Exchangeable Potassium Research Articles

SYNERGISTIC EFFECT OF BACILLUS MUCILAGINOSUS AND PSEUDOMONAS FLUORESCENS ON THE AVAILABILITY OF SOIL POTASSIUM, GROWTH AND YIELD OF CUCURBITA PEPO L.

A field experiment was carried out at the field of Agricultural Research and Experiments Station during the season 2021-2022 in order to study the synergestic effect and compatible between Bacillus mucilaginosus and Pseudomonas fluorescens when they added as combination on potassium availability in the soil and on some plant growth characteristics and yield of Cucurbita pepo L. The experiment included four treatments B0, control , B1 addition of Bacillus mucilaginosus inoculum, B2 addition Pseudomonas fluorescens inoculum and B1 B2 addition of acombination of B1 and B2 inoculum . The experiment was conducted by using randomised complete blocks design in three replicates . The results showed that the co- inoculation with Bacillus mucilaginous and Pseudomonas fluorescens significant effect on quantity of soluble,exchangeable potassium as well as the plant height, dry weight of shoots, percentage of potassium in the shoot and in the fruits and total yield as compared with individual inoculation for any bacteria B1 or B2 which refers to positive synergestic effect. B1B2 treatment achieved the highest mean of soluble, exchangeable potassium which amounted to(0.163,0.856) cmol kg-1 soil respectively with an increase of (21.642 %, 15.676%) and (33.606%, 22.636%) of what was achieved by treatment (B1, B2) for the mean of soluble, exchangeable potassium respectively . B1B2 treatment achieved the lowest mean of( non-exchangeable and mineral) potassium which amounted to (35.280) cmol kg-1 soil.

Solid-to-gas phase transition kinetics of diverse potassium occurrence forms during biomass pellet combustion: Time-resolved detection and multi-step modeling

The solid-to-gas phase transition of potassium during biomass combustion significantly impacts ash-related issues in bioenergy systems, affecting operational efficiency and equipment longevity. However, the specific mechanisms and kinetics of this transition process remain inadequately understood. This work investigates the time-resolved transition of solid-phase potassium to the gas phase during the combustion of rice husk and wheat straw pellets, combining experimental measurements with theoretical modeling. Tunable diode laser absorption spectroscopy (TDLAS) was employed to measure atomic potassium concentrations 15 mm above burning pellets tray, where gas-phase equilibrium is approached. Key combustion characteristics including thermogravimetric profiles, spectral radiation, and temperature were simultaneously monitored. A novel multi-step model was developed to describe the transition of different forms of solid-phase potassium (organic, exchangeable, and inorganic) to the gas phase. This model integrates TDLAS measurements, observed combustion characteristics, and biomass physicochemical properties. Thermodynamic equilibrium calculations were used to estimate the atomic potassium fraction from total gaseous potassium. The results showed that the solid-to-gas phase transition of organic potassium synchronizes with volatiles release. In contrast, the maximum emission rates of inorganic and exchangeable potassium occurred at the onset of char combustion. The developed model agrees well with the online detection experiments and were further validated by offline ICP analysis of residual ash. While not directly simulating gas-solid interface reactions near the particle surface, this work lays groundwork for future multi-scale modeling of particle-laden flows and reactor-scale phenomena in biomass combustion systems.

Effect of Green Cowpea Manure on the Quality Properties of Sandy Soils Under the Specific Conditions of the Dry Climate in Romania

This study was carried out on the rotation of cowpea-rye + cowpea in successive crops for green manure-sorghum grains, with the objective of increasing the fertility of sandy soils by incorporating green cowpea manure into the soil in combination with chemical fertilization with NPK. In this sense, after harvesting the rye plant, the cowpea was sown, which was then incorporated into the soil during the formation of the beans in the pod. Before incorporating the cowpea biomass into the soil, the initial fertility status of the soil was assessed, and in the spring, the soil was sown with sorghum grain in two fertilization variants (N80P80K80 and N150P80K80). The soil chemical analyses carried out at the end of the vegetation cycle of the sorghum plant showed that by incorporating 52.4 t/ha green cowpea biomass (9.24 t/ha dry biomass), the quality properties of the soil were significantly improved, with annual increases of 0.17–0.29 g/kg in total nitrogen, 9.5–13.33 mg/kg in extractable phosphorus, 11.33–24 mg/kg in exchangeable potassium, and 0.08–0.12 g/kg in organic carbon, also depending on the sorghum fertilization system. It has also been shown to reduce the acidity of the soil pH and improve the water holding capacity of the soil.

Variability of soil chemical properties and rice productivity in salt-affected soil in the north coastal rice field of Central Java, Indonesia

A coastal rice field is generally characterized by salt-affected soil and low soil quality for rice cultivation. Identifying soil chemical properties in these areas is necessary to determine soil management options for rice production. Therefore, soil samples were collected from 33 sampling points in the Wedung Sub-district of Demak Regency in the late dry season of 2021 to evaluate the variation among soil chemical characteristics in a coastline rice field. Soil samples were obtained beneath the topsoil (0-20 cm soil depth) and observed for electrical conductivity, exchangeable potassium, sodium, calcium, magnesium, and cation exchange capacity. Soils in the research field were categorized as slightly salty (0.75-2 dS m-1) to lightly salty (2.0-4.0 dS m-1) with very high sodium (>2 cmol(+) kg-1). Exchangeable potassium was dominated by moderate (0.3-0.7 cmol(+) kg-1) and low categories (0.2-0.3 cmol(+) kg-1). Based on soil calcium-to-magnesium ratios, around 6% of all samples were classified as calcium-deficient. The range of soil cation exchange capacity was 22-30 cmol(+) kg-1 and classified as high soil cation exchange capacity. Rice productivity in the salt-affected soil was around 4 t ha-1. Strategies for soil and controlling plants, such as soil amelioration and salt-tolerant rice cultivars, should be pursued to support plant growth and enhance rice productivity in the salt-affected soil, particularly in the coastal area.

Fundamentals of copper(II) adsorption on phyllosilicate minerals relevant to crud formation in solvent extraction from heap leach liquors

Because of the common presence of different silicate minerals, like kaolinite, montmorillonite and muscovite as gangue minerals in the beneficiation of copper oxide ores, the interaction between copper(II) ions in solution and each of these minerals is a field of strong interest, considering their implications on the aggregation of these minerals in the extreme pH conditions typical of hydrometallurgical unit operations for copper production. After copper adsorption isotherms determination at pH 2 and 4, specific adsorption data were fitted to both Langmuir and Freundlich models. It was found that adsorption is systematically larger at pH 4, and that montmorillonite is the mineral that displays a larger adsorption capacity, as in principle expected by its larger cation exchange capacity, CEC. A good fitting to the Langmuir model was obtained for the three samples, and montmorillonite also appears to conform to Freundlich isotherm predictions, as the tested concentrations of copper(II) do not allow to reach saturation. Furthermore, some desorption is measured for kaolinite and muscovite at the highest copper concentrations, probably because of significant interactions between the adsorbed ions. No such desorption was detected in montmorillonite samples. An XPS analysis of the surfaces of the three minerals suggests that copper adsorption in kaolinite is not associated to a cation exchange process but rather to electrostatic interactions between silica-like faces of the clay. In contrast, ionic exchange of structural calcium (for montmorillonite) or potassium (in the case of muscovite) seems to be the predominant mechanism of Cu(II) adsorption in the other two samples. Electrophoretic mobility determinations agree with this hypothesis: the mobility (always negative, with no traces of charge inversion) decreases in absolute value when kaolinite particles are in contact with solutions of increasing copper concentration at pH 2 or pH 4. On the other hand, the electrophoretic mobility values of muscovite and montmorillonite showed a weak pH and copper concentration dependence, a result that matches well with the ion exchange processes detected in the XPS measurements.

Role of organic amendments in improving the morphophysiology and soil quality of Setaria italica under salinity

Salinity negatively impacts soil fertility by impairing the development and physiological functions of foxtail millet plants. Organic amendments have emerged as a viable solution in the reclamation and management of salinity inflicted soils and improve the performance of crop. In this regard, a pot experiment was carried out to examine the effect of organic amendments (OAs) on soil quality and its influence on the growth and physiology of foxtail millet under saline and non-saline condition. The findings indicated that under salt stress conditions, the levels of proline, hydrogen peroxide (H2O2), and electrolyte leakage (EL) risen, whilst other physiological parameters decrease in foxtail millet. However, the addition of OAs, particularly dhaincha and biochar (BC), has shown a promising salt tolerant amendment among others. Its addition improved the growth performance of salinity-stressed plants, including plant height, fresh and dry biomass, simultaneously decreased sodium ion (Na+) and improved calcium (Ca2+), potassium (K+), and nitrate ion (NO3−). They also increased proline build up by 6–17 %, reduced H2O2 (19–38 %) and malondialdehyde (16–18 %). Furthermore, they elevated the relative water content (RWC) (25 %), chlorophyll content, and reduced EL (29–50 %). Once more, dhaincha and BC enhanced the number of rhizobia, phosphorus-solubilizing bacteria (PSB) and overall bacterial population in the soil. In saline soil, daincha and BC could enhance soil organic matter (628 %), total nitrogen (1630 %), available phosphorus (32–38 %), and exchangeable potassium (54–73 %). A potential strategy for improving setaria italica performance under salt is suggested to be the following order, dhaincha > biochar > vermicompost > duckweed. The study would assist stakeholders in these salinity-prone areas in strategizing the use of OAs to their fallow land for cultivation and agricultural activities.

Evaluation of Exchangeable Potassium Concentration in Sri Lankan Rice Paddy Soils with ICP-MS Using CaCl2 Extraction

ABSTRACT With the advancement of analytical techniques, multi-element extraction and detection have been developed. Universal extractans like CaCl2 and detection technologies like inductively coupled plasma-mass spectrometry (ICP-MS) could facilitate simultaneous analysis of multiple-elements, and would be useful in commercial scale soil analytical laboratories. The type of extractant and detection method could influence the concentration of exchangeable potassium (ex-K) determined in different soils. This study evaluated the effectiveness of 0.01 M CaCl2 as a multi-element extractant (CC) and ICP-MS and flame photometry (FP) as detection technologies when determining ex-K in soils. The widely used protocol for Sri Lankan soils, i.e. 1 M ammonium acetate (AA) as an extractant and FP as detection method, was used as the control for comparison of results. Altogether, 1,250 soil samples representing rice-growing regions in Sri Lanka were used. Soils were grouped under 16 categories based on soil type. Ex-K varied widely (26 to 1376 mg kg−1 from AA-FP method). Ex-K determined using three methods were in the order of AA-FP>CC-FP >CC-ICP-MS. On average, the values obtained from CC-FP and CC-ICP-MS methods were 53% and 24%, respectively, of those from AA-FP. Soil type-dependent variation in the detection of K using three methods was evident. In the 16 soil categories, coefficient of determination (R2) ranged from 0.23 to 0.86 for AA-FP and CC-ICP-MS, and from 0.05 to 0.70 for AA-FP and CC-FP. As a result, soil ex-K determined using CC-FP and CC-ICP-MS methods cannot be related to the results generated through AA-FP method across different soil types.

Effects of occasional tillage on soil physical and chemical properties and weed infestation in a 10-year no-till system

Few studies have investigated how one-time targeted tillage of long-term no-till fields impacts topsoil properties and weed dynamics. An on-farm trial was implemented in 2020 to test the effects of occasional tillage (OT) in Morocco with a long-term no-tillage (NT) system and rainfed field crops: durum wheat (Triticum durum), faba bean (Vicia faba minor), and chickpea (Cicer arietinum). Four treatments were established, namely, continuous NT with crop residues maintained (“NT + residue”); continuous NT with crop residues not maintained (“NT-residue”); shallow inversion tillage (“shallow OT”); and deep non-inversion tillage (“deep OT”). We assessed the effect of these treatments on soil physical and chemical properties in 0–10 and 10–20 cm soil depths after crop harvest of the 2020–2021 (year 1) and 2021–2022 (year 2) growing seasons corresponding to 1 and 2 years after OT, respectively. In addition, we evaluated the effect of the treatments on weed populations and the effect of the legume crop rotated with wheat on soil nitrogen (N) and weed density. In year 1, deep OT reduced the water content at field capacity and available water capacity at 0–10 cm compared to continuous NT; the cation-exchange capacity (CEC) under deep OT was lower than in NT-residue and NT + residue at 0–10 cm and 10–20 cm, respectively. Furthermore, deep OT increased ammonium-N (NH4-N) at 0–10 and 10–20 cm compared to NT + residue but reduced exchangeable potassium (K) at 10–20 cm depth compared to NT-residue. In year 2, shallow OT had lower total porosity at 10–20 cm than NT + residue, while shallow and deep OT recorded higher water-stable aggregates at 0–10 cm than NT + residue; at 10–20 cm, deep OT recorded lower CEC than NT + residue. However, deep OT had higher nitrate-N (NO3-N) and available sulfur (S) than NT-residue at 10–20 cm. Occasional tillage did not significantly affect 10 out of 19 of the soil properties evaluated, including soil organic matter (SOM), in all the years and did not help reduce the stratification of soil nutrients in NT. In year 1, 50 days after OT, deep OT reduced the weed density by 46% compared to NT + residue, while in year 2, 406 days after OT, shallow OT reduced weed density by 53% compared to NT-residue. Regarding the effect of the legume rotated with wheat, faba bean appeared to be the better preceding or following wheat crop as it resulted in higher residual soil mineral N and lower weed infestation than chickpea.

Эффективность поверхностного компостирования табачной пыли с использованием микробных смесей

Abstract. Tobacco dust is the main waste in the production of smoking products. The purpose is to study the possibility of tobacco dust utilization by surface composting together with microbial mixtures “Stimiks Kompost”, “Probioks Agro” and “Geostim”, directly in the field conditions, contributing to the restoration of soil fertility. Methods. In the years of research (2020–2021) tobacco dust was applied in doses of 5 and 8 t/ha in pure form and together with microbiological preparations. Scientific novelty. The method of using tobacco production waste as a fertilizer together with microbiological preparations is proposed. Results. It was established that for 30–60 days, tobacco dust application together with destructors, the content of basic nutrient elements in the soil increased: ammonium nitrogen form by 65–207 %, nitrate nitrogen by 83–225 %, available phosphorus by 21–107 %, exchangeable potassium by 80–194 %. Also Increasing of soil biological activity indicators was determined. The process of nitrifying ability of soil increases by 70–194 %, cellulose-destroying activity of microorganisms increases by 27–133 %, the amount of produced CO2 from soil increases by 61–129 %. The content of organic matter (humus) increases up to 4.2–5.5 % for the period of counting (4.0–4.7 % on the reference). Increase of moisture-holding capacity of soils in variants of experiment with tobacco dust and destructors was established (soil moisture for the period of research amounted to 18.4–25.5 %, in control – 17.1–18.7 %). The best results for surface composting of tobacco dust were obtained under wet conditions in 2021 (Hydrothermal coefficient (HTC) = 1.38), in 2020 HTC = 0.87. Mycological analysis revealed a decrease in soil infestation with pathogenic micro-mycetes in the variants of the experiment with tobacco waste. The increase in yield of bitter pepper (variety Baraniy rog) on the background of a mixture of tobacco dust and biodegraders amounted to 12–32 % (2020), seed cucumber (variety Dal’nevostochnyy 27) – 20–33 %.

Mitigation of soil salinity by addition of different rice straw biochar doses in salt-affected acid soil

The current study was carried out to evaluate the effect of rice straw biochar amendment and to identify the appropriate dose of biochar application to reduce soil acidity, salinity, toxicity, and sodicity in salt-affected acid soils. The rice straw biochar at 4 different rates of 0%, (control) 1%, 3%, and 5% (w/w) was mixed with 6 salt-affected acid soils: S1 (non-saline), S2 and S3 (low saline), and S4, S5, and S6 (moderate saline). The mixture was continuously shaken in distilled water for 7 days. The biochar application significantly increased soil pH and saturated electrical conductivity (ECe) with an increasing biochar application rate compared with the control. Significant decreases in sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) values below the critical level of sodicity were observed above the biochar application rate of 1%. Soluble chloride (Cl–) and soluble and exchangeable sodium (Na+) were significantly reduced above the biochar application rate of 1%. The biochar application (≥ 1%) led to a significant increase in soluble and exchangeable potassium (K+) and declines in soluble and exchangeable calcium (Ca2+) and magnesium (Mg2+). This study concluded that the biochar application rate of 1% was suitable for reducing soil acidity to a safe level for rice plants. The rice straw biochar application improved soil toxicity and sodicity by reducing soluble Cl– and soluble and exchangeable Na+, decreasing SAR and ESP. The biochar application also increased available K+, essential for rice plant growth and development in salt-affected soils.

Flood sediments as a source of replenishment of alluvial soils with plant nutrition elements

Flood sedimentation in conditions of regular floodplain flooding is a key factor in the formation of alluvial soil. The nature of the passage of hollow waters and their composition affect the quantitative and qualitative characteristics of flood sediments, while having a significant impact on the agroecological state of the floodplain agricultural landscape. The aim of the research was to study the role of flood sediments in enriching the underlying alluvial soil with nutrients. The experiment was conducted on reclaimed arable lands of the Ryazan region in 2023. Determination of the sediment load level and sampling on the surface were carried out using plastic sedimentation samplers fixed on the soil surface, located at a distance of 200 m from each other. The installation was carried out on March 23, the duration of sediment collection was 42 days before the descent of the hollow waters. The average sediment load level of 15.4 t/ha was established, the agrochemical properties of flood sediments and underlying soil were studied, the structure of organic matter, macro– and microelements with flood sediments and their removal from the corn harvest to silage was analyzed. Together with sediments the soil received (kg/ha): total nitrogen – 107.80, total phosphorus – 43.10, total potassium – 104.70, organic matter – 2464,0, mobile phosphorus 15.20, exchangeable potassium 17.80; trace elements (g/ha): boron – 11.86, molybdenum – 1.54, zinc – 122.74, manganese – 1215.06, copper – 200.20, cobalt – 52.05. With a corn harvest for silage of 36.1 kg/ha, the takeaway was: N – 105 kg/ha, P2O5 – 33 kg/ha, K2O – 105 kg/ha. The conducted studies indicate the undoubted agronomic value of flood sediments, they can partially meet the need for fertilizers, therefore, it is necessary to take into account the mass of the substances used to carry out appropriate adjustments to the fertilizer application system. In 2023, the mass of incoming substances with flood sediments completely covered the need for nitrogen; for mobile phosphorus the need decreased to 17.8 kg/ha, for exchangeable potassium the need decreased to 87.2 kg/ha.

Study on Betaine and Growth Characteristics of Lycium chinense Mill. in Different Cultivation Environments in South Korea.

Betaine is a useful compound that has various activities and is the marker compound of Lycium chinense fruit in Korean Pharmacopoeia. we seek to support the stable production of medicinal goji berries, which have significant potential in the pharmaceutical industry due to their high values, and to provide foundational data for consistent quality control. This study's purpose was to examine the correlation among betaine content, environmental variables, and the growth characteristics of L. chinense fruits. The fruits were collected from 25 cultivation sites across South Korea. We investigated five growth characteristics and betaine contents in L. chinense fruits and twelve soil physicochemical properties, and seven meteorological data at cultivation sites. The fruit's growth characteristics included a length of 15.62-26.49 mm, a width of 7.09-11.38 mm, a fresh weight of 0.73-1.62 g, and a sugar content of 11.10-19.62 Brix°. Its betaine content ranged from 0.54% to 0.97%. The betaine content was positively correlated with electrical conductivity (0.327 **), exchangeable potassium (0.314 **), and sodium (0.259 *) and negatively correlated with annual average minimum temperature (-0.256 *) and annual average temperature (-0.242 *). Also, betaine showed a positive correlation with the length of the fruit (0.294 *) and the fresh weight of the fruit (0.238 *). These results can be used to find the best cultivation method and to manage quality control for the highly economical L. chinense fruit.

Effect of Prolonged Action of Mineral Fertilizers under Conditions of Temperature Stress on Silage Maize Yield in the Steppe Zone of the Southern Urals

In modern agriculture in the Southern Urals, an important agronomic technique is to counteract drought. Of particular importance in increasing the feed base is the cultivation of maize for silage, which ensures maximum yields in extreme conditions. The aim of the study was to determine the potential possibilities of increasing the yield of green mass of maize for silage under the influence of temperature stress in conjunction with the prolonged action of mineral fertilizers and precursors in arid conditions. The study was carried out in the central zone of the Orenburg region from 1993 to 2022 on a stationary site with the southern carbonate heavy loamy chernozem soils with a humus content of 3.2–4.0%. The experiment was carried out with and without mineral fertilizers. The content of nitrate nitrogen in the soil was determined by the ionometric method of Tyurin, mobile phosphorus – by Machigin, exchangeable potassium – by Maslova. A thermostatic-weight method was used to determine soil moisture. On average, over 30 years of research, when cultivating maize for silage in a 6-field crop rotation, an increase in yield was noted with the use of mineral fertilizers from 0.23 to 0.84 t/ha. The annual application of mineral fertilizers in permanent sowing of maize provided an increase in the yield of green mass of 2.51 t/ha. In years with severe aridity, the yield of leaf-stem mass on a fertilized background decreased by an average of 1.61 t/ha. In very dry years, maize plants consumed less nitrate nitrogen (by 2 or more times) than in years with different humidity, but at the same time, potassium consumption increased.

Evaluation of substrates for optimizing vermicomposting products

The high global market value of fresh mushrooms implies high importance of spent mushroom substrate (SMS) as a by-product that poses environmental challenges, if not properly treated. Reported studies demonstrate the positive effects of SMS on earthworm growth and reproduction, particularly when combined with other substrates such as cow dung (CD). This study utilized SMS and CD as substrates in varying ratios. A total of 375 young non-clitellated Eisenia fetida were randomly assigned to plastic containers, ensuring similar average individual worm weight, and maintained at 50% to 60% moisture. Weekly observations were made on earthworm average weight, cocoon production, and hatchling count. The growth and reproduction of earthworms differed significantly among treatments, with Treatment 3 (T3) (50:50 SMS and CD) showing the highest growth and Treatment 5 (T5) (0:100 SMS and CD) the lowest. Changes in pH, EC, total Kjeldahl nitrogen (TKN), total organic carbon (TOC), C/N ratio, and total available phosphorus (TAP) were observed over the experimental period, indicating dynamic nutrient dynamics within the substrates. The exchangeable potassium decreased with increasing proportions of CD, while the exchangeable sodium content showed variation across treatments. The observed variations can be attributed to differences in initial substrate composition and microbial activity during vermicomposting.

The influence of shade tree species and coffee varieties on selected soil physicochemical properties in coffee-based farming system of southwestern Ethiopia

Different shade tree species are used in various coffee production systems across the world. Outside the benefits of biodiversity protection, temperature protection, and carbon sequestration shade trees can influence soil nutrient states through litter inputs and nitrogen fixation. However, little information is available in coffee plantations whether shade tree species and type of coffee variety planted under shade tree have an influence on soil physical properties and nutrient status in coffee-based farming systems of southwestern Ethiopia. Hence, the study was carried out to investigate the effect of shade tree species and coffee varieties in coffee plantation on the physicochemical properties of the soil. The study was conducted in Chora Botor district (Chalalaki coffee plantation), located in Jimma Zone, Oromia regional states of Ethiopia. The study was superimposed on coffee farm that has been established using four released coffee varieties (7440,744, F59 and 75227) under three recommended coffee shade trees (Albizia gummifera, Millettia feruginea and Acacia abyssinica). Soil physical properties and nutrient status were investigated in response to shade tree species, coffee varieties and their combination. The results indicated that the physical and chemical properties of the soil vary across the shade trees and coffee variety grown. The effect of shade tree species on soil depends on the type of coffee varieties grown under the shade tree species, Albizia gummifera and Acacia abyssinica trees enhanced more soil nutrient content and water-holding capacity of the soil than Millttia ferrugnia. Total nitrogen, organic matter, available phosphorous, exchangeable potassium, Cations Exchange Capacity, and bulk density were higher underneath Albizia gummifera than other coffee shade tree species. On the other hand, moisture content, available P, exchangeable K and CEC were higher beneath Acacia abyssinica than other coffee shade tree species. Soil pH was negatively correlated with Millettia ferruginia. Use of Acacia abysinica and Albizia gummifera shade tree species with compatible coffee varieties could be a viable option to augment soil fertility management practices in the coffee production systems of the southwest Ethiopia.

Soil degradation and herbicide pollution by repeated cassava monoculture within Thailand's conservation region.

In a national park in Northeast Thailand, agricultural land has been converted from natural forest by small-scale farmers for cassava agriculture. We hypothesise that long-termed cassava monoculture leads to the degradation of soil properties. To test the hypothesis, we conducted a five-year (2016-2020) study on the physical and chemical properties of soil in cassava farmland, and also examined the soil properties of its adjacent natural forests, as a control. The examined cassava farmland was converted from the natural forest during the five years from 2011 to 2015. The significant decrease in organic carbon and the increases in exchangeable potassium and bulk density were found in 2016, indicating that these soil properties varied quickly following the farmland conversion. On the other hand, the significant increase in soil nitrogen and the decrease in pH were found later in 2020, indicating that these soil properties were gradually altered by repeated agricultural activities, such as fertilizer application and trampling. In contrast, there were no significant differences in available phosphate, electrical conductivity, cation exchange capacity, and the soil texture (the fractions of sand, silt, and clay) among the forest and farmland soils. The cation exchange capacity was positively correlated to the fraction of clay, the organic carbon, and pH. The use of glyphosate and paraquat herbicides is prohibited within national parks in Thailand. However, in 2020, glyphosate was detected in farmland soil (up to 5.0 mg kg-1) during both the rainy and dry seasons, and glyphosate (up to 2.5 mg l-1) was detected in stream water from the farmland during the dry season at least in 2020. Soil degradation and herbicide pollution may carry a high risk of causing irreversible changes in terrestrial ecosystems. We discuss the root causes of this issue from perspectives of agricultural production, economy, and the environmental impact, and propose effective policy measures.

Effect of sideral binary mixtures with sunflower on the quality and fertility of typical chernozems

In the field experiment, the effect of binary sideral mixtures with sunflower on the content of humus, mobile phosphorus and exchangeable potassium in arable and sub-arable horizons of typical heavy loamy chernozem was studied.It is shown that the use of mixed agricultural communities for sideration can be one of the sources of reproduction of potential and effective fertility of chernozems in theCentralСhernozemDistrict.It was found that the influence of the agrocenotic effect in binary mixtures of sunflower with soy, payza, buckwheat of theKrylataya variety and buckwheat of theDemeter variety led to a significant increase in the content of humus, mobile phosphorus and exchangeable potassium in the arable and sub-arable horizons of chernozems under these agricultural communities.It was shown that the effect of the agrocenotic effect on the increase in humus content was equivalent to the introduction of litter manure into the arable horizon of 15.4–25.3 t/ha, in the sub–arable–13.6–23.0 t/ha.This led to a significant improvement in the quality of the studied soils.An increase in the content of mobile phosphorus under the influence of the mixing factor could be achieved by introducing 88–200 and 88– 138 kg ofP2O5/ha into the layers of 0–25 and 25–40 cm of soil, respectively.An increase in the content of exchangeable potassium under sideral mixtures in a layer of 0–25 cm of soil by 1.0–2.4 and in a layer of 40–50 cm by 1.7–2.0 mg/100 g of soil would correspond to doses of 300–720 and 510–600 kgK2O/ha.

Effect of increased soil available phosphorus from vermicompost application on the bioavailability, chemical form, and bioaccessibility of heavy metals.

Phosphorus (P) plays an important role in immobilizing heavy metals (HMs), thereby preventing their accumulation, especially in edible parts of crops. In this study, vermicompost (VM) and chemical fertilizers (CFs) were used as soil amendments to increase the available P concentration in soil contaminated with cadmium (Cd) and nickel (Ni), with the aim of reducing their bioavailability, uptake, and bioaccessibility. Using CF and VM as soil amendments substantially increased the available P and exchangeable potassium concentrations in the soil. Furthermore, VM addition led to an increase in OM content and in exchangeable calcium and magnesium, resulting in the improved growth of lettuce. It also reduced the uptake of Cd and Ni in the two lettuce cultivars tested in the study. However, CF addition boosted the accumulation of Cd and Ni by increasing the soil acidity. CF addition, and especially VM addition, altered the chemical forms of Cd and Ni from active to inactive. Overall, the results of this study underscore the positive impact of using VM as a soil amendment on lettuce growth and the prevention of HM accumulation in edible parts of lettuce. VM addition led to decreased bioavailability, uptake, and bioaccessibility of HMs in soil, which could improve food safety and reduce potential risks associated with HM contamination.

Эффективность комплексного применения минеральных удобрений и биопрепарата Мизорин на посевах люцерны сорта Айслу в почвенно-климатических условиях Республики Татарстан

Field experiments on alfalfa crops of the Aisylu variety were conducted in 2020-2022 on the basis of the Agrobiotechnopark of the Kazan State Agrarian University (Narmonka village of the Laishevsky municipal district of the Republic of Tatarstan). The soils of the experimental site are gray forest with the following agrochemical indicators: the content of humus according to Tyurin is 3.0%, mobile phosphorus is very high (> 250 mg/kg) and exchangeable potassium is increased (145 mg/kg according to Kirsanov). The reaction of the soil medium was close to neutral (pH 6.6). The aim of the research was to develop methods to increase the yield and quality of the green mass of alfalfa on the basis of the use of various types of mineral fertilizers and the biological preparation Mizorin. The scheme of the experiment included the following options: control (without fertilizers and biologics); root dressing in spring and after the first mowing with ammonium nitrate of 100 kg/ha; root dressing in spring and after the first mowing with nitrogen strip of 100 kg/ha; root dressing in spring and after the first mowing with ammonium nitrate of 100 kg/ha in combination with leaf dressing with the biopreparation Mizorin 2 l/ha; root dressing in spring and after the first mowing with a 100 kg/ha nitrogen strip in combination with a leaf dressing with the biopreparation Mizorin 2 l/ha. Early spring feeding of alfalfa and after the first mowing with ammonium nitrate at the rate of 100 kg / ha provided additional 4.7 t/ha of green mass. In the variant of azofoska top dressing, the yield increase increases to 29.8 t/ha of the green mass of the research object. The maximum yield of the studied crop was obtained in variants of combining root and leaf fertilization, the increase in green mass increased to 64.4 and 92%, respectively.

Восстановление почвенного покрова на техногенной территории в условиях нижнего Дона

The article presents an analysis of the dynamics of soil cover formation in a technogenic territory. The humus content in the soil varies from 1.42 to 2.34% (Table.1), there was an increase in the humus content over the years of the study. The content of nitrate nitrogen and exchangeable potassium in the soil is very low. Organic residues are decomposing in the turf horizons, so the content of mobile phosphorus is average. The content of carbonates increases from 0.68 to 1.12% over the years of research, the quarry soils are not saline, the cationic-anionic composition of the aqueous extract is chloride-sulfate. The structural condition of the quarry soils is good. Perennial herbaceous vegetation has a beneficial effect on the structural condition of the soils. The soil cover has been radically disrupted at the abandoned sand quarry, therefore, at this stage, vegetation and soils are gradually being restored. The soils of the abandoned sand quarry are at the stage of initial soil formation. Keywords: SOIL COVER, TECHNOGENIC TERRITORY, SOIL FORMATION, SAND QUARRY, SOIL RESTORATION