Intensive Agricultural Land Use Research Articles

Temporal and spatial patterns of riparian vegetation in the Colastiné Basin (Argentina) and riparian ecological quality estimation as tools for water management

ABSTRACT Information on the riverbanks can improve our ability to monitor water quality and generate adequate management strategies. This research seeks insights into the riverbanks of eight Colastiné River Basin (Argentina) streams, which have been influenced by intensive agricultural land use for decades. We aim to (a) describe the temporal and spatial distribution patterns of riparian vegetation, (b) assess their current riparian quality through riverbank quality indices, and (c) estimate whether the riparian quality is linked to the water quality. Results of the Normalized Difference Vegetation Index (NDVI) showed an increasing trend in the vegetation cover with seasonal periodicities during the last 22 years in only 2 streams. Overall, 41% of plant species registered were exotic although native species dominated in most streams. The overall riverbank quality, based on the mean values of four riverbank quality indexes, was regular-to-bad. The overall water quality of the streams was low and significantly correlated to the Riparian Quality Index, suggesting a link between both compartments. More studies are needed to determine the main variables that establish this connection. Further effort is also needed to generate appropriate indices for this region, as no current ones are still developed.

Seasonal movements of small-island birds along habitat and elevation gradients highlights the conservation value of small-scale agroforests

Knowledge on species distributions and seasonal movement patterns within landscapes is important for understanding their ecology and roles in agroecosystems, and is critical for enabling their effective conservation and monitoring, particularly in small-island states where conservation resources are limited. We undertook bird surveys to examine species distributions across a range of agricultural land-use intensities and elevations on the Caribbean island of Grenada by collecting data over 6 repeated monthly surveys (3 wet season, 3 dry season) at sites located in a variety of habitats spread over 6–300 m elevation. We observed a gradual upslope increase in bird species diversity and abundance from the mid-wet season to the late-dry season, as well as a movement from reduced-canopy habitats to closed-canopy habitats in the dry season. The mid-elevation hillsides of Grenada consist of a diverse mosaic of closed canopy secondary forest patches, interspersed among more open agroforests and small-scale cropping and grazed areas. These agroecosystems appear to provide important habitats to birds throughout the year, especially open canopy agroforests in the wet season. We also found that open mixed agroforests contained a greater diversity of fruit, flower, and seed resources than closed canopy habitats such as secondary forest, cacao agroforests, young secondary forests, or dry forest scrub; and that plant food diversity was highest in the wet season. However, bird abundance significantly increased in closed canopy forest habitats during the dry season, suggesting that intact canopy forests provide important dry season habitat for many Grenadian birds, which may be particularly important for species in drier lowland areas experiencing more intensive agricultural land use and urban and resort development. Overall, this research demonstrates the importance of maintaining the functional connectivity of treed habitats at local and landscape scales for species conservation, as well as the contribution of diverse, small-scale agriculture to maintaining small-island bird communities.

Land use intensity is a major driver of soil microbial and carbon cycling across an agricultural landscape

Soil carbon (C) storage is a critical ecosystem function that underpins human health and well-being. The acceleration of human-driven land use change, such as agricultural intensification, is a major driver of soil C loss globally. Developing sustainable land use practices that enhance agricultural productivity whilst protecting essential ecosystem functions such as soil C storage is vital. The soil microbiome has a critical role in regulating soil biogeochemical cycling processes, including soil C cycling. Examining the impacts of land use intensity on the soil microbiome enables us to assess the potential effects on long-term soil C stocks. Using metagenomic DNA sequencing and phospholipid fatty acid analysis, we investigated differences in the activity, diversity, and function of the soil microbiome associated with five contrasting land uses across an agricultural landscape. The land uses covered a gradient of disturbance intensities and included remnant native forest, regenerating native bush, exotic plantation forest, dryland pasture, and irrigated pasture. We identified pronounced differences in the soil microbiome associated with each land use, including the diversity and abundance of microbial C and nitrogen (N) cycling genes. Notably, intensive agricultural land uses had a significantly higher diversity and abundance of microbial C-degrading genes, whilst land uses of remnant native forest had the lowest diversity and abundance of microbial C-degrading genes. Our findings suggest that intensive agricultural land use may increase the functional potential of the soil microbiome to mineralize soil C, potentially resulting in a greater loss of soil C as respired CO2 into the atmosphere. This research may be used to support the development of sustainable management practices that promote the persistence of soil C across agricultural landscapes, such as the protection of remnant native forest fragments and greater incorporation of regenerating native vegetation.

Farmers’ perceptions of sustainable agriculture in the Red River Delta, Vietnam

While economic growth and food security in Vietnam's Red River Delta are heavily reliant on agriculture, the intensive use of agricultural land has resulted in various negative impacts on the environment, such as soil degradation, water pollution, biodiversity loss, and health effects on humans and animals. The current situation emphasizes an increased need for sustainable agriculture practices in the region. Understanding farmers' decision-making processes and identifying factors that influence their choices is crucial in order to promote their adoption of sustainable agriculture practices. This study examines the impact of attitudes, subjective norms, perceived behavioral control, age, and gender on farmers' intention to adopt sustainable agriculture practices using the Theory of Planned Behavior and Partial Least Squares Structural Equation Modeling. The results show that attitude towards sustainable agriculture practices showed a path coefficient of 0.310 (p < 0.001), and perceived behavioral control had a coefficient of 0.305 (p < 0.001), indicating strong positive relationships with intention. However, subjective norms, despite a positive coefficient, did not significantly affect intentions (path coefficient 0.099, p > 0.05). Age was found to have a moderating effect; older farmers are less likely to adopt sustainable agriculture practices compared to their younger counterparts. Gender, however, did not present a significant influence. In light of these findings, policymakers face a challenge in creating incentives to encourage farmers' engagement in sustainable agriculture practices in the Red River Delta and at the same time discourage youth out-migration from the agricultural sector more generally. Overall, this study enriches our theoretical understanding of the factors influencing sustainable agriculture adoption in developing countries and offers practical insights for policymakers and agricultural stakeholders in the Red River Delta to promote more effective and targeted sustainable agriculture practices.

Landscape correlates of sand racer species (Lacertidae; &lt;em&gt;Psammodromus&lt;/em&gt;) segregation in their contact area along the Conquense Drove Road (Cuenca, Iberian Peninsula)

The Edwards’s sand racer (Psammodromus edwarsianus) was recognised as distinct from the Spanish sand racer (P. hispanicus) a decade ago, but both their distributions and interspecific range limits are poorly defined. Results of sampling both species along 70km of the Conquense Drove Road (Central Spain) indicate a clear North/South segregation, with P. edwarsianus inhabiting the area North of Las Pedroñeras and P. hispanicus the South. The segregation corresponds with lithological and vegetation differences, hard calcareous substrates in the North and softer sandy sedimentary material in the South. The latter is associated with more intensive agricultural land-use in contrast to the persistence of copses and scrub on the calcareous terrain. The results provide new data on the regional distribution of both species. They also highlight the potential value of this species-pair as a model for study of interactions and habitat segregation in lacertids.

Chemical degradation of agricultural soil under arid conditions by the accumulation of potentially toxic elements and salts

This study evaluates agricultural soil degradation by accumulation rates of chemical species and salinity/sodicity, their distribution, and the degree of contamination. Soil samples were collected from farmlands with intensive production system in the northern part of the Jiménez-Camargo aquifer, Chihuahua, Mexico. The physicochemical parameters and the chemical species were obtained based on Mexican regulations and UV–Vis spectrophotometry. The soil degradation was assessed using contamination-degree and soil-quality indices. A log-transformation (clr) of data facilitated cluster multivariate and related spatial distribution analysis. Chemical properties were found grouped within geogenic elements and salts. The results showed an alkaline pH with a wide range of ECe of 0.24 to 4.91 dS m−1. About 72% of the agricultural land showed a high sodicity/salinity degree, contributing to soil damage in the root zone of crops. Soil quality also is negatively affected by As, P, S, as well as salinity/sodicity, contributing to agri-environmental vulnerability of these farmlands. Hence, intensive agricultural land use contributes to severe ecological consequences such as groundwater depletion and water-quality degradation, as well as salinity/sodicity of soil, increased irrigation demand to flush salts from the soil zone, and enhancement of potentially toxic elements in soil-water-crops. In conclusion, monitoring these lands and source-water management are needed to mitigate soil-water degradation combined with agri-environmental policies through sustainability strategies that control supply and demand of land and water. The indices used here provide the metrics needed to help monitor and assess these changes for decision makers guiding sustainability and food security.

Phosphorus speciation along a soil to kettle hole transect: Sequential P fractionation, P XANES, and 31P NMR spectroscopy

Phosphorus (P) is an essential element for all living organisms but can also be an important factor in the eutrophication of aquatic/marine ecosystems. Kettle holes are often situated in regions under intense agricultural land use where there is a high risk of nutrient transfer to larger waterbodies. The chemical speciation of soil P influences its rate of transfer from arable fields to aquatic environments. However, there is a paucity of information on the P speciation in kettle holes and their effect on the P cycle. Thus, we investigated the P composition of arable soils and kettle hole sediments in surface and subsurface layers along a transect of an agricultural field. Multiple P analyses were carried out including modified sequential Hedley P fractionation, P K-edge X-ray absorption near edge structure (XANES) spectroscopy, and 31P nuclear magnetic resonance (NMR) spectroscopy. The Pt concentrations ranged from 680 to 1123 mg kg−1 in the soils and 797 to 2591 mg kg−1 in the sediments. A predominance of the residual-P fraction, characterized as not extractable P, occluded P or stable forms of organic P (Po) was determined by sequential fractionation, ranging from 37 to 67 % followed by 3 to 38 % H2SO4-Pi and 3 to 16 % NaOH-Po of total P (Pt) in the soils and sediments. Analyses with P K–edge XANES spectroscopy assigned 61 to 100 % Fe- and Al-P, 0 to 14 % Ca-P, and 0 to 39 % Po in the arable soils and 46 to 74 % Fe- and Al-P, 14 to 43 % Ca-P, and 0 – 38 % Po in the adjoining kettle hole sediments. Solution 31P NMR spectra on alkaline extracts revealed a broad signal in the phosphomonoester region, which was the most abundant form of organic P across all samples. Besides, the proportion of ‘complex’ phosphomonesters (broad signal) to that of total extractable P was about 2-fold greater in the kettle hole sediments than in soils. Complex forms of organic P are known to be strongly associated with organic matter (OM) and appear to accumulate on a decadel timeframe. Therefore, it is desirable that kettle hole sediments are conserving P (and carbon), which will help reduce the transfer of P from agricultural fields to other, more vulnerable aquatic/marine ecosystems.

Conversion from farmland to orchards has minor effects on nitrogen biological processes in deep loess deposits

High nitrate (NO3--N) accumulation has been observed globally in vadose zones due to the overuse of synthetic fertilizer, but its impacts on nitrogen (N) biological processes remain poorly understood, especially after land use conversion from farmlands to deep-rooted apple orchards. In this study, we collected paired soil samples to determine available N contents, NO3--N isotopes, and abundances of N functional genes (NFGs) in 10-m loess profiles under cultivated farmlands and adjacent apple orchards (n = 300). The average NO3--N accumulation under orchards was 4773 kg N ha−1 (10 times higher than farmlands), with the NO3--N profiles resembling a parabolic curve within 0 – 4 m below the surface. Regardless of excessive fertilizer application and well-developed root systems, the deep-rooted orchards had minor effects on N sources and biological processes in deep loess deposits, as indicated by our estimates of isotopes and NFGs abundances. We hypothesized that the limited and inactive microorganisms in the subsoil are more resistant to environmental disturbances, and that carbon source and ammonium substrate dominated the gene expression and occurrence of NFGs-indicated biological processes. The limited root biomass per unit depth and the inhibition effects of a dry soil horizon on root turnover and exudate release likely contributed to the less perturbed N biological processes under orchards. As the first study to explore N transformation processes in 10-m loess deposits, this study provided insights for complicated N biogeochemical cycles in arid regions with deep unsaturated soils and intensive agricultural land use.

Agriculture and climate change are reshaping insect biodiversity worldwide

Several previous studies have investigated changes in insect biodiversity, with some highlighting declines and others showing turnover in species composition without net declines1-5. Although research has shown that biodiversity changes are driven primarily by land-use change and increasingly by climate change6,7, the potential for interaction between these drivers and insect biodiversity on the global scale remains unclear. Here we show that the interaction between indices of historical climate warming and intensive agricultural land use is associated with reductions of almost 50% in the abundance and 27% in the number of species within insect assemblages relative to those in less-disturbed habitats with lower rates of historical climate warming. These patterns are particularly evident in the tropical realm, whereassome positive responses of biodiversity to climate change occur in non-tropical regions in natural habitats. A highavailability of nearby natural habitat often mitigates reductions in insect abundance and richness associated with agricultural land use and substantial climate warming but only in low-intensity agricultural systems. In such systems, in which high levels (75% cover) of natural habitat are available, abundance and richness were reduced by 7% and 5%, respectively, compared with reductions of 63% and 61% in places where less natural habitat is present (25% cover). Our results show that insect biodiversity will probably benefit from mitigating climate change, preserving natural habitat within landscapes and reducing the intensity of agriculture.

Functional Responses of Phytoplankton Assemblages to Watershed Land Use and Environmental Gradients

Watershed land-use changes have been identified as major threats to lake fauna, subsequently affecting ecosystem functioning. In this study, the functional-based approach was used to examine the effects of land use and environmental changes on phytoplankton communities in four selected lakes in Northeast China. We also identified the sensitive functional traits as indicators of environmental stressors. The integration of RLQ analysis with the fourth-corner approach significantly identified five of 18 functional trait categories, including flagella, filamentous, unicellular, mixotrophic, and chlorophyll c, as potential indicators to changes in watershed land-use intensity and environmental gradients. Significant relationships between traits and land use and water quality highlighted the consequential indirect impact of extensive agricultural and urban development on phytoplankton via allochthonous nutrient inputs and various contaminants. In addition, the functional richness of phytoplankton assemblages generally increased along with surface area and forests, but decreased along with intensive agricultural and urban land use, implying that functional homogenization may cause a reduction in ecosystem productivity and reliability to land-use intensity. Given the superior performance of the functional-based approach, our findings also highlighted the importance of the application of both the biological traits and functional diversity index in monitoring programs for lake ecosystems.

Environmental drivers and sources of stream oxygen consumption in an agricultural lake catchment

The combination of ongoing climate change and the historical loss of streams and wetland areas have presented new ecological challenges. These challenges became evident during a massive fish kill in Lake Fil, Denmark, in August 2018. We know that high amounts of labile organic matter entered the lake after a particularly heavy rainfall that followed a long period of heat and drought. Bacteria decomposed the organic matter, resulting in a quickly deoxygenated lake and an extensive fish kill. However, we do not know whether there is spatial variation in the amount of transportable labile matter across the catchment area. Identifying catchment ‘hotspots’ that sustain particularly high oxygen consumption rates will help managers to pursue interventions that can promote a high ecological quality of Lake Fil and its catchment. The method we developed to identify hotspots can be used by practitioners everywhere to prepare for and mitigate events similar to the 2018 disaster at Lake Fil. To identify hotspots in the stream network that feeds into Lake Fil, we measured oxygen consumption rates and environmental variables at 13 sites on five occasions. We found that oxygen consumption rates varied 2–16-fold between sites and 2–13-fold between sampling days. Oxygen consumption rates were positively related to the concentration of tryptophan-like material and ammonium but negatively related to the complexity of humic substances. Together, these variables accounted for 65% of the variation in the oxygen consumption rate across sub-catchments. High levels of tryptophan-like material and dissolved nutrients derive from intensive agricultural land use in the catchment. However, all oxygen consumption rates measured in this paper were apparently lower than those during the fish kill of August 2018, when the catchment fed higher concentrations of labile organic matter into the lake. The risk of anoxic water and fish kills can be mitigated by reducing and dispersing the input of labile organic matter following shifting periods of drought and heavy rain, which can be done by creating wetlands in the stream network or by implementing biogas facilities, thereby reducing pulses of organic matter and nutrients entering the stream.

Performance analysis of regional AquaCrop (v6.1) biomass and surface soil moisture simulations using satellite and in situ observations

Abstract. The current intensive use of agricultural land is affecting the land quality and contributes to climate change. Feeding the world's growing population under changing climatic conditions demands a global transition to more sustainable agricultural systems. This requires efficient models and data to monitor land cultivation practices at the field to global scale. This study outlines a spatially distributed version of the field-scale crop model AquaCrop version 6.1 to simulate agricultural biomass production and soil moisture variability over Europe at a relatively fine resolution of 30 arcsec (∼1 km). A highly efficient parallel processing system is implemented to run the model regionally with global meteorological input data from the Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2), soil textural information from the Harmonized World Soil Database version 1.2 (HWSDv1.2), and generic crop information. The setup with a generic crop is chosen as a baseline for a future satellite-based data assimilation system. The relative temporal variability in daily crop biomass production is evaluated with the Copernicus Global Land Service dry matter productivity (CGLS-DMP) data. Surface soil moisture is compared against NASA Soil Moisture Active–Passive surface soil moisture (SMAP-SSM) retrievals, the Copernicus Global Land Service surface soil moisture (CGLS-SSM) product derived from Sentinel-1, and in situ data from the International Soil Moisture Network (ISMN). Over central Europe, the regional AquaCrop model is able to capture the temporal variability in both biomass production and soil moisture, with a spatial mean temporal correlation of 0.8 (CGLS-DMP), 0.74 (SMAP-SSM), and 0.52 (CGLS-SSM). The higher performance when evaluating with SMAP-SSM compared to Sentinel-1 CGLS-SSM is largely due to the lower quality of CGLS-SSM satellite retrievals under growing vegetation. The regional model further captures the short-term and inter-annual variability, with a mean anomaly correlation of 0.46 for daily biomass and mean anomaly correlations of 0.65 (SMAP-SSM) and 0.50 (CGLS-SSM) for soil moisture. It is shown that soil textural characteristics and irrigated areas influence the model performance. Overall, the regional AquaCrop model adequately simulates crop production and soil moisture and provides a suitable setup for subsequent satellite-based data assimilation.

Elevated uranium in drinking water sources in basement aquifers of southern India

Groundwater resources in the crystalline basement complex of India are crucial for supplying drinking water in both rural and urban settings. Groundwater depletion is recognised as a challenge across parts of India due to over-abstraction, but groundwater quality constraints are perhaps even more widespread and often overlooked at the local scale. Uranium contamination in basement aquifers has been reported in many parts of India, locally exceeding WHO drinking water guideline values of 30 μg/L and posing a potential health risk. In this study 130 water samples were collected across three crystalline basement catchments to assess hydrochemical, geological and anthropogenic controls on uranium mobility and occurrence in drinking water sources. Groundwaters with uranium concentrations exceeding 30 μg/L were found in all three study catchments (30% of samples overall), with concentrations up to 589 μg/L detected. There appears to be a geological control on the occurrence of uranium in groundwater with the granitic gneiss of the Halli and Bengaluru study areas having higher mean uranium concentrations (51 and 68 μg/L respectively) compared to the sheared gneiss of the Berambadi catchment (6.4 μg/L). Uranium – nitrate relationships indicate that fertiliser sources are not a major control on uranium occurrence in these case studies which include two catchments with a long legacy of intense agricultural land use. Geochemical modelling confirmed uranium speciation was dominated by uranyl carbonate species, particularly ternary complexes with calcium, consistent with uranium mobility being affected by redox controls and the presence of carbonates. Urban leakage in Bengaluru led to low pH and low bicarbonate groundwater hydrochemistry, reducing uranium mobility and altering uranium speciation. Since the majority of inhabitants in Karnataka depend on groundwater abstraction from basement aquifers for drinking water and domestic use, exposure to elevated uranium is a public health concern. Improved monitoring, understanding and treatment of high uranium drinking water sources in this region is essential to safeguard public health.

Bridging mechanistic conceptual models and statistical species distribution models of riverine fish

Statistical species distribution models (SDMs) are widely used to quantify how taxa respond to environmental conditions and to predict their distribution. However, the application of SDMs to freshwater fish taxa is complicated by the active dispersal of fish taxa through river networks, and the species- and habitat-dependent observation process (i.e., the sampling method and effort) required to accurately sample their distributions. Many studies have applied presence-absence models (PAMs) to fish taxa, while more recent studies have proposed zero-inflated models (ZIMs) to account for count observations with many zeroes. However, relatively few studies have incorporated the observation process into the model structure, which would facilitate the combination of data from various monitoring programs that differ in their observation process. In this study, we use conceptual models to identify potentially dominant natural and anthropogenic environmental conditions with a direct, mechanistic effect on the distributions of freshwater fish taxa in Switzerland, a region with a large range of environmental conditions, from alpine streams that are mainly affected by hydromorphological alterations to lowland streams in densely populated areas with intensive agricultural land use. Moreover, numerous barriers impede fish migration along the entire river network. Using combined data from two fish monitoring programs in Switzerland, we applied an exhaustive cross-validation procedure to select a set of environmental variables with the highest (out-of-sample) predictive performance for the PAM and ZIM for fish density (individuals/m2) of the seven most prevalent fish taxa (Salmo spp., Cottus spp., Squalius spp., Barbatula spp., Barbus spp., Phoxinus spp., Gobio spp.). We used these variables to develop a PAM and ZIM for each taxon that accounts for differences in sampling methods and sampling effort. We quantified the quality of fit during calibration using all samples and predictive performance during 5-fold cross-validation of each model.Results show that stream temperature and stream morphology within the accessible habitat commonly appear among the best predictive presence-absence models for multiple taxa. Spatial variables that account for migration barriers and quantify morphological conditions within the accessible habitat were selected for 6 out of 7 taxa. The selected PAMs performed well for all taxa with an intermediate prevalence (10–40%), with an explanatory power (D2) of between 0.32 - 0.37 during calibration using all samples and only minor decreases in explanatory power during cross-validation (D2= 0.34 – 0.44). As expected, the PAM for the highly prevalent Salmo spp. (91%) failed to predict the few absence data points. By contrast, the ZIM model performed best for Salmo spp., with a standardized likelihood ratio of 1.56. For all other taxa besides Barbus spp. the ZIM models also had likelihood ratios above one, indicating a better predictive performance than the null model. We hope this study stimulates the development and application of fish species distribution models based on prior knowledge of causally linked environmental variables and incorporating observation errors to improve their predictive performance. This can facilitate learning from biomonitoring data to support management.

Hydrological, geochemical and land use drivers of greenhouse gas dynamics in eleven sub-tropical streams

Greenhouse gas (GHG) emissions from freshwater streams are poorly quantified in sub-tropical climates, especially in the southern hemisphere where land use is rapidly changing. Here, we examined the distribution, potential drivers, and emissions of carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) from eleven Australian freshwater streams with varying catchment land uses yet similar hydrology, geomorphology, and climate. These sub-tropical streams were a source of CO2 (74 ± 39 mmol m−2 day−1), CH4 (0.04 ± 0.06 mmol m−2 day−1), and N2O (4.01 ± 5.98 µmol m−2 day−1) to the atmosphere. CO2 accounted for ~ 97% of all CO2-equivalent emissions with CH4 (~ 1.5%) and N2O (~ 1.5%) playing a minor role. Episodic rainfall events drove changes in stream GHG due to the release of soil NOx (nitrate + nitrite) and dissolved organic carbon (DOC). Groundwater discharge as traced by radon (222Rn, a natural groundwater tracer) was not an apparent source of CO2 and CH4, but was a source of N2O in both agricultural and forest catchments. Land use played a subtle role on greenhouse gas dynamics. CO2 and CH4 increased with catchment forest cover during the wet period, while N2O and CH4 increased with agricultural catchment area during the dry period. Overall, this study showed how DOC and NOx, land use, and rainfall events interact to drive spatial and temporal dynamics of GHG emissions in sub-tropical streams using multiple linear regression modelling. Increasing intensive agricultural land use will likely decrease regional CO2 and CH4 emissions, but increase N2O.

Water quality assessment of six rivers of the Pacific side of Guatemala

The seas of Latin America are of great marine richness; however, river contaminants that drains to the seas, the growing human settlements around the coast, overfishing and growing agricultural activity, limit the ecosystem benefits. Guatemala is the most populous country in Central America with 17 million and the agricultural activity has been growing, mainly with monocultures that demand a large amount of water. High human population densities and intensive agricultural land use have negative impacts on the environment. In addition, Guatemala does not have a water quality regulation that allows river water quality monitoring and its effect on the oceans; therefore, the condition of its rivers and its impact on the seas is currently unknown. The objective of this research was to evaluate the quality of several rivers on the Pacific side of Guatemala using Costa Rica’s water quality regulations in conjunction with a quality index developed for that nation. It was determined that the rivers sampled for a year showed from moderate to very severe pollution. The main quality indicators that caused such contamination was due to high concentrations in fecal coliforms, phosphates and organic matter load, which vary depending on rainfalls as well as river flow changes.

Changes in anti-deflation resistance of chernozem typical under different tillage and fertilizers

The scale wind erosion is increasing in Ukraine in connection with the arid climate and intensive agricultural land use. Deflation causes significant damage not only to the soil cover, but also to the environment. Research showed that the resistance of soils to deflation depended on their structural state. The aim of the present study was to establish the influence of different tillage systems and fertilizers on agrophysical parameters of the soil. According to the method of dry sieving according to Savvinov, the content of particles larger than 1 mm and the number of agronomically valuable particles per 1% of humus according by V. V. Medvedev were determined in the soil. The research was conducted on a stationary experiment of the M. K. Shikula Department of Soil Science and Soil Conservation in Separated subdivision of NULeS of Ukraine “Oleksandr Muzychenko Velykosnytinske Educational and Research Farm” of Fastiv district of Kyiv region. The soil of the experimental site is chernozem typical. It was found that in the variant with the application of straw, green manure and mineral fertilizers for reduced tillage, the content of particles larger than 1 mm was the highest and amounted to 75.1-77.5%. Conservation tillage systems provided a deflation-resistant soil surface, as the content of particles over 1 mm was greater than 60%. Reduced tillage together with the fertilizer variant "Straw 1.2 t / ha + N12 + N78P68K68" creates the best conditions for aggregation in a layer of 0-30 cm of chernozem typical. On non-plowing tillage, more favorable aggregation conditions were on the variant "Straw 1.2 t / ha + green manure N12 + N78P68K68". On variant with plowing, the indicators of the structural state of chernozem typical deteriorated

Response of Andisols to intensive agricultural land use: Implication on changes in P accumulation and colloidal surface charge

The response of Andisols to intensive agricultural practices were not fully explored although intensive cultivation has been practiced for a long period of time. The objective of the review is to bring together all findings, which have been documented with the focus on changes in soil organic matter, P content and retention, and colloidal surface charge. The Andisols contain an abundance of nano-clay consisting mainly of hollow allophane spherules forming globular aggregates of about 100 nm in diameter, indicating the large reactive surface area. A huge quantity of P has been accumulated in the uppermost two soil horizons, deriving from residue of continuous application of P fertilizer. Andisols have a strong ability to retain organic C through ligand exchange of metal hydroxyl functional groups with organic functional groups. The soil colloids bear a positive charge at soil pH less than 5. The colloidal negative charge is continuously increased with increasing soil pH over 5.0. Hence, the Andisols should be managed by maintaining soil pH above pH 5.0 by adding lime or compost to allow soil capability to retain cation and reduce P fixation. Nano-clay has positive impact on carbon stabilization and therefore C sequestration.

The Application of Digital Monitoring in Studying Soil Water Holding Capacity and Implications for Conservation Agriculture in the South-Western Siberia

The Kulunda Steppe is an example of soil degradation resulting from the intensive agricultural land use in the South Siberia. In this region, water is a limiting factor for crop production. Soil cultivation affects the soil’s physical properties, thus its water retention capacity. The study presents and discusses the results of measurements of the volume and availability of soil moisture at depths of 30cm, 60cm, and 120cm of loamy, low humus southern chernozems in the south of Western Siberia in the dry Kulunda Steppe during the 2013 and 2016 vegetation periods. We revealed some advantages of soil moisture conservation in the No-Tillage [NT] system compared with the system of deep tillage [DT]. At depths of up to 30 cm, there was a lower volume moisture level. Nevertheless, at depths of 60 cm, there was a higher moisture level in the NT system that could be considered a potential stock for individual crops during drought. Further measurements are needed to identify additional features of the NT soil conservation system.

Changes in antideflation resistance of chernozem typical under different tillage and fertilizers

The scale wind erosion is increasing in Ukraine in connection with the arid climate and intensive agricultural land use. Deflation causes significant damage not only to the soil cover, but also to the environment. Research has shown that the resistance of soils to deflation depends on their structural state. The aim of our work was to establish the influence of different tillage systems and fertilizers on agrophysical parameters of the soil. According to the method of dry sieving according to Savvinov, the content of particles larger than 1 mm and the number of agronomically valuable particles per 1% of humus according by V. V. Medvedev were determined in the soil. The research was conducted on a stationary experiment of the Department of Soil Science and Soil Conservation named prof. M. K. Shikula in Separated subdivision of NULeS of Ukraine “Oleksandr Muzychenko Velykosnytinske Educational and Research Farm” of Fastiv district of Kyiv region. The soil of the experimental site is chernozem typical. It was found that in the variant with the application of straw, green manure and mineral fertilizers for reduced tillage, the content of particles larger than 1 mm was the highest and amounted to 75.1-77.5 %. Conservation tillage systems provided a deflation-resistant soil surface, as the content of particles over 1 mm was greater than 60%. Reduced tillage together with the fertilizer variant "Straw 1.2 t / ha + N12 + N78P68K68" creates the best conditions for aggregation in a layer of 0-30 cm of chernozem typical. On non-plowing tillage, more favorable aggregation conditions were on the variant "Straw 1.2 t / ha + green manure N12 + N78P68K68". On variant with plowing, the indicators of the structural state of chernozem typical deteriorated.