Land Soil Research Articles

Changes in the population and diversity of plant parasitic nematodes and their effects on sugarcane growth at Wonji‐Shoa Sugar Estate, Ethiopia

AbstractIn Wonji‐Shoa Sugar Estate (WSSE), sugarcane (Saccharum spp. hybrid) yields have declined by about 48% over the last 70 years. One of the causes for the decline is assumed to be the long‐term monoculture production system that results in the buildup of plant parasitic nematodes (PPNs). Therefore, the population and diversity of PPNs were investigated by conducting soil sampling using a biosequential method (simultaneous sampling of the soils of adjacent cultivated land [CL] and uncultivated land [UL]) and a chronosequential method (taking soil samples at different times from the same site). The samples were subjected to analysis using standard procedures to determine the change in the population, and identify the genera of PPNs. Additionally, a pot experiment that involved fumigation was conducted on top soils sampled from the CL and UL of the plantation. The results revealed that about 10 genera of PPNs (Meloidogyne, Helicotylenchus, Hoplolaimus, Rotylenchulus, Hemicycliophora, Discriconemella, Xhiphinema, Pratylenchus, Tylenchorhynchus, and Scutellonema) were detected, of which the first four were newly identified. The population density and the number of genera of PPNs found in the CL were 36‐fold and 4.5‐fold higher than those found in the UL, respectively. Furthermore, fumigation reduced the population of the PPNs by 61% and increased production of cane biomass by 63%. It is concluded that the soils of the WSSE are infested by PPNs, which consequently have detrimental effects on sugarcane growth. While amending soil fertility is crucial, reversing the decline in sugarcane yields also necessitates implementing an integrated soil management system that includes PPNs.

Spatial Heterogeneity of Soil Nutrient in Principal Paddy and Cereal Production Landscapes of Fengtai County within the Huai River Basin, Eastern China

The problem of cultivated land soil quality in the Huaihe River Basin has become increasingly prominent. How to accurately and quantitatively evaluate the soil quality of regional cultivated land and realize its efficient use has become an urgent problem. In order to explore the spatial autocorrelation and variation in soil nutrients in cultivated land in the plain of Fengtai County in the Huaihe River Basin, a total of 306 soil samples and mature wheat samples were collected in the study area to analyze soil pH, total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), available potassium (AK) and slow-release potassium (SK) content and wheat biomass, and combined with geostatistical methods and GIS technology. The Kriging interpolation method and Moram‘s I index method were systematically analyzed. Principal component analysis (PCA) and Pearson correlation analysis were used to establish the minimum data set (MDS) of soil quality, which was used to calculate the soil quality index (SQI) and determine the key factors affecting soil quality. The results showed that the soil pH was in weak variation, and the other nutrient indexes were in medium variation. The spatial variability of soil-available potassium nutrients was affected by random factors such as human activities and structural factors such as soil parent materials. The spatial autocorrelation of organic matter, total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, available potassium and mitigation potassium was weak, which was mainly affected by random factors such as human activities. An unequivocal positive spatial nexus was discerned across all nutrients. Cumulatively, the nutrient dispersion across the investigated territory was somewhat diffuse, manifesting in a mosaic pattern with pronounced zonal nutrient allocation disparities in the meridional, median, and septentrional segments. An explicit latitudinal dichotomy delineating zones of nutrient opulence and paucity was also observed. These insights can pave the way for tailored fertilization strategies and judicious pedological stewardship in Fengtai County.

Spatial Differentiation Characteristics of Soil Organic Carbon and Its Influencing Factors in Cultivated Land in Major Grain-producing Areas： A Case Study of Hebei Province

Assessing the spatial differentiation characteristics of soil organic carbon （SOC） in cultivated land in major grain-producing areas is important for regional cultivated land quality management and national food security. We investigated 519 soil profiles of cultivated land in Hebei Province （0-120 cm equally divided into six layers）, and obtained 2961 samples. We used geostatistical methods and spatial exploratory analysis to reveal the spatial distribution pattern of SOC in cultivated land in Hebei Province and the impacts of climate, topography, geomorphology, soil properties, and anthropogenic use on the spatial distribution of SOC in cultivated land soils. The results showed that： ① The SOC content of cultivated land in Hebei Province showed a decreasing trend with the increase in soil depth, with the highest mean value of ω（SOC） of 9.57 g·kg-1 in A1 （0-20 cm） and the lowest mean value of 4.17 g·kg-1 in A6 （100-120 cm）, and the coefficient of variation showed an increasing trend with the increase in soil depth. ② The SOC at different depths of cultivated land in Hebei Province had similar horizontal spatial distribution characteristics, and in general, showed a trend of being high in the northwest and low in the southeast. ③ Soil texture and topography were the main influencing factors for the spatial variation of SOC in cultivated land in Hebei Province, showing that the more clay-rich the soil texture, the greater the SOC content, and the higher the elevation, the greater the SOC content. Soil pH also influenced the SOC content of the profile. The SOC content of the surface layer is mainly affected by anthropogenic use, whereas the bottom layer is affected by the cumulative temperature.

Содержание валовых форм цинка, свинца и кадмия в дерново-подзолистых супесчаных почвах земель сельскохозяйственного назначения

Abstract. Purpose and objectives. The research is aimed at studying the peculiarities of the distribution of gross forms of zinc, mumps, cadmium according to the soil profile of sod-podzolic sandy loam soils of agricultural lands of the Ryazan region and determining the current regional background. Methodology and methods. To solve the tasks set, pits with a depth of 1.5 m were laid in different regions of the region, the depth and structural features of the soil layer and the effect on the migration conditions of the studied elements were analyzed. Based on the results of determining the content of the studied elements in the soil at intervals of 0.1–0.2 m to the maternal, the calculation of background concentrations was performed. A comparative analysis of the proposed background values with well-known values of world and domestic researchers has been carried out. The scientific novelty of the conducted research lies in the fact that the proposed background values are modern and calculated directly for the sod-podzolic sandy loam soil of the Ryazan region. Results. The structure of soil profiles of sod-podzolic sandy loam soil at a depth of 110–120 cm has the following form: O – A – EL – ELBt – Bt – BtC – C. At the same time, noticeable geochemical barriers delaying the migration of heavy metals are noted in the horizon A and Bt. The obtained values of the studied elements were in the concentration ranges for Zn (5.4–12.8 mg/kg), Pb (2.1–7.4 mg/kg), Cd (0.031-0.081 mg/kg). Background concentrations are proposed: Zn – 8.3 mg/kg, Pb – 4.2 mg/kg, Cd – 0.053 mg/kg, which differ from the well-known values of world and domestic researchers presented in a comparative analysis and give a modern idea of the regional background content of gross forms of zinc, lead and cadmium in sod-podzolic sandy loam soils Ryazan region.

Heavy metals in homestead soil: Metal fraction contents, bioaccessibility, and risk assessment

Rapid urbanization in China has led to the disappearance of countless villages and the transformation of homestead land into cultivated land or grassland. The quality of homestead soil (HS) plays a pivotal role in land-use conversion and reuse strategies, so the current state of heavy metal pollution in HS deserves attention. This study determined the fraction contents, bioaccessibility, risks, and affecting factors of Hg, As, Cd, Pb, Cu, and Zn in HS by comparing them with soil in cultivated land (CS), grassland (GS), homestead-converted cultivated land (HCS), and homestead-converted grassland (HGS). Results demonstrate that the contents of the six metals exceed background values, especially for Cd and Hg, resulting in significant pollution and elevated ecological risk. Distinct from the dominant residual fraction of other metals, the extractable fraction of Cd shows the highest proportion, which also contributes most to the high values of the Risk Assessment Code and extreme pollution conditions in HS, GS, and CS. Moreover, pH shows predominantly negative relations with the effective available and potentially available contents, while the effects of organic carbon fractions are notably the opposite. Furthermore, CS and GS suggest higher non-carcinogenic and carcinogenic risks than in the converted soil. This study indicates that HS has a lower metal accumulation risk compared with cultivated land and grassland, and homestead conversion seems to restrict the bioaccessibility of metals in soil.

Inventory of methane and nitrous oxide emissions from freshwater aquaculture in China

Aquaculture is a major emission source of atmospheric methane (CH4) and nitrous oxide (N2O). However, its contribution remains highly uncertain because the source has been neglected in global and national greenhouse gas inventories. Here, we present an inventory of CH4 and N2O fluxes from five freshwater aquaculture systems in China, which accounted for more than half of global freshwater aquaculture production during 2000-2020. We show that total CH4 and N2O emissions were 2.5 (0.6-4.2) Tg CH4 yr-1 and 18.3 (3.8-32.2) Gg N2O yr-1, respectively, with 75% coming from ponds and paddy fields. CH4 and N2O effluxes from freshwater aquaculture were 5 and 2 times higher than the average from other inland water bodies, respectively. Aquaculture accounts for half of the national inland water emissions, and outweighs the land soil methane sink. We suggest that tracking aquacultural emissions and their reduction through aerated systems could provide additional opportunity to reduce agricultural non-CO2 emissions without compromising food security.

Feasibility of Vis-NIR spectroscopy approach to predict soil biological attributes in arid land soils.

Visible and near-infrared (Vis-NIR) reflectance spectroscopy has recently emerged as an efficient and cost-effective tool for monitoring soil parameters and provides an extensive array of measurements swiftly. This study sought to predict fundamental biological attributes of calcareous soils using spectral reflectance data in the Vis-NIR range through the application of partial least square regression (PLSR) and stepwise multiple linear regression (SMLR) techniques. The objective was to derive spectrotransfer functions (STFs) to predict selected soil biological attributes. A total of 97 composite samples were collected from three distinct agricultural land uses, i.e., sugarcane, wheat, and date palm, in the Khuzestan Province, Iran. The samples were analyzed using both standard laboratory analysis and proximal sensing approach within the Vis-NIR range (400-2500 nm). Biological status was evaluated by determining soil enzyme activities linked to nutrient cycling including acid phosphatase (ACP), alkaline phosphatase (ALP), dehydrogenase (DEH), soil microbial respiration (SMR), microbial biomass phosphorus (Pmic), and microbial biomass carbon (Cmic). The results indicated that the developed PLSR models exhibited superior predictive performance in most biological parameters compared to the STFs, although the differences were not significant. Specifically, the STFs acceptably accurately predicted ACP, ALP, DEH, SMR, Pmic, and Cmic with R2val (val = validation dataset) values of 0.68, 0.67, 0.65, 0.65, 0.76, and 0.72, respectively. These findings confirm the potential of Vis-NIR spectroscopy and the effectiveness of the associated STFs as a rapid and reliable technique for assessing biological soil quality. Overall, in the context of predicting soil properties using spectroscopy-based approaches, emphasis must be placed on developing straightforward, easily deployable, and pragmatic STFs.

Does the diversity of vegetation and diatoms correlate with soil and water factors in a tropical cloud forest's complex land use/land cover scenario?

Soil and water characteristics in micro basins with different land uses/land cover (LULC) can influence riparian vegetation diversity, stream water quality, and benthic diatom diversity. We analyzed 18 streams in the upper part of the La Antigua River basin, México, surrounded by cloud forests, livestock pastures, and coffee plantations. Concentrations of P, C, and N were elevated in the humus of forested streams compared to other land uses. In contrast, cations, ammonium, and total suspended solids (TSS) of water streams were higher in pastures and coffee plantations. These results indicate that LULC affects stream chemistry differently across land uses. Vegetation richness was highest (86-133 spp.) in forest streams and lowest in pastures (46-102), whereas pasture streams had the greatest richness of diatoms (9-24), likely due to higher light and temperatures. Some soil and water characteristics correlated with both true diversity and taxonomic diversity; soil carbon exchange capacity (CEC) correlated with vegetation diversity (r = 0.60), while water temperature correlated negatively (r = - 0.68). Diatom diversity was related to soil aluminum (r = - 0.59), magnesium (r = 0.57), water phosphorus (r = 0.88), and chlorophyll (r = 0.75). These findings suggest that land use affects riparian vegetation, while physical and chemical changes influence diatom diversity in stream water and soil. The lack of correlation between vegetation and diatom diversity indicates that one cannot predict the other. This research is an essential first step in understanding how land use changes impact vegetation and diatom diversity in mountain landscapes, providing valuable insights for environmental monitoring and conservation efforts in tropical cloud forests.

The distribution of particulate organic matter in the heterogeneous soil matrix - Balancing between aerobic respiration and denitrification

Denitrification, a key process in soil nitrogen cycling, occurs predominantly within microbial hotspots, such as those around particulate organic matter (POM), where denitrifiers use nitrate as an alternative electron acceptor. For accurate prediction of dinitrogen (N2) and nitrous oxide (N2O) emissions from denitrification, a precise quantification of these microscale hotspots is required. The distribution of POM is of crucial importance in this context, as the local oxygen (O2) balance is governed not only by its high O2 demand but also by the local O2 availability.Employing a unique combination of X-ray CT imaging, microscale O2 measurements, and 15N labeling, we were able to quantify hotspots of aerobic respiration and denitrification. We analyzed greenhouse gas (GHG) fluxes, soil oxygen supply, and the distribution of POM in intact soil samples from grassland and cropland under different moisture conditions. Our findings reveal that both proximal and distal POM, identified through X-ray CT imaging, contribute to GHG emissions. The distal POM, i.e. POM at distant locations to air-filled pores, emerged as a primary driver of denitrification within structured soils of both land uses. Thus, the higher denitrification rates in the grassland could be attributed to the higher content of distal POM. Conversely, despite possessing compacted areas that could favor denitrification, the cropland had only small amounts of distal POM to stimulate denitrification in it. This underlines the complex interaction between soil structural heterogeneity, organic carbon supply, and microbial hotspot formation and thus contributes to a better understanding of soil-related GHG emissions.In summary, our study provides a holistic understanding of soil-borne greenhouse gas emissions and emphasizes the need to refine predictive models for soil denitrification and N2O emissions by incorporating the microscale distribution of POM.

Soil compounding promotes the improvement of aeolian sandy soil in the Mu Us Sandy Land

Soil compounding promotes the improvement of aeolian sandy soil in the Mu Us Sandy Land

Soil erodibility results of revegetation using bitti plant at various ages reclamation of quarry a lime stone mine at Pt Semen Tonasa, Pangkep District, South Sulawesi

Background: Limestone mine reclamation carried out by PT Semen Tonasa is carried out periodically as an effort to restore land conditions in a sustainable manner. The reclamation was carried out in the form of revegetation using endemic plants, namely the bitti plant (Vitex cofassus R.) which grows a lot in the southern part of Sulawesi. This study aims to determine the erodibility of the soil in limestone mine reclamation land planted with bitti plants. Methods: The method used is the survey method by determining the location of soil samples using the purposive sampling method based on the reclamation age planted with bitti plants in 2019, 2015 and 2010 and determining the erodibility value using the formula according to Wischmerier and Smith (1978). Parameters used included soil texture, soil structure, organic matter, soil permeability, soil pH, and soil unit weight. Findings: The results of this study indicate that the erodibility of the soil in the limestone mine reclamation land planted with bitti plants is classified as high due to the high dust content which is influenced by the parent material. The results of this study indicate that the erodibility value of the land reclamation in 2019 was classified as moderately low to moderately high, the land reclamation in 2015 was classified as moderate to moderately high, and the land reclamation in 2010 was classified as moderate to high. Conclusion: The factor affecting the erodibility of the soil in the reclamation area is the M value (percentage of very fine silt and sand). Novelty/Originality of this Study: The novelty of this study lies in the examination of soil erodibility changes over different reclamation ages in a limestone mine using endemic bitti plants. This research highlights the unique relationship between reclamation age and soil properties, contributing valuable insights into effective land reclamation practices in tropical karst environments.

ТРАНСФОРМАЦИЯ ПЛОДОРОДИЯ ПОЧВ ЗАЛЕЖЕЙ ЛЕСОСТЕПНОЙ ЗОНЫ ПРИ РАЗЛИЧНОМ НАПРАВЛЕНИИ ИХ ИСПОЛЬЗОВАНИЯ

The purpose of research is to provide a comprehensive comparative assessment of the fertility of gray fallow soils in the forest-steppe zone of the Krasnoyarsk Region, overgrown with forest, used for hayma-king and re-developed into arable land. The studies were conducted in 2007–2020 in the Krasnoyarsk and Achinsk-Bogotol forest-steppe on gray soils of fallow lands no longer used for agricultural purposes. Stu-dies were carried out to assess the indicators of the potential and effective fertility of gray soils of fallow lands of the Krasnoyarsk and Achinsk-Bogotol forest-steppe with their various post-agrogenic use. It has been established that forests regenerated on fallow lands do not lead to degradation of soil fertility, especially in terms of the content of humus and agronomically valuable aggregates. The emerging forest litter and tree litter accelerate the accumulation of organic matter, a source of humus. There is weak spatial va¬riation in most indicators of effective and potential fertility in soils under regenerating forest compared to pure fallow lands. With the re-involvement of fallow land into arable land, nitrification somewhat increases, spatial variation in soil properties decreases, and the content of humus and absorbed bases decreases. The structural composition of the soils of all study objects is characterized as excellent (ACF 88–77 %) with an insignificant value of the coefficient of variation of fractions (4–7 %). When reclaiming fallow lands into arable land, the proportion of the blocky fraction is significantly reduced. The spatial variability of the structural composition of soils in fallow lands and hayfields is higher than on arable land, which is asso¬ciated with the “clumpiness” of the ground cover and root system of plants on uncultivated soils. In terms of fertility, post-agrogenic gray soils used for haymaking occupy an intermediate position between clean fallow lands and those overgrown with forest. The productivity of the phytomass of fallow lands, arable land and hayfields in the Krasnoyarsk and Achinsk-Bogotol forest-steppe is more closely correlated with the indicators of the potential fertility of post-agrogenic gray soils. In most cases, the values of the correlation coefficients are closer between phytomass reserves and indicators of effective fertility in the Achinsk-Bogotol forest-steppe, which is associated with more favorable hydrothermal conditions in this research area and optimal water-physical properties.

СОСТОЯНИЕ И ПЕРСПЕКТИВЫ ВОВЛЕЧЕНИЯ ЗАЛЕЖНЫХ ЗЕМЕЛЬ КАНСКОЙ ЛЕСОСТЕПИ В СЕЛЬСКОХОЗЯЙСТВЕННЫЙ ОБОРОТ

The purpose of the study is to assess the soil fertility of unused arable land in the Kansk forest-steppe of the Krasnoyarsk Region. The results of a soil-agrochemical survey of unused arable land in 9 districts of the Kansk forest-steppe of the Krasnoyarsk Region are presented. The studies were carried out by the Federal State Budgetary Institution "Station of Agrochemical Service "Solyanskaya" (FGBU "SAS "Solyanskaya") of the Rybinsk District in 2022–2023 within the framework of the state task of the Ministry of Agriculture to conduct surveys (soil, agrochemical and environmental-toxicological) of unused arable land for agricultural purposes. It has been established that the soil cover of unused arable land in the Kansk forest-steppe is dominated by chernozems and gray forest soils. Soils not used for arable land are characterized by medium and high humus content with a weighted average of 6.1 to 8.3 %. The soils are characterized by slightly acidic and close to neutral (5.1–6.3 pH units) environmental reaction. The exception is the sod-podzolic and sod-soil-gley soils of the Taseevo and Uyar Districts, where pHxl has a mode¬rately acidic reaction (4.6–4.9 pH units). Mobile phosphorus in soils is distributed extremely unevenly for soils of the same genetic origin in different administrative regions. The soils of unused arable land located in the northern and central parts of the region are much better provided with this element. Here, the weighted average content of available phosphorus is 211–319 mg/kg. In the southern subzone, the amount of available phosphorus in soils decreases, not exceeding 140 mg/kg. In terms of the content of exchangeable potassium, the fallow soils of the Kansk forest-steppe are provided with a medium to high level. The content of mobile sulfur in the surveyed soils is, as a rule, low and average (0.4–12.0 mg/kg). In the soils of unused arable land in the Aban and Irbey Districts, a high content of this element was noted (12.2–13.3 mg/kg).

Distribution Characteristics, Risk Assessment, and Source Analysis of Heavy Metals in Farmland Soil of a Karst Area in Southwest China

Soil environmental quality related to the residents’ life, health, and safety, has been the hotspot issues in science of ecological environment protection. Evaluating the distribution characteristics, ecological risk, and source of heavy metals in farmland is important for protecting soil resources. The agricultural area of Lianhua town, Gongcheng County, Guilin is a typical karst landform. In response to the problem of heavy metal pollution and complex sources in the soil of this area, the characteristics and sources of heavy metal pollution in the soil profiles from farmland, abandoned land, and forest were studied using the single-factor index method, the geoaccumulation index (Igeo) principal component analysis (PCA) and positive matrix factorization (PMF) model. The results showed that: (1) that the contents of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in the soil profile of the study area were higher than that of the soil elements background values in Guangxi. The total and available forms contents of all heavy metal elements exhibited the characteristics of accumulation in the surface profile; (2) among the six heavy elements, the contents of Cd were in a moderately to heavily polluted state. The contents of Cd in some soil profiles exceeded the control standard for agricultural land soil pollution. The contents of Zn and Ni were from slightly to moderately polluted in areas with frequent agricultural activities; (3) according to the PCA and PMF model, there were three main sources of heavy metals in the study area. Among them, Cd, Cu, Ni, and Zn are related to agricultural activities; the elements As, Cd, Cr, and Hg are closely related to geological background; Pb and Zn are mainly affected by atmospheric sedimentation of transportation. Agricultural activities and natural geological background are the main contribution sources of heavy metals in soil. Human activities are the main factors that cause the accumulation of heavy metals in soil. This research has theoretical guidance and practical significance for the prevention and control of soil heavy metal pollution and the protection of farmland environmental quality in the region.

Plant species composition and key‐species abundance drive ecosystem multifunctionality

Abstract Global biodiversity loss has generated great interest in the role of plant communities in driving ecosystem functions. There is limited understanding of how soil properties, plant richness and plant community composition interact to affect ecosystem multifunctionality. We conducted a constructed ecosystem experiment by simultaneously manipulating soil origin (i.e. fertile farmland soil and relatively infertile bare land soil), plant richness and community composition (one‐species monoculture, and all possible two‐, three‐ and four‐species combinations of five plants) to evaluate their influence on ecosystem multifunctionality related to the accumulation of biomass, carbon (C) and nitrogen (N) in plants, greenhouse gas emissions, soil nutrients, soil N fixation and mineralization of N and phosphorus (P). We found that ecosystem multifunctionality was significantly affected by soil origin, plant community composition and the community‐weighted mean (CWM) of plant biomass, but not by plant richness. We grouped the community composition into the N‐fixing group (including N‐fixing plants) and the non‐N‐fixing group (excluding N‐fixing plants). The N‐fixing plant group exhibited significantly higher multifunctionality than the non‐N‐fixing species group in both soil origins. For bare land soil, multifunctionality increased with the increasing relative abundance and biomass ratio of Albizia julibrissin (N‐fixing species) in communities, but decreased with the biomass ratio of Platycladus orientalis (non‐N‐fixing species). For farmland soil, multifunctionality increased with the abundance of Toona sinensis (non‐N‐fixing species) and the biomass ratio of Albizia julibrissin, but decreased with the abundance and biomass ratio of Morus alba (non‐N‐fixing species). These results indicate that the key species determining ecosystem multifunctionality vary under different soil conditions. Synthesis and applications: We propose that plant community composition and the relative abundance and biomass ratio of key species drive ecosystem multifunctionality. We suggest that selecting the appropriate plant combination under different soil conditions should be emphasized in ecological restoration projects. Our study highlights the differentiated roles of key species on ecosystem functions under different resource conditions. The N fixation in general plays a crucial role in driving ecosystem multifunctionality and the N‐fixing plants can serve as restoration tools in nutrient‐poor degraded lands.

Содержание и запасы подвижных форм фосфора в постагрогенных почвах Приморского края

The soils of the southern Far East are characterized by low levels of mobile phosphorus forms with an elevated concentration of its residual forms. The aim of this work is to study the dynamics of mobile phosphorus forms and their stocks in abandoned and anthropogenically transformed dark-humus podbels in Primorsky region of Russia. The study was conducted on abandoned agricultural fields (15, 20, 35, and 80 years after abandonment). As a reference site, we used samples from arable land. During the study, it was established that predomi-nantly mobile phosphorus forms accumulated in the upper plow layer, especially in the soils of arable land. Overall, the content of mobile phosphorus forms in the studied soils is assessed as very low. Throughout the examined postagrogenic development, there was a decrease in the stocks of mobile phosphorus forms throughout the soil profile.

Chemical Characterization of Soils from Kole Land Ecosystem of Thrissur District, Kerala, India

Chemical characteristics of acid sulphate soils (Kole) of Thrissur district were done after the flood in 2018, in order to access the fertility and productivity of the soil. A total of 25 random samples were collected from different locations of AEU 6 in Thrissur district and its chemical characterization and mapping were done. Soils of Kole lands of Thrissur district were ultra to moderately acid in reaction (3.31 to 6.42) with an average pH of 4.98 and with medium to high organic carbon content (1.17 to 4.41 %) and 92 per cent of soil samples were high in available nitrogen which was resulted due to the presence of more organic matter and clay. Forty percent of soils were low in available phosphorus content. Almost 80 per cent of soil samples showed sufficiency in potassium content. Among the secondary nutrients, calcium and sulphur were sufficient while 52 per cent of soil samples showed deficiency in available magnesium. Among the micro nutrient content in collected soil samples, available Fe, Mn and Zn were high and no Zn deficiency was noticed. Cation exchange capacity ranged from 7.57 to 22.01 cmol (+) kg-1 with a mean content of 13.92 cmol (+) kg-1. The present study on mapping and primary characterisation form the base for further detailed study of Kole land ecosystem of Thrissur district in post flood scenerio.

Processes of humus loss in leached chernozem soils of the North Kazakhstan region

This article discusses the processes of dehumification and loss of humus in leached chernozem soils of agricultural lands of the North Kazakhstan region due to mineralization and as a result of erosion processes. Modern rates of soil dehumification lead to a decrease in the fertility of agricultural land and a decrease in yields, soil fertility is a valuable resource. The intensive process of decomposition of organic matter and its dehumidification occurs as a result of plowing virgin soil and as a result of its improper use in agricultural conditions. In the North Kazakhstan region, after the development of virgin lands, trends of intensive soil dehumidification are widespread. It was found that the object of study, leached chernozem, loses 0.69 t/ha by mineralization of humus and 0.011 t/ha as a result of erosion processes. Due to the long-term agricultural use of the land, improper construction of soil protection works, lack of organic substances that complement the humus composition of the soil, the balance of humus is disturbed, and organic substances connect soil structures with each other, increasing resistance to environmental factors. The destruction of soil structures of the plowed soil layer, the predominance of dust structures, thinning of the humus layer and the intensity of erosion processes were revealed.

Soil Modeling and Prediction Methods in Dredging Construction Areas

In the current implementation process for dredging projects, due to the lack of an accurate understanding of underwater soil characteristics, construction teams often find it difficult to accurately understand the soil condition. Not only does this lead to a reduced dredger operation efficiency, but it may also cause delays to the project’s progress, as well as increasing its cost. Therefore, there is an urgent need to closely integrate soil analysis technology with dredging construction to ensure that projects can be completed efficiently and to a high standard. Therefore, this paper proposes a soil modeling and prediction method based on a three-dimensional point cloud model. The research objective is to propose a new method of soil mass identification with a strong generalization ability and function, which can not only be applied to dredging engineering but can also identify and analyze statistics of land soil and its mass. The accuracy of this method, based on a convergent grid, can reach 95%.

Evaluation of Soil Quality of Pingliang City Based on Fuzzy Mathematics and Cluster Analysis

Pingliang City has a complex topography and diverse soil types. To realize the improvement of soil according to local conditions and the reasonable and sustainable use of soil resources, an evaluation of soil quality in Pingliang City was carried out, based on the soil distribution situation in Pingliang City, adopting a method combining fuzzy mathematics and cluster analysis of the main evaluation factors, such as soil organic matter, topsoil depth, soil erosion intensity, soil moisture regime, effective soil thickness, soil texture, soil profile structure, soil nutrient status and topographical parts, to carry out a comprehensive evaluation. A comprehensive evaluation of soil quality was conducted in seven counties under the jurisdiction of Pingliang City, and the evaluation results were compared and analyzed against the national standard, “Cultivated land quality grade”, to provide a basis for the selection of scientific soil improvement methods. The results of the arable land quality grades indicate that the quality of farmland in Pingliang City is divided into three to ten grades, and the average quality grade of farmland is 6.83, which is in the middle–lower level, and the overall grade distribution shows the characteristics of low in the middle and high in the east and west. The results of fuzzy mathematics combined with cluster analysis indicated the following trends in soil quality for the 12 soil genera: Chuan black gunny soil > yellow moist soil > sandy soil > silt soil > mulching helilu soil> loessal soil> loamy soil > slope loessal soil > arenosol > tillage leaching gray cinnamon soil > calcareous gray cinnamon soil > red clay soil. The results of the combination of fuzzy mathematics and clustering were significantly correlated with the results of the evaluation of the soil quality of arable land; the correlation coefficient was 0.884. This indicates that the method can accurately and objectively review the advantages and disadvantages of arable land soil and can be effectively applied to the evaluation of the soil quality of agricultural soils in other regions. It is a complement to the existing evaluation of the soil quality of arable land and at the same time provides a reference for the improvement of soil quality in agricultural regions.