Exchangeable Potassium Content Research Articles

Application of thermally treated sludge residues on an e-waste contaminated soil: effects on PTE bioavailability, soil physicochemical and biological properties, and L. perenne growth.

In the context of sustainable development, potentially toxic element (PTE) contamination of soil and large-scale disposal of sludge are two major environmental issues that need to be addressed urgently. It is of great significance to develop efficient and green technologies to solve these problems simultaneously. This study investigated the effects of a 5% addition of thermally treated sludge residues (fermentation and pyrolysis residues) in synergy with L. perenne on soil organic matter, mineral nutrients, PTE speciation, and PTE uptake and transport by L. perenne in an e-waste-contaminated soil through pot experiments. The results showed that the thermally treated sludge residues significantly increased soil electrical conductivity, cation exchange capacity, organic matter, available phosphorus, and exchangeable potassium contents. New PTE-containing crystalline phases were detected, and dissolved humic substances were found. Sludge fermentation residue significantly increased dissolved organic matter content, whereas sludge pyrolysis residue showed no significant effect. The combination of thermally treated sludge residues and L. perenne increased the residual fractions of Cu, Zn, Pb, and Cd. The thermally treated sludge residues promoted L. perenne growth, increasing fresh weight, plant height, and phosphorus and potassium uptake. The uptake of Cu, Zn, Pb, and Cd by L. perenne was significantly reduced. This approach has the potential for applications in the ecological restoration of e-waste-contaminated soils.

Impacts of Organic and Non-Organic Cultivation Practices on Soil Fertility Parameters of Selected Paddy Lands Based on the Duration of Cultivation in Wet and Intermediate Climate Zones of Sri Lanka

Sri Lanka has been practicing the cultivation of rice as its main staple food in two major agricultural techniques; organic and non-organic. The major aim of the present study was to analyze and compare the time duration-based impacts of the above two agricultural practices on paddy soil fertility indicators as the preliminary step of a long-term research project. Organic and non-organic paddy fields that have been cultivated for 2 seasons in Thorapitiya in the Matale district were selected as short-term cultivated lands. Land cultivated for 10 years organically in Homagama and land with a non-organic cultivation history of 20 years in Kottawa was selected as long-term cultivated lands. A total number of 35 samples were collected including the control samples from adjacent uncultivated land during the first phase of the Maha season 2021/2022. The samples were dried, sieved and then analyzed in their physical and chemical properties; color, texture, particle size distribution, pH, electrical conductivity (EC), organic carbon content (OCC), total nitrogen content (TNC), available phosphorus content (APC), exchangeable potassium content (EPC), and exchangeable magnesium content (EMC). The soil samples from Thorapitiya had a reddish-brown nature while most of the samples from Kottawa and Homagama had a grayish-brown color. Higher clay percentages were found in the soil samples from long-term organically cultivated lands in Homagama. The uniformity coefficient (Cu) values for soils from study areas except Homagama lie in the range for well-graded soil while the coefficient of gradation (Cc) values of all three areas were not in the above range. Short-term cultivation using organic and non-organic fertilizers did not show a significant difference in soil texture, pH, EC, APC, EPC, and EMC values. Most of their cultivated lands had a lower pH (~5.5–6.0) than the corresponding control plots (~5.8–6.4). The TNC levels in non-organically cultivated lands were significantly higher than in organic lands. Practicing agricultural activities for a prolonged period has resulted in significant differences in soil texture, pH, EC, OCC, TNC and APC between organic and non-organic lands. Higher OCC and lower pH, EC and APC values have been obtained for long-term organically cultivated lands than their non-organic counterparts. The TNC, APC and EPC levels were higher in most of the long- term organic and non-organic lands than in their control samples. Several amendments have to be made to bring the fertility parameters to an optimum level in long-term cultivated lands. 
 Keywords: Soil fertility, Paddy soil, Cultivation history, Organic cultivation, Non-organic cultivation

Study of the Sustainability of Ecological and Chemical Indicators of Soils in Organic Farming

Organic farming is often seen as a sustainable alternative to intensive agricultural systems. The studies conducted in this direction analyze various factors, as well as their assemblies, and show contradictory results. In order to assess the impact of the organic method of soil cultivation on the stable composition of the most important mineral and organic substances in the production process, the organic agriculture procedure was implemented with an agrochemical analysis for 12 years. The content of mobile phosphorus, exchangeable potassium, and humus in the soil was determined. An elemental analysis of soil samples was conducted for a more in-depth analysis of its composition. It was established that the soils of the farm contained a sufficient amount of exchangeable potassium and humus. The content of these components remained stable during the study period. It was discovered that the soils of the farm have a low content of mobile phosphorus, which also remained stable during the study period. In the studied farm, the applied farming technologies contribute to the stable content of the main nutrient components of the soil. But to correct the content of mobile forms of phosphorus, additional agrotechnical measures are required.

DYNAMICS OF FERTILITY INDICATORS OF LIGHT-CHESTNUT SOIL AND OIL FLAX PRODUCTIVITY UNDER BOGARIAN CONDITIONS OF SOUTHEAST KAZAKHSTAN

The suitable research aims to ascertain the optimum dose of mineral fertilizers and methods of soil processing and preparation for successful flax (Linum usitatissimum L.) cultivation in the semi-arid conditions of the Almaty Region, Kazakhstan, focusing on achieving high crop productivity with good seed quality. Agrochemical investigations also employed modern devices and widely accepted methods. Studying parameters, such as total humus, labile humus, nitrate nitrogen, mobile phosphorus, exchangeable potassium, soil composition density, structural-aggregate composition, and moisture supply, ensued using specific techniques. The study observed an enhancement in nitrate nitrogen content in the soil, from an initial level of 11–19 mg/kg to 36–91 mg/kg during flax harvest in all experimental variants. On the contrary, the mobile phosphorus exhibited a decline in the soil from the beginning of crop vegetation until harvest; however, determining the available phosphorus in different practices showed medium, high, higher, and very high. Moreover, a decline in exchangeable potassium content (from 344–446 mg/kg to 175–215 mg/kg) emerged during the flax crop across all the experimental variants. The application of mineral fertilizers NPK at the rate of 60:60:30, with the application of a growth regulator Ecorost at the rate of 2 liters per ton of seeds, and employing a flatcut treatment (10–12 cm) on light chestnut soil in the semi-arid zone with super dry season of Almaty Region, resulted in the highest flax yield in cv. Karabalykskaya (410 kg/ha

Study of the soybean varieties quantitative traits variability in the Central Non-Chernozem Earth Region conditions

In the experiments, the formation of the yield of new early-ripening soybean varieties Georgiy, Slavyanka and Snezhana under the conditions of the Central Non-Chernozem Region was studied and an assessment was made of the influence of hydrothermal conditions on the variability and conjugation of soybean agronomic traits. Field experiments were carried out in 2020-2022. at the Institute of Seed Production and Agrotechnologies, a branch of the FGBNU FNAC VIM (Ryazan region), located in the forest-steppe agro-climatic zone of the Non-Chernozem zone of the Russian Federation. The soil is dark gray forest, heavy loamy in granulometric composition, of medium fertility (humus content - 4.54%), with an average content of exchangeable potassium and mobile phosphorus. Through correlation analysis, a significant positive relationship was established between the duration of the growing season and the HTC (r = 0.916 + 0.09), with the average daily temperature in August (r = 0.896 + 0.04). The height of plants and the height of attachment of the lower bean in the varietal section changed to an average degree (V = 7.96-21.38%). The greatest variability over the years was noted for the number of beans (V=31.92%) and the weight of seeds per plant (V=38.03%). The weight of 1000 seeds changed the least during the years of the study (V = 8.54-13.38%). The yield of the studied varieties is directly related to the number of beans and seeds per plant, and has no significant relationship with the height of the plant. The results of the research were used in the development of varietal technologies for the cultivation of soybeans in the conditions of the Ryazan region.

Effects of Landscape Variables on Exchangeable Potassium Content in the Floodplain Soils of the Amur River

This article considers exchangeable potassium levels in the floodplain soils of the Amur River. The accumulation of exchangeable potassium in these soils was found to be largely determined by their age and weathering extent. In the young and highly weathered soils, the content of exchangeable potassium was lower than in the middle-aged soils. In the humus-accumulating horizon, it was 100–400 mg/kg and 200 mg/kg in the Upper and Middle Amur River, respectively. As for the mineral horizons, it ranged from 20 mg/kg in the young alluvial soils to 150 mg/kg in the residual-floodplain rusty soils. Interestingly, a significant increase in exchangeable potassium was observed for the coniferous-birch forests of the Upper Amur River (reaching an average of 400 mg/kg), but not for the oak forests in the Middle Amur River. Due to the asymmetry of the rate and ratio of zonal processes in the floodplain soils of the Upper and Middle Amur River, the residual-alluvial soils turned out to be sharply differentiated by the exchangeable potassium profiles. On average, the brown soils (Fluvic Cambisols) of the Upper Amur River contained up to 350 mg/kg of exchangeable potassium. The Fluvic Cambisols of the Middle Amur River had the lowest content of exchangeable potassium as compared to other studied soils.

Применение удобрений на клещевине (результаты исследований во ВНИИМК) (обзор)

The researches conducted in the V.S. Pustovoit All-Russian Research Institute of Oil Crops showed that castor plant yield increased by 0.08–0.20 t/hа after fertilizers application on leached chernozem. The more effective dose of a primary fertilizer under castor is N40P60, which applied in autumn separately under the plowing. Higher doses of the fertilizers are less effective. Application of potassium fertilizers jointly with nitrogen-phosphorus ones in both typical (K40–45) and increased (K80–120) doses did not caused the yield increase of castor plant. Under application of the different doses of the nitrogen-phosphorous or full mineral fertilizers, oil content in castor seeds did not change significantly comparing with unfertilized control, and oil yield was determined by seed yield and increased by 0.06–0.09 t/hа. The local application of N20P30 during castor plant sowing proved the same level of yield comparing with the dose N40P60 – 1.73–1.74 t/hа. The local application of fertilizers during sowing is the most effective when placing the fertilizers strips in a distance of 2 cm sideways of the seeds. Against the backfilling into the soil of 6.2–6.6 t/hа of winter wheat residues, the application of mineral fertilizers under castor plant caused the increase of seed yield by 0.21–0.29 t/hа, oil yield – by 0.11–0.14 t/hа. The dependence of castor plant yield on nitrate nitrogen, mobile forms of phosphorous, and exchangeable potassium contents the in leached chernozem in spring was revealed. It is determined the castor plant does not react positively on the addi-tional fertilizer application when contents of mobile forms of phosphates and exchangeable potassium in a soil layer of 0–20 cm are equal to 26–28 mg/100 g (in the hood by Chirikov F.V.) and 31–32 mg/100 g (in the hood by Maslova А.L.), respectively, and content of nitrate nitrogen in a soil layer of 0–60 cm is more 17–18 mg/kg (by Grandval-Lyazhu).

CORRELATION AND VARIABILITY OF SOIL PROPERTIES OF ARABLE СHERNOZEMS IN THE SOUTH OF THE CENTRAL RUSSIAN UPLAND

Search for correlations between different soil properties and assessment of their variability is important for understanding soil functioning, allows more optimal planning of field and laboratory research and creates the basis for fertilizing management and precision agriculture. This work is based on the data on the content of organic carbon, pH, bulk density, texture (fractions 1-0,25 mm; 0,25-0,05 mm; 0,05-0,01 mm; 0,01-0,005 mm; 0,005-0,001 mm and <0,001 mm and <0,01 mm), exchange calcium and magnesium carbonates for twelve sites of plowed Chernozems studied in the southern part of the Central Russian Upland (Belgorod oblast). Soil samples were taken layer by layer every 20 cm to 3 m depth. Weak correlation was revealed among studied soil characteristics of the plowed Chernozems. The least correlation with other soil characteristics is characteristic of bulk density, organic carbon content, content of fraction 0,25-0,05 mm and 0,01-0,005 mm. Correlation between the content of bicarbonates and pH values is observed only for accumulative - carbonate horizon and transition horizons. The largest number of correlations between different soil characteristics is for the non-plowed part of humus horizon and the top of transition horizon. The least amount of correlations between soil characteristics was found at depths from 80 to 100 cm. Comparison of the coefficients of variations calculated for different soil layers of a single profile (i. e. intraprofile variability) and for the same soil layers but from different profiles (i. e. lateral variability) showed that the intraprofile variability exceeds the lateral one for the organic carbon, exchangeable potassium and calcium content.

Potash State of the Soil and Crop Productivity when Applying Mineral Fertilizers and Plant Residues

In micro-field experiments conducted on gray forest soil, changes in the forms of potassium under the influence of mineral fertilizers and plant residues were studied. It is shown that the soil potassium contained in a water-soluble and easily exchangeable form varied widely. In the conditions of 2012, when applying K60 on the background of nitrogen and phosphorus, the content of water–soluble potassium increased by about 2 times compared with the control, and the content of light-exchange potassium increased by 4 times. In the case of embedding plant residues in the soil, the potassium content in the water–soluble form increased by 2 times, light-exchange – by 2.5 times, respectively. The content of exchangeable potassium changed little in the variants, the changes affected the non-exchangeable form to a greater extent. In particular, the content of non-exchangeable potassium in 2018 decreased by 1.5–2.0 times compared to 2012, which required the creation of a more reliable basis for obtaining objective information about the state of the potash fund of the soils of the forest-steppe zone. Under the influence of K-fertilizers in combination with plant residues, plant productivity stabilized, and at the same time a positive balance of potassium in the soil was formed.

Fertility Status of Soils of Patuakhali Science and Technology University in Bangladesh

Soil is a heterogeneous body and different soil have different fertilizer requirement for crop production depending on fertility status. This research work was conducted to evaluate the fertility status of the soils of the research field of Patuakhali Science and Technology University (PSTU). The soils of PSTU were collected and analyzed for the determination of following soil parameters viz. particle size distribution, texture, pH, organic matter, total nitrogen, available phosphorus, available sulphur and exchangeable potassium. The results showed that the particle size distribution of the collected soils varied significantly with each other. A remarkable variation was observed in textural classes of the soils. The textural classes of the soils were sandy loam, clay and clay loam. The soils were neutral to slightly alkaline in reaction and the pH ranged from 7.01 to 7.73. The organic matter content was very low and ranged from 0.50 to 0.96%. The soils were found to be deficient in total nitrogen with a range of 0.06 to 0.11%. The available phosphorus, available sulphur and exchangeable potassium content of collected soils ranged from 8.76 to 15.90 ppm, 1.04 to 3.06 ppm and 0.12 to 0.26 meq/100 g soil, respectively. The fertility status of the soils was very low to medium level due to very low organic matter content.

SOIL FERTILITY ISSUES OF AGRICULTURAL LANDS IN THE REPUBLIC OF CRIMEA

Information on the soil cover structure in the Republic of Crimea and the soil's essential nutrient content is presented. An analysis of numerous literature sources and statistical data was conducted to highlight the main issues affecting the efficiency of agricultural production. The main problem lies in the need for more supply of cultivated crops with nutrients and organic matter. Weak accumulation of organic matter and nutrients leads to their deficiency and a shortfall in the quantity and quality of the obtained products. There needs to be more application of organic fertilisers to allow for the complete restoration of soil fertility. Although chernozem soils and their varieties dominate the soil structure of the Crimean Peninsula, there is a low content of available phosphorus and organic matter. The content of exchangeable potassium is characterised as elevated. Among micronutrients, the reserves of zinc, cobalt, copper, and manganese are characterised by low content, while the range of molybdenum and boron shows high levels. Agricultural producers can obtain environmentally friendly products since their concentration does not exceed the maximum permissible level.

Effect of plant growth regulators on accumulation of radiocaesium in potato tubers

An important place among the problems of modern agriculture is occupied by the problems of rational use and protection of land and the ecologically dangerous state of the environment. The Zhytomyr region is one of the most affected by the accident at the Chernobyl nuclear power plant. A significant part of agricultural land has a density of contamination with cesium-137 up to 5 Ki/km2, which is 75 % of all contaminated land in the districts, about 20 % of agricultural land has a density of contamination from 5 to 15 Ki/km2, 5 % – above 15 Ki/km2. On lands with a higher density of pollution, it is necessary to apply a complex of agrochemical, agrotechnical and organizational measures to reduce the transfer of radionuclides from the soil to plants. Solving problems related to farming in radioactively contaminated territories occupies one of the leading places in the complex of measures to mitigate the consequences of the Chernobyl accident. The purpose of the research was to establish the effect of different doses and types of plant growth regulators on the productivity of potatoes, the level of radioactive contamination in the agro-ecological conditions of Polissia. Our research was carried out in the agro-ecological conditions of Polіssia LLC. Councilors of Ovrutsky district of Zhytomyr region. The transition of the radioactive isotope cesium-137 from the soil to the plants depends on the content of exchangeable potassium in the soil, the saturation of the soil-absorbing complex with bases, the reaction of the soil solution, the bonification of the soil, and the content of humus. When the agrochemical parameters of the soil improved, in particular when the content of exchangeable potassium in the soil increased from 2.3 mg/100 g of soil to 14.8 mg/100 g of soil, the specific activity of radiocesium in plants de-creased by 3.4 times. The results of our research show that the foliar treatment of potato plants with Biosil and Poteitin contributed to a decrease in the specific activity of tubers from 29.2 to 6.4–2.1 Bq/kg. It was established that foliar spraying of potato plants with Biosil and Poteitin contributed to the reduction of the coefficient of 137Cs transition to 0.03 and 0.01.

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

Soil Fertility Evaluation for Cashew Production at Iyapo Farm Estate, Offa, Kwara State

Cashew (Anacardium occidentale L) is an important commodity crop with great potential as a foreign exchange earner. It is grown principally for it nuts and apple and is a hardy crop which is adapted to a wide range of agro-ecologies. The increase in the price of cashew nuts globally, has resulted in increased interest in the cultivation of cashew. The Management of Iyapo farms limited in its desire to key into this sector requested the technical assistance of Cocoa Research Institute of Nigeria (CRIN) to carry out soil fertility evaluation of the 50 hectares of land proposed for establishment of cashew. The farm was divided into three main sections (A, B and C) based on topography and four land use types (water logged, cassava plot, previously cultivated land and excavated land). Section A was parallel to River Oyun followed by section B in the middle of the farm, while the last section C ran parallel to the road from Ijagbo town. The land use types were scattered within the three blocks. The water logged area was however confined only to section A which was close to river Oyun.
 Soil samples were collected at soil depths of 0-20 cm and 20-40 cm soil depth and at a distance of 20 m apart. The soil collected was put in nylon bags and properly labelled. Soil samples collected were air dried, passed through 2 mm sieve and analyzed for some of its physical and chemical properties. In section A, total soil nitrogen at 0-40 cm soil depth ranged between 0.07 g kg-1 to 0.18 g kg-1 with a mean value of 0.11 gkg-1 soil while mean soil available phosphorus at 0-40 cm soil depth was 3.16 mg kg-1 The exchangeable potassium content across 0-40 cm soil depth ranged between 0.09cmol kg-1 to 0.35 cmol kg-1 with a mean value of 0.25 cmolkg-1 and 0.19 cmol kg-1 for 0-20 cm and 20-40 cm soil depth respectively. In section B, nitrogen across the various soil depths ranged between 0.04 gkg-1 to 0.12 gkg-1 with nitrogen content of the soil decreasing with increasing soil depth. This falls below the soil critical level of 1 gkg-1 required for cashew and was grossly inadequate to meet nitrogen need for cashew. There is need for nutrient supplementation as nitrogen fertilizer is required to meet the nitrogen needs of the cashew. Similarly, phosphorus was also inadequate across the soil depths with a range of 2.47 mgkg-1 to 4.51 mgkg-1 across the various soil depth and a mean value of 3.24 mgkg-1 and 2.65 mgkg-1 for 0-20 cm and 20-40 cm soil depths respectively. This was below the soil critical value of 3.7 mgkg-1. There is therefore need to apply phosphorus fertilizer to boost cashew productivity.
 Soil exchangeable potassium was adequate across the various soil depths with a range of 0.13 to 0.20 cmol kg-1 and a mean value of 0.18 cmol kg-1 and 0.16 cmol kg-1 for 0-20cm and 20-40 cm soil depths respectively. There is no need for potassium fertilizer application. The results above indicated that sections A, B and C requires 180 kg ha-1 of urea and 31.5 kg of Single Super Phosphate (SSP). The cassava plot and previously cropped bare land requires 189 kg ha-1 urea and 9.9 kg ha-1 SSP, while the excavated land requires 194.2 kg urea 25.8 kg SSP and 32.28 kg MOP. Cashew should not be grown on the water-logged section.

Changes in the Indicators of Effective Soil Fertility of the Stone Steppe under the Influence of Forest Strips of Various Landscape Accessories

Within the framework of the program on the subject of the state task in 2021–2022, studies were conducted on changes in the indicators of effective fertility in space and time under the influence of forest strips of various landscape accessories (forest strip No. 40 on the watershed, forest strip No. 72 on the slope). All works were performed in the Voronezh FASC named after V.V. Dokuchaev. It was found that the soils of the watershed area were characterized by the greatest availability of mobile phosphorus and exchangeable potassium. The provision of soils with nitrate nitrogen during the growing season in the watershed and slope areas was at the same level. The watershed area was characterized by a decrease in the amount of mineral elements on the soils of the deposit and the edges of the forest strip No. 40. As for the forest strip itself, the maximum indicators were noted in the center of the forest strip, gradually decreasing in the direction of the edges. Considering the indicators of fertility of arable land, it was noted that they increase at a distance from the forest strip, their maximum was detected at a distance of 75–150 m from the forest strip. On the arable land adjacent to the Baltic forest strip No. 72, an increase in the content of mobile phosphorus and exchangeable potassium was noted when approaching the forest strip. The content of nitrate nitrogen, on the contrary, decreased downhill, reaching a minimum near the forest strip. It is proved that by the end of the growing season, the content of nitrate nitrogen and exchangeable potassium increased in the watershed, and the content of mobile phosphorus decreased. At the slope site, by the end of the growing season, there was an increase in all the studied fertility indicators.

Assessment of suitability of abandoned lands for oats cultivation based on the forecast of the yield according to long-term monitoring data (the case of a specific farm)

The paper presents the results of predicting the yield of oats in the conditions of abandoned lands of the former pilot production farm (PPF) of the All-Russian Research Institute of Reclaimed Lands, located in the center of the Tver region. There were used the data of long-term monitoring (1997-2020) of the yield of this crop in clean and cover crops (with under-sowing of grasses) on the agroecological transect of the Gubino agroecopolygon located within the PPF. With the help of statistical and mathematical modeling, regularities in the formation of oat yields within the transect were revealed. On the basis of these formulas, predicted oat yields were calculated for the entire territory of abandoned lands, and maps of its variability under the conditions of the protected area and measures for intensifying grain production were also created. It has been established that oats in pure crops react most strongly to the content of exchangeable potassium in soils, to water supply and humus content, while in cover crops the yield largely depends on mobile phosphorus in the soil and the degree of illumination and swampiness of the territory. More than 92 % of the PPF area is potentially capable of providing oat yield in clean crops from 2.7 to 3.1 centners/ha, and an increased oat yield (3.0-3.3 centners/ha) in cover crops can be obtained only on ≈ 44 % of the farm area. The main methods for increasing the yield of oats in pure crops are the application of potash and organic fertilizers, as well as the preservation of moisture in the soil, while expanding the area of cover crops involves the use of oat varieties that react poorly to excess phosphorus in the soil. Intensification of oat production in clean crops is possible on the area of 6026 ha, and in cover crops only 790 ha, since in the rest of the territory its productivity is limited by insufficient illumination and waterlogged soils.

Satellite based assessment of agronomically important properties of agricultural soils with consideration of their surface state

Satellite data have been used for a long time to assess various properties of arable soils. At the same time, there are certain difficulties associated with the fact that a number of agronomically important soil properties do not directly affect spectral reflectance of their surface, which complicates the remote assessment of such properties. In addition, to obtain reproducible models, it is necessary to take into account the state of the open soil surface during the survey. The aim of the study was to demonstrate a method for detecting agronomically important properties of arable soils based on Landsat 8-9 OLI satellite data and including information about the state of their open surface using the example of a test field in the Serebryano-Prudsky district of the Moscow region. Depending on the soil property, R2cv of the models developed based on Landsat 8-9 OLI satellite data varied from 0.57 to 0.91. The best models with R2cv>0.8 were obtained for organic matter and properties higly correlated with it such as the content of exchangeable calcium and magnesium cations, the content of total nitrogen, pH of water and salt extracts. The involvement of information on the state of the open surface of arable soils for most properties made it possible to obtain models of higher quality and predictive ability, regardless of the survey period. Based on the models obtained, maps of the spatial variation of agronomically important properties of arable soils were constructed as part of the demonstration of the method. The resulting models can be used for remote monitoring of the analyzed properties of arable soils of the test field. At the same time, for such properties as the content of exchangeable potassium and phosphorus compounds, it is necessary to search for the approaches that will take into account their high variability, as well as to perform a prior assessment of the informativity of the survey periods in which the open soil surface is not transformed.

The fate and supply capacity of potassium in biochar used in agriculture

We used chemical extraction, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) to study the potassium (K) in biochar prepared from corn straw at different temperatures (300 °C, 500 °C, 700 °C and 900 °C). The characteristics of biochar were analyzed through Fourier transform infrared spectroscopy (FTIR) and specific surface area analysis. We found that the potassium in biochar can be divided into water soluble potassium, exchangeable potassium, non-exchangeable potassium, and insoluble potassium according to the availability of agricultural potassium. The fate of potassium in straw changed as follows: with increasing pyrolysis temperature, the proportion of the sum of exchangeable and non-exchangeable potassium decreased, and the proportions of insoluble and lost potassium increased. The total, water soluble and exchangeable potassium contents in biochar were highest at 700 °C. The non-exchangeable and insoluble potassium contents were highest at 300 °C and 900 °C, respectively. Kinetics experiments were conducted to determine the different fates of potassium released from biochar at different temperatures; pot experiments were also undertaken. The release of different forms of potassium in biochar at different temperatures is mainly dominated by heterogeneous diffusion. Biochar increased not only the content of different forms of potassium in soil but also the potassium content of soybean stems and leaves. We calculated the potassium supply capacity of biochar by two strategies, measurements of the potassium content in biochar and the conversion rate of potassium in straw during pyrolysis. The most active and efficient potassium supply capacities were 33.60 g·kg−1 and 9.53 g·kg−1 at 700 °C and 300 °C, respectively. Biochar provides readily available (water soluble and exchangeable) potassium and a long-term (non-exchangeable) potassium supply to soil.

Effect of different natural habitats on the variation in essential oil components of Origanum onites L.

Origanum onites L., which is native to the Mediterranean region, is among one of the economically significant medicinal and aromatic plants that are not only gathered in the wild, but also cultivated in our country. The purpose of this study was to determine how the region in which Origanum onites grows affects the amount of essential oil and essential oil components in the plant's flowers and leaves. In this context, the effect of the plant's growing location on the essential oil content and essential oil components of the flowers and leaves of the Origanum onites, which grows naturally between 0-100 m in the Serik-Aksu, Demre, and Kaş regions of Antalya, was investigated together with the soil properties. The essential oils were extracted from the plant samples' leaves and flowers using the hydrodistillation method. The analysis of essential oils was done using gas chromatography-mass spectrometry (GC-MS) systems. Soil samples were analyzed for their pH, EC, CaCO3, texture, organic matter, total N, available P, and K values. The organic matter and exchangeable potassium contents of the soils, as well as the content of essential oil in the flowers and leaves of the plants, were found to increase gradually towards the west of Antalya. It has been demonstrated that the amounts of essential oil components of the plants varied depending on the region in each of the three different study locations.

The effect of crop rotations and mineral fertilizers on the fertility of chestnut soil

Relevance. The task of preserving and increasing soil fertility is urgent, since it is closely related to crop yields.Methods. The research was carried out in the arid zone of the Stavropol Territory at the Prikumskaya experimental breeding station in four 6-pole crop rotations from 1969 to 2022.The purpose of the research is to study the effect of saturation of grain crop rotations with pure steam on various nutrition backgrounds on the fertility of chestnut soil in the conditions of the Eastern Caucasus.Results. Over 53 years of research, the content and reserves of humus in the arable soil layer in grain-steam crop rotations decreased by 0.18–0.22% and 4.7–5.8 t/ha at the control, on a fertilized background — 0.04–0.08% and 1.0–2.0 t/ha, and in crop rotation without pure steam, on the contrary, increased, respectively, by 0.05% and 1.3 t/ha and 0.21% and 5.5 t/ha. On a natural background, the mineralization of organic matter took place much more intensively than on the variants with the introduction of fertilizers. Nitrate nitrogen reserves in crop rotations with 50.0% and 33.3% of pure steam decreased by 7.6 kg/ha and 1.3 kg/ha at the control, and on a fertilized background in crop rotation with 50.0% of pure steam — by 3.5 kg/ha. In other variants of the experiment, the amount of nitrogen increased. The maximum content of this element on all food backgrounds was noted in the crop rotation without pure steam. In all variants of the experiment, the content of mobile phosphorus and exchangeable potassium increased at the control by 0.7–2.5 and 31–62 mg/kg, and on a fertilized background by 7.2–20.0 and 12–38 mg/kg of soil. The application of mineral fertilizers contributed to an increase in phosphorus reserves by 13.6–44.6 kg/ha and a decrease in potassium by 20–63 kg/ha compared to the control.