Soil Nutrient Regimes Research Articles

Late spring-early summer drought and soil properties jointly modulate two pine species' decline and climatic sensitivity in temperate Northern China

Increasing temperatures and severe droughts threaten forest vitality globally. Prediction of forest response to climate change requires knowledge of the spatiotemporal patterns of monthly or seasonal climatic impacts on the growth of tree species, likely driven by local climatic aridity, climate trends, edaphic conditions, and the climatic adaption of tree species. The ability of tree species to cope with changing climate and the effects of environmental variables on growth trends and growth-climate relationships across diverse bioclimatic regions are still poorly understood for many species. This study investigated radial growth trends, interannual growth variability, and growth-climate sensitivity of two dominant tree species, Pinus tabulaeformis (PT) and Pinus sylvestris var. mongolica (PS), across a broad climatic gradient with a variety of soil properties in temperate Northern China. Using a network of 83 tree ring chronologies (54 for PT and 29 for PS) from 1971 to 2010, we documented that both species maintained constant growth trends at wet sites, while both displayed rapid declines at dry sites. We reported the species-specific drivers of spatial heterogeneity in growth trends, interannual growth variability, and growth-climate relationships. Calculated climatic variables and soil properties were identified as the most critical factors affecting the growth trends and growth-climate relationships. However, climatic variables play more essential roles than soil properties in determining the spatial heterogeneity of the growth-climate relationship. Lower clay content and higher soil nutrient regimes can exacerbate the moisture-related susceptibility of tree growth. Our findings highlight that soil properties emerged as important modulating factors to predict the drought vulnerability of forests in addition to climatic variables. Considering the continued climate warming-drying trend in the future, both pines will face a more severe growth decline and increase in drought vulnerability at drier sites with lower clayed soil or higher nutrient regimes.

Arbuscular mycorrhizal communities respond to nutrient enrichment and plant invasion in phosphorus‐limited eucalypt woodlands

Abstract Arbuscular mycorrhizal fungi (AMF) facilitate ecosystem functioning through provision of plant hosts with phosphorus (P), especially where soil P is limiting. Changes in soil nutrient regimes are expected to impact AMF, but the direction of the impact may depend on context. We predicted that nitrogen (N)‐only enrichment promotes plant invasions and exacerbates their P limitation, increasing the utility of AMF and promoting AMF diversity. We expected that enrichment with N, P and other nutrients similarly promotes plant invasions, but decreases the benefit and diversity of AMF because P is readily available for both native and exotic plants. We tested these hypotheses in eucalypt woodlands of south‐western Australia, that occur on soils naturally low in P. We evaluated AMF communities within three modified ground‐layer states representing different types of nutrient enrichment and associated plant invasions. We compared these modified states to near‐natural reference woodlands. AMF richness varied across ground‐layer states. The moderately invaded/N‐enriched state showed the highest AMF richness, while the highly invaded/NP‐enriched state showed the lowest AMF richness. The reference state and the weakly invaded/enriched state were intermediate. AMF richness and colonisation were higher in roots of exotic than native plant species. AMF community composition differed among ground‐layer states, with the highly invaded/NP‐enriched state being most distinct. Distinctions among states were often driven by family‐level patterns. Reference and moderately invaded/N‐enriched states each supported distinct groups of zero‐radius operational taxonomic units (zOTUs) in Acaulosporaceae, Gigasporaceae and Glomeraceae, whereas Gigasporaceae and Glomeraceae were nearly absent from the highly invaded/NP‐enriched state. Further, Diversisporaceae and Glomeraceae were most diverse in the moderately invaded/N‐enriched state. Synthesis. Both the nature of soil nutrient enrichment and plant provenance matter for AMF. N‐only enrichment of low‐P soils increased AMF richness, likely due to the introduction of AMF‐dependent exotic plant species and exacerbation of their P limitation. In contrast, multi‐nutrient enrichment, decreased AMF richness potentially due to a decrease in host dependence on AMF, regardless of host provenance. The changes in AMF community composition with nutrient enrichment and plant invasion warrant further research into predicting the functional implications of these changes.

Joint Impacts of Meloidogyne incognita and Soil Nutrition on Solanum lycopersicum var. cerasiforme.

Strategies for plant nutrient resource allocation under Meloidogyne spp. infection and different soil nutrient conditions are not well established. In response, the objectives of this research are to determine if increased vegetative growth of Solanum lycopersicon var. cerasiforme (cherry tomato) under high nutrition enhances resistance to M. incognita and whether adaptive strategies for growth, reproduction, and nutrient uptake by cherry tomato infected with M. incognita alter nutrient availability. The study was conducted under greenhouse conditions using high, medium, and low soil nutrient regimes. The research results indicate that the total biomass of cherry tomato was less in the presence of M. incognita infection under all three nutrient conditions, compared with plants grown in the absence of this nematode. However, the increase in the root/shoot ratio indicates that cherry tomato allocated more resources to belowground organs. Under the combined impacts of M. incognita infection and low or medium soil nutrition, the nitrogen content in root system tissues and the phosphorus content in shoot system tissues were increased to meet the nutrient requirements of galled root tissue and plant fruit production. It is suggested that plants increase the allocation of reproductive resources to fruits by improving phosphorus transportation to the aboveground reproductive tissues under low and medium nutrient conditions. Overall, the study highlights a significant impact of soil nutrient levels on the growth and resource allocation associated with M. incognita-infected cherry tomato. In response, soil nutrient management is another practice for reducing the impacts of plant-parasitic nematodes on crop production.

Monitoring of soil EC for the prediction of soil nutrient regime under different soil water and organic matter contents

Smart farms and precision agriculture require automatic monitoring and supply of water and nutrients for crops, but sensors to monitor plant available nutrients in soil are not available. Soil electrical conductivity (EC) is related to nutrients in soil solution, which can be affected by soil organic matter, soil texture, temperature, and water content. Therefore, the objective of this study is to evaluate factors influencing soil EC sensor values by monitoring EC under different soil organic matter and water contents. Ten soil samples with various sand and clay contents, EC, pH, and organic matter contents were selected and saturated with water. Volumetric water content and EC of the soil were monitored while drying the soil. Humic acid and manure were added to soils in order to evaluate the effect of organic matter on soil EC. Soil EC values linearly increased with increasing water content at 10–25% which is favorable water content for plant growth. The EC increased when organic matter was added to soils, which was related to ions released from the organic matter. Soil EC calibration factor for soil water content increased when EC of the soil was high and organic matter was added. The sensor EC values in sandy loam and loam soils was related to the ion contents in pore water, and exchangeable ions in soil, respectively. Sensor EC values were highly correlated with organic matter and K contents in soil and can be used as an indicator for plant available nutrients in soil. Therefore, the sensor EC at optimal soil water content for plant growth can be used to monitor changes in plant available nutrients in soil.

МНОГОЛЕТНИЕ БОБОВЫЕ ТРАВЫ ПРИ ОРОШЕНИИ – ГАРАНТ УСТОЙЧИВОГО КОРМОПРОИЗВОДСТВА В НИЖНЕМ ПОВОЛЖЬЕ

Purpose: to develop rational combinations of species and varieties of perennial leguminous grasses, soil water and nutrient regimes, which will contribute to obtaining stable fodder yields with high levels of protein and energy content. Materials and methods. Research is being carried out on perennial leguminous grasses on the experimental field of the institute. The experiment is three-factor and includes three options for maintaining the pre-irrigation soil moisture limit (60, 70 and 80 % of the lowest moisture capacity), three options for the soil nutritional regime (NPK₁, NPK₂ and control – without fertilizers), eight types of legumes are studied according to the third factor. The generally accepted experimental methods were used when setting up experiments and conducting research. Results. In the full germination phase there were from 294 to 386 plants of grass species per 1 sq. m. Their height before harvesting varied according to the experimental variants from 0.60 to 1.01 m in the first cutting, from 0.38 to 0.94 m in the second and from 0.25 to 0.66 m in the third cutting. The grass stand total water consumption in the year of seeding was 4.2–4.7 thous. cub. m/ha, increasing in subsequent years to 4.8–5.7 thous. cub. m/ha. The soil water regime and fertilizers had a significant impact on crop yield. In control options with a pre-irrigation limit of 60 % of the lowest moisture capacity, the green mass yield in the second year was 26.6–40.9 t/ha. With improved soil nutrition and good water supply, the yield increased to 48.2–87.8 t/ha. Sainfoin and blue-hybrid and variegated alfalfa plants responded to the improved growing conditions most actively; 54–88 t/ha of green mass were gathered from these sites during the season. Conclusions. Selection of optimal combinations of soil water and nutrient regimes, as well as the new promising perennial leguminous grasses species and varieties introduction into the field feed production in the Lower Volga region will ensure high and stable yields of fodder rich in energy and nutrients.

Application of Poultry Manure Improves the Soil Sorption Capacity and Nutrient Regime of Vineyard Soils

ABSTRACT The sorption capacity and nutrient regime under different soil management practices (C – control, T – tillage and PM – tillage + poultry manure) in productive vineyard soil (Rendzic Leptosol) in the Nitra vineyard region (Nitra-Dražovce, Slovakia, Central Europe) were studied for the years 2013–2022. With T and PM, the soil pH was significantly lower than with C. The soil sorption capacity for both studied depths (0–30 and 30–60 cm) increased in the following order: T < PM < C. For all the soil management practices and soil depths, the soil sorption complex was fully saturated with basic cations. With T, in the 0–30 cm layer, the total nitrogen (Nt) content was lower by 218 and 292 mg kg−1, respectively, than with C and PM. However, in the period 2013–2022, the Nt increased statistically significantly, by 50.9, 87.6 and 97.8 mg kg−1 year−1 with T, C and PM, respectively. The application of PM had a positive effect on the increase in available phosphorus (P) – there was an increase with C and T of 96 and 112%, respectively. The content of available P increased linearly with all soil management practices. However, in the case of T, it was statistically significant (increase of 23.2 mg kg−1 year−1) over the period of 10 years. With PM, at 0–30 cm, the content of available potassium was significantly higher, by 29 and 91%, than with treatments C and T.

Humus state and nutrient regime of typical chernozem depending on fertilisation in short crop rotations

The fertiliser system is the most effective factor in the intensification of crop cultivation technologies. The basis for scientifically sound fertiliser application systems, along with obtaining the planned level of yield of the appropriate quality, is the study of the organic matter content and soil nutrient regime during crop rotation. The purpose of this study was to determine the mineral nitrogen, mobile phosphorus, exchangeable potassium, and humus content in typical chernozem under different fertilisation systems in short-term crop rotations. To solve the problem of soil fertility, an important approach is to conduct field and laboratory research to determine changes in the humus state according to Tyurin, nitrogen, phosphorus, and potassium regimes of the soil according to Machigin, and dispersion methods to determine the reliability of experimental data. As a result of the research, it was found that the highest humus content in the soil was recorded under the organic-mineral fertilisation system at the end of the second rotation in the grain crop rotation by 0.13% compared to the fruit crop rotation. The use of a mineral fertiliser system in a row crop rotation reduced the humus content by 0.12%. An increase in the humus content of typical chernozem was recorded under fruit crop rotation and grain-row crop rotation. The organic-mineral fertilisation system tended to increase the mineral nitrogen content of the soil compared to the other systems. The mineral nitrogen content of the mineral fertilisation system decreased by 5.5 mg/kg of soil compared to the unfertilised variant. Under the organic-mineral and mineral fertilisation system, the content of mobile phosphate increased in all crop rotations. The content of mobile phosphorus in the tilled crop rotation was substantially reduced compared to the fruit crop rotation and grain-row crop rotation. The highest content of exchangeable potassium in the soil was recorded under the mineral fertilisation system. The materials of the publications are of practical importance in the analysis of the main elements of mineral nutrition of typical chernozem in short crop rotations

A quantitative approach to defining soil nutrient regimes within ecosystem classifications for Northwestern Ontario

Soil nutrient regimes (SNRs) are often incorporated in ecosystem classifications. Evaluation of actual nutrient levels associated with these SNRs and the development of complementary soil chemistry regimes (SCRs) could broaden their utility. Using data from 618 forest stands in northwestern Ontario, we developed five-category SCRs using K-means clustering and examined relationships among individual nutrients, SCRs, and the SNRs of the Canadian National Vegetation Classification Associations and the Ontario Ecological Land Classification Ecosites. F, A, and B horizon samples were analyzed for organic C (OrgC), total N (TotN), C:N ratio (C:N), cation exchange capacity (CEC), exchangeable bases, base saturation (BaSat), and pH. CEC, pH, and BaSat showed good correspondence across horizons, and together with C:N accounted for much of the variation in chemical properties. There was broad agreement between Association and Ecosite SNRs and B horizon (BHorz) and All horizon (AllHorz) SCRs. C:N decreased while pH and cation metrics increased with increasing SNR and SCR richness. User's accuracies (SNRs vs. SCRs) for the classifications ranged from 31%–39% but increased to 80%–86% for SNR values within ±1 SCR class. Classification trees identified pH class, soil texture, and overstory composition as the principal field-measured factors related to BHorz SCRs.

Nutrient regime of the soil depending on the share of sunflower in short-rotational crop

Sunflower requires a sufficient amount of nutrients for growth and development. Therefore, it is important to determine the impact of sunflower cultivation on the soil nutrient regime, taking into account the frequency of its return to the previous place. The aim of the study was to determine the influence of the share of sunflower in short rotation crop rotations on the soil nutrient regime. The research was conducted at the experimental field of the Kharkiv V.V. Dokuchaev National Agrarian University, which is located in the Left-Bank Forest-Steppe of Ukraine. The research and accounting were carried out on typical heavy loamy chernozem in accordance with generally accepted methods. The experimental scheme included five-field crop rotations with sunflower saturation of 0, 20, 40 and 60%. The research results show that an increase in the share of sunflower in short rotation crop rotations does not lead to a deterioration in the nutrient regime of the topsoil. There was no significant difference between the variants in the content of nutrients. The most supplied with nutrients was the topsoil in the control variant (crop rotation without sunflower). With an increase in the share of sunflower in crop rotations, the amount of nutrients in the tilth layer of soil decreased slightly. Regardless of the studied crop rotation options, the availability of easily hydrolysable nitrogen was low, mobile phosphorus was average, and exchangeable potassium was high. Increasing the share of sunflower in short rotation crop rotations led to a decrease in the yield of the crop itself. The yield of sunflower seeds was at the same level in the variants with 20 and 40%. There is a close relationship between sunflower yield and its saturation, which significantly depends on the soil nutrient regime. The yield level is most affected by the content of phosphorus and potassium in the topsoil. The correlation is 0.91 and 0.98, respectively. The practical value of this study is due to the possibility of using the obtained results to justify the feasibility of increasing the share of sunflower in the structure of crop rotations

Influence of the fertiliser system on the soil nutrient regime and onion productivity

Modern approaches to optimising the nutrition of vegetable plants often have low efficiency and negatively affect various components of the agrobiocoenosis (soil, microbiota). In this regard, the purpose of the study was to determine the influence of various fertiliser systems on the yield and quality of onions in irrigated vegetable-fodder crop rotation, changes in the main agrochemical and microbiological parameters of the soil. The study was conducted in the laboratory of agrochemical research and quality of products of the Institute of Vegetable and Melon Growing of NAAS of Ukraine. Research methods: long-term stationary field experiment; laboratory determination of agrochemical and microbiological parameters of soil and biochemical composition of bulbs; statistical data processing. It is determined that a significant increase in the content of nitrate nitrogen in the arable soil layer is provided by the use of mineral fertilisers, mobile compounds of phosphorus and potassium – mineral and systems. The use of mineral fertilisers leads to an increase in the number of fungi in the soil rhizosphere and a decrease in the potential activity of nitrogen fixation, which worsens the microbiological activity of the soil. The application of organic fertilisers in combination with mineral fertilisers leads to an increase in the number of nitrogen-fixing microorganisms and potential nitrogen-fixing activity, which improves soil fertility. The use of organo-mineral and mineral fertiliser systems leads to an increase in the yield of onions by 6.6-8.6 t/ha or 41.3-53.8%. When using biologised nutrition optimisation systems, the yield increases by 19.4-23.8%. The maximum level of onion yield is indicated for the introduction of organo-mineral fertiliser systems(63 t/ha of humus + randomly N45P45K45; 36 t/ha of humus + locally N45P45K45); causing an increase in yield by 8.2-8.6 t/ha.There is a certain pattern of a decrease in the dry matter content in bulbs and an increase in the nitrate content undervarious fertiliser systems. The research materials are of practical value for the implementation of nutrition optimisationsystems aimed at both sustainable growth in the yield of vegetable products and maintaining the level of soil fertilityof vegetable agrobiocoenoses

Climate Sensitivity of the Arid Scrublands on the Tibetan Plateau Mediated by Plant Nutrient Traits and Soil Nutrient Availability

Climate models predict the further intensification of global warming in the future. Drylands, as one of the most fragile ecosystems, are vulnerable to changes in temperature, precipitation, and drought extremes. However, it is still unclear how plant traits interact with soil properties to regulate drylands’ responses to seasonal and interannual climate change. The vegetation sensitivity index (VSI) of desert scrubs in the Qaidam Basin (NE Tibetan Plateau) was assessed by summarizing the relative contributions of temperature (SGST), precipitation (SGSP), and drought (temperature vegetation dryness index, STVDI) to the dynamics of the normalized difference vegetation index (NDVI) during plant growing months yearly from 2000 to 2015. Nutrient contents, including carbon, nitrogen, phosphorus, and potassium in topsoils and leaves of plants, were measured for seven types of desert scrub communities at 22 sites in the summer of 2016. Multiple linear and structural equation models were used to reveal how leaf and soil nutrient regimes affect desert scrubs’ sensitivity to climate variability. The results showed that total soil nitrogen (STN) and leaf carbon content (LC), respectively, explained 25.9% and 17.0% of the VSI variance across different scrub communities. Structural equation modeling (SEM) revealed that STN and total soil potassium (STK) mediated desert scrub’s VSI indirectly via SGST (with standardized path strength of −0.35 and +0.32, respectively) while LC indirectly via SGST and SGSP (with standardized path strength of −0.31 and −0.19, respectively). Neither soil nor leave nutrient contents alone could explain the VSI variance across different sites, except for the indirect influences of STN and STK via STVDI (−0.18 and 0.16, respectively). Overall, this study disentangled the relative importance of plant nutrient traits and soil nutrient availability in mediating the climatic sensitivity of desert scrubs in the Tibetan Plateau. Integrating soil nutrient availability with plant functional traits together is recommended to better understand the mechanisms behind dryland dynamics under global climate change.

IMPROVEMENT OF TECHNOLOGY OF OBTAINING HIGH QUALITY OF ORGANIC FERTILIZERS WITH THE USE OF ASSOCIATED LAYER WATER AND PROBIOTICS

At the current level of development of agricultural production there are facts of environmental degradation due to the use of agrochemicals. The introduction of scientifically sound ecological technology of agriculture, which is based on the system of ecological safety of the environment and human health, can prevent possible negative effects. To ensure the sustainable development of modern agricultural production and the use of chemicals in limited quantities, there is a problem of their partial replacement by alternative low-cost measures based on natural processes of self-renewal. The aim of our studies was to determinate the effectiveness of obtaining high-quality organic fertilizers using associated water (SPV) and probiotic preparations that accord the requirements of environmentally friendly resource-saving technologies for growing crops. Ecological and trophic groups of soil microorganisms were determined by seeding certain dilutions of soil suspensions. The results of experiments show positive changes in quality and phytosanitary state of organic manure during three months of combined use of SPV (150 l t) and probiotics (100 l/t). The results of bacteriological research show that the level of pathogenic microorganisms decreased by 98-100% after 3 months of composting with native and 10% probiotic solution. Salmonella and Escherichia coli pathogens have not been identified. The cleaning efficiency was lower at 1% and 0.1% probiotic solution. According to mycological research the total number of fungi was 206.9 thousand/g, by 27% more than the control sample. The content of pathogenic fungi decreased by 88% compared to control. It was found that SPV and probiotics changes the chemical composition of manure. Although SPV does not contain large amount of essential mineral nutrients, but SPV are a valuable natural source of microelements that have a positive effect on the crops growth. In particular, the content of potassium in manure increased by 20.8%, phosphorus - by 41.8%, total nitrogen - by 45.8%, organic matter - by 10%. Thus, the integrated use of SPV and probiotics can destroy ruderal vegetation, reduce the germination of weed seeds, improve the quality of manure by enriching it with microelements, disinfect manure from pathogenic microorganisms and fungi. All these advantages make it possible to obtain high-quality organic fertilizer that allows you to optimize the soil nutrient regime. Research results show that the use of SPV and probiotics contribute to increase biological activity in the top soil layer, which determines the specific conditions of transformation of organic matter and productivity of agrobiocenosis. The proportion of microorganisms in the microbial cenosis with SPV 1200 l/ha and probiotics 100 l/ha is 19.2 ± 0.90 million (number of cells in 1 gram of completely dry soil), which is much higher than control (5.9 ± 0.21 million). Using SPV 1200 l/ha and probiotics 100 l/ha stimulates the growth and development of microscopic fungi and cellulose-destroying microorganisms involved in the decomposition of crop residues. There is an increase in the number of oligonitrophilic microorganisms that complete the mineralization of organic residues.

Optimal growing regulations – guarantee of high productivity of sunflower

Optimal growing regulations – guarantee of high productivity of sunflower

Does long-term application of mineral fertilizers improve physical properties and nutrient regime of sandy soils?

In modern agriculture, mineral fertilizers are considered to be a significant enhancing factor. They promote soil fertility, particularly in sandy soils. Farmers should be aware of the effects of fertilizers on the soil environment. Here, we report the results of three long-term experiments with durations of 25, 41 and 94 years conducted in a sandy soil at the experimental station of the Warsaw University of Life Sciences – SGGW in Skierniewice, Poland. The soil physical properties and nutrient regime were monitored under a set of experimental treatments: Control – no fertilizer, NPK – NPK fertilizers, CaNPK – CaNPK fertilizers in the 41-year and 94-year-long experiments, and FYM – farmyard manure as control, FYM+NPK – farmyard manure+NPK fertilizers and FYM+CaNPK – farmyard manure+CaNPK fertilizers in the 25-year-long experiment. Only the 41-year-long experiment showed a significant decrease in bulk density by 7% under NPK treatment compared to control. Total and available P increased significantly across experiments and fertilization treatments compared with the corresponding controls, most remarkably in the 41-year-long experiment. In the 94-year-long experiment, total Ca and Mg rose by 168% and 45% under CaNPK treatment, respectively, relative to the control. Total organic carbon increased considerably across experiments. Similarly, total N and S increased in NPK treatment significantly by 67% and 56%, respectively compared with the control in the 41-year-long experiment. Overall, the highest number of correlations between soil physical properties and nutrient content was determined in the 94-year-long experiment. The obtained results show positive effects of FYM on the content of soil nutrients.

Afforestation With Different Tree Species Causes a Divergent Evolution of Soil Profiles and Properties

Land-use change and specifically a change in the type of vegetation cover affects soil morphology, chemistry, biology, and nutrient regimes. Numerous studies have documented that in land-use conversions from agricultural land to forest, or from plantations to restored natural savanna most soil attributes and functions undergo changes. The purpose of the present study was to evaluate the changes brought about by afforestation of degraded croplands and to understand the impact of forest vegetation on soil evolution in a semiarid region where soils originally co-evolved with a savanna biotope. We used long-term experiments (&amp;gt;40 years) of five tree species: Pinus halepensis (PH), Pinus halepensis inoculated with ecto-mycorrhiza at planting (PM), Pinus pinea (PP), Eucalyptus spp. (E), and Gleditsia triacanthos (G) and compared these to an agricultural soil (A) at the same site near Santa Rosa, La Pampa in the semiarid center of Argentina. Soil profiles were described, and samples taken for chemical and physical analyses of soil properties [organic matter (OM), pH, cation exchange capacity (CEC) and exchangeable cations, particle size distribution (texture), aggregate stability (MWD), bulk density (BD), porosity (TP), and water holding capacity (WHC)]. We found a strong effect of tree species on soil profile morphology, even taxonomy, and on all studied variables. PM and G had highest OM, CEC, neutral pH, higher TP, WHC, while PH, PP, and E had acid pH, lower base saturation, OM, TP, and WHC. The effect of tree species on the soil profile was noticeable a depth of about 40 cm, comprising the A and AC, but not the C horizons. The results showed that to obtain reasonable results of OM sequestration under forest systems, tree species should be chosen to include legumes to improve C/N stoichiometry for C fixation, or inoculation with mycorrhiza to promote microbial transformation of forest litter.

Model Prediction of the Soil Moisture Regime and Soil Nutrient Regime Based on DEM-Derived Topo-Hydrologic Variables for Mapping Ecosites

Ecosites are required for stand-level forest management and can be determined within a two-dimensional edatopic grid with soil nutrient regimes (SNRs) and soil moisture regimes (SMRs) as coordinates. A new modeling method is introduced in this study to map high-resolution SNR and SMR and then to design ecosites in Nova Scotia, Canada. Using coarse-resolution soil maps and nine topo-hydrologic variables derived from high-resolution digital elevation model (DEM) data as model inputs, 511 artificial neural network (ANN) models were developed by a 10-fold cross-validation with 1507 field samples to estimate 10 m resolution SNR and SMR maps. The results showed that the optimal models for mapping SNR and SMR engaged eight and seven topo-hydrologic variables, together with three coarse-resolution soil maps, as model inputs, respectively; 82% of model-estimated SNRs were identical to field assessments, while this value was 61% for SMRs, and the produced ecosite maps had 67–68% correctness. According to the error matrix, the predicted SNR and SMR maps greatly alleviated poor prediction in the areas of extreme nutrient or moisture conditions (e.g., very poor or very rich, wet, or very dry). Thus, the new method for modeling high-resolution SNR and SMR could be used to produce ecosite maps in sites where accessibility is hard.

ЭФФЕКТИВНОСТЬ ПРИМЕНЕНИЯ КОМПЛЕКСА ОРГАНИЧЕСКИХ УДОБРЕНИЙ В ТЕХНОЛОГИИ ВОЗДЕЛЫВАНИЯ ОЗИМОЙ ПШЕНИЦЫ В ЛЕСОСТЕПИ ПОВОЛЖЬЯ

The paper presents results of studying the effectiveness of a complex of organic fertilizers (straw, green manure, biological product) in the technology of winter wheat cultivation. Experimental field studies were carried out on the experimental field of Ulyanovsk State Agrarian University in 2018 - 2020 in a five-field grain-green manure crop rotation: green manure fallow - winter wheat - millet - spring wheat - barley. The experiment scheme included 6 variants: 1. Control, 2. Forecrop straw (barley) + green manure (vetch-oat mixture), 3. Straw + 10 kg N / t straw + green manure, 4. Straw + biological product + green manure, 5. Biological product + green manure, 6.N64P32K54 (NPK). The experiment was carried out in a 4-fold repetition with a randomized placement of plots, the record area of which was 72 m2 (4x18), total - 120 m2 (6x20). Mineral fertilizers are calculated for the planned yield of winter wheat of 4.5 t / ha. “Biocomposite-correct” product produced by AO Shchelkovo Agrokhim was used as a biological fertilizer. The experiment focused on the change of soil agrochemical parameters (typical medium-thick medium-loamy black soil) depending on application of fertilizers, grain yield, its quality and environmental safety; economic assessment of winter wheat cultivation technology with application of fertilizers was conducted. A significant improvement of the soil nutrient regime was found in case of application of a complex of organic methods, which was slightly inferior to the variant with full fertilization. The yield increase of winter wheat grain in case of combined usage of straw, green manure and a biological product was 0.67 t / ha (control - 5.83 t / ha). The usage of a complex 80 of biological techniques for winter wheat cultivation is environmentally safe and cost effective.

Productivity and economic efficiency of growing sunflower depending on the sowing time and plant density in the Right-Bank Steppe of Ukraine

The article covers the results of research on the management of elements of technology and the influence of factors on the productivity of sunflower. The field experiment was conducted in the experimental field of IAS NAAS Kirovohrad region. The level of sunflower productivity is determined by the conditions of water and nutrient regimes of soil. According to the results of research it was established that at the time of sowing reserves of available moisture in 0–100 cm of the soil layer were the largest during the first sowing period and amounted to 178.6 mm. Such moisture reserves create favorable conditions for moistening the seed layer of soil to obtain friendly and full seedlings when sowing in the first – second decade of April. The use of moisture by sowing sunflowers can be regulated by sowing dates to some extent. Shifting sowing dates to earlier ones makes it possible to change the conditions of growth and development of sunflower plants, namely, the plants are better provided with moisture, and it is possible to avoid critical temperature periods of plant development. The high reserves of productive moisture for plants in 0–100 cm soil layer, in crops of Forward, LG 56.32, LG 54.85, LG 55.82 hybrids were for plant density of 60 thousand per hectare, at the first sowing period – in the flowering phase they were 127 mm. The content of nutrients the soil changed both over the years and under the influence of different fertilizer backgrounds. Application of nitrogen, phosphorus, potassium fertilizers in the dose of N40P40K40 and N40P40K40 + by-products of the predecessor allows to increase the content of nutrients available to plants in soil and to increase soil fertility. Due to economic indicators, the optimal time of sunflower sowing for hybrids LG 55.82 and LG 54.85 is warming soil at the depth of seed wrapping up to 5–6 °C, for hybrids Forward and LG 56.32 is warming soil at the depth of seed wrapping up to 9–10 °C, optimal density – 60 thousand/ha. In such conditions, the LG 55.82 hybrid formed the highest yield – 3.85 t/ha, LG 54.85 hybrid – 3.64 t/ha, Forward – 3.09 t/ha, LG 56.32 hybrid – 3.62 t/ha. Key words: sunflower, soil nutrient regime, water regime of soil, yield, profitability, net profit.

Nutritional regime of gray forest soil аt different anthropogenic loads

The aim of the research is to establish the peculiarities of the formation of the nutrient regime of gray forest soil with different systems of basic cultivation, fertilization and sealing of by-products of crops in short-rotation 4-field grain crop rotation – winter wheat–corn for grain–barley–soybean. Evaluate the quantitative inflow of biomass, participation in the formation of the nutrient regime of gray forest soil, especially the differentiation of 0–40 cm of soil layer depending on the distribution of nutrients in different tillage soil systems. The studies were carried out in a long-term stationary experiment of the department of soil cultivation and weed control of the NSC «Institute of Agriculture of the NAAS», founded in 1969. The fertilization system consisted of the application of mineral fertilizers N65Р58К68 kg acting things per 1 ha of crop rotation area. As an organic fertilizer, we used by-products of crop rotation, where during 2009–2013 received an average of 5,17–5,50 t/ha, and 2014–2017 – 6,65–7,76 t/ha of crop rotation. The existing yield of the main product significantly influenced the volume of the non-commodity part, with the growth of the main product, the growth of by-products also took place in direct proportion. Nitrogen removal averaged 105 kg/ha, and with biomass it returned on average 55,4 kg/ ha, nitrogen with a full mineralization cycle, in general, this corresponds to 45–47 % of the share of costs. In general, the return of phosphorus from by-products for the rotation of 5 received an average of 12,0–16,7 kg/ha and 4-field crop 26 rotation 19,5–22,0 kg/ha, which was 35–40 % of the total removal harvest. The soil received many times more potassium from the biomass of agricultural crops than part of the cost of the main product, due to the attraction of the maize leaf mass, from which an average of 177–253 kg/ha enters the soil, and for crop rotation – 61,4–95,4 kg/ha per hectare of sown area. Key words: gray forest soil, soil nutrient regime, recycling of nutrients, main and by-products of crops.

Агротехнические приемы возделывания люцерны на семена в условиях орошения в Нижнем Поволжье

Abstract. Legumes play a leading role in providing farm animals with high-quality and highly nutritious feed, while in the Lower Volga region, the traditional alfalfa crop plays a leading role. The productivity of alfalfa in production conditions is only a tenth of its potential. The purpose of the research is to determine the impact of reduced seeding rates, varietal characteristics, seeding time and use of siderates instead of mineral fertilizers on the seed productivity of the crop. The field experience included 2 terms of sowing – spring and summer, 3 variants of the soil nutrient regime: the natural background of nutrition and plowing of two types of sideral mixtures (sunflower + vetch and oats + radish); three variants of the density of herbage (40, 80 and 400 thousand plants/ha). Observations were made on three varieties of alfalfa (Leninskaya mestnaya, Vega 87 and Unitro). Records and observations were made in accordance with the generally accepted methods of experimental work. Results and practical significance. As a result of research, a favorable influence of sideral masses on the formation of a symbiotic apparate on alfalfa roots was revealed. In comparison with the natural background of nutrition, the number of nodules significantly increased in the variants with the plowing of siderates. The yield of seed alfalfa was also influenced by the density of sowing. More productive organs were formed in sparse grass stands, which contributed to an increase in the collection of seeds. The use of sideral mixtures also had a positive effect on productive shoot formation. The number of stems, brushes and seeds in the bean was 25–30 % more than in the control. Summer sowing favourably affected the seed productivity of alfalfa, its indicators were 1.2–1.6 times higher than the data obtained from the grass stands of the spring sowing season. Scientific novelty. For the irrigated conditions of the Lower Volga region, a comprehensive assessment of the participation of the main agrotechnical techniques in the implementation of alfalfa seed productivity is given: terms, methods and seeding rates with the use of siderates for soil fertilization.