Arable Soils Research Articles

Strong rhizosphere priming effects on N dynamics in soils with higher soil N supply capacity: The ‘Matthew effect’ in plant-soil systems

Appropriate N management can improve soil fertility and favour crop growth and production. Plant activities (e.g. N uptake and root exudates) also have feedback effects on soil N transformations and influence soil N supply and retention capacity. However, the inherent mechanisms between the feedback effect intensities and soil fertilizer are not fully elucidated. Thus, we carried out 15N tracing studies with arable soils at various long-term N fertilizer applications, including unfertilized control, synthetic N fertilizer, biochar, pig manure with and without synthetic N fertilizer, crop residues with and without synthetic N fertilizer. Soil gross N transformation rates, maize N uptake rates, and rhizosphere priming effects (RPE) on soil gross N transformations were quantified to explore mechanisms of soil N dynamics. Results showed that long-term N fertilizer applications significantly stimulated soil mineral N production rates, i.e. gross rates of N mineralization (M) and autotrophic nitrification (ONH4), and further enhanced maize N uptake and yield. Negative RPE on M were observed following long-term N fertilizer applications, ranging from −6.71 to −17.44 mg N kg−1 d−1. Furthermore, the strongest negative RPE on M were found for the combinations of chemical and organic N fertilizers. RPE on ONH4 (ranging from −3.10 to −31.91 mg N kg−1 d−1) also showed a similar trend to RPE on M in different treatments. Microbial N immobilization rates (ITN) and dissimilatory NO3− reduction to NH4+ (DNO3) were stimulated by the presence of maize, showing an obvious positive RPE on ITN and DNO3. Therefore, N retention capacity in the rhizosphere was enhanced via a strong negative RPE on ONH4, and a positive RPE on ITN and DNO3 in presence of maize following long-term N fertilizer applications. The stronger capacity of soil N supply in response to appropriate N management leads to higher maize activities and stronger feedbacks between plant and soil N transformation to improve N retention in rhizosphere, suggesting that the “Matthew effect” also applies to nutrient dynamics in the rhizosphere. Our results show that the combined applications of chemical and organic N fertilizers are the best way to enhance yield, NUE and N retention, and reduce the risks of soil N losses in arable soils.

Bayesian-Based Approaches to Exploring the Long-Term Alteration in Trace Metals of Surface Water and Its Driving Forces.

Trace metal pollution poses a serious threat to the aquatic ecosystem. Therefore, characterizing the long-term environmental behavior of trace metals and their driving forces is essential for guiding water quality management. Based on a long-term data set from 1990 to 2019, this study systematically conducted the spatiotemporal trend assessment, influential factor analysis, and source apportionment of trace elements in the rivers of the German Elbe River basin. Results show that the mean concentrations of the given elements in the last 30 years were found in the order of Fe (1179.5 ± 1221 μg·L-1) ≫ Mn (209.6 ± 181.7 μg·L-1) ≫ Zn (52.5 ± 166.2 μg·L-1) ≫ Cu (5.3 ± 5.5 μg·L-1) > Ni (4.4 ± 8.3 μg·L-1) > Pb (3.3 ± 4.4 μg·L-1) > As (2.9 ± 2.3 μg·L-1) > Cr (1.8 ± 2.4 μg·L-1) ≫ Cd (0.3 ± 1.1 μg·L-1) > Hg (0.05 ± 0.12 μg·L-1). Wavelet analyses show that river flow regimes and flooding dominated the periodic variations in metal pollution. Bayesian network suggests that the hydrochemical factors (i.e., TOC, TP, TN, pH, and EC) chemically influenced the metal mobility between water and sediments. Furthermore, the source apportionment computed by the Bayesian multivariate receptor model shows that the given element contamination was typically attributed to the geogenic sources (17.5, 95% confidence interval: 13.1-17.6%), urban and industrial sources (22.1, 18.0-27.2%), arable soil erosion (24.2, 16.4-31.5%), and historical anthropogenic activities (35.2, 32.8-43.3%). The results provided herein reveal that both the hydrochemical influence on metal mobility and the chronic disturbance from anthropogenic activities caused the long-term variation in trace metal pollution.

Tolerance mechanisms to aluminum in popcorn inbred lines involving aluminum compartmentalization and ascorbate-glutathione redox pathway.

Inbred line 11-133 of popcorn showed the lowest apoplast Al and total Al concentrations and Al-lumogallion complex, associated with a more efficient antioxidant system, mainly due to glutathione metabolism. Popcorn (Zea mays L. var. everta) is largely intended for human consumption. About 40% of the world's arable soils are acidic. In soils acidic, aluminum (Al) ionizes producing the trivalent cation, which is highly toxic to plants. Hence, this work aimed to: (1) evaluate the Al toxicity sites and its effect on the structure of the root tips, (2) quantify Al concentrations in the apoplast and symplast of the roots, and (3) to elucidate the modulation on the activity of antioxidant enzymes and metabolites of the ascorbate-glutathione cycle in two popcorn inbred lines (ILs) 11-133 and 11-60, classified as tolerant and sensitive to this metal, respectively. Aluminum toxicity did not affect the shoot growth; however, there was a yellowing of the oldest leaf blade only in 11-60. The better performance of 11-133 is related to lower apoplastic and total Al concentrations and Al accumulation in the root associated with a lower fluorescence of Al-lumogallion complex at the root tip, indicating the presence of mechanisms of chelation with this metal. Consequently, this IL showed less change in root morphoanatomy and lower reactive oxygen species and malondialdehyde content, which are associated with a more efficient enzymatic and non-enzymatic system, mainly due to the higher content of the glutathione metabolite and the higher activities of superoxide dismutase, monodehydroascorbate reductase, dehydroascorbate reductase, γ-glutamylcysteine synthetase, and glutathione peroxidase enzymes. Thus, these findings illustrated above indicate how internal mechanisms of detoxification respond to Al in popcorn, which can be used as tolerance biomarkers.

Розрахунковий метод визначення рівня забезпеченості рослин макроелементами живлення

The purpose of the article is to highlight the results of research and substantiate the possibility of using the calculation method for determining the level of provision of plants with macronutrients. Improving the information and methodological support for sustainable management of crop nutrition in a state of war is of particular importance – this will allow much more efficient use of very limited fertilizer resources. Applied materials and methods: – results of many years of research in a stationary field experiment; analysis, generalization and statistical processing of data from stock and modern literary materials (partially combined in an electronic database); analysis and synthesis of data from the agrochemical service in the country. Investigated objects: the main soils of Ukraine, including typical chernozem (Haplic Chernozem), theoretical substantiation of mathematical formalization and interpretation of the assessment of the nitrogen, phosphate and potassium status of Ukrainian soils. It has been established that the total content of nitrogen, phosphorus and potassium compounds in the soil can be predicted quite accurately by building a mathematical model. The corresponding regression equations are proposed. Unfortunately, the practical significance of such models is low. It has been proved that a direct attempt to build a model of the dependence of the content of mobile compounds of phosphorus or potassium on the composition of the soil or its properties is doomed to failure. At the same time, the identified features of the nitrogen, phosphate, and potassium systems of soils (as thermodynamic systems) made it possible to theoretically substantiate the possibility of mathematical formalization of the assessment of the trophic state of arable soils (the level of provision with natural mineral nitrogen), as well as mobile compounds of phosphorus and potassium under their extensive conditions. intensive and post-intensive use. It has been confirmed that all, without exception, chemical methods of analysis (acidic, alkaline, saline) have the ability to clearly reflect the presence of phosphorus or potassium, which entered the soil in the form of water-soluble fertilizers. Since the value of the phosphate or potassium level of unfertilized or poorly fertilized arable soils is a constant value, it is not advisable to conduct any additional examination of them, especially in war conditions. Mathematical models have been developed for extrapolation and interpolation of data on the content of mobile compounds of nitrogen, phosphorus and potassium in arable soils formed under the influence of natural or anthropogenic factors.

Impact of anthropogenic pollution on the soil near the industrial area of Hrazdan town

Identifying the distribution of a number of heavy metals near the industrial area, taking into account the wind rose in the region during the period of operation of the Hrazdan Thermal Power Station and the Hrazdan Cement Plant was investigated in a radius of one km. In a series of experiments, was found a decreased concentration of arsenic and mercury in soil samples by an average of 27% with distance from the industrial area. In that direction, in the soil sample, there is an increase in the concentration of zinc and nickel by an average of 25.5%, as well as an increase in the concentration of copper by 19%. At the same time along the sampling line, the comparative series generally has the following sequence: As<Ni<Co<Cu<Zn<Pb. In the quantitative assessment of soil, contamination was compared to geo-ecological coefficients: the danger level of soil contamination and the total pollution index. Their calculation was based on the values of heavy metals concentration according to Clark and their maximum allowable concentration. Our forthcoming studies will focus on identifying the dose-effect-rose-wind relationship in arable soils with varying degrees of metal contamination as a result of long-term anthropogenic pollution.

Microelements in the agricultural landscapes of the Altai region

The aim of the study was to assess ecological, biogeochemical and sanitary-hygienic aspects of arable soils of the Altai region and spring wheat grain produced there. Location and time of the study. The representative study sites of arable land were located in various agroecological zones of the Altai region: Kulundinskaya (dry steppe on chestnut soils of the Kulunda lowland), Rubtsovskoye (arid steppe on chernozems of the southern Priobskoye plateau), Zarinskaya (deciduous forests and steppe meadows on leached chernozems of the Bie-Chumyshskaya elevated plain and podzolized chernozems and dark gray forest soils of the Salair Foothills), Piedmont (meadow steppe on the chernozems of the Prealtai Plain), Priobskaya (split steppe on ordinary chernozems of the Priobsky plateau), Aleiskaya (moderately arid steppe on ordinary chernozems of the Priobsky plateau), Biyskaya (forest steppe on leached and gray forest soils of the Bie-Chumysh Upland). The research was carried out in 2018. Methods. The content of trace elements in soils and wheat grain was determined by atomic emission and atomic absorption spectrometry according to PND F 14.1:2:4. 139; 140-98; НСАМ №450С; РД 52.24.479-95. Results. It was found that in the arable soils of the Altai region the elements, necessary for plants, animals, and humans, were contained in optimal quantities (average content of Mn 714, Zn 65, Cu 25.7, Co 12.3 mg/kg), maintaining the normal functioning of living organisms. Most toxic elements were found at the levels, comparable with average concentrations in soils of the world and with the data for uncontaminated soils in West Siberia, not exceeding the maximal permissible concentrations. The average concentrations of Cd, Pb, As and Hg in the studied soils were 0.089, 13.6, 5.0, 0.037 mg/kg, respectively. No biogeochemical province had been identified for any of the elements. The studied soils have a fairly high buffering capacity for heavy metals. The chemical elements’ content in the spring wheat grain, the main crop in the region, was close to the corresponding world data for grain. The amount of regulated substances (lead, cadmium, mercury, arsenic) meets domestic standards and the requirements of the Technical Regulations of the Customs Union "On Grain Safety". Conclusions. The arable soils of the Altai region are not contaminated with heavy metals. Trace elements such as manganese, zinc, copper, cobalt are contained in soils in optimal quantities for living organisms. However, using the grain as monofeed can result in Co deficiency in animals. The content of chemical elements is soils resulted from the initial content of elements in soil-forming parent rocks. The degree of heavy metals’ buffering by the studied arable soils, depending of the metal, ranged from medium to high.

Изменение гидротермических условий в пахотном слое чернозема при мульчировании резаной соломой

The research goal was to study the trends in the influence of the mulching layer of cut straw on the change in hydrothermal conditions of the arable soil layer. The object of study was one of the most common soils of the Altai region – leached loamy chernozem. The plots for the experiment were laid on a steam field. One of the sections was mulched on the surface with a layer of cut straw 10‑15 mm thick, on the other section the mulch layer was 20‑25 mm. The third section of the black vapor was used for contrast control measurements. According to the measurements, it was revealed that in the mulched observation areas there was a noticeable decrease in soil temperature during the daytime both on the surface and in the entire arable layer compared to the control one. At night, a layer of cut straw prevented a sharp change in temperatures and contributed to the preservation of heat. The thickness of the mulching layer determined the temperature values of the arable layer during the daytime and at night. A layer of mulch on the soil surface contributed to the preservation of soil moisture reserves in the arable soil horizon. With an increase in the size of the mulching layer, there was a tendency for better moisture retention. The use of mulching of the surface layer of the soil with cut straw is advisable in arid regions to reduce the absolute values of the temperatures of the arable layer and reduce the evaporation of soil moisture from its surface, as well as to preserve moisture in the arable horizon of the soil.

Изучение эффективности различных систем землепользования для смягчения климата посредством измерения эмиссии парниковых газов

The relevance of the research lies in the application of the Li-8100 (Campbell Scientific) automated system for continuousmeasurement of CO2 emissions from soil corresponding to various cultivation techniques (no tillage, application of manure-based and mineral fertilizers) and various main crops (corn, wheat, rye) in Almaty Region. The article presents the field research data obtained in the foothill zone with the aim of assessing GHG emissions from arable light-dark chestnut soils while using different fertilizers, types of basic tillage, and crops. In accordance with the data presented, it can be argued that of the scientifically substantiated types of crops and soil cultivation methods studied within the framework of this research, all manure based options demonstrated high GHG emission values. The use of mineral fertilizers showed insignificant association between greenhouse gas emission reduc-tion and the no tillage option. Different crops showed varying degrees of GHG emission reduction depending on fertilizer application; yet, wheat responded most strongly due to additional biomass and yield growth. The research suggests the application of mineral fertilizers as a potential appropriate way to cut GHG emissions. However, further investigation is necessary to study the underlying mechanisms and processes influencing GHG and better understand the feedback effects in resource efficient (conservation) agriculture.

Environmental impact assessment of land consolidation

Land consolidation (LC) is an important tool for the improvement of agriculture and rural development, which also includes environmental issues in most of the countries in Europe. This paper presents the most important results of the environmental impact assessment (EIA) of land consolidation, conducted in the municipality of Vrsac through a pilot project based on the EU methodology set within the project: ?Strengthening Municipal Land Management in Serbia?, supported by the Deutsche Gesellschaft f?r Internationale Zusammenarbeit (GIZ) GmbH. During the summer of 2018, field survey was carried out at 90 locations, documenting the natural, semi-natural and man-made landscape elements of ecological or cultural values, assessing their quality and estimating the potential harmful environmental impacts of the land consolidation. The already existing negative impacts of intensive agriculture were also registered, such as abandonment or overgrazing of pastures and meadows, converting grasslands into arable land, soil erosion and habitat fragmentation. Although the area of LC is without natural forest and extremely poor in semi-natural elements of rural landscape, the existing entities were revealed as refuges for protected species. Some of the grassland fragments belonged to protected habitat types. The final categorization of the landscape elements was conducted in three levels. Category I landscape elements had to remain undisturbed; Category II landscape elements could be removed with obligatory ecological compensation, while the Category III landscape elements could be removed without environmental compensation. Recommendations were given pointing out the possibilities for improving the environmental characters of the area by the land consolidation process.

Organic matter of virgin and arable soddy-podzolic soil in the Urals

Organic matter of virgin and arable soddy-podzolic soil in the Urals

Eutrophication of Arable Soil: The Comparative Effect of Mineral and Organic Fertilizer Systems

Agrogenic eutrophication refers to the artificial enrichment of soil with organic carbon and nutrients in result of applying mineral and organic fertilizers to increase soil fertility and plant productivity. Eutrophication of gray forest soils (Luvic Retic Greyzemic Phaeozems (Loamic)) was created by annual application of increasing doses of mineral (N 90–360, P2O5 75–300 and K2O 100–400 kg/ha) and organic (fresh cattle manure from 25 to 100 t/ha) fertilizers under plants of a 5–field crop rotation for 9 years in microplots experiment. The NPK amounts applied with the manure were approximately equal to the corresponding doses of mineral fertilizer. The rates of soil enrichment by Corg under mineral and organic fertilizer systems were, respectively, 0.29–0.38 and 0.76–1.56 g/kg per year, Ntot – 0.04–0.06 and 0.06–0.09 g/kg per year, available P2O5 – 4–57 and 11–55 mg/kg per year, available K2O – 5–44 and 6–31 mg/kg per year. The fertilizer doses under both systems were the most significant factor in the accumulation of nitrate nitrogen, available forms of phosphorus and potassium in the soil, while the Ntot contents was controlled by the duration of fertilizer application. The Corg content in the soil with organic and mineral fertilizers depended on the dose of manure and the duration of NPK application, respectively. Soil eutrophication with mineral fertilizers was accompanied by a decrease in soil pH, and eutrophication with organic fertilizers, on the contrary, led to an increase in pH. It is emphasized that over–fertilization and long–term use of fertilizers are the main factors in the development of soil eutrophication and the concomitant change in soil pH.

ГРАНУЛОМЕТРИЧЕСКИЙ СОСТАВ КАК ВАЖНЫЙ ЭКОЛОГИЧЕСКИЙ ПОКАЗАТЕЛЬ ПЛОДОРОДИЯ ПОЧВ БАГАЕВСКОГО РАЙОНА

Purpose: to study the effect of granulometric texture on soil fertility, especially on the humus content and its structural state in the soils of Bagaevsky district Rostov region. Materials and methods. The studies were carried out on the soils of Bagaevsky district Rostov region. Samples were taken from the main genetic soil horizons. The granulometric texture was determined by the pipette method according to N. A. Kachinsky, and the soil structure was determined according to N. I. Savinov or granulometric (grain). Statistical data processing was carried out according to B. A. Dospekhov using the Microsoft Excel software product. Results. The main soil of Bagaevsky district is chernozems, they occupy about 64 % of the total land area of the district, chestnut soils occupy more than 26 % of the total area of the district, and floodplain soils occupy more than 7 %. The relationship with an approximation coefficient R² = 0.51 was revealed between the content of the fraction of physical clay and humus in the studied soils. Our studies of humus amount in the soils of Bagaevsky district showed that they are characterized by a very low and low content. In the studied soils, a close relationship between the structural state and the content of physical clay was determined (R² = 0.83). An analysis of soil humus status shows that the balance of organic matter is unfavorable for the prevailing part of arable land. An analysis of the research results by some authors shows that for the period from 1960 to 2021, the decrease in the humus content in arable soils of Bagaevsky district was 0.7 %. For its deficit-free balance, it is necessary to apply up to 6 t/ha of organic fertilizers. Conclusions. Our studies, combined with data analyses of studies conducted in Rostov region by a number of authors, made it possible to identify a significant effect of granulometric texture on the humus content and, as a consequence, soil fertility in general.

Change of water-physical properties of mountainous meadow-chernozem soils of the republic of Armenia under the influence of anthropogenic factor

The aim of the article is to study the direction of negative changes in water-physical properties occurring in meadow-chernozem soils under the influence of anthropogenic factor. The "soil keys" method was used to determine the location of transects. Field researches were conducted on the same-type relief areas, when comparing virgin and arable variants of soils. Soil samples were taken from the main sections by genetic horizons. In the article results of research on the influence of anthropogenic factors on the change of the water-physical properties of the mountain meadow-chernozem soils of the Republic of Armenia are presented. At the present stage the issues of storing and improving fertility of mountainous meadow-chernozem soils are very acute. These soils, under long-term use under agricultural crops, undergo considerable changes in the direction of deterioration, leading to activation of degradation processes of soils. Long-term and unsystematic agricultural use of mountainous meadow-chernozem soils leads to increase of their density. Soil porosity, its moisture capacity, mechanism of moisture movement, etc. depend on soil density. The studies conducted have shown that the density of the tilled layer of virgin soils is generally favourable for the growth and development of plants, but the upper part of the soil profile is somewhat compacted in the tilled variants. The data on porosity of mountain meadow-chernozem soils show that the soils studied are characterised by satisfactory general porosity. High porosity is especially in the whole-loam soil variants. In the arable soils some deterioration of water properties is observed. The results of maximum hygroscopicity, maximum field moisture capacity, and range of active moisture and moisture content of stable wilting slightly decrease.

Improvement of housing with knives crushers for non-tillage technology

The paper gives justification of the options of the housing with crumbling knives for non-tillage technology. The dumpless housing with crumbles carries out intensive crumbling of the soil of the lower and middle arable soil layer. The body consists of a ploughshare, a ploughshare expander, knives and a chisel. When determining the parameters of a non-shaft housing based on a ploughshare, adopt a triangular wedge. Analytical dependences for determining the parameters of the components body without shaft are obtained. According conducted theoretical studies, without a tipper is 0. 45 m, entry angle the ploughshare on the soil is 25°, nook of installation relative to the direction of travel is 42°, corner of installation with respect to the bottom egate is 35°, grinder the blade quantity 4, the elevated is 35 mm, the longitude is 120-140 mm, the angle of installation regarding the direction of peregrinate is 10°, the installation related to the skyline is 30°, the height body sans a tipper is 420 mm processing is provided.

Resource-saving technologies for the basic cultivation of chernozem typical in the northeastern region of the Central Chernozem region

The research was carried out with the aim of solving the problem of optimizing the system of basic tillage, providing a reduction in energy costs, obtaining high crop productivity and profitability of production in a grain-fallow crop rotation in the conditions of the northeast of the Central Chernozem Region. The work was carried out in 2013-2021, in a stationary field experiment on a typical heavy loamy chernozem with a high supply of mineral nutrients with a humus content in the arable layer of 6.8-7.0%. The scheme of the experiment included the following options for the main tillage systems: traditional mid-depth moldboard, for soybean at 25-27 cm (control); resource-saving: surface (disking by 10-12 cm) for all crops and non-moldboard mid-depth, 25-27 cm for soybeans and 20-22 cm for cereals; combined: moldboard-less plowing (25% plowing for soybeans + 75% non-moldboard semi-deep plowing for cereals) and moldboard-surface (25% plowing for soybeans + 75% surface plowing for cereals). Against the background of treatments for crop rotation, fertilizers and plant protection products were used. It was found that resource-saving non-moldboard and combined tillage for sowing, on average, for crop rotation crops, accumulated more moisture in the arable layer by 12.1-13.8%, by 3.9-7.8% in the meter layer, compared with traditional moldboard cultivation. . Surface tillage reduced the reserve of productive moisture in the arable layer by 4.4%, in the meter layer - by 5.1%. It has been studied that the best nitrogen, phosphorus and potassium regimes are established with traditional dump and combined dump-surface treatments. In the variants with surface and non-moldboard tillage, a decrease in the content of mineral nutrition elements in the arable soil layer is noted. At the same time, there was an increase in the process of differentiation of the arable layer by fertility with a concentration of nutrients in the layer of 0-10 cm and a significant decrease in them in the layer of 20-30 cm. 2.1 times without herbicides, 2.2 times against the background of herbicide treatment, in terms of the number of weeds and 1.4 and 1.5 times in terms of their mass, in comparison with traditional moldboard treatment. The use of herbicides contributed to a decrease in the number of weeds and the mass of the weed component on average for the variants of the experiment by 55.4 and 60.0%, respectively. It was analyzed that the use of surface and non-moldboard tillage systems led to a decrease in the productivity of a hectare of arable land in crop rotation by 0.09 tons of grain units without protection and by 0.11-0.14 tons in combination with plant protection. The combined (dump-surface) system of tillage ensured the productivity of arable land at the level of the traditional dump system at different depths. It has been proved that the highest profitability of production in crop rotation (250.3%) was achieved using a combined (dump-surface) tillage system in combination with the use of complex protection products (seed dressing + pesticides for crop vegetation). Resource-saving processing systems (surface and non-moldboard) worsened economic performance. Income from the use of these tillage systems decreased by 4.8-5.5%, profitability decreased by 1.6-2.7% compared to the traditional mid-depth moldboard tillage system in crop rotation.

The study of the dynamics of the content of nutrients in the soil when growing crops

The study was conducted in the soil and climatic conditions of the Krasnoyarsk forest–steppe (station Minino) on leached chernozem. The scheme of the experiment with mineral fertilizers provided for the introduction of ammonium nitrate, ammophos and azophos in a dose of 80 kg / d.v.ha and the introduction of plant protection products. Soil samples for agrochemical analysis were selected in the phase of stalking, flowering and full ripeness. The content of nitrate nitrogen was carried out in accordance with GOST 26951-86, mobile compounds of phosphorus and potassium were determined by the Chirikov method (GOST 26204-91). The conducted studies have shown that the introduction of ammonium nitrate allowed to significantly increase the amount of nitrate nitrogen (up to 25.2 mg / kg) in the arable soil layer, in the control version, the level of nitrate nitrogen did not exceed 3.3 mg / kg during the growing season. In the soil of the experimental site, the content of mobile phosphorus varied from 16.4 to 29.7 mg/100 g. The introduction of ammophos did not significantly increase the phosphorus content in the arable horizon. The content of mobile potassium in the soil was high and varied from 10.0 to 17.5 mg/100 g of soil.

Effects of nitrogen-contaminated irrigation methods on the growth and development of rice and nitrogen movement through cultivation layers in the Red River Delta, Vietnam

The experiment was conducted in the field to evaluate the effect of nitrogen-contaminated irrigation methods on the growth, development, and yield of rice (Oryza sativa L.) and the movement of nitrogen through the cultivation layers. The experiment was arranged in a Randomized Complete Block Design with three replicates. It was conducted in the summer season of 2022 at the rice experiment area of the Faculty of Environment, Vietnam National University of Agriculture, with three treatments, namely: T1 (control; continuous flooding (CF) with clean water), T2 (alternate wetting and drying (AWD) with nitrogen-contaminated water), T3 (CF with nitrogen-contaminated water). Experimental results indicated that different irrigation methods with nitrogen-contaminated water affect the growth, development, and yield of rice and the movement of nitrogen in the cultivated soil layers (at 35 cm depth, 70 cm – depth, 120 cm – depth). T2 treatment was the best irrigation method for reducing the amount of water for irrigation of rice and limiting the amount of excess nitrogen on the arable soil layers, which affects the quality of shallow groundwater. The movement of nitrogen nitrates through shallow groundwater was less than that of ammonium nitrogen form, and there was no difference in nitrogencontaminated irrigation using water-saving (T2) and flooded irrigation (T3) methods and within the safe threshold (QCVN 09-MT:2015/BTNMT).

Eutrophication of Arable Soil: A Comparative Effect of Mineral and Organic Fertilizers Systems

Eutrophication of Arable Soil: A Comparative Effect of Mineral and Organic Fertilizers Systems

Анализ лимитирующих почвенно-агроэкологических факторов выращивания сои в условиях повышенной внутрипольной пестроты лесостепных черноземов Курской области

The paper presents the results of a comprehensive agroecological assessment of the lands of a representative field agroecosystem in conditions of increased within-field diversity of forest-steppe chernozems of the Kursk region with a comparative assessment of soil-agroecological factors potentially limiting the yield and quality of soybean grain. A complex combination of leached and typical chernozems was studied on a slightly sloped plakor of the southern exposure in the peasant farm of the Pristensky district. Ten elementary key plots were laid on the field with soybeans of the Belgorod 7 variety, with sampling for analysis the aboveground biomass and soybean grain in fourfold repetition on sites of 0.25 m2, and the arable soil horizons too. The conducted studies have shown an almost twofold within-field variation in the biological yield of soybeans. Among the identified unregulated limiting agroecological factors, microrelief forms dominate (R = 0,69). The main regulated limiting factor is the content of available forms of phosphorus (R = 0,62). The quality of soybean grain is largely influenced by the content of ammonium nitrogen in the topsoil, as well as the phytosanitary condition of the studied area (R = -0,68). Operational adjustment of the limiting agroecological factors identified in the conditions of a representative field agroecosystem for obtaining the planned yield of high-quality soybeans will optimize the agricultural technology used in the field, bringing it closer to the characteristics of the best available technologies. Keywords: AGROECOLOGICAL ASSESSMENT, BIOLOGICAL YIELD, GRAIN QUALITY, CHERNOZEMS, LIMITING FACTORS, SOYBEANS, THE BEST AVAILABLE AGRICULTURAL TECHNOLOGIES, WITHIN-FIELD DIVERSITY

Crawfish shell- and Chinese banyan branch-derived biochars reduced phytoavailability of As and Pb and altered community composition of bacteria in a contaminated arable soil

Globally, soil contamination with arsenic (As) and lead (Pb) has become a severe environmental issue. Herein, a pot experiment was conducted using pak choi (Brassica chinensis L.) to investigate the effects of biochars derived from crawfish (Procambarus clarkia) shells (CSB) and Chinese banyan (Ficus microcarpa) branches (CBB) on the phytoavailability of As and Pb, and bacterial community composition in soils. Our results showed that the application of CSB and CBB decreased the concentrations of DTPA-extractable Pb in soils ranging from 26.8 % to 28.8 %, whereas CSB increased the concentration of NH4H2PO4-extractable As in soils, compared to the control. Application of both biochars reduced the uptake of As and Pb in the edible part of pak choi. In addition, application of CBB significantly (P < 0.05) increased the activities of α-glucosidase, β-glucosidase, cellobiohydrolase, and acid phosphomonoesterase by 55.0 %, 54.4 %, 195.1 %, and 76.7 %, respectively, compared to the control. High-throughput sequencing analysis revealed that the predominant bacteria at the phyla level in both biochar-treated soils were Firmicutes, Proteobacteria, and Actinobacteriota. Redundancy and correlation analyses showed that the changes in bacterial community composition could be related to soil organic carbon content, As availability, and nutrient availability in soils. Overall, the Chinese banyan branch biochar was more suitable than the crawfish shell biochar as a potential amendment for the remediation of soils co-contaminated with As and Pb.