Soil Organic Carbon Research Articles

Different cropping systems impact soil health by improving soil biological activities and total organic carbon content

ABSTRACT This study assesses the impact of different cropping systems on changes in total organic carbon (TOC), its fractions and biological activities to evaluate the changes in soil health. The rice-wheat cropping system (RWCS) had significantly higher total organic carbon (TOC) (38.8%) and soil organic carbon (SOC, 43.6%) compared to the pearl millet-mustard cropping system (PMCS). Active C pools were significantly higher in soils under cotton-wheat (CW) and pearl millet-wheat cropping systems (PWCS) than RWCS, whereas passive C pools (63% of TOC), the microbial biomass carbon (MBC) and dehydrogenase activity (DHA) were highest under RWCS than other systems. Soils under these cropping systems exhibited a significant polynomial relationship of TOC with SOC and dissolved organic carbon (DOC). Two significant canonical discriminant functions involving TOC, SOC, DOC, very labile carbon (CVL), labile carbon (CL), less labile carbon (CLL), recalcitrant carbon (CR), MBC and DHA could distinguish the different cropping systems and contributed 94.7%. The principal component analysis identified that TOC, SOC, pH and EC were the most reliable and contributing variables for assessing soil health under different cropping systems. Three PCs explained the 79.2% variability of the total variance of the original data set.

Delineation of Management Zones for Site‐Specific Soil Nutrient Management for Sustainable Crop Production

ABSTRACTSoil nutrients deficiencies are one of the major causes of soil degradation in different parts of World, adversely impacting crop production. Delineation of soil nutrients management zones (MZs) is one of the commonly used techniques for evaluating spatial distribution pattern of soil parameters for adoption of site‐specific nutrient management. We, therefore, conducted the present study to understand the spatial distribution pattern of soil nutrients and their associated soil properties, and to delineate soil nutrients MZs in a north‐western Indian Himalayan (NWIH) region. A total of 18,930 representative surface (0–15 cm depth) soil samples were collected and processed. The processed soil sample were analyzed for pH, and electrical conductivity (EC), soil organic carbon (SOC), available N (AN), available P (AP), available potassium (AK), exchangeable Ca (Ex. Ca), exchangeable Mg (Ex. Mg), available S (AS), available Zn (AZn), available Fe (AFe), available Cu (ACu), available Mn (AMn) and available B (AB). The values of studied soil parameters varied widely with coefficient of variation ranging from 11.8% to 156%. Semivariogram analysis revealed stable, exponential and Gaussian best‐fit models for different soil parameters with weak (AP and AB), moderate (rest of soil parameters) and strong (AS) spatial dependence. Varied distribution pattern of soil parameters was visualized from ordinary kriging interpolation. Five soil nutrient management zones (MZs) were identified (using fuzzy performance index and normalized classification entropy values) by employing the techniques of principal component analysis and fuzzy c‐means clustering. Principal components with Eigen value > 1 were considered for further analysis. The soil parameters of identified MZs differed significantly. Thus, the study highlighted the usefulness of MZ delineation technique for site‐specific soil nutrient management in different cultivated areas for sustainable crop production. The developed MZ maps could suitably be used for efficient management of agronomic inputs especially fertilizer nutrients for improved environmental and economic efficiency.

Carbon Budgeting of a Long-term Rice-rice Cropping Sequence in the Typic ustipsamments of Kerala, India

A judicious management practice to improve the soil's organic carbon level and soil fertility is essential for agricultural and environmental sustainability. The present study was undertaken to assess the long-term effect of various management practices on soil carbon dynamics and agricultural sustainability by computation of indices like carbon pool index (CPI), carbon lability index (CLI), carbon management index (CMI), critical carbon input and carbon budgeting. CMI has been used as a more sensitive indicator to evaluate capacity of a management practice to promote soil quality. Sensitivity index was used to determine the degree of changes in each carbon fraction due to management practices. The study was carried out in a permanent manurial trial plot started in 1964 under a long term rice-rice cropping sequence in Kerala. Based on the results obtained, integrated application of NPK fertilizers along with FYM showed significantly higher carbon indices, increased soil carbon fractions, and carbon sequestration compared to other management practices. The study revealed that applying organics coupled with inorganic fertilizers will manage the SOC level and result in enhanced soil fertility, productivity, and agricultural sustainability.

Nitrogen induced soil carbon gains are resistant to loss after the cessation of excess nitrogen inputs

Nitrogen (N) deposition has increased soil carbon (C) storage across eastern US temperate forests by reducing microbial decomposition. However, the fate of these N-induced soil C gains are uncertain given strong declines in N-deposition rates and rising soil temperatures. As N deposition has reduced soil pH and plant C investments into the rhizosphere, we compared the extent to which removing limitations to microbial decomposition by increasing soil pH, adding artificial root exudates, or elevating soil temperature would increase microbial decomposition in soils that have and have not received excess N inputs. We hypothesized that alleviating these microbial decomposition limitations would prime soil C losses from soils that have received excess N inputs. To test this hypothesis, we conducted a soil microcosm experiment where we compared microbial respiration, microbial biomass, and soil enzyme activity in soils from an unfertilized watershed and a previously N-fertilized watershed 4 years after the end of a 30-year N deposition experiment at the Fernow Experimental Forest in West Virginia. In both watersheds, we found that removing pH, plant carbon, or temperature limitations to decomposition stimulated microbial respiration. However, microbial decomposition and soil C losses were consistently lower in the previously N-fertilized watershed across all treatments. This response, coupled with a lack of differences in microbial biomass between watersheds and treatments, suggests that long-term N fertilization has fundamentally altered soil microbial communities and has led to a sustained impairment of the ability of the microbial community to decompose soil organic matter. Collectively, our results indicate that the legacy effect of N deposition on microbial communities may influence the persistence of soil C stocks in the face of global change.

Plant and Microbial Carbon Are Important Drivers of Free‐Living Nitrogen Fixation in Tropical Forest Soils: A New Discovery of Carbon‐Driven Nitrogen Input

AbstractNitrogen (N) availability limits plant growth and soil carbon (C) sequestration in N‐limited ecosystems, however, plant and soil C feedback on the free‐living nitrogen fixation (FLNF) process is poorly understood. Moreover, whether this feedback is influenced by initial N availability in leguminous and non‐leguminous forest soils has not been clarified. Here, we found that the addition of plant‐ and microbial‐derived C significantly enhanced soil nitrogenase activity (13∼28%) and that microbial‐derived C had a more positive impact. These positive effects were attributed to the direct C‐energy supply (0.49∼0.84) rather than variations in soil microbial activity (−0.01∼0.21) and substrate resources (−0.45∼0.27). Long‐term N addition did not inhibit FLNF. C addition promoted FLNF in soils of the two forests, but the response rate was higher in the leguminous forest soils. Our study reveals that increased soil C availability can drive FLNF in tropical forests, enhancing our understanding of the soil C‐N coupling mechanism.

Identification of dominant drivers of streamflow spatiotemporal variations in typical mountainous areas in the Hexi Corridor, China

Study regionTypical mountain areas in the Hexi Corridor, China. Study focusWater security and ecosystem sustainability of arid inland river basins are highly dependent on upstream streamflow. However, due to the complex geographical environment and limited observation data in the study region, the attribution of spatiotemporal variations in streamflow influenced by climate change and/or human activities remains unclear. Here, we used partial least squares regression (PLSR) and the Budyko framework to unravel the dominant drivers of spatiotemporal variation in streamflow over the past 30 yr. New hydrological insight for the regionPrecipitation, topographic wetness index, slope, forest land, gross primary productivity, hydrological connectivity, soil organic carbon content, silt content, relative relief, NDVI and gravel content dominated spatial variation in streamflow. Temporal variation of streamflow was sensitive to precipitation and land surface. Specifically, increased precipitation and land surface alteration dominated the increase in streamflow in 50 % of the watersheds and the decrease in streamflow in 33 % of them, respectively. Further, land surface alteration was dominated by expansion of agricultural and built-up areas, weakened hydrological connectivity, increased landscape aggregation and forest cover. Controlling agricultural and built-up areas and the scale of afforestation, and focusing on the dynamics of hydrological connectivity and landscape patterns in the upstream reaches are imperative to maintain the security and sustainability of water resources in the arid inland river basins.

The effect of polyvinyl chloride microplastics on soil properties, greenhouse gas emission, and element cycling-related genes: Roles of soil bacterial communities and correlation analysis

Different shapes (membranes and particles) and concentrations (1 % (w/w) and 2 % (w/w)) of polyvinyl chloride (PVC) microplastics (MPs) were investigated to determine their impact on the soil environment. The incorporation of MPs can disrupt soil macroaggregates. Compared with 1 % (w/w) MPs, 2 % MPs resulted in a significant increase in soil organic carbon content. MP particles significantly increased soil CO2 emissions, and CH4 emissions were enhanced by both membrane and particle MPs at high concentrations. Microplastics can alter the abundance of Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteriota, and Firmicutes at the phylum level, and Nocardioides, Rhodococcus and Bacillus at the genus level. MP particles had a more significant impact on soil bacterial communities than MP membranes. The relative abundances of genes involved in the C, N, and P cycles were detected by qPCR, and more remarkable changes were observed in MP membrane treatments. The relative abundance of Vicinamibacteraceae and Vicinamibacterales exhibited a positive correlation with most C/N/P cycle-related genes, whereas Pseudarthrobacter and Nocardioides demonstrated a negative correlation. This study highlights that the influence of MPs on soil parameters is mediated by soil microorganisms, providing insight into the effects of MPs on the soil microenvironment.

Paddy straw biochar amended sediment enhances pond productivity, growth and physiological profile of Penaeus vannamei cultured in inland saline nursery ponds.

The growing interest in commercial Inland saline aquaculture has taken momentum across the globe due to the available technologies for aquaculture and the abundant resources of saline groundwater. However, the critical problems in inland saline ponds are degraded soil and imbalanced or deficient nutrients. To address these issues, a 75-day experiment was conducted to explore the effects of Paddy Straw Biochar (PSB) as a sediment amendment on sediment quality, water characteristics, growth parameters, and the well-being of Penaeus vannamei reared in inland saline environments. PSB was applied to the nursery ponds at 1 ton/hectare (Treatment, T1) and 2 ton/hectare (Treatment, T2). The findings of water quality parameters showed a significant increase in K+ and Mg++ with a decrease in ammonia-N levels in biochar-applied ponds. Similarly, the addition of biochar to ponds (T2) resulted in improved sediment characteristics with enhanced water holding capacity (24.75%), increased soil organic carbon content (77.94%), pH levels (0.37 units), cation exchange capacity (43.15%), available potassium (16.3%), and lower bulk density (12.61%) compared to ponds subjected to control conditions at the end of the experiment. Over the experiment, improvements in sediment and water quality parameters followed the T2 > T1 > control trend. Growth characteristics showed a significant rise in the percentage of weight gain (12.398 ± 0.12), SGR (11.80 ± 0.01% day-1) and PER (2.39 ± 0.01) with reduced FCR (1.19 ± 0.00) in biochar-treated ponds (T2), followed by T1 and control. The digestive enzyme activity (amylase) and metabolic enzymes like hepatopancreatic alanine aminotransferase (ALT) and muscle ALT activities were significantly higher in shrimps raised in the biochar-applied ponds. On the other hand, the oxidative stress enzyme superoxide dismutase (SOD) in gills, muscles, and hepatopancreas (HP) exhibited lower values, suggesting reduced oxidative stress due to the biochar amendment of the pond sediment. Overall, the study recommends incorporating PSB at a rate of 2 t/ha into nursery pond sediment to enhance water quality, physiological status, and the growth of P. vannamei juveniles. Moreover, this approach improves soil and water characteristics in saline soils, making it an effective culture practice in degraded environments.

When are you measuring soil β‐glucosidase activities in cropping systems?

AbstractIn situ soil respiration is driven by annual patterns of temperature and soil moisture, but what about extracellular enzyme activities responsible for depolymerizing soil organic matter? We conducted biweekly measurements of potential soil β‐glucosidase activities during a 4‐month period from March soil thawing through July in annually cropped field plots in eastern South Dakota. Our objective was to determine the best sampling time to resolve the effects of crop rotational diversity on soil microbial activities. Potential β‐glucosidase activities were elevated immediately following soil thaw, peaked in May, and declined to their lowest value in mid‐summer. Temperature and precipitation had no value in predicting enzyme activities; however, enzyme activities were affected by crop rotational diversity and responded to current crop and previous crop. These findings are pertinent to the use of soil extracellular enzymes in soil health assessments and as indicators of microbial substrate preference with implications for soil carbon stabilization.

Integrating Livestock with Crops and Forestry for Sustainability

Global per capita consumption of animal protein is set to rise, particularly in developing economies, leading to a dramatic increase in meat consumption from 133 million tons in 1980 to 452 million tons by 2050. Notably, 86% of this increase, or 279 million tons, is expected to occur in developing countries. The expansion of animal-based agricultural systems, which cover 45% of the Earth's land area, presents significant challenges. These systems contribute substantially to agricultural emissions, including greenhouse gases such as nitrous oxide (N2O) and methane (CH4), and account for 8% of global water usage. The livestock sector is largely comprised of resource-constrained smallholders in developing nations. Environmental impacts arise from the lack of integration with other agricultural and forestry practices, disrupting the natural cycles of carbon, water, nitrogen, phosphorus, and sulfur. This disruption leads to increased emissions of N2O and CH4, water contamination, land degradation, and biodiversity loss. To address these challenges and support the United Nations' Sustainable Development Goals (SDGs) related to poverty reduction (SDG #1), hunger alleviation (SDG #2), clean water and sanitation (SDG #6), and climate action (SDG #13), it is essential to integrate livestock with crop and tree farming. Strategies to improve sustainability include incorporating pastures into crop rotations, using controlled grazing techniques, practicing agro-forestry such as alley cropping, and implementing systems like ley farming. Additional measures include precision feeding and protein matching to reduce enteric fermentation, repurposing emissions of CH4 and N2O, and effective manure management. Addressing greenhouse gas emissions through diverse approaches, reducing product wastage, minimizing antibiotic use, and restoring rangelands to enhance soil carbon storage are also critical for achieving sustainable livestock practices.

Spatial distribution characteristics and influencing factors of soil organic carbon based on the geographically weighted regression model.

Quantifying the effects of environmental factors on soil organic carbon and spatial distribution is fundamental to soil quality regulation, restoration, and response to climate change. The present study aims to explore the spatial distribution characteristics of the soil organic carbon (SOC) contents in Anhui Province, China, based on national soil data. In addition, we used the geographically weighted regression (GWR) model to quantify the influence degrees of environmental factors on the soil organic carbon density (SOCD). The results showed that the spatial distribution of SOCD in Anhui Province in both 1985 and 2018 was characterized by high in the south and low in the north. The GWR model prediction results of the 0-30cm SOCD showed local coefficients of determination (local R2) ranging from 0.21 to 0.96 and 0.14 to 0.96 in 1985 and 2018, respectively. Therefore, the predicted results were effective in evaluating the overall spatial distribution of the SOCD in Anhui Province. The regression coefficients of the normalized difference vegetation index (NDVI) and air temperature ranged from - 0.39 to 5.67 and - 0.17 to 3.11, respectively, demonstrating their strong controlling effects on the spatiotemporal variations in the 0-30cm SOCD in Anhui Province.

Correlations between Tree/Shrub Diversity and Herbaceous Biomass with Soil Physico-chemical Properties under Acacia saligna Canopy

Acacia saligna (A. saligna) is originated from South Western Australia, and it was brought to the Tigray region of Ethiopia in 1972 with the intention of restoring the ecosystem and conserving soil and water. This study aims to evaluate the correlations between tree/shrub diversity and herbaceous biomass with some soil physico-chemical properties under Acacia saligna canopy and away from the canopy in Atsibi Wemberta district, Tigray, Ethiopia. For collecting of vegetation data, herbaceous cover and soil sample, twelve A.saligna tree stands were used as a replication.Woody species identification, herbaceous cover and biomass production were collected under the canopy of A.saligna and 50 m away from the canopy at 1 m2 for woody species, and 0.25 m2 for herbaceous cover, and biomass production. Soil samples were taken using auger at 20 cm soil depth under the canopy and in the canopy gap A.saligna. The species richness under the canopy of A.saligna was positively insignificant correlated with pH (r = 0.48, p = 0.11), availability of phosphorus (Av.P) (r = 0.16, p = 0.63), total nitrogen (TN (r = 0.12, p = 0.7) and Silt (r = 0.71, p = 0.009). However, it is also negatively correlated with soil organic carbon (SOC (r = -0.06, p = 0.85), and sand (r = -0.77, p = 0.003). The Pearson’s correlation matrix in the canopy gap of A.saligna showed that, Shannon diversity index is insignificantly positively correlated with SOC (r = 0.19, p = 0.53), Av.P (r = 0.46, p = 0.12), availability of potassium (Av.K) (r = 0.43, p = 0.16) and TN (r = 0.13, p = 0.69). However, species richness and Shannon diversity index have insignificantly negatively correlated with pH(r = -0.13, p = 0.68, r = -0.15, p = 0.63) and sand (r = -0.23, p = 0.51, r = -0.44, p = 0.14), respectively. In the canopy gap of A.saligna, the herbaceous biomass was positively correlated with Av.K (r = 0.47, p = 0.12), silt (r = 0.39, p = 0.20), and clay( r = 0.37, p = 0.24), but the Pearson’s correlation matrix between herbaceous biomass and some soil parameters in the canopy gap is observed to be insignificantly negatively correlated with pH (r = -0.24, p = 0.44), SOC (r = -0.04, p = 0.9), Av.P (r = -0.34, p = 0.28), and TN (r = -0.33, p = 0.31).The species richness, Shannon diversity indexes and herbaceous biomass were insignificantly positively correlated with pH under the canopy of A.saligna, but for similar parameters in the canopy gap was observed negatively insignificant correlated with pH. Overall, the small positive correlation found in the current study between same soil physico chemical and diversity indexes under the A. saligna canopy suggests that the presence of these large A. saligna trees may increase soil nutrient availability through litterfall. The study found clear relationships between plant density and Shannon diversity with herbaceous biomass in Acacia saligna's canopy gap and beneath its canopy. In particular, both settings showed a substantial negative connection between herbaceous biomass and plant density, suggesting that increased plant density tends to diminish herbaceous biomass. On the other hand, a strong positive association was seen between Shannon diversity and herbaceous biomass, indicating that higher species diversity is linked to higher herbaceous biomass. Therefore, it is imperative to manage and conserve A. saligna and the woody species growing beneath the canopy in order to preserve and strengthen the favorable connections that exist between diversity indexes and the physical and chemical characteristics of soil.

Innovative Tillage Practices to Establish Productive and Sustainable Forage Production Systems in Degraded Alfalfa Pastures in Semiarid Regions

ABSTRACTTillage management practices play a critical role in maintaining sustainable forage production systems in degraded alfalfa (Medicago sativa L.) pastures. However, climate change leads to the precipitation exhibits greater variability, the impacts of tillage practices on alfalfa productivity and forage quality as well as the relationships between water consumption and soil properties remain poorly understood. The field trial conducted from 2018 to 2020 aimed to investigate the impacts of different tillage treatments (i.e., no tillage [CK], strip subsoiling tillage [ST], strip rotary tillage [RT], and strip rotary tillage after strip subsoiling [SRT]) on soil properties, water use efficiency (WUE), and forage productivity. Compared with CK, tillage practices significantly increased forage biomass and crude protein yield (CPY), particularly in the case of the SRT treatment, in which the increase was 20.8% and 25.3% higher, respectively (p < 0.05). Meanwhile, the net income in the SRT treatment exhibited the greatest value (US $1922.0 ha−1), showing a 17.0% increase compared with that in the CK treatment. The relationship of soil structure and crop water consumption became evident when tillage practices were applied in the degraded alfalfa pasture. The soil bulk density under the ST, RT, and SRT treatments decreased by 6.9%, 5.4%, and 8.6%, whereas the soil porosity increased by 8.6%, 6.7%, and 10.7% in the 0–60 cm soil layer, respectively (p < 0.05). Furthermore, the soil water content at a depth of 0–60 cm increased by 12.1% in the SRT treatment compared with the CK treatment at the harvesting stage, and the SRT treatment obtained the highest WUE of dry matter (16.9 kg ha−1 mm−1) and precipitation use efficiency of dry matter (15.8 kg ha−1 mm−1). In addition, total nitrogen in the ST, RT, and SRT treatments increased significantly by 21.4%, 11.1%, and 27.0%, respectively, and soil organic carbon in the ST, RT, and SRT treatments also increased significantly by 5.5%, 3.3%, and 10.4%, respectively, compared with those in the CK treatment (p < 0.05). Our study has demonstrated that tillage practices can optimize soil structure, improve water utilization, and increase soil fertilizer for enhancing forage productivity. The SRT practice could be a preferable approach for sustainable agricultural production of degraded alfalfa grassland in the semiarid region of China.

Assessment and Delineation of GPS-GIS Based Soil Fertility Maps of Instructional Farm, Malegaon Tehsil Baramati

The present investigation was conducted in the year 2023-24 at division of Soil Science, Dr. Sharadchandra Pawar College of Agriculture, Baramati with an objectives to assess the soil available nutrient status and delineation of GIS based maps of soil available nutrients. Using Arc-GIS 10, Version 10.8, fertility maps of the available macro nutrients were created. The area under the Instructional Farm had soil pH ranged from 7.11 to 8.32, categorized into the slightly alkaline to moderately alkaline categories while the EC varied from 0.21 to 1.99 dSm-1, indicating that most of the soils were non-saline. The soil's organic carbon and calcium carbonate contents ranged from 0.21 to 0.97 per cent and 1.50 to 19.75 per cent and they were classified into low to high and low to very high categories respectively. In the Instructional Farm, the ranges of available nitrogen, phosphorus and potassium content were 85.50 to 360.75, 23.29 to 80.08 and 202.5 to 968.68 kg ha-1 respectively. The Instructional Farm soils had very low to moderate levels of available nitrogen, moderately high to very high levels of available phosphorus and moderately high to very high levels of available potassium. The implementation of GPS-GIS-based techniques for soil sampling represents a significant advancement that will allow researchers and institute officials to track changes in soil fertility over the years. The soil fertility maps created for the Instructional Farm will be invaluable for establishing a scientifically sound fertilization schedule.

Understanding how corn-yellow melilot intercropping combined with straw return increased stable organic carbon pool in Mollisols by reducing the application of chemical fertilizer

Long-term cultivation with persistent use of chemical fertilizers causes a rapid decline in organic matter content of Mollisols. But practicing intercropping along with straw return instead of the use of chemical fertilizer have the potential to reverse the decline and improve soil organic carbon (SOC) content. A field experiment with five treatments at two sites of Songnen Plain of Northeast China included the following treatments (1) corn monoculture with no chemical fertilizers and no straw return (c), (2) corn monoculture with chemical fertilizers and no straw return (c + F), (3) corn-yellow melilot intercropping and straw return combined with full application of chemical fertilizers (c&m + S + F), (4) corn-yellow melilot intercropping and straw return combined with half dose of chemical fertilizers (c&m + S + F/2), and (5) corn-yellow melilot intercropping and straw return without chemical fertilizers (c&m + S). The results showed that c&m + S + F, c + F, and c&m + S + F/2 decreased specific gravity and c&m + S + F increased water content. The c&m + S + F, c&m + S + F/2, and c&m + S improved SOC with 18.7%, 7.95%, and 8.17% (P < 0.05), respectively. The c&m + S + F and c&m + S + F/2 increased mineral-associated organic carbon, humus organic carbon, and heavy fraction organic carbon content. These findings provide a method for utilizing intercropping and straw return to replace chemical fertilizers to improve SOC and stable organic carbon content to ameliorate soil quality.

Soil carbon sequestration potential of different land use systems: evidence from sub-humid southern plains and Aravalli hills of Rajasthan, India.

This study has assessed total soil organic carbon (TOC) fractions, carbon management index (CMI), and carbon sequestration economic value under diverse land use systems (LUSs) of sub-humid Southern plains of Rajasthan, India. The study dealt with six LUSs: barren land (BL), agricultural land (AL), agri-horticulture (AH), horticultural land (HL), grassland (GL), and natural forest land (FL) were selected for the study. FL contained the highest TOC (13.04 ± 0.74gkg-1), particulate organic carbon (POC) (2.2 ± 0.19gkg-1), mineral-associated organic carbon (MAC) (10.84 ± 0.54gkg-1), and CMI (230.36 ± 4.13), whereas BL had the lowest amount of TOC (3.53 ± 0.4gkg-1), POC (0.47 ± 0.06gkg-1), MAC (3.06 ± 0.32gkg-1), and CMI (54.60 ± 4.2). The impact of LUSs on soil carbon lability index (LI) was minimal in all LUSs except FL exhibited statistically insignificant variations in LI. TOC stock showed the highest decline in BL (71.04%), AL (55.29%), AH (44.38%), and HL (25.92%) uses compared with the FL system. Different LUSs result in varying amounts of carbon stocks, representing the relative carbon credit gain. The maximum carbon credit was achieved by FL, which was roughly US $49,303 and 245% higher than BL. These results indicate the reinstatement of BL and AL towards HL and AH systems, and effective recycling of residues could improve the TOC storage in the study region.

The Role of Fertilization on Soil Carbon Sequestration in Bibliometric Analysis

The soil carbon pool is the largest and most dynamic carbon reservoir in terrestrial ecosystems. Fertilization, an important component of agricultural management, is a significant factor influencing soil carbon sequestration. This study analyzed literature from the Web of Science from 2008 to 2024 using CiteSpace. The results revealed a steady increase in publications on this topic, with a significant surge in the recent four years. The analysis highlighted key collaborations among countries, institutions, and authors, and identified main journal sources and seminal works in the research on the role of fertilization in soil carbon sequestrations. Keyword analysis indicated that current research hotspots include ‘soil organic carbon dynamics and organic matter decomposition’, ‘microbial community dynamics and carbon cycling’, and ‘agricultural management practices on carbon sequestration’. In the context of climate change, future research is likely to focus on enhancing sustainable agricultural practices, promoting biochar and resource utilization, and utilizing microbial communities to optimize soil carbon sequestration. This study provides a comprehensive overview of the role of fertilization in soil carbon sequestration, providing important insights for improving soil carbon sequestration strategies.

Enhancing Water Use Efficiency and Carbon Profitability Through the Long-Term Impact of Sustainable Farming Systems

This study aims to enhance water use efficiency, maximize productivity, and minimize environmental impact through the implementation of sustainable agricultural systems using drip irrigation systems. It investigates the effects of biodynamic farming compared to those of organic and conventional methods over a six-year period and focuses on soil properties, water use efficiency, crop yield, and environmental and economic perspectives. Using a biodynamic farming system resulted in an average increase in water use efficiency of 1.96 and 10.67% for maize and 3.62 and 10.68% for faba bean and an increase in maize yield of 1.68 and 0.99%, while the faba bean yield reached 3.25 and 1.57% compared to the organic and conventional farming systems, respectively. The biodynamic system sequestered the highest average soil carbon of 6.16 tons/ha (which is equivalent to 22.45 tons/ha of CO2 emissions), representing a 13% increase compared to the organic system. Additionally, the biodynamic system yielded an increase in total net profit of 5.70 and 21.66% for the maize crop and 6.72 and 22.19% for the faba bean crop compared to the organic and conventional farming systems, respectively. The farming system significantly influenced the soil carbon sequestration and organic carbon.

Effect of Liquid Microbial Consortium on Physio Chemical Properties of Rice Field (Oryza Sativa) in a Vertisol

A study was conducted during kharif 2020 on "Effect of liquid microbial consortium (Azotobacter, Azospirillum, PSB (Pseudomonas mallei, Pseudomonas cepaceae, Penicillium sp.) and KSB) on physio chemical properties and microbial population of rice field (Oryza sativa) in a Vertisol" at the Indira Gandhi Krishi Vishwavidyalaya's Research cum instructional farm in Raipur (C.G.). Experiment included seven treatments viz. control (no fertilizer, no liquid NPK microbial consortia), two independent applications of 75 % RDF (90:45:30) and 100% RDF ((120: 60: 40) N, P2O5, and K2O kg ha-1 and four various combinations of seed and soil application of liquid NPK microbial consortia. Seed coating with NPK consortia @5ml kg-1, with 75% and 100% RDF and Seed coating with NPK consortia @5ml kg-1 + Soil application of NPK consortia @3 L ha-1 at 21 DAS with 75%RDF and 100%RDF. In the experiment, liquid biofertilizer products, such as liquid microbial NPK consortia were used. The population of Azotobacter, Azospirillum, phosphorous solubilizing bacteria (PSB), potassium solubilizing bacteria (KSB) and total bacterial population were significantly influenced by application of consortia as seed treatment @ 5ml kg-1 only and by a combination of seed treatment @ 5ml kg-1 seed + soil application @ 3 L ha-1 at 21 DAT with 75 or 100 % recommended dose of fertilizers and showed statistically significant higher microbial population in comparisons with the treatments of untreated alone applications of 75 or 100 % RDF. The results showed that the soil reaction, (pH) salt concentration (Electrical conductivity) and organic carbon status were not significantly influenced by the different treatments of fertilizer levels and microbial consortia applied. Slight decrease in the soil reaction (pH) and slight increase in the OC status after the harvesting of rice were observed from their initial soil values (before application of treatments). It might be due to the addition of organic matter as plant residues (straw and roots) of rice crop gown in the field. As compared to untreated- control (T1) a slight decrease in pH and increase in organic carbon content due to application of fertilizer and microbial consortia were also recorded. The residual available nitrogen in the soil after the harvesting of rice was not significantly influenced by the fertilizer levels and NPK consortia applied. The initial status of the experimental soil was low for available nitrogen (224 kg ha-1), medium for available phosphorus (24.5 kg ha-1) and high for available potassium (384 kg ha-1). Due to the addition of nitrogen through the fertilizer (90-120 kg ha-1) and less uptake of native nitrogen from the soil, a marginal increase in the residual available N in the soil from the initial level was observed in all treatments except the control (no fertilizer, no consortia). The residual status of available potassium was also not significantly influenced by the applied fertilizer doses and NPK consortia. A marginal decrease in the residual available K status after the harvesting of rice was observed in all treatments. A decrease was found in the control plot. A decrease in the K status (from the initial level) was observed less where a full dose of NPK fertilizers (100%) was applied with the NPK consortia. Ramlakshmi et al. [1], also observed slight reduction in soil pH and increase in organic carbon content in biofertilizer inoculated treatments as compared to the un-inoculated control soil [2].

Biological soil crusts significantly improve soil fertility and change soil microbiomes in Qinghai-Tibetan alpine grasslands.

Biological soil crusts (BSCs), a vital component of ecosystems, are pivotal in carbon sequestration, nutrient enrichment, and microbial diversity conservation. However, their impact on soil microbiomes in alpine regions remains largely unexplored. Therefore, this study aimed to determine the influence of BSCs on alpine grassland soil microbiomes, by collecting 24 pairs of soils covered by biological and physical crusts along a transect on the Qinghai-Tibetan Plateau. We found that BSCs significantly increased the contents of soil moisture, organic carbon, total nitrogen, and many available nutrients. They also substantially altered the soil microbiomes. Specifically, BSCs significantly increased the relative abundance of Cyanobacteria, Verrucomicrobiota, and Ascomycota, while decreasing the proportions of Gemmatimonadota, Firmicutes, Nitrospirae, Mortierellomycota, and Glomeromycota. By contrast, microbial abundance and α-diversity demonstrated low sensitivity to BSCs across most study sites. Under the BSCs, the assembly of prokaryotic communities was more affected by homogeneous selection and drift, but less affected by dispersal limitation. Conversely, soil fungal community assembly mechanisms showed an inverse trend. Overall, this study provides a comprehensive understanding of the effects of BSCs on soil properties and microbial communities, offering vital insights into the ecological roles of BSCs.