Soils Of Agroecosystems Research Articles

Continuous Monoculture Shapes Root and Rhizosphere Fungal Communities of Corn and Soybean in Soybean Cyst Nematode-Infested Soil

The rhizosphere effect shapes microbial communities around and within plant roots and may lead to the enrichment of fungi involved in both positive and negative plant-soil feedbacks. We used internal transcribed spacer 1 amplicon sequencing to investigate how continuous monoculture affects the fungal communities in the corn and soybean rhizosphere, rhizoplane, and root endosphere in a long-term crop rotation experiment where soils were infested with a major soybean pathogen, the soybean cyst nematode (SCN, Heterodera glycines). Community-level statistical analyses showed evidence of selective filtering and enrichment of fungi in and around corn and soybean roots and in SCN cysts. Patterns of relatedness between fungal communities in various agroecosystem compartments suggested that SCN cysts are colonized by soybean root endophytic fungi and that colonization of roots and cysts may aid proliferation of these fungi in the bulk soil agroecosystem compartment over time. Natural antagonists of the SCN such as nematode-trapping fungi and nematode endoparasites increased in relative abundance in the rhizosphere and root endosphere, respectively, over continuous soybean monoculture. In contrast, arbuscular mycorrhizal and plant-pathogenic fungi, several of which were negatively correlated with corn yield, increased in relative abundance over continuous corn monoculture. These results suggest the possibility of positive plant-soil feedbacks involving nematophagous fungi over continuous soybean monoculture and negative plant-soil feedbacks involving plant pathogens and some nonbeneficial arbuscular mycorrhizal fungi over continuous corn monoculture.

Ecological risk assessment of cerium for tropical agroecosystems

Cerium (Ce) is present in high technology materials and in mineral P fertilizers and the use and discharge of such resources may change the natural status of Ce in the soil environment. Brazilian soils in farming areas are significantly exposed to increased levels of unintentionally-added Ce through intensive input of phosphate fertilizers. The aims of this study were to evaluate the ecotoxicological risk to plants growing in tropical soils contaminated with Ce, as well as to create a database to support future legislation regulating the limits of this element in Brazilian and conceivably other tropical soils. Eight crop species (corn, sorghum, rice, wheat, soybeans, sunflower, radish, and beans) were exposed to a Ce concentration gradient in two typical tropical soils (Oxisol and Inceptsol), and an artificial soil. Our findings showed that among the endpoints measured, Ce phytotoxicity was more pronounced on shoot dry matter than on percent germination and germination speed index. Sensitivity of plants is species specific and our data showed that sunflower and radish exposed to Ce were the most sensitive crop species. Soil properties such as pH, cation exchange capacity, and organic carbon may have influenced the severity of Ce phytotoxicity. Because of that, the Oxisol contaminated with this element caused higher phytotoxicity than the other soils tested. Our risk assessment results (hazardous concentration, HC5 = 281.6 mg Ce kg−1) support the idea that unintentional Ce input through P fertilizers does not pose a risk to soils of Brazilian agroecosystems.

Dung beetle activity improves herbaceous plant growth and soil properties on confinements simulating reclaimed mined land in South Africa

Mining activities contribute greatly to economic growth and development in South Africa. However, post-mining soils have limited land-use potential due to low fertility, deficiency in organic matter content and poor physical, chemical, and microbiological properties. Dung beetles could potentially improve several aspects of soil degradation, complementing current rehabilitation efforts. Studies in relatively undisturbed soils of agro-ecosystems have found that dung burial introduces essential nutrients in dung to the plant root zone, which would otherwise remain on the soil surface and mostly volatilize in the absence of dung beetles. Furthermore, dung beetles create tunnels under dung pats, improving water infiltration rates, bulk density, soil aeration and pasture yields. The aim of the study was to determine whether these effects could be maintained on soil simulating reclaimed mined land, where very high rates of compaction may prevent tunnelling altogether. Three experimental treatments of dung + beetles (D + B), dung only (D) and control/no dung, no dung beetles (X) were applied twice over 2 years on 1 m3 experimental confinements. Various soil and herbaceous plant properties were assessed one and six months after each application of dung and beetles. Results obtained showed that water infiltration rate and plant biomass was significantly higher for all confinements containing dung beetles. Penetration resistance (soil strength) was significantly reduced for confinements with dung beetles. Magnesium and potassium levels in the soil were significantly higher for D + B treatments when compared to D and X treatments. In conclusion, results showed that dung beetles were able to maintain their activities in soils typical of reclaimed mine land, significantly improving soil properties and herbaceous plant growth. Incorporating the application of dung beetles to the conventional approach to rehabilitation has the potential to improve the efficacy of coal mine reclamation. This biological approach may also prove to be cost-effective over time as it provides a seasonal source of bioturbation, which does not disturb plant growth and reduces the requirements for soil rejuvenating tillage practices.

Soil Water Retention in the Semiarid Region of Brazil

From the physics point of view, soil structure is a dynamic attribute that is affected by genetic conditions and anthropogenic changes and requires an integrated approach. Soil water retention curve is one of the main tools used in soil structure evaluations. The objective of this work was to evaluate the structural and chemical attributes of soils of different classes and agroecosystems in the Terra de Esperança Settlement (Governador Dix Sept Rosado, Rio Grande do Norte, Brazil) to distinguish these environments. Disturbed and undisturbed soil samples were collected in horizons of 10 soil profiles of the soil classes: Cambissolo Háplico (Haplustepts), Latossolo Vermelho-Amarelo (Eutrustox), Chernossolo Rêndzico (Calciustolls), and Neossolo Flúvico (Usticfluvents). The soil physical attributes evaluated were granulometry, soil density, total porosity, aeration porosity, macroporosity, microporosity, field capacity, permanent wilting point, available water, and water retention curve. The results were expressed in averages of four replicates per horizon (in laboratory) by multivariate analysis, which detected the most sensitive attributes for the distinction of the environments. The soil physical attributes of the different classes and its inorganic fractions, especially silt and clay, were determinant to distinguish the environments; they affected the microporosity; aeration porosity; and available water. The source material of the Chernossolo Rêndzico, which is rich in calcium and magnesium, affected its physical attributes, characterized by the predominance of the silt fraction. Clay was the determinant fraction of the Cambissolo Háplico, and Neossolo Flúvico; and the sand fraction on the surface layer, and clay fraction in the Bw horizon were determinant of the Latossolo Vermelho-Amarelo. The more expressive physical attributes were soil density, sand content, macroporosity (Latossolo Vermelho-Amarelo), microporosity, field capacity, available water, permanent wilting point, total organic carbon, mass-based moisture, volume-based moisture, clay, aeration porosity (Cambissolo Háplico, and Neossolo Flúvico), and silt (Chernossolo Rêndzico).

Redesign of the traditional Mesoamerican agroecosystem based on participative ecological intensification: Evaluation of the soil and efficiency of the system

Mexico is one of the countries with the highest importation levels of basic foods worldwide; it is therefore highly desirable to adopt measures to guarantee local food autonomy. Agricultural production alternatives that present an appropriate relationship with the environment are required. The objective of this study was to generate, implement and evaluate different strategies of participative ecological intensification. These strategies were focused on improving soil quality and agricultural productivity based on the traditional Mesoamerican maize-based “milpa” agrosystem. Management agrosystems were determined and implemented in conjunction with producers in an experimental community plot over a period of two years (2012 and 2013). The alternative management practices included the use of organic amendments (solid and organic) and synthetic fertilizers. Changes in soil chemical characteristics and yields (maize, beans) were measured, as well as indices of economic efficiency, labor and fertilizer use. After 2 years, the organic management treatments showed a clear increase in soil pH (from 5.02 to 5.5–5.6), in contrast to the conventional treatment in which the soil acidified (pH 4.9) and presented reduced P availability. As a result of the higher soil acidity, yields were lower compared to the systems that used organic conditioners. Soil nitrate (NO3) concentration in the year 2012 was greater in plots with chemical fertilizers and vermicompost than in the other treatments. However, in the former, there were higher losses of N through lixiviation that year (112.6 kg ha−1) and in 2013 (212.2 kg ha−1), which were related to the occurrence of high precipitation (972 mm in 2012 and 1231 mm in 2013). Yields of maize were greater in the conventional system but lower than the bean yield. In contrast, in 2013, a stormy year, the organic system (bokashi + lime) was the most resilient in terms of both maize and bean yields. The treatments of highest annual total cost in 2012 and 2013 were those that used liquid amendments, due to the increased number of working days required for fertilizer application. In contrast, the lowest cost treatments in 2012 were those with vermicompost and, in 2013, with bokashi and bokashi + lime. The conventional treatment presented the highest fertilization costs. Application of solid organic fertilizers allowed improvement of the milpa agroecosystem soil chemical characteristics in the mountain region of Guerrero. This system presented the most efficient use of resources and labor and proved to be more resilient against the impact of storms. Moreover, it produced higher bean and maize yields compared to the milpa with conventional inputs.

Bridging Gaps in the Agricultural Phosphorus Cycle from an Animal Husbandry Perspective—The Case of Pigs and Poultry

Since phosphorus (P) is an essential element for life, its usage and application across agricultural production systems requires great attention. Monogastric species such as pigs and poultry can significantly contribute to global food security but these animals remain highly dependent on the supply of mineral inorganic P in their feeds. Pig and poultry, which represent 70% of the global meat production, are also major P excretors and thus represent important sources of environmental P inputs. Balancing the P cycle within farming systems is crucial to achieve P sustainable and resilient livestock production. Therefore, the interconnection of animal feed, livestock farming, manure, and soil/aquatic ecosystems requires multidisciplinary approaches to improve P management. With regard to a sustainable agricultural P cycle, this study addresses aspects of feeding strategies and animal physiology (e.g., phase feeding, P conditioning, liquid feeding, phytase supplementation, genetics), soil agroecosystems (e.g., P cycling, P losses, P gains), reuse and recycling (e.g., manure, slaughter waste), measures of farmers’ economic performance (e.g., bio-economic models), and P governance/policy instruments (e.g., P quota, P tax). To reconcile the economic and ecological sustainability of animal husbandry, the strategic objective of future research will be to provide solutions for a sufficient supply of high-quality animal products from resource-efficient and economically competitive agro-systems which are valued by society and preserve soil and aquatic ecosystems.

Formation of the structure of microbiocenoses of soils of agroecosystems depending on trophic and hydrothermal factors

Ground soil, as the product primarily of the activity of microbiota, is under the permanent influence of ecological and anthropogenous factors. Soils are especially subject to pressure in agroecosystems, which increases due to the considerable fluctuation of climate system parameters. Using graph analysis, we have estimated the results of multiyear monitoring research on the functioning of microbiocenoses of three soil types in agroecosystems depending on the fertilizing and hydrothermal mode. It enabled us to detect peculiarities of formation of the structure soil microbiocenoses and to better understand ecologically important relations between functional groups of microorganisms in the soil depending on action of different factors. It has been determined that neither application of organic and mineral fertilizers into chernozem nor action of hydrothermal factors (temperature air and humidity) is a crucial characteristic of changing in the structure of its microbiocenosis. Microorganisms-producers of exopolysaccharides, which have a strong relationship with all trophic groups of microorganisms as they are their structural components, turned out to be the main block constructing factor, which is due to their strong influence on total content of microbal mass in soil. For soil of agroecosystems with dark-grey type of soil characteristic of content of total biomass of microorganisms is a basis for block constructing gremium, which affirms the state of microbiocenosis and processes occurring there under the action of researched biotic and abiotic factors. Microbiocenosis of sod-podzolic soil, unlike the other researched types of soils, reacted distinctly on applying of fertilizer and depended on the action of hydrothermal factors. Contrast in the range of hydrothermal regime caused a chaotic character of interaction between the basic characteristics in microbiocenosis of sod-podzolic soil with appearance of a direct and mediated relationship among them. Regardless of changes in hydrothermal factors , interactions between characteristics of total microbial mass content, eutrophic microorganisms, which use mineral and organic forms of nitrogen, and producers of exopolysaccharides were stable. It has been proved that estimating of ecological state of soil and influence of applicable agromeasures on it should be conducted according to the indices of total microorganism biomass content in the soil and correlation between the number of microorganisms which form the graph gremium.

The Impact of Veterinary Medicine and Animal Husbandry on the Biophysical Characteristics of Soils in Neotropical Agroecosystems

The neotropical agroecosystems are important areas in the global scene in terms of livestock production. Therefore, a good conservation of their soils is crucial in order to both guarantee food safety and reduce the impact of land degradation processes. Conservation of neotropical soils used for farming activities could be obtained using veterinary medicine and adopting new grazing systems in the last decades. A wide bibliographical review was carried out which illustrates current issues in neotropical agroecosystems, the importance of their soil properties highlighting the role played by dung beetles within the edaphofauna, and the effects of the most common anti-parasitic practices as well as some natural alternatives. Finally, we present commonly adopted grazing systems and how they are affecting soil properties and animal welfare. The conversion of forest into agricultural and pasture land is altering the biochemical quality of soils. Furthermore, the use of ivermectin is dangerously reducing the total amount of dung beetles that are a key element in nutrient recycling processes. The implementation of new grazing systems (e.g., Voisin, Savory) is progressively fragmenting the habitat of many species. Nevertheless, there are also some benefits in this kind of practices and some natural alternatives to anthelmintics are being tested.

Assessment of trace elements and its influence on physico-chemical and biological properties in coastal agroecosystem soil, Puducherry region

The concentration of trace elements Ba, Sr, V, Cr, Ni, Pb, Cu, Zn, As, Mn, and Co were assed in the surface soil of agricultural lands, Puducherry region. The ranking order of occurrence of the heavy metals in 10 farms soils was Ba > Sr > Mn > Cr > V > Zn > Ni > Cu > Pb > Co > As indicating that Ba concentration was high. Trace elements such as, Cu, Cr, V, Zn, Pb, Ni, Co, and As enrichment levels were high in current years. Most of the farming soil showed metals Ba and Sr were higher than maximum permissible limit. Organic farming (farm 3, 6, and 9) soils were containing higher amount of plant available nutrients, sol microbial population and β-glucosidase activity. Cr, Zn, Cu, Pb, Co, and As trace elements were stronger inhibitory effects on soil biological properties. The enrichment of these trace elements in agriculture soil samples conforms their higher input of trace element contaminated organic manures, synthetic fertilizer, and fungicides by the farmers.

Digging deeper: A holistic perspective of factors affecting soil organic carbon sequestration in agroecosystems

The global magnitude (Pg) of soil organic carbon (SOC) is 677 to 0.3-m, 993 to 0.5-m, and 1,505 to 1-m depth. Thus, ~55% of SOC to 1-m lies below 0.3-m depth. Soils of agroecosystems are depleted of their SOC stock and have a low use efficiency of inputs of agronomic yield. This review is a collation and synthesis of articles published in peer-reviewed journals. The rates of SOC sequestration are scaled up to the global level by linear extrapolation. Soil C sink capacity depends on depth, clay content and mineralogy, plant available water holding capacity, nutrient reserves, landscape position, and the antecedent SOC stock. Estimates of the historic depletion of SOC in world soils, 115-154 (average of 135) Pg C and equivalent to the technical potential or the maximum soil C sink capacity, need to be improved. A positive soil C budget is created by increasing the input of biomass-C to exceed the SOC losses by erosion and mineralization. The global hotspots of SOC sequestration, soils which are farther from C saturation, include eroded, degraded, desertified, and depleted soils. Ecosystems where SOC sequestration is feasible include 4,900Mha of agricultural land including 332Mha equipped for irrigation, 400Mha of urban lands, and ~2,000Mha of degraded lands. The rate of SOC sequestration (Mg C ha-1 year-1 ) is 0.25-1.0 in croplands, 0.10-0.175 in pastures, 0.5-1.0 in permanent crops and urban lands, 0.3-0.7 in salt-affected and chemically degraded soils, 0.2-0.5 in physically degraded and prone to water erosion, and 0.05-0.2 for those susceptible to wind erosion. Global technical potential of SOC sequestration is 1.45-3.44Pg C/year (2.45Pg C/year).

Soil micronutrient pools and their transfer to paddy-crops in semi-arid agro-ecosystems, Central India

Irrigation is a key component of crop productivity, environmental protection and sustainable agriculture. To understand this, paddy-crops and soil samples were collected from rainfed (RFS) and irrigated (IRS) soils of semi-arid agro-ecosystems, Central India. The objectives of the current study were to (1) determine total concentrations of Cu, Fe, Mn and Zn in paddy-soils and paddy-crops, (2) chemical fractionation of operationally defined pools of Cu, Fe, Mn and Zn content in paddy-soils. Total micronutrient concentrations followed the order as: Fe > Mn > Zn > Cu with higher values in RFS paddy-soils. High residual fraction indicated the existence of micronutrients within mineral lattice structure, which resulted in low to moderate mobility factor (MF) of Cu, Fe, and Zn in the paddy-soils. The high Mn concentrations in non-residual fractions resulted in MF more than 50%. The transfer factors of total micronutrients (TFTM) showed high transfer of Zn and Mn to paddy-crops. The high TFEMF (transfer factor of exchangeable micronutrient fractions) of Cu and Fe revealed significant accumulation in paddy-roots. Paddy-grains differed significantly (P < 0.05) in total micronutrient content with high values in IRS agro-ecosystems. The correlation and multiple linear regression analyses showed control of micronutrient fractions on availability, uptake, transfer and translocation in paddy-crops through root system.

Effects of biotic and abiotic factors on soil organic matter mineralization: Experiments and structural modeling analysis

Soil organic matter (SOM) mineralization is affected by various abiotic and biotic factors, as well as the input of exogenous organic substances. Our previous studies have shown that SOM mineralization in flooded rice paddies is lower than that in adjacent upland soils in subtropical agro-ecosystems. However, the main factors contributing to the differences in SOM mineralization remain unclear. To compare the effects of biotic and abiotic factors on SOM mineralization between upland and paddy soils, we incubated upland and paddy (flooded) soils with three low molecular weight organic substances (LMWOS, i.e., glucose, acetic acid, or oxalic acid) for 30 days under field conditions. Generally, the average CO2 efflux from upland soil was higher than that in paddy soil with the same LMWOS addition. The total content of phospholipid fatty acids (PLFAs) in paddy soil was 2–5 times higher than that of upland soil, irrespective of the LMWOS added. Redundancy analyses indicated that microbial community composition was influenced mainly by the low redox potential (Eh) and dissolved organic carbon in paddy soil. Structural equation modeling revealed that, among abiotic factors, temperature exerted indirect effects on SOM mineralization by influencing biotic factors in both soils; Eh has a positive and direct effect on SOM mineralization in paddy soil. In terms of biotic factors, SOM mineralization in upland soil was mainly regulated by the quantity of bacteria. In paddy soil, SOM mineralization was largely influenced by the ratio of fungal to bacterial PLFAs and peroxidase activity.

Microplastic Incorporation into Soil in Agroecosystems.

Microplastic Incorporation into Soil in Agroecosystems.

Antibiotic resistant microorganisms in agroecosystems as a factor of risk for human health

The article presents results of soil research from agroecosystems where cultivated medicinal plants: Mentha piperita, Inula helenium, Thymus serpillum, Rosa odorata, Calendula officinalis. Verification and identification of antibiotic-resistant microorganisms were done. A total of 106 isolates from soil of agro ecosystem with medicinal plants were examined for resistance to 9 antibiotics. Two bacteria Serratia marcescens and Yersinia enterocolitica isolated from soil with cultivated Thymus serpillum have displayed the moderate resistance to most of tested antibiotics. From the rizosphere of Inula helenium was isolated one of the most antibiotics resistant bacteria among of others tested — Pantoea agglomerans. Serratia odorifera biogroup 1 was isolated from agroecosystem of Mentha piperita and used for tests. Strain was resistant to vancomycin, lincomycin, ampicillin and moderately resistant to cefepime. From agroecosystems of Calendula officinalis and Rosa odorata, where used organic manure, high level of antibiotic resistance was detected for Enterococcus faecalisss and Bacillus cereus. Isolated pathogenic and opportunistic pathogenic microorganisms: Serratia marcescens, Bacillus cereus, Enterococcus faecalis, Serratia odorifera biogroup 1, Pantoea agglomerans, Yersinia pestis, possess antibiotic resistance and are the risk factors for human health

Biodiagnostics and bio-security of soils of agroecosystems

The scientific experience in the development of methods for complex biological diagnostics of soils in agroecosystems and creation of an informative, representative and objective system for assessing their state are presented. The developed system allows to conduct an environmental assessment of the applied elements of agrotechnology, to carry out early diagnostics and prevention of development in the soil of undesirable processes as a result of anthropogenic impact. An assessment of the natural state and the degree of anthropogenic damage to soils on a number of biodiagnostic criteria can ensure the safety of agricultural production, namely the conservation of soil fertility and the production of high-quality agricultural products

Increasing crop diversity increased soil microbial activity, nitrogen-sourcing and crop nitrogen, but not soil microbial diversity

The relationships between crop diversity, soil microbial diversity and agroecosystem functioning are not well understood. Soils under wheat monoculture, wheat–medic, and wheat–medic plus clover rotations from a 19-year-old wheat rotation trial in South Africa were measured for soil microbial functional and genetic diversity using community-level physiological profiling and automated rRNA intergenic spacer analysis. A 15N–13C dual isotope mixing model determined the nitrogen (N) sourcing when wheat was supplied with N from fertiliser and sheep dung (monoculture), or fertiliser, diazotrophy from one or two legumes, and sheep dung (wheat in rotation). Historical wheat yields and foliar [N] were 28% and 106% higher in wheat–legume rotations compared with wheat monoculture. Increasing crop diversity was related to increased soil microbial activity, but not increased microbial richness or diversity, which depended more on known abiotic drivers of microbial community structure. The δ15N mixing models revealed an increasing dependence on legume-derived N with increasing legume species in rotation. This suggests that enhanced N cycling and yield in crop–legume rotations is not a result of microbial diversity per se, but rather increased microbial activity when keystone legume species and their associated N2-fixing symbionts were present.

Organic Carbon Stocks, Dynamics and Restoration in Relation to Soils of Agroecosystems in Ethiopia: A Review

Soils represent the largest carbon pool and play important roles for carbon storage for prolonged periods in agroecosystems. A number of studies were conducted to quantify soil organic carbon (SOC) worldwide. The objective of this review was to evaluate organic carbon stocks, dynamics and restoration in soils of agroecosystems in Ethiopia. Soil data from 32 different observations, representing four different agroecosystems, were analysed. The mean SOC stocks in the four agroecosystems varied and ranged from 25.66 (sub-humid agroecosystem) to 113.17 (humid mid-highland agroecosystems) Mg C ha-1 up to one meter depth. The trend of mean SOC followed (in descending order): humid mid-highland (113.17 Mg C ha-1) &gt; per-humid highland (57.14 Mg C ha-1) &gt; semi-arid (25.77 Mg C ha-1) &gt; sub-humid (25.66 Mg C ha-1). Compared with soils of tropical countries, those in Ethiopian agroecosystems contained low SOC storage potential. This might be associated with differences in measurement and analysis methods as 53.1% of the studies employed the Walkley-Black Method, which is known to underestimate carbon stocks in addition to ecological and management effects. However, shifts of land management from rain-fed to irrigation farming systems exhibited progress in the improvement of mean SOC storage potential. The analyses showed that farming systems involving irrigation sequestered more carbon than rain-fed farm systems. The mean SOC in the various agricultural land uses followed the following trend (in descending order): agroforestry (153.57 Mg C ha-1) &gt; grazing land (34.61 Mg C ha-1) &gt; cereal cultivation (24.18 Mg C ha-1). Therefore, the possible solutions for improvement of organic carbon stocks would be implementation of appropriate restoration strategies based on agroecosystems.INTERNATIONAL JOURNAL OF ENVIRONMENT Volume-6, Issue-1, Dec-Feb 2016/17, page: 1-22

Coupled biochar amendment and limited irrigation strategies do not affect a degraded soil food web in a maize agroecosystem, compared to the native grassland

AbstractClimate change is predicted to increase climate variability and frequency of extreme events such as drought, straining water resources in agricultural systems. Thus, limited irrigation strategies and soil amendments are being explored to conserve water in crop production. Biochar is the recalcitrant, carbon‐based coproduct of biomass pyrolysis during bioenergy production. When used as a soil amendment, biochar can increase soil water retention while enhancing soil properties and stimulating food webs. We investigated the effects of coupled biochar amendment and limited irrigation on belowground food web structure and function in an irrigated maize agroecosystem. We hypothesized that soil biota biomass and activity would decrease with limited irrigation and increase with biochar amendment and that biochar amendment would mitigate the impact of limited irrigation on the soil food web. One year after biochar addition, we extracted, identified, and estimated the biomass of taxonomic groups of soil biota (e.g., bacteria, fungi, protozoa, nematodes, and arthropods) from wood‐derived biochar‐amended (30 Mg ha−1) and nonamended soils under maize with limited (two‐thirds of full) and full irrigation. We modeled structural and functional properties of the soil food web. Neither biochar amendment nor limited irrigation had a significant effect on biomass of the soil biota groups. Modeled soil respiration and nitrogen mineralization fluxes were not different between treatments. A comparison of the structure and function of the agroecosystem soil food web and a nearby native grassland revealed that in this temperate system, the negative impact of long‐term conventional agricultural management outweighed the impact of limited irrigation. One year of biochar amendment did not mitigate nor further contribute to the negative effects of historical agricultural management.

Soil health-ecosystem health: From problem identification to diagnosis and treatment

The need for the general use of the category 'soil ecosystem' (SE) as objectively more comprehensive and more specific than the laconic term 'soil' is discussed and supported by arguments. Agroecosystem soils in organic and intensive farming are compared. Soil health (SH) as a new, basic property of SE is commented upon. Methods for determining SH and its characteristic parameters are specified. The need to assess the health of SEs depending on their type and utilization is emphasized. The topics covered include soil health maintenance and protection options, natural and induced suppressiveness of SEs, and potential routes to diagnosis and treatment of soils in modern agroecosystems.

TAXONOMIC AND FUNCTIONAL STRUCTURE OF THE MICROBIAL COMMUNITIES OF DARK GREY SOIL

We analyzed the functional and taxonomic structure of microbial community of dark grey soil, depending on the effects of the weather and fertilizer systems. It was shown that fallow soil is characterized by integrated and more stable microbial community compared with agroecosystems soil. However, under the effect of such abiotic factors as increased average monthly temperatures and moisture deficiency, some imbalance of trophic interactions in microbiocenosis is observed.&#x0D; Agroecosystems are characterized by less stable functional and taxonomic structure of the soil, which is defined by the hydrothermal conditions of the growing season and types of fertilizers applied. This is supported by a smaller number of correlations and a simplified structure of correlation pleiades of the soil of agroecosystems during unfavourable periods of vegetation periods, especially in the soil without fertilizers and using only mineral fertilizers. The use of organic and mineral fertilizer system brings the state of the soil microbiocenosis of agroecosystems soil to that of fallow soil.