Soil Fertility Dynamics Research Articles

The Impact of Beneficial Microorganisms on Soil Vitality: A Review

The paper summarizes the literature on the critical impact of beneficial microorganisms on soil vitality. Common soil microorganisms, including bacteria, fungi, algae, protozoa, and viruses contribute significantly to enhancing soil fertility through processes such as nitrogen fixation, phosphorus solubilization and mobilization, sulfur cycle, composting, and heavy metal remediation. Their abundance and biomass vary significantly across taxa within the uppermost 15 cm of soil, with bacteria dominating numerically and fungi contributing substantially to biomass. These microorganisms mediate essential biogeochemical cycles in soil, including carbon, nitrogen, and phosphorus cycles, by facilitating the decomposition of organic matter and recycling soil nutrients. Nitrogen-fixing bacteria like Rhizobium are prevalent symbionts capable of biologically fixing nitrogen. Additionally, bacteria such as Micrococcus spp., Enterobacter aerogens, Pseudomonas capacia, fungi including Aspergillus niger, A. flavus, A. japonicas, Penicillum spp., and actinomycetes like Streptomyces play crucial roles in phosphorus solubilization, making phosphorus available for plant uptake. This synthesis underscores the critical role of beneficial microorganisms in maintaining soil vitality. These organisms interact with plants through beneficial relationships, influencing soil fertility dynamics by enhancing nutrient availability, promoting plant growth, and controlling pathogens. The use of biofertilizers has emerged as a sustainable strategy to improve crop yields and restore soil fertility, reducing environmental impacts linked to chemical fertilizers. Understanding the intricate dynamics of soil-beneficial microorganism and their interactions with Plants are pivotal for optimizing agricultural practices, ensuring long-term soil health, and enhancing productivity in sustainable farming systems.

Soil Fertility Dynamics and Identify the Most Limiting Nutrients Affecting Walnut Productivity in Nepal

This study aimed to assess the soil nutrient status in walnut orchards of different ages in Jajarkot district, Nepal, to understand soil fertility dynamics and identify the most limiting nutrients affecting walnut productivity. The research employed a randomized complete block design (RCBD) with three treatments representing different age groups of walnut orchards (1-5 years, 6-10 years, and 11-15 years), each replicated seven times across various municipalities. The study was conducted in Jajarkot district, Karnali Province, Nepal, encompassing municipalities including Nalgad, Junichadey, and Barekot, from March to April 2023. Soil samples were collected from multiple depths (1, 2, and 3 feet) in each orchard and analyzed for pH, soil organic matter (SOM), total nitrogen, available phosphorus, and available potassium. Data analysis included descriptive statistics, one-way analysis of variance (ANOVA), and correlation analyses to explore relationships between soil parameters and orchard age. The study showed that significant variations were observed among different age groups of walnut orchards for soil pH, SOM, nitrogen, phosphorus, and potassium levels. Soil pH decreased with orchard age, while SOM, nitrogen, and phosphorus tended to increase with orchard age. Phosphorus was identified as the most limiting nutrient across all sampled soils, followed by nitrogen and potassium. Moreover, strong correlations were found between orchard age and soil N (r = 0.894, p < 0.01) and P (r = 0.776, p < 0.01), underscoring age-dependent nutrient dynamics. The study highlights the critical role of orchard age in shaping soil nutrient dynamics in walnut orchards. Older orchards exhibited higher levels of SOM, nitrogen, and phosphorus, indicating the accumulation of organic matter and nutrients over time. Phosphorus emerged as the primary limiting nutrient, essential for root growth, flowering, and fruiting in walnut trees. These findings underscore the importance of targeted fertilization strategies to optimize soil fertility and sustain long-term walnut productivity in the region.

Проблемы опустынивания в восточной зоне Ростовской области

The article presents an analysis of the dynamics of soil fertility, trace elements, pH, aridity index and normalized index. Salt lakes in the complex from 30-50 % occupy 68.3 thousand hectares. The humus content in the arable layer is low. There is a decrease in the content of humus (from 2.2% to 1.7%) and phosphorus (from 18.6 mg/kg to 18.2 mg). The content of exchangeable potassium is generally within the optimal range. The processes of loss of humus and nutrients in the soils of the area are a manifestation of the desertification process. The content of sulfur and trace elements (copper, zinc, manganese, cobalt) is low, insufficient for grain crops. The soils of the district are slightly alkaline (pH – 8.1). The aridity index of the Zavetinsky district is 0.41, and the normalized index is 0.59. According to the normalized aridity index – 0.59, the territory of the Zavetinsky district belongs to the moderately arid (NIA =0.5—0.6). Keywords: DESERTIFICATION, SALT LAKES, ARIDITY INDEX, SOIL FERTILITY, TRACE ELEMENTS

Unveiling Soil Fertility Dynamics in Rawalpindi Region: Implications for Sustainable Agriculture and Fertilizer Strategies

In Pakistan, the adoption of high-yielding crop varieties and intensive farming practices since the commencement of the green revolution has led to a degradation in soil quality and fertility. Particularly in rainfed areas, rapid mineralization of soil organic matter (SOM) has exacerbated widespread nutrient deficiencies. This study, conducted in Rawalpindi district, aimed to evaluate the extent of soil nutrient deficiencies to formulate precise fertilizer recommendations for management of soil health and fertility to obtain sustainable crop production. A comprehensive analysis of 4080 soil samples from various tehsils within Rawalpindi district was carried out. Results revealed that the majority of soils (79%) were classified as loam, with an overwhelming percentage (88%) exhibiting alkaline pH (7.5 to 8.5). Furthermore, 99% of soils had an electrical conductivity (EC) within the safe limit of <4.00 dS m−1. However, more than 96% of soils displayed poor levels of SOM, and deficiency of available phosphorus was observed in 99% of the samples. Conversely, 63% of soils had adequate extractable potassium. These findings underscore that deficiency of SOM, available-P, and alkaline soil pH are the major contributing factors in Rawalpindi region to the poor soil fertility. Therefore, soil fertility management strategies must consider the findings of this study to obtain the maximum agronomic benefits. Furthermore, farmers are recommended to get their soil tested after every three years to revise the nutrient management programs.

Soil fertility in mixed crop-livestock farming systems of Punjab, Pakistan: The role of institutional factors and sustainable land management practices

CONTEXTSoil salinization is a significant environmental challenge prevalent in arid and semi-arid regions, causing adverse effects on crop yields and jeopardizing household food security. Previous research has examined the influence of institutional dynamics and the adoption of sustainable land management practices in bolstering agricultural output, and some have investigated the interplay among socioeconomic determinants, institutional frameworks, and the uptake of climate-resilient and sustainable methodologies, or the association between soil health and agricultural productivity. Yet, there has been a lack of studies that considered this relationship altogether and their role in enhancing soil fertility. OBJECTIVEWe investigate the relationship among socioeconomic and institutional factors, adoption of sustainable land management practices, and the resulting changes in soil fertility between 2016 and 2019 within the context of mixed crop-livestock farms in the three irrigated agroecological zones of Punjab, Pakistan. A household survey was conducted in 2019 to complement soil attributes data collected by the Government of Punjab in 2016. Households that implemented sustainable land management practices between 2016 and 2019 were analysed to investigate the effect of various factors on soil fertility, including the adoption of sustainable land management practices and their influence on soil fertility dynamics. METHODSA structural equation model was employed to examine the relationship among exogenous variables, moderating variables, and endogenous variables, to explain their collective influence on soil fertility between the two periods. RESULTS AND CONCLUSIONSThe key findings highlight the significant role of institutional factors, including access to formal information channels such as extension services, demonstration trials, and credit facilities, alongside secure land rights, in predicting the adoption of sustainable land management practices such as gypsum application, laser land leveling, farmyard manuring, and agroforestry. Furthermore, specific SLM practices, particularly agroforestry featuring intercropping with Acacia spp. and farmyard manure application, exhibited positive impacts on change in soil organic matter, albeit with agroforestry showing a negative influence on soil phosphorus levels. The adoption of gypsum and LLL displayed positive effects on soil phosphorus levels over time, contrasting with LLL's adverse impact on soil organic matter. SIGNIFICANCEOur findings suggest that soil fertility benefits from policies enacted through public-private partnerships that lead to improved access to sustainable land management information, reduced credit barriers, establishment of local soil testing facilities, and expedited land entitlement processes. These findings highlight the critical role of collaborative partnerships and institutional arrangements in enhancing agricultural productivity and environmental sustainability.

Soil organic carbon stocks and fertility in smallholder indigenous agroforestry systems of the North-Eastern mountains, Tanzania

Soil organic carbon and soil fertility are critical components of soil health and play a significant role in sustaining agricultural productivity. Indigenous agroforestry practices have been identified as an interesting avenue to sequester carbon and enhance soil fertility in tropical smallholder farms. However, that potential remains poorly quantified. To better understand the dynamics of soil organic carbon stocks and fertility, this study evaluated and compared 4 different smallholder indigenous agroforestry systems (i.e., Kihamba, Ginger, Miraba, and Mixed spices) in the northeastern volcanic and block mountains of Tanzania. Specifically, we compared old and young agroforestry systems in terms of soil organic carbon stocks and soil fertility (proxied by effective cation exchange capacity (eCEC)). In each agroforestry system, a network of old and young tree farm plots were selected for soil sampling at different depths and physico-chemical parameters were analyzed (soil organic carbon, texture, bulk density, pH-H2O, and eCEC). Our findings showed that there was no significant difference between young and old agroforestry systems in terms of soil organic carbon stocks, except in the Kihamba system on the slopes of Kilimanjaro. The highest soil carbon sequestering potential was found in the old Kihamba (located on Nitisols) compared to other systems on Acrisols. Young agroforestry in Ginger and Miraba appeared to have a higher capacity to sequester soil carbon than Mixed spices. Regarding eCEC levels, there was a significant difference between old and young agroforestry systems in both the Kihamba and Miraba system. At the 0–10 cm depth, the highest eCEC levels were found in young agroforestry for Kihamba, Miraba, and Mixed spices. Our results implied that specific management and restoration strategies should focus on optimizing soil fertility and carbon sequestration potential of agroforestry systems in the South Pare and Usambara Mountains characterized by low-fertility Acrisols.

Soil Fertility Dynamics and Identify the Most Limiting Nutrients Affecting Walnut Productivity in Nepal

Soil Fertility Dynamics and Identify the Most Limiting Nutrients Affecting Walnut Productivity in Nepal

Dynamics of Organic Carbon Fractions, Soil Fertility, and Aggregates Affected by Diverse Land-Use Cultivation Systems in Semiarid Degraded Land

Dynamics of Organic Carbon Fractions, Soil Fertility, and Aggregates Affected by Diverse Land-Use Cultivation Systems in Semiarid Degraded Land

Assessing Soil Fertility Dynamics and Carbon Sequestration Potential in Groundnut (Arachis hypogaea L.) Cultivation Areas of Sri Satya Sai District, Andhra Pradesh, India

In 2021-2022, a study was conducted at the Agricultural Research Station in Anantapur, Andhra Pradesh, India, focusing on soil fertility changes and carbon storage potential in Sri Satya Sai district. A total of 300 soil samples were collected, 150 before and 150 after groundnut (Arachis hypogaea L.) cultivation in three blocks (i.e., Chennekothapalle, Ramagiri, and Roddam) of Sri Satya Sai District, Andhra Pradesh, India. Chennekothapalle exhibited a decline in pH from 6.83 to 6.53 after groundnut (Arachis hypogaea L.) cultivation, accompanied by a decrease in electrical conductivity (EC) levels from 0.22 to 0.18. Similarly, Ramagiri displayed a similar trend with a drop in pH from 7.03 to 6.63 and a decrease in EC from 0.22 to 0.20 dS/m. Roddam experienced a slight reduction in pH from 6.52 to 6.48 and a decrease in EC from 0.18 to 0.16 dS/m. Organic carbon (OC) content showed varying trends, with notable increases in Chennekothapalle (from 0.44% to 0.94%), Ramagiri (from 0.43% to 1.13%), and Roddam (from 0.3054% to 0.4454%) after cultivation. Nitrogen levels witnessed an increase in all three blocks, Chennekothapalle rising from 141.3 to 171.3 kgs/ha, Ramagiri from 162.11 to 192.11 kgs/ha, and Roddam from 129.44 to 154.44 kgs/ha. Additionally, Posphorus levels increased in Chennekothapalle (from 16.76 to 19.76 kgs/ha), Ramagiri (from 13.62 to 18.62 kgs/ha), and Roddam (from 30.24 to 35.24 kgs/ha) after cultivation. Similarly, Potassium levels showed increases in Chennekothapalle (from 159.07 to 184.07 kgs/ha), Ramagiri (from 161.04 to 195.04 kgs/ha), and Roddam (from 154.49 to 174.49 kgs/ha), indicating distinct patterns of soil fertility dynamics across these regions. In Chennekothapalle, the soil organic carbon content (TOC) increased from 0.004% to 0.009%, and there was a substantial rise in soil carbon stock (SCS) from 18.11 to 39.37 kgs/m². Carbon turnover, measured through mean CO2 levels, increased from 160.45 gms to 343.7 gms, and the Carbon Sequestration Potential (CSP) was 6900 Kgs. In Ramagiri, TOC saw an increase from 0.004% to 0.011%, with SCS improving from 30.92 to 37.38 kgs/m², indicating greater soil carbon storage. A significant rise in CO2 levels from 158.69 gms to 415.3 gms was observed, and CSP was 7700 Kgs. In Roddam, TOC increased from 0.003% to 0.004%, and SCS rose from 20.24 to 30.06 kgs/m², signaling improved soil carbon stocks. CO2 levels increased from 111.98 gms to 163.3 gms, reflecting enhanced carbon turnover, and remarkably, CSP was 3150 Kg. In comparing the three blocks, it's evident that Ramagiri exhibited the most substantial increase in soil fertility and carbon sequestration potential. While Chennekothapalle is showing significant improvements, Roddam experienced relatively modest changes in all parameters.

Long‐term soybean–maize rotation experiments in cereal‐based farming systems at Bako, Western Ethiopia

AbstractMaize monoculture is one of the major restrictions limiting maize productivity in Western Ethiopia. Although the inclusion of legumes in cropping systems is an essential approach for the sustainable management of farming systems and for reducing the nitrogen (N) fertilizer requirement for maize production in the long term, the effects of soybean on the sustainability of maize productivity and soil fertility are unclear in Ethiopia. Continuous cropping of maize has led to extensive degradation of soil and a decrease in crop productivity in Western Ethiopia. Thus, the study was conducted to compare the long‐term impact of soybean on the sustainability of the production system in soybean–maize rotation and to monitor soil fertility dynamics in soybean–maize rotational systems. Nine different soybean–maize rotation treatments were laid out in Randomized Complete Block Design (RCBD) with three replications. The study results showed that soybean–maize rotation gave a relatively steady yield compared to the maize mono‐cropping system. Soybean–maize rotation improves the productivity of component crops in cropping systems. The highest maize grain yield was recorded from soybean–maize rotation with fertilizer application for the two components (RS + M+) and soybean–maize rotation without fertilizer application for the soybean component (RS‐M+), respectively. Soybean grain yield was significantly correlated with OC (%), OM (%), and TN (%), whereas maize yield was adversely correlated with soil parameters, except soil pH. Overall, the knowledge we can contribute to the readers from this study is that soybean–maize rotation plays an important role in achieving sustainable agriculture by increasing soil fertility and achieving stable soybean and maize yields and soybean should be inoculated with Rhizobium strain year after year continuously. Thus, it can be concluded that soybean–maize rotation with fertilizer applications (RS + M+) for two components can be used in maize belt areas of Western Ethiopia.

Soil quality and fertility dynamics under a continuous cassava-maize rotation in the semi-deciduous forest agro-ecological zone of Ghana

The practice of crop rotation is known to significantly influence soil nutrient dynamics, depending on the type of rotation and the crops involved. As such, a field study was conducted to find out the effect of continuous cassava-maize rotation, where mineral fertilizer was only applied to the maize crop, on soil nutrients dynamics and soil quality thereof under varying rotation periods. The study revealed that Soil Organic Matter (SOM) and levels of soil nutrients, such as total nitrogen, available phosphorus and exchangeable cations (potassium, calcium, magnesium, and sodium) significantly declined with rotation period. Long term maize–cassava rotation led to subsoil (20–50cm) acidification. Soil quality as measured by Carbon Management Index (CMI) on the different aged rotations decreased with age, with the longest rotation period giving the least quality. These results and observations imply that long term cassava-maize rotation reduced soil quality and the resilience of the cropping system for continuous sustainable crops production. A regression analysis of soil nutrients with CMI under the continuous cassava-maize rotation identified the crucial role of soil total N (r2 = 0.56) and exchangeable K (r2 = 0.44) in sustaining productive cassava-maize rotation system and improved soil quality within the semi-deciduous forest agro-ecological zone. It is thus, recommended that enhanced and targeted organic and inorganic fertilization regime could be deployed on the cassava-maize rotation system to improve the inherently low levels of nutrients and increase crop yields.

THERMODYNAMIC ASPECTS OF THE GEOSYSTEM FUNCTION OF THE PEDOSPHERE

Modern unceasing processes of dehumification and degradation of arable soils require the search for new non-traditional approaches to solving this global environmental problem, which determines the relevance of the research. After all, plowing significantly disrupts the thermodynamic interaction of the soil with environmental factors. The purpose of the publication is to consider the regularities of the evolution of the properties of the pedosphere from a geosystem perspective, to define the concept of geomembrane properties, and to reveal the mechanism of regulating the thermodynamic interaction of the soil with the environment based on the concept of its homeostasis, which will allow a more reasonable explanation and forecast of modern evolutionary changes in the properties of soils and soil cover from a higher perspective organizational level of the geosystem. The main tasks are defined as: the development of a methodology for studies of the thermodynamic interaction of soil with climatic factors, the creation of tools for monitoring the course of thermodynamically unbalanced processes in the soil environment, and their approbation in the Forest-Steppe zone of Ukraine. It is proposed to consider the soil as a dissipative thermodynamic non-equilibrium system that is constantly in the process of self-stabilization and self-organization due to interaction with climatic factors of the environment. Therefore, soil homeostasis means the presence of subordinate energy-consuming processes of a certain intensity, which form the structure of the thermodynamic system of the soil, as the structure of its pore space. It was determined that the general direction of the development of the pedosphere, as an element of the Earth's lithospheric shell, is the densification of the parent rock with the formation of structural macroporosity of the soil and the development of heterogeneity. It is shown in the example of Ukraine, that the geomembrane properties of soils have a zonal nature and are aimed at limiting the power of the zone of active energy-mass exchange.
 The concept of the dynamics of geomembrane properties of the pedosphere, as a manifestation of a higher hierarchical level of geosystem organization, is proposed to be used to solve purely applied issues, such as assessing the impact of climate change, humus formation, and modern dynamics of soil fertility, increasing the sustainability and ecological safety of soil use.

Faster accumulation and greater contribution of glomalin to the soil organic carbon pool than amino sugars do under tropical coastal forest restoration.

Microbial metabolic products play a vital role in maintaining ecosystem multifunctionality, such as soil physical structure and soil organic carbon (SOC) preservation. Afforestation is an effective strategy to restore degraded land. Glomalin-related soil proteins (GRSP) and amino sugars are regarded as stable microbial-derived C, and their distribution within soil aggregates affects soil structure stability and SOC sequestration. However, the information about how afforestation affects the microbial contribution to SOC pools within aggregates is poorly understood. We assessed the accumulation and contribution of GRSP and amino sugars within soil aggregates along a restoration chronosequence (Bare land, Eucalyptus exserta plantation, native species mixed forest, and native forest) in tropical coastal terraces. Amino sugars and GRSP concentrations increased, whereas their contributions to the SOC pool decreased along the restoration chronosequence. Although microaggregates harbored greater microbial abundances, amino sugars and GRSP concentrations were not significantly affected by aggregate sizes. Interestingly, the contributions of amino sugars and GRSP to SOC pools decreased with decreasing aggregate size which might be associated with increased accumulation of plant-derived C. However, the relative change rate of GRSP was consistently greater in all restoration chronosequences than that of amino sugars. The accumulation of GRSP and amino sugars in SOC pools was closely associated with the dynamics of soil fertility and the microbial community. Our findings suggest that GRSP accumulates faster and contributes more to SOC pools during restoration than amino sugars did which was greatly affected by aggregate sizes. Afforestation substantially enhanced soil quality with native forest comprising species sequestering more SOC than the monoculture plantation did. Such information is invaluable for improving our mechanistic understanding of microbial control over SOC preservation during degraded ecosystem restoration. Our findings also show that plantations using arbuscular mycorrhizal plants can be an effective practice to sequester more soil carbon during restoration.

МОНИТОРИНГ АГРОЛАНДШАФТА И ДОЛГОСРОЧНОЕ ПРОГНОЗИРОВАНИЕ ПЛОДОРОДИЯ ПОЧВ В ДЕЛЬТЕ РЕКИ КУБАНЬ

The article discusses the issues of monitoring the forecasting of soil fertility and substantiates the methods applied to the agrolandscape of the Kuban River Delta on the example of assessing the initial state of arable land fertility. An analysis of the properties of deltaic geosystems was carried out: openness, integrity, functioning, dynamics, evolution and structure of the geosystem. When considering the geosystems of the Delta, environmental factors are indicated. On the example of the delta of the Kuban River, the dependence of the surface radiation balance on the features of the relief is considered. The need for a comprehensive assessment of the agro-resource potential is justified in connection with the development of degradation processes in the soil. The criteria for long-term forecasting as a single integrated approach to the methodology for assessing the resource potential of agriculture are substantiated. To assess fertility, an integral indicator of soil fertility was used. Specific natural-technogenic complexes of individual parts of deltaic geosystems in relation to the Kuban River have been identified. The impact of human anthropogenic activity has led to a noticeable decrease in soil fertility, a reduction in the reserves of biomass, humus and basic nutrients in the soil, a unified comprehensive monitoring of the assessment of the agro-resource potential of its presence and use as a result of the development of degradation processes is needed. The assessment of land resources to determine the trend of soil formation processes and the dynamics of soil fertility in a particular area is very relevant. It is necessary to substantiate the identification of the main factors influencing the process of changing soil fertility, biomass, humus and basic nutrients.

МЕТОДИКА РАСЧЕТА БАЛАНСА ГУМУСА И ОСНОВНЫХ ПИТАТЕЛЬНЫХ ЭЛЕМЕНТОВ ПОЧВЫ НА ПРИМЕРЕ ОРОШАЕМОГО СЕМИПОЛЬНОГО КОРМОВОГО СЕВООБОРОТА

In the article under consideration, the authors propose to form a general idea of the balance and dynamics of soil nutrients that form a stable concept of soil fertility on the basis of a seven-field irrigated fodder crop rotation located in the north-eastern zone of the Krasnodar Territory and using the methodology for calculating the main organic and mineral nutrients of the soil (Mathematical model of soil fertility dynamics). Fertility mainly depends on the number, composition of organic, as well as key mineral nutrients in the basis of it: nitrogen, phosphorus, potassium. In agricultural turnover, there is a decrease in biomass reserves in the soil, and over time there is a shortage of humus. The losses of humus and soil minerals were observed due to the large removal of nitrogen with the harvest and weak replenishment of soil nutrients by applying organic and mineral fertilizers. As a result, a pronounced trend was formed for the negative dynamics of the main nutrients of the soil. The results of the methodological analysis show that as a result of irrigation reclamation of the proposed fodder crop rotation, a positive balance of organic and mineral substances in the soil is observed, however, there is also a deficiency of phosphorus and potassium. There is a need to increase the positive balance of the mineral component of soil fertility, as well as to form a clear stable process of soil fertility stabilization. A balance in the content of humus and the main mineral nutrients of the soil can be achieved when its consumption is fully compensated by the introduction of organic fertilizers, sowing of perennial grasses and decomposition of plant residues.

Clay content mapping and uncertainty estimation using weighted model averaging

Accurate prediction of clay is the basis for soil quality assessment and decision making in land use because it governs soil moisture and fertility dynamics. However, using laboratory methods to determine clay across a large district and at multiple depths is tedious and expensive. An alternative is to use proximally and remotely sensed digital data, that can be coupled to laboratory measured clay through models. This study aims to predict topsoil (0–0.3 m) and subsoil (0.9–1.2 m) clay at district scale by comparing; i) importance of proximally (i.e., apparent soil electrical conductivity – ECa) and remotely (i.e., γ-ray spectrometry, digital elevation model – DEM) sensed data, ii) models including a linear mixed model (LMM) and machine learning models (MLs, i.e., Cubist, random forest [RF], support vector machine regression [SVMR], quantile regression forests [QRF], extreme gradient boosting [XGBoost] and bagEarth), iii) two model averaging techniques (i.e., Granger–Ramanathan averaging (GRA) and Lin’s concordance (LCCC) weights) from the top four best models, and iv) uncertainty of the prediction. The results showed that the γ-ray data was most important for topsoil clay prediction, while in the subsoil the slope was most important. Moreover, for topsoil clay prediction the RF was best with fair accuracy (RPD = 1.64), followed by QRF (1.62), Cubist (1.61) and LMM (1.55) which outperformed bagEarth (1.51), SVMR (1.47) and XGBoost (1.47). For the subsoil, all seven models achieved poor accuracy (RPD < 1.4) with RF (1.34) again being the best. The 90% prediction interval was larger in the subsoil compared to topsoil. Furthermore, while both averaging methods improved the prediction in both depths, the improvement using GRA was more pronounced. Therefore, we recommend the GRA be adopted as a protocol for district-scale clay prediction.

Dynamics of soil fertility and microbial community response to stocking density in rice-turtle co-culture

Co-culture modes of rice and aquatic animals as rice-crayfish, rice-fish and rice-turtle have expanded rapidly in paddy rice cultivation regions, due to its ecological efficiency, contributions to food security, food productivity and economic benefits. However, different co-culture strategies have great influences on rice or aquatic animal growth and related ecological benefits. In this study, we investigated the effect of turtle stocking density on the dynamics of paddy soil fertility and microbial community characteristics in a rice-turtle co-culture ecosystem. The Chinese soft-shell turtles (Pelodiscus sinensis) were allocated to experimental paddy fields at four gradient stocking densities ranging from 360 to 540 kg· ha−1. In comparison with conventional rice cultivation with a higher input rate of chemical fertilizer, rice yields were higher in the rice-turtle paddies. In addition, soil pH and organic matter were relatively stable in the rice-turtle mode, whereas both parameters decreased over time in conventional paddies. Stocking density significantly benefited soil fertility, with soil organic matter increasing in response to higher stocking density. Total soil nitrogen concentration was lower in the conventional rice cultivation and low stocking density co-culture groups, compared with the high stocking density groups. Furthermore, the soil microbial communities were also affected by turtle stocking density. Redundancy analysis showed that soil pH, organic matter and available potassium concentration were the major factors influencing the abundance of the dominant microbes. The findings revealed the responses of paddy soil fertility and microbial community characteristics in rice-turtle co-culture modes, which could help optimize the co-culture mode and provide a basis for soil nutrient management in such ecosystems.

Soil fertility dynamics and yield responses of four plantain genotypes to different nutrient management systems in Nsukka, southeastern Nigeria

Soil fertility dynamics and yield responses of four plantain genotypes to different nutrient management systems in Nsukka, southeastern Nigeria

Current State of Soil Fertility Level of the Northern Forest Steppe of the Republic of Bashkortostan

The research aims to study the dynamics of soil fertility of agricultural lands of the Northern forest-steppe. For this, in the process of field surveys, soil sections were laid, a description of the morphological structure with the selection of soil samples by genetic horizons. The field stage is carried out by route inspection, according to the coordinates of the previously designated points; sections are laid out with a description of all genetic horizons for the subsequent determination of the name of the soil. Based on the results of field, a digital soil map of agricultural lands was compiled.

Monitoring of the Agricultural Landscape and Long-Term Forecasting of Soil Fertility in the Kuban River Delta

The article considers the issues of soil fertility forecasting monitoring and substantiates the methods applied to the agricultural landscape of the Kuban river Delta on the example of assessing the initial state of arable land fertility. There was conducted the analysis of the properties of the Delta geosystems: openness, integrity, functioning, dynamics, evolution and structure of the geosystem. Environmental factors are indicated when considering the Delta geosystems. The dependence of the surface radiation balance on the terrain features is considered on the example of the Kuban river Delta. The need for a comprehensive assessment of agro-resource potential is justified due to the development of degradation processes in the soil. The criteria for long-term forecasting as a single integrated approach to the methodology of assessing agricultural resource potential are substantiated. An integral indicator of soil fertility was used to assess fertility. The specific natural-technogenic complexes of separate parts of the Delta geosystems in relation to the Kuban river are identified. The impact of human anthropogenic activity has led to a noticeable decrease in soil fertility, reduced reserves of biomass, humus and basic nutrients in the soil, a single comprehensive monitoring of the assessment of agro-resource potential of its availability and use is necessary as a result of the development of degradation processes. Assessment of land resources to determine the trend of soil formation processes and soil fertility dynamics of a specific territory is very relevant. It is necessary to justify the identification of the main factors that affect the process of changing soil fertility, biomass, humus and basic nutrients.