Intensive Agricultural Use Research Articles

Sensitivity of Tropical Insectivorous Birds to the Anthropocene: A Review of Multiple Mechanisms and Conservation Implications

Epigraph: “The house is burning. We do not need a thermometer. We need a fire hose.” (P. 102, Janzen and Hallwachs, 2019). Insectivorous birds are declining widely, and for diverse reasons. Tropical insectivorous birds, more than 60% of all tropical birds, are particularly sensitive to human disturbances including habitat loss and fragmentation, intensive agriculture and pesticide use, and climate change; and the mechanisms are incompletely understood. This review addresses multiple, complementary and sometimes synergistic explanations for tropical insectivore declines, by categorizing explanations into ultimate vs. proximate, and direct versus indirect. Ultimate explanations are diverse human Anthropocene activities and the evolutionary history of these birds. This evolutionary history, synthesized by the Biotic Challenge Hypothesis (BCH), explains tropical insectivorous birds' vulnerabilities to many proximate threats as a function of both these birds' evolutionary feeding specialization and poor dispersal capacity. These traits were favored evolutionarily by both the diversity of insectivorous clades competing intensely for prey and co-evolution with arthropods over long evolutionary time periods. More proximate, ecological threats include bottom-up forces like declining insect populations, top-down forces like meso-predator increases, plus the Anthropocene activities underlying these factors, especially habitat loss and fragmentation, agricultural intensification, and climate change. All these conditions peak in the lowland, mainland Neotropics, where insectivorous bird declines have been repeatedly documented, but also occur in other tropical locales and continents. This multiplicity of interacting evolutionary and ecological factors informs conservation implications and recommendations for tropical insectivorous birds: (1) Why they are so sensitive to global change phenomena is no longer enigmatic, (2) distinguishing ultimate versus proximate stressors matters, (3) evolutionary life-histories predispose these birds to be particularly sensitive to the Anthropocene, (4) tropical regions and continents vary with respect to these birds' ecological sensitivity, (5) biodiversity concepts need stronger incorporation of species' evolutionary histories, (6) protecting these birds will require more, larger reserves for multiple reasons, and (7) these birds have greater value than generally recognized.

Soil carbon stock estimations: methods and a case study of the Maranhão State, Brazil

Soils feature significant variations in soil carbon stocks through land-use changes, management practices, and intrinsic characteristics. The aim of this study was to estimate the changes in soil carbon stock under different scenarios of land use and agricultural management in the Maranhao State, Brazil, considering the conversion from the conventional agriculture into conservationist management systems. Changes in soil carbon stocks were estimated from the scenario t0 to the current scenario (2010), followed by the adoption of a conservationist scenario by the year 2030. Soils under pasturelands presented the highest average of carbon stocks (62.19 Mg ha−1), followed by forestry lands (61.60 Mg ha−1) and agricultural lands (38.28 Mg ha−1). The conversion of native vegetation into an intensive agricultural use contributed to soil carbon losses of 1.57 Mt C, with pasturelands accounting for 1.36 Mt C and agricultural lands for 0.21 Mt C by 2010. The replacement of intensive agricultural systems into conservationist systems in the current areas has a technical potential for soil carbon sequestration of 0.6 Mt by 2030, with livestock and agricultural lands accounting for 0.54 and 0.03 Mt C, respectively.

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.

ПЛОДОРОДИЕ ОРОШАЕМЫХ ЗЕМЕЛЬ В ЮЖНОЙ ЛЕСОСТЕПИ ОМСКОЙ ОБЛАСТИ

Unsustainable irrigation of chernozems can lead to secondary salinization and other negative consequences. The purpose of the research was to assess the fertility and hydrochemical composition of meadow-chernozem soil of the forest-steppe of Western Siberia under conditions of prolonged irrigation. The surveys were carried out in the fields of the agricultural production cooperative (APC) “Pushkinsky” and Federal State Unitary Enterprise (FSUE) “Omskoye”; cultivation technology – adaptive system of irrigated agriculture. The studies were conducted in 2015–2020 on the Pushkin irrigation system. The object of the research – irrigated meadow-chernozem heavy loamy soil. The methods of route field research and laboratory analyzes were used. The results obtained were compared with the baseline values (1978). With long-term irrigation and intensive agricultural use, the fertility indicators of meadow-chernozem soil did not significantly deteriorate. The arable horizons have a neutral and close to neutral reaction (pH 5.8–6.2), average humus content (5.9–7.2%). The supply of nitrate nitrogen, as a rule, remained at a low and medium level (6.0–14.7 mg/kg) due to the high removal by vegetative crops and the absence of fallow fields in the structure of irrigated arable land. Long-term systematic application of phosphorus-containing fertilizers and creation of a positive P balance led to the improvement of soil phosphate status (99–177 mg/kg). The content of exchangeable potassium remains high (144–353 mg/kg) and is stable over time, which is a feature of chernozems with a heavy particle size distribution. The content of mobile forms of lead, zinc and cadmium does not exceed approximate permissible concentrations in the soil. When analyzing the cation-anionic composition of the water extract of the soil profile of FSUE “Omskoe”, a weak salinity of the chloride type was revealed in the 0.6-1.4 m layer; of the sulfate-chloride type – in the 1.4-1.8 m layer. In the future, it may lead to secondary salinization and serve as a limiting factor for high yields. The absorbing complex of meadow-chernozem soil in the southern forest-steppe is highly saturated with bases. Sodium concentration is minimal; calcium and magnesium cations prevail. The groundwater samples are moderately fresh and of good quality. Among the anions, HCО3- prevails, among the cations – Mg2+ and Ca2+, which indicates the need to control the groundwater level to maintain a favorable ecological state of meadow-chernozem soil.

Analysis of Spatial-Temporal Changes of Agricultural Land Use During the Last Three Decades in the Araban District of Turkey Using Remote Sensing

Agricultural land use and land cover dynamics were investigated in the Araban district of Turkey during the periods 1984–2019 by the use of Remote Sensing and Geographic Information Systems (GIS). Landsat‑TM and Landsat‑TIRS / OLI satellite imageries were used to determine land use and land cover changes. Using unsupervised classification method of ERDAS 8.3 software, three main agricultural activities were identified namely irrigated farming, dry farming, and horticultural / garden farming. The analysis has revealed that during the last three decades dry farming has decreased significantly by 14.69% (3802.14 ha) whereas horticultural/garden crops and irrigated farming lands have increased by 11.32% (667.19 ha) and 2.51% (2929.41 ha) respectively. Araban has been under intensive agricultural use due to its fertile soil and preference for horticultural crops such as pistachio, grapes and olives that provide more profit over dry farming crops such as wheat and barley has changed land use. Decrease in dry farming in a semi‑arid climate where Araban is located, has a potential ecological consequence, including a rapid drop of groundwater level, drying of wetlands and the disappearance of the biodiversity, thus, a necessary measures should be taken to implement an environmentally friendly, sustainable agriculture and settlement plan.

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.

The current state of mountain meadow soils of subalpine pasture ecosystems of the Central Caucasus (elbrus altitudinal zonality)

Intensive recreational, agricultural and logistics land use in uplands leads to their transformation and degradation. Subalpine meadow ecosystems of Central Caucasus are traditionally used for grazing and mowing. The work determined the current state of soils on pastures (mountain meadow-steppe subalpine soil and mountain meadow subalpine soil) and the level of changes of their properties under different stages of pasture degradation were defined. The efficacy of 4-stage assessment system for evaluating the pasture degradation of grasslands dominated by Bromus variegatus M. Bieb. was shown for the assessment of soil cover condition. The reduce of estimated soil indicators and degradation of soils under pastures with maximal degradation stage (DS3) of meadow ecosystems was statistically significant.

Patterns of land system change in a Southeast Asian biodiversity hotspot

Growing demand for agricultural commodities like rubber or oil palm is causing rapid change in Southeast Asia's biodiversity-rich forested landscapes. This change is particularly pronounced in Myanmar, whose economy is developing at great speed after the end of decades-long economic and political isolation and armed conflicts. Interventions are needed to ensure that development is sustainable. Designing successful interventions requires spatially explicit knowledge of recent landscape changes. To provide such knowledge, we applied a landscape mosaic approach and analysed land system change in Tanintharyi Region in southern Myanmar between 2002 and 2016. Our findings show that nearly half of the study region experienced degradation of the vegetation cover, intensification of agricultural use, or a combination of both. Although intact forest was still the prevailing vegetation cover of land systems in Tanintharyi Region in 2016, it had suffered from degradation in wide parts of the region. Land systems without or with only extensive agricultural use in 2002 had become dominated by smallholders' shifting cultivation systems and permanent betel nut gardens and paddy rice fields by 2016. Elsewhere, smallholder dominated land systems were intensified through the expansion of oil palm and rubber plantations, pointing to potential displacement effects. The land system maps offer a sound basis for planning interventions to slow the degradation of biodiversity-rich forests and support smallholder farmers in coping with the fast-paced expansion of commercial cash crop plantations and its social and environmental impacts. Sustainable development in this global biodiversity hotspot requires careful land use planning to support nature and people, along with continued efforts for peace-building.

Use of machine-learning and receptor models for prediction and source apportionment of heavy metals in coastal reclaimed soils

Quantitative estimations of sources and spatial distribution of soil heavy metals (HMs) is essential for strategizing policies for soil protection and remediation. As a special soil ecosystem, the intensified human activities on coastal reclaimed lands generally causes soil contamination with HMs. This study aimed to apportion sources of HMs and predict their spatial distributions on coastal reclaimed lands. A total of 241 surface (0–20 cm) soil and sediment samples were collected from a reclamation zone following intensive agricultural use of eastern China. The concentrations of soil and sediment As, Cr, Cu, Ni, Pb, Zn, Cd, and Hg were measured along with organic carbon, nitrogen, phosphorus, pH, Cl, clay, silt, sand, CaO, Fe2O3, Al2O3, and SiO2. The potential sources of HMs were identified and apportioned using random forest (RF) and positive matrix factorization (PMF) models. According to the models, natural and a portion of anthropogenic sources, agricultural activities, and human emission from solar power generation and vehicle exhaust contributed 42.9%, 28.9%, and 28.2% of the total HMs, respectively. Separately, 65.0% of As, 36.6% of Cr, 49.1% of Cu, 46.4% of Ni, 39.5% of Pb, and 44.0% of Zn were originated from natural and some anthropogenic sources. Agricultural activities contributed 54.9% of Cd and 46.4% of Hg to the reclaimed soils. Emissions from solar power generation and vehicle exhaust had significant influences on Cr and Pb, with contributions of 39.0% and 28.0%, respectively. Furthermore, the RF model yielded satisfying results in predicting HM distributions based on the measurement of soil variables. When only considering independent variables, the RF model revealed slightly lower but still satisfactory abilities in HMs prediction. In reclaimed soils, the temporal increase and close relationship between soil Cd and phosphorus signified the potential threats of Cd contamination in coastal reclaimed soils. Therefore, the applications of Cd-rich phosphoric fertilizers should be considered with high concern.

Identification of Novel Alleles of the Rice Blast-Resistance Gene Pi9 through Sequence-Based Allele Mining

BackgroundAs rice (Oryza sativa) is the staple food of more than half the world’s population, rice production contributes greatly to global food security. Rice blast caused by the fungus Magnaporthe oryzae (M. oryzae) is a devastating disease that affects rice yields and grain quality, resulting in substantial economic losses annually. Because the fungus evolves rapidly, the resistance conferred by most the single blast-resistance genes is broken after a few years of intensive agricultural use. Therefore, effective resistance breeding in rice requires continual enrichment of the reservoir of resistance genes, alleles, or QTLs. Seed banks represent a rich source of genetic diversity; however, they have not been extensively used to identify novel genes and alleles.ResultsWe carried out a large-scale screen for novel blast-resistance alleles in 1883 rice varieties from major rice-producing areas across China. Of these, 361 varieties showed at least moderate resistance to natural infection by rice blast at rice blast nurseries in Enshi and Yichang, Hubei Province. We used sequence-based allele mining to amplify and sequence the allelic variants of the major rice blast-resistance genes at the Pi2/Pi9 locus of chromosome 6 from the 361 blast-resistant varieties, and the full-length coding region of this gene could be amplified from 107 varieties. Thirteen novel Pi9 alleles (named Pi9-Type1 to Pi9-Type13) were identified in these 107 varieties based on comparison to the Pi9 referenced sequence. Based on the sequencing results, the Pi2/Pi9 locus of the 107 varieties was divided into 15 genotypes (including three different genotypes of Pi9-Type5). Fifteen varieties, each representing one genotype, were evaluated for resistance to 34 M. oryzae isolates. The alleles from seven varieties with the highest resistance and widest resistance spectra were selected for transformation into the susceptible variety J23B to construct near-isogenic lines (NILs). These NILs showed resistance in a field test in Enshi and Yichang, indicating that the seven novel rice blast-resistance tandem-repeat regions at the Pi2/Pi9 locus of chromosome 6 could potentially serve as a genetic resource for molecular breeding of resistance to rice blast.ConclusionsThe thirteen novel Pi9 alleles identified in this study expand the list of available of blast-resistance alleles. Seven tandem-repeat regions of the Pi2/Pi9 locus from different donors were characterized as broad-spectrum rice blast-resistance fragments; these donors enrich the genetic resources available for rice blast-resistance breeding programs.

Land use and episodic rainfall as drivers of nitrogen exports in subtropical rivers: Insights from δ15N-NO3−, δ18O-NO3− and 222Rn

Ongoing land-use intensification in subtropical catchments is expected to release more inorganic nitrogen to downstream coastal waters similar to historical changes in temperate ecosystems. Here, we examined spatial and temporal drivers of stream nitrogen loads across a subtropical land-use gradient using the isotopic compositions of nitrate (NO3−-N) and radon (222Rn), a natural groundwater tracer. We investigated eleven subtropical creeks/rivers over contrasting hydrological conditions in Australia. NOx-N (nitrite (NO2−-N) + nitrate (NO3−-N)) accounted for 13.1%, 34.0%, and 42.6% of total dissolved nitrogen (TDN-N) in forest, peri-urban and agricultural creeks, respectively. Following an 80 mm rain event, loads of dissolved inorganic nitrogen (DIN-N) from agriculture catchments reached 368 mg N m−2 catchment area day−1. Forest and peri-urban catchments had aquatic TDN-N loads 17.8% and 31.1% of loads from agricultural catchments. Radon observations suggest that nitrogen and phosphorus loads were driven primarily by surface runoff rather than groundwater discharge. The δ15N-NO3− and δ18O-NO3− values in the agriculture, forest and peri-urban catchments indicate fertilisers and soil nitrogen as the main sources of NO3−-N. However, one of the catchments (Double Crossing Creek) received a mixture of recirculated greywater and chemical nitrogen fertilisers. Isotopic signatures imply significant NO3−-N losses via denitrification during dry conditions. Groundwater discharge played a minor role because regional aquifers were not contaminated by nitrogen. Overall, intensive agricultural land use and episodic rainfall events were the major spatial and temporal drivers of nitrogen loads.

Understanding the role of water and tillage erosion from <sup>239+240</sup>Pu tracer measurements using inverse modelling

Abstract. Soil redistribution on arable land is a major threat for a sustainable use of soil resources. The majority of soil redistribution studies focus on water erosion, while wind and tillage erosion also induce pronounced redistribution of soil materials. Tillage erosion especially is understudied, as it does not lead to visible off-site damages. The analysis of on-site/in-field soil redistribution is mostly based on tracer studies, where radionuclide tracers (e.g. 137Cs, 239+240Pu) from nuclear weapon tests are commonly used to derive the erosion history over the past 50–60 years. Tracer studies allow us to determine soil redistribution patterns but integrate all types of soil redistribution processes and hence do not allow us to unravel the contribution of individual erosion processes. The aim of this study is to understand the contribution of water and tillage erosion leading to soil patterns found in a small hummocky ground moraine kettle hole catchment under intensive agricultural use. Therefore, 239+240Pu-derived soil redistribution patterns were analysed using an inverse modelling approach accounting for water and tillage erosion processes. The results of this analysis clearly point out that tillage erosion is the dominant process of soil redistribution in the study catchment, which also affects the hydrological and sedimentological connectivity between arable land and the kettle hole. A topographic change up to 17 cm (53 yr)−1 in the eroded parts of the catchment is not able to explain the current soil profile truncation that exceeds the 239+240Pu-derived topographic change substantially. Hence, tillage erosion already started before the onset of intense mechanisation since the 1960s. In general, the study stresses the urgent need to consider tillage erosion as a major soil degradation process that can be the dominant soil redistribution process in sloped arable landscapes.

Research on Environmental Risk Control of Highly Intensive Agricultural Land Use Based on Computer Technology and Landscape Scale

Under the background of China’s rigid population growth and the reduction of cultivated land area, the degree of agricultural intensification has been increasing. Pesticides and fertilizers have greatly increased crop yields. However, the large amount of agricultural chemicals input leads to the decline of soil and environmental quality. The environmental pollution caused by agricultural activities is increasing, especially in the high intensive agricultural areas with high land use intensity and a large amount of agricultural chemicals input. Agricultural land use is facing the dual challenges of ensuring food security and ecological environment security, which is an arduous and urgent task to realize the sustainable and healthy development of China’s agricultural countryside. High intensive agriculture gains higher economic benefits, but it also leads to serious environmental consequences. In the face of the increasingly serious problems of agricultural ecological environment, how to guarantee the economic development and control the environmental risk of agricultural land use is an urgent practical problem. Based on this, this paper uses computer technology to analyze the environmental risk control strategy of highly intensive agricultural land use based on the landscape scale.

Development of a machine model for planting potatoes for seeds with active bed formers

One of the main problems of the Russian agriculture is the production of agricultural products in the necessary quantities. In connection with exceeding the norms of impact on agricultural landscapes due to their long and intensive agricultural use, it led to a violation of energy and mass exchange between its components, the progressive development of degradation phenomena, a decrease in soil fertility and productivity of agrocoenoses due to the action of abiotic and biotic stressors. The article considers the technique of planting seed potatoes with two-row placement of tubers in a row. The intensification of potato cultivation technology based on the use of modern science-intensive technical means is one of the main factors for obtaining these strategic agricultural crop high-resistant and high-quality yields. A machine for forming rows of loosened soil with simultaneous planting of sprouted and non-sprouted calibrated potatoes with a given pitch and depth of potato tubers seeding in order to increase the energy efficiency of potato production for seeds, reduce agrotechnological impacts, time, fuel and labor costs due to the simultaneous formation of rows by active cutter working bodies with the planting of potatoes in two rows was developed.

Long‐Term Shifts in U.S. Nitrogen Sources and Sinks Revealed by the New TREND‐Nitrogen Data Set (1930–2017)

AbstractReactive nitrogen (N) fluxes have increased tenfold over the last century, driven by increases in population, shifting diets, and increased use of commercial N fertilizers. Runoff of excess N from intensively managed landscapes threatens drinking water quality and disrupts aquatic ecosystems. Excess N is also a major source of greenhouse gas emissions from agricultural soils. While N emissions from agricultural landscapes are known to originate from not only current‐year N input but also legacy N accumulation in soils and groundwater, there has been limited access to fine‐scale, long‐term data regarding N inputs and outputs over decades of intensive agricultural land use. In the present work, we synthesize population, agricultural, and atmospheric deposition data to develop a comprehensive, 88‐year (1930–2017) data set of county‐scale components of the N mass balance across the contiguous United States (Trajectories Nutrient Dataset for nitrogen [TREND‐nitrogen]). Using a machine‐learning algorithm, we also develop spatially explicit typologies for components of the N mass balance. Our results indicate a large range of N trajectory behaviors across the United States due to differences in land use and management and particularly due to the very different drivers of N dynamics in densely populated urban areas compared with intensively managed agricultural zones. Our analysis of N trajectories also demonstrates a widespread functional homogenization of agricultural landscapes. This newly developed typology of N trajectories improves our understanding of long‐term N dynamics, and the underlying data set provides a powerful tool for modeling the impacts of legacy N on past, present, and future water quality.

Effect of lon 10.22271/phyto.2020.v9.i5ao.12791 g term zero tillage on soil organic carbon and its fractions: A review

Soil tillage disruption is a major cause of loss of organic matter and a decline in the number and stability of soil aggregates as natural habitats are transformed into agriculture. Compared to conventional tillage, zero tillage cropping systems typically demonstrate increased aggregation and soil organic matter. To feed the rising population on a sustainable basis without degrading natural resources, there is a need to increase farm productivity and total food production. Although the country's green revolution technologies implemented during 1966-67 led to food protection, intensive agriculture, insufficient and imbalanced use of fertilizers, high yielding crop varieties, the use of heavy machinery, excess tillage, etc., resulted in degradation of soil health and quality for more than five decades and increased pollution of air, soil and water. There is a great lack of a systematic approach to relating tillage practices to chemical soil properties. The most significant pillar of conservation farming is zero tillage. The need for an hour is conservation farming. It is a win-win operation for farmers as well as for the environment. The goal of Tillage was to establish a soil environment conducive to plant growth, but to have negative effects on soil resources, structure and eventually on the environment in the long run. Zero tillage has the ability to enhance the chemical properties and environment of the soil in the long run. Keeping all of these under consideration, this analysis is compiled to create a perfect tillage scheme, i.e. zero tillage, which eliminates the adverse effects of tillage and retains soil resources and eventually contributes to sustainable agriculture. The magnitude of changes in soil organic matter in response to zero tillage, however, differs between soils and the stabilisation mechanisms of organic matter in zero tillage systems.