Soil Quality Indicators Research Articles

Soil test crop response nutrient prescription equations for improving soil health and yield sustainability—a long-term study under Alfisols of southern India

IntroductionEnhancing soil health and nutrient levels through fertilizers boosts agricultural productivity and global food security. However, careful fertilizer use is essential to prevent environmental damage and improve crop yields. The soil test crop response (STCR) is a scientific approach to fertilizer recommendation that ensures efficient use, supporting higher crop production while protecting the environment and preserving resources.MethodologyA long-term field experiment on the STCR approach was initiated in 2017 at the Zonal Agriculture Research Station, University of Agricultural Sciences, Bangalore, India. The experiment aimed to study the impact of STCR-based nutrient prescription along with farmyard manure (FYM) for a targeted yield of soybean (Glycine max), sunflower (Helianthus annuus), dry chili (Capsicum annuum), aerobic rice (Oryza sativa L.), foxtail millet (Setaria italica), okra (Abelmoschus esculentus), and kodo millet (Paspalum scrobiculatum) on yield and changes in soil health in comparison with other approaches of fertilizer recommendation.ResultsThe results showed a significant and positive impact of the integrated use of fertilizer with FYM based on the STCR approach on the productivity of all the crops and soil fertility. Significantly higher yields of soybean (23.91 q ha−1), sunflower (27.13 q ha−1), dry chili (16.67 q ha−1), aerobic rice (65.46 q ha−1), foxtail millet (14.07 q ha−1), okra (26.82 t ha−1), and kodo millet (17.10 q ha−1) were observed in the STCR NPK + FYM approach at yield level 1 compared to the general recommended dose and soil fertility rating approach. This approach outperformed the standard recommendations, enhancing nutrient uptake and efficiency across various crops. Utilizing the principal component analysis, the soil quality index effectively reflected the impact of nutrient management on soil properties, with the STCR NPK + FYM treatment at yield level 1 showing the highest correlation with improved soil physical and chemical parameters.DiscussionThe STCR approach led to improved yield, nutrient uptake, utilization efficiency, and soil health, thanks to a balanced fertilization strategy. This strategy was informed by soil tests and included factors like crop-induced nutrient depletion, baseline soil fertility, the efficiency of inherent and added nutrients through fertilizers and farmyard manure, and the success of yield-targeting techniques in meeting the nutritional needs of crops.

Soil quality index to access the impacts of long‐term vinasse application in sugarcane areas

AbstractSoil quality index (SQI) helps quantify management practices impacts on the soil, providing information for producers in decision‐making. Through evaluation in sugarcane areas, soil indicators were used to develop SQI to access and quantify the impacts of long‐term vinasse application on the soil. The treatments consisted of two soil types: clayey (490 g kg−1 clay) and sandy (80 g kg−1 clay) and two conditions: with (70 m3 ha−1 year−1) and without vinasse application for 10 years. Soil samples were collected in the 0‐ to 10‐cm, 10‐ to 20‐cm, and 20‐ to 30‐cm layers in each treatment. Four soil functions were developed to calculate SQI: root environment quality (REQ), air/water ratio (AWR), soil chemical quality (SCQ), and soil tolerance to erosion (STE). Twelve soil indicators related to soil fertility and aggregation/structure were used. The long‐term vinasse application increased water storage (32%–58% of soil porosity), sum of bases (11–19 mmolc dm−3) and aggregate stability index (41% vs. 78%) compared to without vinasse treatment in sandy soil. In the clayey soil, vinasse increased (p < 0.05) the REQ, SCQ, and STE functions by 10%, 14%, and 13%, respectively, besides not affecting AWR. The long‐term application of vinasse promoted greater benefits, proportionally, in the sandy soil, with increments (p < 0.05) of 30% in AWR, 25% in SCQ, and 27% in STE. According to the SQI, long‐term vinasse application increased the capacity of the clay soil to perform its functions by 8%, while it increased to the sandy soil was 22%.

Sustainable Cropping Sequences to Improve Soil Fertility and Microbiological Properties

Different cropping systems and nutrient management techniques impact the microbiological characteristics of soil and nutrient availability for plants. This study assessed four cropping systems—rice–wheat, cotton–wheat, pearl millet–wheat, and pearl millet–mustard in Hisar district, Haryana, using 80 soil samples (20 from each system) collected in April 2022 after the Rabi crop harvest. The cotton–wheat system had the highest accessible nitrogen (N) at 155.9 kg ha−1, while both the cotton–wheat (59.3 kg ha−1) and rice–wheat (54.0 kg ha−1) systems had higher available sulfur (S) levels compared to pearl millet–wheat (41.2 kg ha−1). Pearl millet–wheat also showed 12.4% higher potassium (K) levels than rice–wheat. The rice–wheat system exhibited the highest phosphorus (P) concentration at 54.3 kg ha−1 and greater DTPA-extractable micronutrients. Soils from the rice–wheat system had higher DTPA-extractable micronutrients (Zn, Fe, Mn, Cu) and superior microbial biomass nitrogen (MBN, 54.7 mg kg−1), urease (37.9 µg NH4+-N g−1 h−1), and alkaline phosphatase activity (APA, 269.7 µg PNP g−1 h−1) compared to other systems. Canonical discriminant functions explained 88.1% of the variability among cropping systems, while principal component analysis identified available P, DTPA-extractable Zn, and Cu as key soil quality indicators, accounting for 66.9% of the variance. These insights can inform policymakers on promoting effective cropping systems and sustainable soil health in northwestern India.

Integrated organic and mineral fertilizer strategies for achieving sustainable maize yield and soil quality in dry sub-humid inceptisols

Maize is one of the important cereal crops grown in rainfed regions of northwestern Himalayas, however, persistent use of chemical fertilizers coupled with poor soil nutrients and water holding capacity due to coarse textured soils poses serious threat to sustaining maize yield and soil health. To address these bottlenecks, a long-term experiment with application of organic manures and mineral fertilizer provides insights to quantify changes in soil organic carbon (SOC), crop yield and rain water use efficiency (RWUE) in rainfed area having low water use efficiency. A twelve years field experiment was conducted under dry sub-humid Inceptisols in northern India to study the potential impacts of organic and mineral fertilization on maize (Zea mays L.) productivity, water use efficiency and soil quality. Ten treatments were assessed, involving different nitrogen levels (20, 30, and 40 kg N ha⁻¹) combined with 10 tha⁻¹ year⁻¹ of farmyard manure (FYM), in-situ green manure from sunhemp, and the incorporation of Leucaena leucocephala leaves at 5 tha⁻¹ year⁻¹, including an unfertilized control. Maize yield increased linearly with increasing nitrogen application rates. The combination of FYM @ 10t ha−1 and 40 kg N ha−1(T4) yielded the highest maize production. Manure addition improved soil organic carbon (SOC) and major soil nutrients (N, P and K) while unfertilized control showed decline in soil nutrients compared to their initial values. Compared with control, incorporation of 10 t ha−1 FYM increased SOC by 1.3, 1.41, 1.44 times at application rate of 20, 30, 40 kg N ha−1, respectively. Application of N@40 kg ha−1 + 10t FYM ha−1 showed highest rain water use efficiency (RWUE) and relative production efficiency index (RPEI) (2.74 kg ha−1 mm−1 and 82, respectively) and the lowest rank sum of 6. Highly significant positive relationship existed between RPEI and RWUE, RPEI and sustainability yield index (SYI), RWUE and SYI indicated the superiority of FYM in combination with mineral fertilizer. Regression models, correlating yield with monthly rainfall and crop growing periods, indicated that the integration of FYM (10 tha⁻¹) with 40 kg N ha⁻¹ was most effective in achieving the highest relative soil quality index (RSQI) of 76 and the greatest sustainability yield index (SYI) of 49.3%. Based on results, we recommend balanced fertilization (N@40 kg ha−1 +10t FYM ha−1) which is easily manageable by farmers as the optimal strategy for improving soil quality and achieving sustainable maize productivity in nutrient depleted Inceptisols of northern India.

The Impact of Ecological Restoration on Soil Quality in Humid Region Forest Habitats: A Systematic Review

Ecological restoration is widely recognized as an essential technique for addressing soil degradation, biomass decline, and biodiversity loss. Improving and maintaining soil quality is critical to ensuring environmental sustainability and successful forest recovery. This systematic review aimed to assess the impact of ecological forest restoration efforts on soil quality in humid regions, as well as to compare the effectiveness of various ecological restoration strategies on soil quality indicators. Subsequently, a systematic search on various databases (e.g., Scopus and Google Scholar) yielded 696 records, of which 28 primary studies met the inclusion criteria. The results emphasized that chemical and physical soil properties are the key indicators for assessing ecosystem performance during forest restoration. The most commonly measured parameters were soil carbon, nitrogen, phosphorus, pH, bulk density, and soil porosity. It was shown that the restoration process required a longer duration to reach a comparable level of recovery as seen in mature forests, particularly in terms of fully restoring soil quality. Additionally, it has been noted that prior land use influences the length of time needed for soil quality recovery. In planted sites, soil quality may keep improving as the site ages, though it tends to stabilize after a certain period.

Biochemical Activity of Litter as an Indicator of Soil Quality in Pine Forests of Eastern Fennoscandia

Biochemical Activity of Litter as an Indicator of Soil Quality in Pine Forests of Eastern Fennoscandia

Effects of microbial communities during the cultivation of three salt-tolerant plants in saline-alkali land improvement.

Planting vegetation on saline-alkaline land enhances soil fertility and sustainability by improving salt-alkali tolerance. Different salt-tolerant plant species interact with soil microorganisms, enriching bacterial communities and promoting nutrient availability. In this study, mechanisms affecting microbial communities in severely saline-alkaline soils planted with salt-tolerant plants are investigated. Over 4 years, the potential to cultivate three salt-tolerant plant species (tall wheatgrass Agropyron elongatum, chicory Chicorium intybus, and alfalfa Medicago sativa) in severely saline-alkaline soils is compared with a non-cultivated control. Bacterial and fungal communities were characterized through high-throughput sequencing of the 16S rRNA gene V3-V4 region and the V4 region, respectively. Cultivating these three plant species significantly reduces soil electrical conductivity values. Chicory cultivation notably increased soil nutrients, bacterial alpha richness, and fungal alpha diversity and richness. Microbial community structures vary considerably between the control and treatments, significantly correlating with the soil quality index. This index enables an assessment of soil health and fertility by integrating variables such as nutrient content, microbial diversity, and salinity levels. In each plant treatment, particularly alfalfa, the relative abundances of fungal pathogens like Neocosmospora and Gibellulopsis increase, which may pose risks to subsequent crops such as tomatoes, requiring careful consideration in future planting decisions. Conversely, in alfalfa and tall wheatgrass treatments, there was an increase in the relative abundances of fungal genera (e.g., Alternaria and Podospora) that antagonize fungal pathogens, while Paraphoma increased in the chicory treatment. The strong relationship between microorganisms and the rise in pathogen-resistant fungi across different plant treatments highlights robust and beneficial structural characteristics. According to soil quality index scores, each treatment, but especially that of chicory, improved the severely saline-alkaline soil environment.

Soil quality assessment and its response to water flow connectivity in different vegetation restoration types, eastern China

Vegetation restoration is the most widely used forest management practice for degraded soils, but the responses of soil quality in different vegetation restoration types may vary. In addition, the relationship between water flow paths connection and soil quality needs to be further explored. In this study, the soil quality index (SQI) and the index of water flow connectivity (IWFC) in the six water flow patterns (PFP, SSB, WSB, CPS, CPW, and CSW) were explored at three forest stands (oak, pine, and bamboo forests) with 50 years for enclosure. The results showed that the bamboo forest stand had the best soil quality as a whole (0.534 ± 0.135), followed by pine (0.530 ± 0.180) and oak forest stands (0.435 ± 0.205). The IWFC in PFP, CPS and CPW water flow patterns decreased gradually with increasing soil depth, while in SSB, WSB and CSB water flow patterns, the IWFC increased at first and then decreased. Finally, the IWFC in the CPW water flow pattern showed the largest positive correlation with the SQI (P < 0.05). The IWFC in the CPW water flow pattern driven by soil physical properties could mainly control the changes in the SQI indirectly (average IE = 0.825) by influencing soil nutrient (average IE = 0.447) and biological (average IE = 0.485) properties, while its direct effects could be ignored (average DE = −0.074), which demonstrated that the joint effects of preferential flow paths and weak stream buffer zones can dramatically reflect the changes in soil quality. The better soil improvement effect of bamboo and pine forest stands compared to the oak forest stand should be given more consideration. This study provided new insights for the assessment of the relationship between soil hydrology and soil quality.

Fire and salvage logging increased recalcitrant soil organic matter and reduced soil functionality in Mediterranean pine forests.

Postfire management actions are used to mitigate damage caused by wildfires. Salvage logging, often employed to restore ecosystem functions in burnt stands, plays an essential role in reducing economic losses and the burn severity of future wildfires. However, its ecological implications for soil functionality still need to be understood, especially in the Mediterranean basin, which is prone to erosion and desertification. This study aimed to investigate the effects of fire on (i) soil organic matter (SOM) quality and composition using differential scanning calorimetry-thermogravimetry (DSC-TG) and solid-state nuclear magnetic resonance (13C CPMAS NMR) and (ii) phosphorus (P) forms using solid-state 31P NMR spectroscopy in a wildfire that affected 3200 ha in southeastern Spain in July 2017. One year after the fire, we monitored four Pinus halepensis Mill. stand categories based on soil burn severity (SBS): unburnt, low SBS, high SBS and high SBS areas with salvage logging (n=36, nine plots per SBS level). We collected soil samples and analysed soil pH, SOM content and SOM quality, along with biological activity indicators (carbon biomass, basal respiration, β-glucosidase, phosphatase activities) and P forms. We ran ANOVA statistical tests to identify significant differences in soil properties among SBS levels. We also established general linear regressions of thermo-recalcitrance values and aromaticity with biological soil quality indices to compare both techniques for detecting changes in SOM quality and composition. The results indicated that fire increased soil pH (up to 0.3), particularly in the plots with higher SBS levels. SOM decreased significantly with increasing SBS level (down to < 5 % at the high SBS level), with a shift from labile compounds (carbohydrates) to more recalcitrant ones (aromatics). Organic P forms were depleted, while orthophosphate levels rose, increasing the risk of irreversible fixation. This study also highlights that DSC-TG is a cost-effective technique for assessing SOM quality changes. Understanding these effects is essential for developing policies to conserve and restore fire-affected areas and to promote practices that enhance soil functionality and resilience.

Changes in soil quality during different ecological restoration years in the abandoned coal mine area of southern China

AbstractUnderstanding the effects of abandoned coal mine ecological restoration on soil quality and function is important to protect the regional ecological environment. This study aims to evaluate the ecological restoration effects of soil quality in abandoned coal mine area. Taking Fengcheng County, a typical coal‐rich area in southern China, as a case, this study took 120 soil samples to investigate the influence of restoration years on soil quality by using an integrated soil quality index (SQI). Results indicated that restoration years had significant effects on the saturated hydraulic conductivity (Ks) by affecting the soil bulk density, clay content, and soil water content. Furthermore, clay, soil organic matter, Ks, and pH were selected to assess the effect of ecological restoration years on soil quality. It was found that the ecological restoration 8 years (ER8) site had higher SQI value, indicating ecological restoration years showed a positive correlation with SQI in abandoned coal mine area. Since there was a 4‐year gap between ecological restoration 4 years site and ER8 site, the ecological restoration may be effective between 5 and 8 years. The results of this study are of great significance for improving the effects of ecological restoration and management in abandoned coal mine area.

Effects of direct and conventional planting systems on mycorrhizal activity in wheat grown in the Cerrado

Direct planting systems offer several benefits to the soil and plants, as reflected in soil organisms. The Arbuscular mycorrhizal fungi are extremely sensitive to environmental changes and can be used as indicators of soil quality. This study focused on the native diversity of mycorrhizae in the region. Thus, the objective of this work was to evaluate mycorrhizal colonization, spore density, soil glomalin content and species diversity in five wheat genotypes under direct and conventional planting systems. This work was carried out in the experimental area of Embrapa Cerrados, Planaltina, DF, Brazil. The rates of mycorrhizal colonization, spore density and easily extractable glomalin were evaluated, and species of arbuscular mycorrhizal fungi were identified in five wheat genotypes under direct and conventional planting. For all the genotypes under conventional planting, there was a decrease in mycorrhizal colonization, the number of spores in the rhizosphere and the amount of easily extractable glomalin. The composition of the arbuscular mycorrhizal fungal community differed among the wheat genotypes and management systems. The richness of morphospecies of AMF in the direct planting system was similar to that in the conventional system, with twelve species each, but the conventional system reduced root colonization and spore density. The most common species were A. scrobiculata, Si. tortuosum and G. macrocarpum, which were found in all the genotypes in both cultivation systems.

Impact of Agroforestry Practices on Soil Microbial Diversity and Nutrient Cycling in Atlantic Rainforest Cocoa Systems.

Microorganisms are critical indicators of soil quality due to their essential role in maintaining ecosystem services. However, anthropogenic activities can disrupt the vital metabolic functions of these microorganisms. Considering that soil biology is often underestimated and traditional assessment methods do not capture its complexity, molecular methods can be used to assess soil health more effectively. This study aimed to identify the changes in soil microbial diversity and activity under different cocoa agroforestry systems, specially focusing on taxa and functions associated to carbon and nitrogen cycling. Soils from three different cocoa agroforestry systems, including a newly established agroforestry with green fertilization (GF), rubber (Hevea brasiliensis)-cocoa intercropping (RC), and cocoa plantations under Cabruca (cultivated under the shave of native forest) (CAB) were analyzed and compared using metagenomic and metaproteomic approaches. Samples from surrounding native forest and pasture were used in the comparison, representing natural and anthropomorphic ecosystems. Metagenomic analysis revealed a significant increase in Proteobacteria and Basidiomycota and the genes associated with dissimilatory nitrate reduction in the RC and CAB areas. The green fertilization area showed increased nitrogen cycling activity, demonstrating the success of the practice. In addition, metaproteomic analyses detected enzymes such as dehydrogenases in RC and native forest soils, indicating higher metabolic activity in these soils. These findings underscore the importance of soil management strategies to enhance soil productivity, diversity, and overall soil health. Molecular tools are useful to demonstrate how changes in agricultural practices directly influence the microbial community, affecting soil health.

The delineation of management zones using soil quality indices for the cultivation of irrigated rice (Oryza sativa L.) in Huila, Colombia

Conventional intensive farming systems can result in degraded soil. It is therefore important to monitor this effect periodically by delineating management zones (MZ) based on soil quality indices (SQI) in order to maintain and improve the soil characteristics in a precision farming environment and obtain homogeneous rice yields. The aim of this study was to determine and spatialise SQI and delineate MZ for cultivating flooded rice in an area of Fluvisols in Huila, Colombia. Forty-one georeferenced soil samples were collected from the 0 to 20 cm layer, and the physical, chemical and biological attributes of the soil were analysed to calculate the Integrated Quality Index (IQI) and the Nemoro Quality Index (NQI) using linear scoring functions. Geostatistical tools were then used to fit semivariogram models of the SQI, and interpolated using ordinary kriging to map the MZ using the QGIS software. The IQI and NQI showed a moderate spatial correlation, which allowed three distinct MZ to be identified and delineated. Attributes, such as bulk density (Bd), total porosity (TP), soil respiration (SR), available water (AW) and soil organic matter (SOM) were significant and can be used as a guide by farmers for restoring the quality of the soil in rice production. The method proved to be effective, and provided an information base to be used in the local management of areas of rice cultivation in the study region.

Evaluating soil quality and carbon storage in Western Ghats Forests, Karnataka, India, for sustainable forest management.

Monitoring soil quality index (SQI) and soil organic carbon (SOC) stock status of the Western Ghats (WG) forests in India is crucial for providing vital ecosystem services alongside sustainable forest management practices. However, comprehensive profile data on SQI and SOC stock across different forest types under WG forests are limited. The study evaluated SQI and SOC stock under three forest types, i.e. tropical wet evergreen (TWE), tropical semi-evergreen (TSE), and tropical moist deciduous (TMD) across WG in Karnataka. SQI was assessed using principal component analysis with two indexing approaches and scoring methodologies, with weightage indexing through nonlinear scoring functions (NLSF) showing superiority over other methodologies. TMD forests exhibited the highest SQI, followed by TWE and TSE, while the lowest was observed in Rippon Pet RF (0.36 surface, 0.28 control section), primarily due to limitations in organic carbon and clay content. SOC stock mirrored SQI trends (TMD > TWE > TSE), with the highest values in Kollegal RF (339.3 MG ha-1) and lowest in Rippon Pet RF (102.5 MG ha-1). Although SOC and SQI were established to be ideal indicators for dynamic ecosystem services (ESs), high OC content in surface soils of Poomale NF induces pedogenic acidification and Al toxicities, indicating potential forest soil degradation. Significant correlation with control section SQI and SOC (p < 0.05) emphasises monitoring subsurface soil status to identify soil degradation, sustainable forestry practices, and complex ESs in forest systems.

Physico-chemical characteristics and quality assessment of soil in parts of the Banganga Basin in northeastern Rajasthan, NW India.

Soil is a vital natural resource that has a bearing on any developmental activity. A database comprising primary physicochemical characteristics and soil suitability would assist the planners in devising an appropriate land use policy and any intervention strategy for soil quality improvement. The physicochemical characteristics of soils in parts of the Banganga Basin, located in the semi-arid terrain of NW India were evaluated mainly through surface samples and sub-surface ones wherever sections were exposed in stream banks. The soil in the studied terrain is a Quaternary age, pale brown to dark brown and occasionally red, alluvial soil. Sandy loam is the dominant soil type, while sandy soil and loamy sand types also occur. The soil maintains a depth-wise consistency in physicochemical characteristics. The average soil pH value is 8.55, indicating a slightly alkaline and healthy soil. The soil has a high available nitrogen content (0.53 to 2.24%), adequate available phosphorus (23.58 and 62.18mg/kg), and low potassium (22.5 and 200mg/kg) contents. The organic carbon, Mg, and Ca levels are generally on the lower side. A consistency in overall soil characteristics is evident in the narrow range of the Soil Quality Index, varying between 10 and 14, and soil can be categorized into three categories with overlapping soil qualities.

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.

Successive monoculture of Eucalyptus spp. alters the structure and network connectivity, rather than the assembly pattern of rhizosphere and bulk soil bacteria

Eucalyptus as a fast-growing timber tree plays a crucial role in maintaining wood supplication and ecosystem balance worldwide. Nonetheless, the management practices of Eucalyptus plantation in southern China have resulted in productivity decline and soil degradation due to high-intensity successive cultivation. Soil bacteria is a sensitive indicator of soil quality, how does the successive planting of Eucalyptus regulate the soil bacterial community structure for instance the abundance of oligotrophic bacteria, network complexity, and soil bacteria assembly remain ambiguity. To explicate the underlying influencing mechanisms of successive cultivation of Eucalyptus plantations on soil bacterial community structure. Four harvests of Eucalyptus plantations that underwent 0, 1, 2, and 3 times of harvesting were conducted to examine variations in the bacterial community between rhizosphere and bulk soils after successive planting of Eucalyptus. An adjacent evergreen broadleaf forest was employed as control. The present study revealed that successive planting of Eucalyptus increased and reduced the relative abundance of Chloroflexi (oligotrophic bacteria) and Proteobacteria (copiotrophic bacteria), respectively. Continuous planting of Eucalyptus did not modify the assembly pattern of soil bacterial communities, which was governed by stochastic processes. Successive planting of Eucalyptus decreased co-occurrence network complexity, and elevated the proportion of rare microorganisms in the keystone bacterial taxa. Soil particle size composition (clay, silt, sand) indirectly influenced the structure of soil bacterial communities by directly affecting pH, carbon, nutrients, and their stoichiometric ratios. Improving soil physical structure, increasing the input of soil carbon, nitrogen, and other nutrient resources, and maintaining a balanced resource allocation may be effective strategies for ensuring enhanced productivity and sustainable utilization of soil in successive Eucalyptus plantations.

Selection of the minimum data set and quantitative soil quality indices for different azalea forest communities in southwestern China

Selection of the minimum data set and quantitative soil quality indices for different azalea forest communities in southwestern China

Soil quality index: a tool to detect the sensitivity to soil erosion in an agricultural catchment from the Middle Atlas of Morocco.

Abstract The present paper focuses on the application of the Soil Quality Index (SQI) within the Tiguert catchment, situated in the Middle Atlas of Morocco. The studied catchment, covering approximately 10.2 km², experiences a semi-arid climate with irregular rainfall and is designated as an agricultural area, making it an ideal site for studying the intricate interactions between natural processes and human activities. The SQI developed as part of the Mediterranean Desertification and Land Use (MEDALUS) project is tailored to the unique conditions of the Mediterranean region. In the case of the Tiguert catchment, SQI is calculated using a formula that considers topographical slope, horizontal depth of soil, parental material, and soil brightness. Consequently, the results depict a promising scenario, with 61% of the soil classified as “High Quality,” indicating robust soil health and resilience despite the challenges posed by a semi-arid climate. The 31% categorized as “Moderate Quality” underscores areas requiring specific management attention, while the 8% identified as “Low Quality” signals localized challenges potentially influenced by irregular rainfall patterns. Furthermore, the SQI results are closely linked to soil erosion dynamics, with higher SQI values associated with improved resistance to erosion. The dynamic connection between precipitation patterns and SQI over a 40-year analysis indicates the impact of varying rainfall on soil health. Extreme rainfall events correspond to higher SQI percentages in the “High Quality” category, while drier periods align with lower SQI percentages, emphasizing the dynamic relationship between climate and soil quality. A comprehensive analysis of SQI across diverse ecosystems in Tiguert reveals variations in soil health, emphasizing the importance of tailored land management approaches for different land use types to optimize overall soil sustainability.

Land use change from rice paddies to upland fields aggravates soil microbial metabolic limitation and reduces soil quality index and ecosystem multifunctionality

AbstractWith rapid urbanization and economic development, the area of paddy fields has seriously declined in rice‐producing region. However, the impacts of land use change (LUC) on soil enzymatic stoichiometry, microbial metabolic limitations and ecosystem multifunctionality (EMF) have not been well‐documented. Hence, four adjacent paired soil samples were collected in rice‐producing areas. Soil microbial carbon (C), phosphorus (P) and nitrogen metabolic limitations were assessed via vector model. The impacts of LUC on soil structure, microbial activity, quality and multifunctionality were evaluated via soil structure stability index (SSI), soil biological activity (SBA), soil quality index (SQI) and EMF, respectively. Result showed that LUC from rice paddies to upland fields markedly decreased soil structure stability by 19.6%. Soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP) and nutrient‐acquiring enzymes activities in the paddy soils were significantly higher than that in upland soil. Compared with paddy soil, microbial relative C and P limitations in upland soil were significantly aggravated by 10.9% and 4.2%, respectively. Additionally, variation partitioning and redundancy analyses revealed that soil pH, available P and P‐acquiring enzymes were the crucial edaphic factors affecting microbial metabolic limitations. Comprehensive assessment showed that LUC from rice paddies to upland fields significantly reduced SBA, SQI and EMF by 5.2%, 17.4% and 17.2%, accordingly. Overall, LUC from rice paddies to upland fields significantly destroyed soil structure, aggravated microbial relative C and P limitations and reduced soil quality. Therefore, artificial managements should be strengthened to counteract the adverse effects of LUC on soil quality and EMF. This study deepened our understanding of sustainable development and efficient management of field under LUC condition.