Olsen P was significantly lower in plots with biomass removed (14 mg ...
Designed to provide students with fundamental knowledge of soil and soil composition. Includes study of soil types, formation factors, physical properties, biological properties, and basic soil chemistry. Units covering tillage, conservation, pH, soil management, plant nutrients, and fertilizer sources are also included. Students gain the skills required to interpret soil test reports and soil survey maps and recognize qualities of various soil types. Students perform soil sampling, residue measurements, compaction assessments, and soil loss determinations per crop rotation guidelines.. ...
Discussion. Effects of soil temperature and moisture on the rate of soil respiration. Our study corroborates findings of other studies, which have shown that soil respiration is greatest at around 25 ºC (e.g. Conant et al. 2004). At this temperature microbes are active but the temperature is not too high to retard their activity (Swift, Heal & Anderson 1979). Our study found that when soil temperatures rose above 28 ºC, soil respiration declined, but this observation is confounded by the low soil moisture, which always coincided with high temperatures. Temperature dependence of respiration therefore remains unclear at the site, as also reported by Williams et al. (2009), although results from Kutsch et al. (2008) suggest that respiration suppression at high temperatures may be occurring. Q is defined, by convention, as the factor by which respiration increases over a 10-degree temperature range, but can be calculated over any temperature difference, and can be thought of as the sensitivity of ...
Now that weve established the composition and components of soil, and described a brief history of soil in Virginia, we can expand on what properties in soil promote growth. We can do this while examining different soils from around central grounds. Three areas we will highlight are Observatory Hill Field (Figure 2), Fayerweather Hall (Figure 3), and the Lawn (Figure 4).. Organic matter. Organic matter broadly alludes to the assortment of dead plant and animal material in the soil. This includes everything from ground-up leaves to compost. Organic matter is essential to soil for its wide range of benefits that it provides. These benefits include being able to "supply nutrients for plants by providing surfaces where nutrients can be held in reserve in the soil, facilitate better drainage by loosening soil structure, store water in soil, help increase air drainage, and increase the activity and numbers of soil microorganisms" (organic matter). The optimal level for organic matter in soil is about ...
The Century model has successfully simulated soil organic matter dynamics in many agroecosystems. However, initial applications in southern Brazil produced mixed results. The objective of this study was to calibrate and validate Century 4.5 to simulate soil carbon (C) and nitrogen (N) dynamics under diverse soil management practices in subtropical Brazil. Soil C and N data from two long-term experiments established on a degraded Acrisol in the early 1980s were used. Treatments were conventional or no-tillage; grass or grass/legume cropping systems; and corn with or without mineral N fertilizer. The calibration process iteratively modified model parameters to match simulated values of C additions and Soil Organic Carbon (SOC) and Soil Organic Nitrogen (SON) stocks to field data measured throughout the 25 years of the experiments. Improved fit between measured and observed data was obtained after key parameter changes. Soil C and N stocks were simulated accurately after these modifications were ...
Well-structured soils are generally considered to have bimodal pore structure, including textural pores between soil particles and structural pores between soil aggregates. Bimodal pore structure has previously been inferred indirectly from the soil water retention curve (SWRC) but our understanding of the precise 3-D pore geometry that regulates this curve is limited. The objective of this study was to investigate the bimodal pore structure of a paddy soil under different fertilization regimes using both SWRC and X-ray micro-Computed Tomography (micro-CT), an imaging approach with the aim of comparing the two methods. Undisturbed soil aggregates and soil cores were collected from the surface layer of a long-term unfertilized control (CK), inorganically fertilized (NPK), and organically and inorganically fertilized (NPKOM) paddy soils. The aggregates and cores were scanned using micro-CT and pore structure analyzed. The SWRCs were measured on the same CT-scanned soil cores. Three widely used ...
Many gypsiferous soils occur in arid lands, where the water retention capacity of the soil is vital to plant life and crop production. This study investigated the effect of gypsum content on the gravimetric soil water retention curve (WRC). We analyzed calcium carbonate equivalent (CCE), equivalent gypsum content (EG), soil organic carbon content (SOC), and electrical conductivity of 43 samples collected from various horizons in soils in the Ebro Valley, NE Spain. The WRC of the fine earth was determined using the pressure-plate method (pressure heads = 0, −33, −100, −200, −500, and −1500 kPa), and the gravimetric water retention curves were fitted to the unimodal van Genuchten function. Soil gypsum content had a significant effect on water retention. Soils that had high gypsum content made WRC with higher water retention at near saturation conditions, and steeper WRC slopes. The EG threshold at which gypsum content had an effect on WRC was about 40%, and EG was positively and ...
Soils are a major reservoir of organic pollutants, and soil-air partitioning and exchange are key processes controlling the regional fate of pollutants. Here, we report and discuss the soil concentrations of polycyclic aromatic hydrocarbons (PAHs), their soil fugacities, the soil-air partition coefficients (KSA) and soil-air gradients for rural and semirural soils, in background areas of N-NE Spain and N-NW England. Different sampling campaigns were carried out to assess seasonal variability and differences between sampling sites. KSA values were dependent on soil temperature and soil organic quantity and type. Soil fugacities of phenanthrene and its alkyl homologues were 1-2 orders of magnitude higher than their ambient air fugacities for all sampling sites and periods. The soil to air fugacity ratio was correlated with soil temperature and soil redox potential. Similar trends for other PAHs were found but with lower fugacity ratios. The ubiquitous source of PAHs from background soils to the ...
Soil biogeochemical cycles are largely mediated by microorganisms, while fire significantly modifies biogeochemical cycles mainly via altering microbial community and substrate availability. Majority of studies on fire effects have focused on the surface soil; therefore, our understanding of the vertical distribution of microbial communities and the impacts of fire on nitrogen (N) dynamics in the soil profile is limited. Here, we examined the changes of soil denitrification capacity (DNC) and denitrifying communities with depth under different burning regimes, and their interaction with environmental gradients along the soil profile. Results showed that soil depth had a more pronounced impact than the burning treatment on the bacterial community size. The abundance of 16S rRNA and denitrification genes (narG, nirK, and nirS) declined exponentially with soil depth. Surprisingly, the nosZ-harboring denitrifiers were enriched in the deeper soil layers, which was likely to indicate that the ...
Research Areas: Abiotic stress- Drought, Environmentally friendly farming practices, Farmer decision-making, Greenhouse experiments, Rhizosphere, Rhizosphere ecology, Root microbiome, Root mycorhhiza, Soil amendments, Soil erosion, Soil fertility, Soil health, Soil microbiology, Soil microbiome, Soil nutrient cycling, Soil plant interactions, Soil ...
MUTURI, J. J. et al. Effect of integrated soil fertility management interventions on the abundance and diversity of soil Collembola in Embu and Taita Districts, Kenya. Trop. subtrop. agroecosyt [online]. 2011, vol.13, n.1, pp.35-42. ISSN 1870-0462.. The study aimed at identifying soil fertility management practices that promote the Collembola population, diversity and survival in the soil. Soil samples were randomly collected from on farm plots amended with: 1-Mavuno ((Ma)-is a compound fertilizer containing 26% Potassium, 10% Nitrogen, 10% Calcium, 4% Sulphur, 4% Magnesium and trace elements like Zinc, Copper, Boron, Molybdenum and Manganese)), 2-Manure (Mn), 3-Trichoderna (Tr) inoculant (is a soil and compost-borne antagonistic fungus used as biological control agent against plant fungal diseases), 4-Farmers practice ((FP) where Tripple Super Phosphate (T.S.P.) and Calcium Ammonium Nitrate (C.A.N.) fertilizers are applied in the soil in mixed form), 5-Tripple Super Phosphate (T.S.P.), ...
Situation in North Carolina Nearly all North Carolina soils are naturally acidic and need lime, which neutralizes the acidity, for optimum growth of crops, forages, turf, trees, and many ornamentals. Even though most of these soils have been limed in the past, periodic additions of lime based on soil tests are still needed. Soil- test summaries and field records compiled by the North Carolina Department of Agriculture and Consumer Services ( NCDA& CS) emphasize that poor management of soil pH accounts for a high percentage of the " crop problems" in North Carolina. Nature and Cause of Soil Acidity " Soil acidity" is the term used to express the quantity of hydrogen ( H) and aluminum ( Al) cations ( positively charged ions) in soils. When levels of hydrogen or aluminum become too high- and the soil becomes too acid- the soils negatively charged cation exchange capacity ( CEC) becomes " clogged" with the positively charged hydrogen and aluminum, and the nutrients needed for plant growth are ...
The majority of the Earths terrestrial carbon is stored in the soil. If anthropogenic warming stimulates the loss of this carbon to the atmosphere, it could drive further planetary warming. Despite evidence that warming enhances carbon fluxes to and from the soil, the net global balance between these responses remains ... read more uncertain. Here we present a comprehensive analysis of warming-induced changes in soil carbon stocks by assembling data from 49 field experiments located across North America, Europe and Asia. We find that the effects of warming are contingent on the size of the initial soil carbon stock, with considerable losses occurring in high-latitude areas. By extrapolating this empirical relationship to the global scale, we provide estimates of soil carbon sensitivity to warming that may help to constrain Earth system model projections. Our empirical relationship suggests that global soil carbon stocks in the upper soil horizons will fall by 30 ± 30 petagrams of carbon to 203 ...
Carbon sequestration is a process where carbon from the atmosphere is stored in the soil, which helps lessen global warming. Plants, ocean, and the soil all capture and store carbon.. The soil of the Everglades, called peat, is largely made up of waterlogged, decomposing plant and animal materials. The peat soil stores a large amount of carbon compared to other soils across the globe.. When the Everglades Agricultural Area was drained, the soil was exposed to higher levels of oxygen. Decomposition of the plant and animal materials happens much faster with more oxygen. When the carbon in the soil decomposes, it becomes carbon dioxide gas. The mass of the soil decreases, and gas goes into the atmosphere. Its a big chemistry equation.. "Its not easy to picture a soil that disappears," says Rodriguez. "The most challenging process I have to explain - and the most striking - is how carbon in the soil goes from the soil to the atmosphere.". The process of soil subsidence can release significant ...
2. How well do we understand the impacts of long-term irrigation on soil structure? What are the effects of soil structure change (within and around the root zone on the flow of water and rate of movement along various pathways of salts? Key issues which the NPSI Board requested should be addressed in the document were ...
Description: Plant roots serve as conduits for water flow not only from soil to leaves but also from wetter to drier soil. This hydraulic redistribution through root systems occurs in soils worldwide and can enhance stomatal opening, transpiration, and plant carbon gain. For decades, upward hydraulic lift (HL) of deep water through roots into dry, litter-rich, surface soil also has been hypothesized to enhance nutrient availability to plants by stimulating microbially controlled nutrient cycling. This link has not been demonstrated in the field. Working in sagebrush-steppe, where water and nitrogen limit plant growth and reproduction and where HL occurs naturally during summer drought, we slightly augmented deep soil water availability to 14 [HL.sub.+] treatment plants throughout the summer growing season. The [HL.sub.+] sagebrush lifted greater amounts of water than control plants and had slightly less negative predawn and midday leaf water potentials. Soil respiration was also augmented under ...
NO fluxes from soils are a significant source for tropospheric NOx, though global and regional estimates of the soil source strength are constrained by the paucity of measurements. In a continuous 18 month effort (2012-2014) soil NO fluxes from an intensively managed arable site in the black soil region of the Southern Ukraine (Odessa region) were measured using an automated dynamic chamber system. Measurements revealed three periods of peak NO emissions (fertigation, re-wetting of soils, and to a lower extend during winter), with a pulse emission peak during soil re-wetting in summer of 88.4 μg N m−2 h−1. The mean annual NO flux was 5.1 ± 8.9 μg N m−2 h−1 and total annual NO emissions were 0.44 ± 0.78 kg N ha−1 yr−1. The fertilizer induced emission factor for NO was 0.63% under beetroot. The combined effect of soil temperature, soil moisture and soil DIN (NH4+ and NO3−) concentrations were identified as drivers of the temporal and spatial variability of soil NO fluxes. This ...
Soil C/N ratio is an important influencing factor in soil nitrogen cycling. Two-year old apple trees (Borkh. cv. Fuji/ Malus hupehensis) were used to understand the effect of soil C/N ratio [6.52 (CK), 10, 15, 20, 25, 30, 35 and 40] on apple growth and nitrogen utilization and loss by using 15N trace technique. The results showed that, with the increasing of soil C/N ratio, apple shoot length and fresh weight increased at first, and then decreased; the higher apple shoot length and fresh weight appeared in C/N=15, 20 and 25 treatments, and there were no significant differences among these three treatments, but significantly higher than the other treatments. Statistical analysis revealed that there was significant difference in nitrogen utilization rate between the different treatments, the highest N utilization rate was occurred in soil C/N=25 treatment which value was 22.87%, and there was no significant difference between soil C/N=25 and C/N=20 treatments, but both the two treatments were
Soil Quality - improving how your soil works is a web site devoted to soil quality concepts, indicators, assessment, management, and practices.
Rhizodegradation is a process by which plant-supplied substrates stimulate microbial populations in plant root zones (rhizospheres) to cause removal of undesirable levels of contaminants in soil. This study characterized rhizodegradation of the insecticide bifenthrin in Armour silt loam and Sullivan fine sandy loam soils that were planted with switchgrass, big bluestem, and alfalfa. After six weeks in soils, plate dilution frequency assays (PDFA) of bacterial populations were higher in all planted soils than in unplanted ones. Planted Sullivan soils contained higher bacteria than corresponding Armour soils and alfalfa rhizospheres of both soil types contained highest bacteria. Bacterial populations generally increased between week 6 and week 10, before declining in each treatment at week 12. Carbon utilization patterns (CUP) of bacterial communities, measured as color development on BIOLOG plates, were higher in planted soils than in unplanted ones. Principal Component Analysis (PCA) constructed
Land use patterns are one of the major sources of patchiness in ecosystem function in the Baltimore area, in both time and space. The area was originally heavily forested (1700), was then almost entirely in agriculture (1850) and is now a mix of forest, agriculture and residential land use. The residential land uses have large areas of grass. Land use influences soil nitrogen cycling through its effects on fertilizer input, soil water, organic matter, pH and disturbance. Quantifying these influences is important for understanding patchiness in ecosystem functions related to soil fertility and the delivery of nitrate (a cause of eutrophication in salt water) to streams and estuaries. There is particular interest in nitrification, the microbial processes that leads to the production of nitrate.. In this study, we sampled 14 forest, 10 row crop agriculture (corn) and 10 grass sites though out the Baltimore metropolitan area in summer 2000. Soils were assayed for microbial biomass carbon and ...
Restoration of tallgrass prairie on former agricultural land is often impeded by failure to establish a diverse native species assemblage and by difficulties with nonprairie, exotic species. High levels of available soil nitrogen (N) on such sites may favor fast-growing exotics at the expense of more slowly growing prairie species characteristic of low-N soils. We tested whether reducing N availability through soil carbon (C) amendments could be a useful tool in facilitating successful tallgrass prairie restoration. We added 6 kg/m2 hardwood sawdust to experimental plots on an abandoned agricultural field in the Sandusky Plains of central Ohio, United States, increasing soil C by 67% in the upper 15 cm. This C amendment caused a 94% reduction in annual net N mineralization and a 27% increase in soil moisture but had no effect on total N or pH. Overall, plant mass after one growing season was reduced by 64% on amended compared with unamended soil, but this effect was less for prairie forbs ...
Many studies of the microbial ecology of agricultural ecosystems focus on surface soils, whereas the impacts of management practice and season on soil microbial community composition and function below the plough zone are largely neglected. Deep soils have a high potential to store carbon; therefore any management driven stimulation or repression of microorganisms in subsoil could impact biogeochemical cycling in agricultural sites. The aim of this study was to understand whether soil management affects microbial communities in the topsoil (0-10 cm), rooted zone beneath the plough layer (40-50 cm), and the unrooted zone (60-70 cm). In a field experiment with different crops [wheat (Triticum aestivum L.) and maize (Zea mays L.)] and agricultural management strategies (litter amendment) we analysed microbial biomass as phospholipid fatty acids (PLFAs) and enzyme activities involved in the C-cycle (β-glucosidase, N-acetyl-β-d-glucosaminidase, β-xylosidase, phenol- and peroxidase) across a depth ...
Inoculation of soil with bacteria (a Gram-negative rod [PD2] and a 4- membered consortium [DC1]) accelerated mineralization of phenanthrene and pyrene (but not naphthalene) added individually to a pristine sand and a pristine organic soil. The half-life of naphthalene was 3.5 days in both soils whether inoculated or non-inoculated. However, the half-life of phenanthrene decreased from 86 days in non-inoculated sand soil and 80 days in the non-inoculated organic soil to 3.6 days in the sand and 3.1 days in organic soil when inoculated with PD2, and to 6.6 days in the sand and 8.7 days in the organic soil when inoculated with DC1. Phenanthrene mineralization ceased after 23 days in DC1-inoculated soil and was 71.3 ± 3.6% (sand) and 63.3 ± 2.8% (organic). This compared with 96.8 ± 3.8% (sand) and 102.8 ± 2.5% (organic) after 8 days in PD2-inoculated soil. Inoculation with DC1 (but not PD2) also accelerated mineralization of pyrene, where the half-life decreased from 155 days to 18 days in the sand soil
Measurement of the apparent dielectric permittivity of soils (dielectric constant) is becoming a popular way of estimating soil volumetric water content. This paper focuses on the measurement of apparent permittivity in four sandy soils using; time domain reflectometry (TDR), a surface capacitance insertion probe (SCIP) and a Theta probe. Measurement of the apparent permittivity using the SCIP and Theta probe are compared with the apparent permittivity measured using the TDR. Calibration of such instrumentation has remained relatively empirical following the engineering approximation presented by Topp et al. (Topp, G.C., Davies, J.L., Anan, A.P., 1980. Electromagnetic determination of soil water content: measurements in coaxial transmission lines. Water Res. Research 16, 574-582.). The refractive index model proposed by Whalley (Whalley, W.R., 1993. Considerations on the use of time domain reflectometry (TDR) for measuring soil water content. J. Soil Sci. 44(1), 1-9.) based on that of Birchak et ...
Only scarce field studies concern the consequences of natural soil organic matter (SOM) and metal interactions on SOM dynamics in soils. We investigated the interactions of four metals (Pb, Zn, Cu and Cd) with the SOM associated to five different size fractions (between 2000 μm and b2 μm) of a sandy top soil contaminated by waste water. Metal, organic carbon and nitrogen concentrations were measured and chemical extractions (with Na4P2O7 and EDTA) were also performed to assess the variations of SOM-metal interactions irrespective of the size fraction. In addition, as in that selected contaminated site, maize (C4 plant), replaced C3 crops 15 years ago, natural isotopic 13C labelling gave new insights into SOM turnover. First, the results suggest that metals influence the SOM dynamics in that sandy soil: a C3 "old carbon" enrichment was observed in the small or clay size fractions, while the "new" C4 carbon associated with sandy soil particles presents a rapid turnover. Metal accumulation in the ...
The Sustainable Development Goals (SDGs), adopted in 2015, establish a clear mandate to manage the planet for both human and environmental wellbeing. Any viable approach to achieving the SDGs requires addressing soil, which is the foundation of both healthy natural and agricultural ecosystems. Soil organic matter (SOM) is an especially important soil property because it is the principle arbiter of soil health and is one of the most responsive soil properties to land management. Management of SOM can increase agricultural productivity (SDGs 1, 2), remove carbon (C) from the atmosphere (SDG 13), and ensure water systems that are safe for human consumption and that support thriving aquatic biodiversity (SDGs 6, 14). Some forms of land management can degrade SOM, causing release of large quantities of C to the atmosphere, lower soil productivity, contaminate drinking water with excess farm nutrients, and cause eutrophication of aquatic ecosystems, which leads to biodiversity declines. Successfully ...
The relationship between total and metabolically active soil microbial communities can provide insight into how these communities are impacted by environmental change, which may impact the flow of energy and cycling of nutrients in the future. For example, the anthropogenic release of biologically available N has dramatically increased over the last 150 years, which can alter the processes controlling C storage in terrestrial ecosystems. In a northern hardwood forest ecosystem located in Michigan, USA, nearly 20 years of experimentally increased atmospheric N deposition has reduced forest floor decay and increased soil C storage. A microbial mechanism underlies this response, as compositional changes in the soil microbial community have been concomitantly documented with these biogeochemical changes. Here, we co-extracted DNA and RNA from decaying leaf litter to determine if experimental atmospheric N deposition has lowered the diversity and altered the composition of the whole communities of ...
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Phosphorus (P) is one of the leading causes of surface water quality decline in the United States, leading to algal blooms and hypoxia in lakes and streams. Decreasing conservation funds dictate that agencies such as the Natural Resources Conservation Service, maximizes its effectiveness and efficiency in implementing practices to address P management and runoff on agricultural lands. Additional information on P behavior in soil is needed to improve P management plans to reduce pollution risk at the watershed, farm, and field scales. This research focuses on the development of total soil P release models, to be included into assessment and management tools to better identify agricultural soils that pose the greatest threat to surface water if eroded, and to improve existing nutrient loss models. Soil P sorption behaviors and relationships with other soil properties were investigated on 313 agricultural surface soils from across the U.S. Different soil grouping schemes were investigated when analyzing
Organic matter - living, dead and very dead - is an important component of healthy soils. Organic materials provide habitat. Living organic matter (protozoa, pathogens, parasites, shredders, predators, grazers, birds and mammals) all work together to create humus. Soil organisms make nutrients available, suppress disease and produce hormones, which encourage plant growth, while plant roots create pores and feed other life within the soil. Recently dead organisms and crop residues supply soil with energy and nutrients, while very dead, very decomposed organic materials (aka humus) hold nutrients and water and store carbon.. Unlike healthy soils, unhealthy soils may be cloddy, crusty and hard. Plants grow poorly, and crop yields are low and declining. Runoff and erosion may be evident, and plants rapidly become stressed during both wet and dry periods. Disease pressure is high. Intensive tillage, soil erosion and decreased organic matter contribute to the decline of otherwise healthy soil. Once ...
Intensive cultivation of native grassland for dryland agriculture continuously depleted soil organic carbon (SOC) and nutrients. In 2010, we evaluated the influence of 80 yr of crop residue and nutrient management practices on SOC and N in 0- to 60-cm soil depth profiles in conventionally tilled winter wheat (Triticum aestivum L.)-summer fallow (WW-SF) system. Residue and N treatments, no N addition with fall burning (FB0), spring burning (SB0), and no burning (NB0), 45 kg N ha⁻¹ with SB (SB45) and NB (NB45), 90 kg N ha⁻¹ with SB (SB90) and NB (NB90), manure (MN, 5.32 Mg dry mass ha⁻¹ yr⁻¹), and pea vines (PV, 0.99 Mg dry mass ha⁻¹ yr⁻¹), were in ordered arrangement, and an undisturbed grassland (GP) was used as a reference. All WW-SF treatments had less SOC and N stocks than GP. The SOC stocks were lowest under FB0 with 50% less SOC than GP. The WW-SF treatments have depleted up to 63 and 26% of SOC and N from surface soil since 1931. Fall burning and MN treatments depleted ...
Sudden pulse-like events of rapidly increasing CO2-efflux occur in soils under seasonally dry climates in response to rewetting after drought. These occurrences, termed "Birch effect", can have a marked influence on the ecosystem carbon balance. Current hypotheses indicate that the "Birch" pulse is caused by rapidly increased respiration and mineralization rates in response to changing moisture conditions but the underlying mechanisms are still unclear. Here, we present data from an experimental field study using straight-forward stable isotope methodology to gather new insights into the processes induced by rewetting of dried soils and evaluate current hypotheses for the "Birch"-CO2-pulse. Two irrigation experiments were conducted on bare soil, root-free soil and intact vegetation during May and August 2005 in a semi-arid Mediterranean holm oak forest in southern Portugal. We continuously monitored CO2-fluxes along with their isotopic compositions before, during and after the irrigation. d13C ...
Some of the worlds most productive soils lie within cold regions. To enhance the productivity and quality of soil resources within these regions, knowledge must be advanced concerning the impact of freezing and thawing on soil properties and processes. The International Symposium on Physics, Chemistry, and Ecology of Seasonally Frozen Soils is a step toward broadening our knowledge of frozen soil processes. This paper emphasizes the physical nature of frozen soil and the importance of freezing and thawing to the transport of water and heat at the Earths surface. We also discuss the chemistry and biology of the soil system as affected by freezing and thawing. Ascertaining changes in ecosystem structure and productivity in response to perturbations in climate or management depends primarily on the use of models; these models require the acquisition of new knowledge to better define linkages among the physical, chemical, and biological components in cold regions. New knowledge concerning the dynamics of
While you might not notice a change in your soil from above ground right away when you implement a solid forage program, you can be sure that there is plenty of action going on below.. Alan Scarrow of Ozarks Natural Foods in Rogersville, Mo., said he allows the forage his cattle graze to stay as tall as possible - the taller the grass, the deeper the root system, and the deeper the root system is, the more nutrients and minerals are drawn back up into the top soil where they are needed.. The root mass and the manure on top of the soil from grazing livestock also adds organic matter back to the soil - according to an article by Farm and Dairy, organic matter has the potential to hold up to 20 percent of its weight in water and nutrients. Soils with one percent organic matter holds 4,000 pounds of water and nutrients, soils with two percent organic matter holds 8,000 pounds, and soils with three percent organic matter holds 30,000 pounds." By making your soil health a priority, producers can ...
Apr 2, 2020 , Soil Health News. Produced by the Soil Health Partnership, "The People of Soil Health" podcast will provide a direct connection into the network of soil health professionals who are focused on the on-farm economic and environmental benefits of soil health.. ...
INTRODUCTION. Soil organic matter (SOM) is generally recognized as one of most important factors of soil fertility, crop production, and protection from soil degradation, erosion and desertification (Senesi et al., 2007). In recent years, the intensive cropping of SOM-rich soils with consequent SOM depletion and the need to cultivate and/or enhance crop production of intrinsically SOM-poor soils and to protect soils from degradation and/or erosion have sparked a series of efforts to find alternative recovery or improvement practices of the SOM content (Senesi et al., 2007). Soil application of sewage sludge (SS) has become a common practice to increase yields, in view of the potential to increase soil fertility and due to the reduction of available disposal sites. It is an excellent way of recycling nutrients and organic matter contained in sludges. However, the health risks associated with the potential presence of pathogens, heavy metals and organic pollutants are well-known, as well as the ...
Soil erosion is a complex process encompassing detachment, transport, and deposition, and is caused by wind, water, and physical disturbance. Soil erosion reduces land productivity, challenges agricultural sustainability, and degrades soil, air, and water quality. Indirectly, soil erosion also degrades environmental quality through contam-inants attached to the sediment. Soil erosion interacts bly with the global carbon cycle and climate change processes. In some conditions, these impacts are so severe that they reduce quality of life and economic well being, and, in poorer nations, they can even threaten survival.. Substantial progress has been made over the past 50 years in understanding erosion and sediment transport and their impact on the environment. This understanding has led to the development and adoption of a wide variety of erosion control practices. But problems caused by erosion and sediment continue and much remains to be accomplished. The increased awareness of erosion impacts on ...
Soil Research is an international journal of soil science publishing high quality research on: soil genesis, soil morphology and classification; soil physics and hydrology; soil chemistry and mineralogy; soil fertility and plant nutrition; soil biology and biochemistry; soil and water management and conservation; soil pollution and waste disposal
Soil Research is an international journal of soil science publishing high quality research on: soil genesis, soil morphology and classification; soil physics and hydrology; soil chemistry and mineralogy; soil fertility and plant nutrition; soil biology and biochemistry; soil and water management and conservation; soil pollution and waste disposal
Surfactants with solvent and wetting abilities are used in the formulation of herbicides to enhance spraying capabilities. These chemicals eventually enter into the soil and may disrupt different chemical, physical and biological processes. The aim of this study was to examine the effects on nutrient uptake in corn and soil microbial community due to application of surfactants at different rates, herbicides, and surfactant-herbicide combinations in silt loam and silty clay loam soils. Surfactants used were Activator 90, Agri-Dex and Thrust. Herbicides used were glyphosate, atrazine, and bentazon. Corn was planted in fertilized soils and moisture levels maintained. After seven weeks, plant foliage were ground and stored for elemental analyses with Inductively Coupled Plasma Emission Spectrophotometer (ICP). Soil samples were analyzed with Polymerase Chain Reaction (PCR-DGGE) and Phospholipid Fatty Acids analyses (PLFA) to assess microbial diversity. The treatments did not greatly affect nutrient ...
Due to the uncertain future of the soil fumigants most commonly used in the EU, there is a need to develop new integrated pest management programmes to control crop diseases. Different nematode management practices, such as solarisation and the use of ecological nematicides, including nematophagous fungi, are used to control populations of plant-parasitic nematodes, one of the most common pests affecting crops. The objective of this study was to determine the effects of organic (neem seed paste and a mixture of nematophagous fungi) and conventional (oxamyl and fenamiphos) nematicides on soil physical chemical properties, soil biodiversity and plant biomass. Such effects were investigated in two types of habitats: low diversity soils from an agricultural farm and high diversity soils from a natural vegetation area. The greater effect was observed with the neem treatment, which induced a large boost of dauer juveniles in the nutrient-depleted soil, while the same treatment induced an increase of
Abstract. CO2 production and transport from forest floors is an important component of the carbon cycle and is closely related to the global atmosphere CO2 concentration. If we are to understand the feedback between soil processes and atmospheric CO2, we need to know more about the spatio-temporal variability of this soil respiration under different environmental conditions. In this study, long-term measurements were conducted in a spruce-dominated forest ecosystem in western Germany. Multivariate analysis-based similarities between different measurement sites led to the detection of site clusters along two CO2 emission axes: (1) mainly controlled by soil temperature and moisture condition, and (2) mainly controlled by root biomass and the forest floor litter. The combined effects of soil temperature and soil moisture were used as a time-dependent rating factor affecting the optimal CO2 production and transport at cluster level. High/moderate/weak time-dependent rating factors were associated ...
Nuclear and related techniques can help develop climate smart agricultural practices by optimizing water use efficiency. The measurement of soil water content is essential to improve the use of this resource in agriculture. However most sensors monitor small areas (less than 1m in radius) hence a large number of sensors are needed to obtain soil water content across a large area. This can be both costly and labour intensive and so larger scale measuring devices are needed as an alternative to traditional point based soil moisture sensing techniques. The cosmic ray neutron sensor (CRNS) is such a device that monitors soil water content in a non invasive and continuous way. This publication provides background information about this novel technique and explains in detail the calibration and validation process.. ...
Copper mining has led to Cu pollution in agricultural soils. In this report, the effects of Cu pollution on bacterial communities of agricultural soils from Valparaiso region, central Chile, were studied. Denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA genes was used for the characterization of bacterial communities from Cu-polluted and non-polluted soils. Cu-resistant bacterial strains were isolated from Cu-polluted soils and characterized. DGGE showed a similar high number of bands and banding pattern of the bacterial communities from Cu-polluted and non-polluted soils. The presence of copA genes encoding the multi-copper oxidase that confers Cu-resistance in bacteria was detected by PCR in metagenomic DNA from the three Cu-polluted soils, but not in the non-polluted soil. The number of Cu-tolerant heterotrophic cultivable bacteria was significantly higher in Cu-polluted soils than in the non-polluted soil. Ninety two Cu-resistant bacterial strains were isolated from three Cu-polluted
Winter wheat root growth was measured and modelled to improve site-specific soil and fertilizer management in commercial wheat fields. Field variations in root length densities were analysed at two contrasting sites in East-Germany during two vegetation seasons. A semi-automated root analysing method was developed to facilitate analyses of large numbers of samples. Influences of variations in soil water states, bulk densities and penetration resistances on spatial distributions of roots were quantified. Differences in soil characteristics were large between the two sites and affected root growth considerably. The same field data was used for validating the soil moisture and root growth calculations of the widely applied growth model CERES-Wheat. Simulations of root length densities, soil physical properties and soil water contents were inadequate. The effects of changes of rainfall variabilities on simulated root length densities and soil water contents were tested by uncertainty analysis but ...
This study aimed to answer the following questions (a) which of the soil variables (chemical, biological, enzyme activities and potential metabolic profile based on the Biolog method) could be used as indicators reflecting differences in soil quality between organically and conventionally managed asparagus fields, (b) how the duration of organic management affects these soil variables and (c) in what extent the soil quality in organic fields is comparable to that in hedgerows. The study included four organically cultivated fields which differed in the time they enter organic treatment: 6 years (O6), 5 years (o5), 3 years (O3) and 2 years (O2), the closest to them hedgerow (Ho), a conventionally managed field (CF) and its adjacent hedgerow (He). Among the chemical and biological variables, those contributing for most to the discrimination of the organic and conventional fields were mainly microbial biomass C (MBC) and N (MBN) and secondly variables related to N-cycle (NO3, N organic, rate of N ...
The remaining soil in the plastic beaker was weighed. Cold tap water was added up to 650 mL. The soil suspension was stirred carefully (star stir or figure of 8) for 30 seconds, using a spatula. Immediately the liquid was poured into wet screens - a stack of 40 mesh on top of a 400 mesh. The screens were rinsed gently with ice cold tap water (from a wash bottle) through the top of the stack, keeping the screens at an angle as the water filtered through. The water was kept on ice at all times. The top screen was removed, and the lower screen rinsed top down, never directly on top of the soil, but at the top of the screen and from behind. The water was allowed to cascade down and carry the particles into the bottom wedge of the angled screen. The side of the screen was tapped gently to filter all the water through. The suspension was rinsed from the front and the back, keeping the screen at an angle and not allowing the water to overflow the edge of the screen. The soil particles were backwashed ...
Liu, Mengyun, David A.N. Ussiri and Rattan Lal. 2016. Soil organic carbon and nitrogen fractions under different land uses and tillage practices. Communications in Soil Science and Plant Analysis 47(12):1528-1541.. ...
Soil Science satisfies the professional needs of all scientists and laboratory personnel involved in soil and plant research by publishing primary research reports and critical reviews of basic and applied soil science, especially as it relates to soil and plant studies and general environmental soil science. Each month, Soil Science presents authoritative research articles from an impressive array of discipline: soil chemistry and biochemistry, physics, fertility and nutrition, soil genesis and morphology, soil microbiology and mineralogy. Of immediate relevance to soil scientists-both industrial and academic-this unique publication also has long-range value for agronomists and environmental scientists.. ...
Paper III of this series reports on effects of ley treatments on the results of procedures for assessing soil nitrogen availability and the relationship between the estimates obtained for various availability procedures and test crop yield. Nitrogen availability procedures investigated included the nitrogen mineralisation potential (No) and the rapid procedures waterlogged incubation (WL), extraction with hot 2 M KCl and extraction with a phosphate-borate buffer (PBB). Values for No on a composite soil sample were 27 mg N kg-1 using the standard nutrient solution and 53 mg N kg-1 using a modified nutrient solution (k values were also significantly different). Values of No using the modified nutrient solution for 0-5 cm soil after the legume treatments showed strong treatment effects with values ranging from 44 to 99 mg N kg-1 for the fertilized plots and lower values for the unfertilized plots. After two test crops values were reduced but in the fertilized legume plots were still higher than for ...
With the Soil Texture Kit, students determine the percentage of sand, silt, and clay in soil samples.Educate yourself or students through hands-on activities related to environmental health and the effects of various chemicals on organisms in real time. Pre-assembled kit options allow you to cut prelab prep time down significantly. Other models are specialized to show particular simulated environmental systems, such as stormwater floodplains and the effects of retention ponds and wetlands in flood management, or human waste composting as part of a long-term educational exercise.
Some lawns require sulfur or lime to maintain a neutral soil pH. When soil is too acid or alkaline, the nutrients in the soil become unavailable to grasses because soil microbes become inactive. A soil test is the best way to determine soil pH.
Citation: Halvorson, A.D., Jantalia, C. 2011. Nitrogen fertilization effects on irrigated no-till corn production and soil carbon and nitrogen. Agronomy Journal. 103: 1423-1431. Interpretive Summary: Converting to no-till (NT) production can impact the amount of N needed to optimize corn yields and soil organic carbon (SOC) and N levels. Nitrogen fertilization impacts on irrigated, NT continuous-corn grain, stalk, cob, and stover yields, stover C and N uptake, and C:N ratios were evaluated for 11 yr on a clay loam soil. Changes in SOC and total soil N (TSN) were also monitored. Grain, stalk, cob, and stover yields increased with increasing N rate, as did N and C uptake. The C:N ratio of stalk residue declined with increasing N rate, but cob C:N ratio was not affected. Nitrogen fertilization increased SOC and TSN levels in the 0-7.6, 0-15.2, and 0-30.4 cm soil depths. Rate of change in SOC and TSN mass was lowest without N application. A decline in the soil C:N ratio with time was observed as TSN ...