Journal of the Indian Society of Soil Science
Journal of the Indian Society of Soil Science is the periodical brought out quarterly since 1953 (March, June, September and December) and it covers all aspects of soil study. The Society organizes seminars, symposia, conferences, meeting etc. enables members of ISSS and others to interact and disseminate knowledge on soil and land. Annual Convention of the Society is held regularly. This Society has celebrated its Golden Jubilee in 1984, Diamond Jubilee in 1994 and Platinum Jubilee in 2009. EDITORIAL BOARD Subscription Information for Print Version
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Assessment of Yield Barrier Nutrient in Black Gram (Vigna mungo L.) Through Nutrient Omission in Dystrudept of Nagaland
Impact of Different Phosphorus and Zinc Levels on Macronutrient Content in Cotton Grown in Alluvial Soils of Punjab, India
Comparison of Empirical and Physically Based Infiltration Models Using In-Situ Measurements in Porous Soils
Enhancing Soil Fertility and Potassium Dynamics in Sandy Loam Soils through Tank Silt and Wood Ash Application in Groundnut Cultivation
Tank silt and wood ash, often considered underutilized by-products, can serve as effective soil amendments for improving soil properties. A field experiment was conducted during the rabi season of 2023 on sandy loam soil to evaluate the effects of tank silt and wood ash on soil chemical properties and potassium dynamics under groundnut cultivation. The study employed a randomized block design (RBD) with three replications, incorporating ten treatments that included tank silt, wood ash, and foliar application of K2SO4 at varying levels of the recommended dose of potassium (RDK). A significant impact was observed on soil chemical properties and the water-soluble and exchangeable potassium fractions. However, fixed and total potassium contents remained statistically unchanged.
Influence of Iron Powder and Water Content on Geotechnical and Electrical Properties
Adding iron powder to soil affects its electrical and geotechnical properties and has numerous uses across various engineering domains. The purpose of this study is to examine how water content and iron (Fe) metal powder affect the electrical and geotechnical characteristics of soil, including plasticity, resistivity, dielectric constant, friction angle, and cohesion. The microstructure and elemental content were characterised using SEM-EDX analysis. The hydrometer method was employed to determine texture. This study investigates the combined impact of moisture levels (0-50%) and metal powder concentration (0-10%) on soil resistivity and other electrical characteristics by precisely varying both. Iron powder increases soil bulk density and decreases soil porosity. As the amount of moisture and iron powder increases, the soil’s cohesiveness, friction angle, and resistivity decrease while its dielectric constant and plasticity rise. Applications include electrical grounding, electromagnetic surveys, and soil stabilisation. These results provide new information on how to modify soil properties. Furthermore, by revealing soil moisture levels in agriculture, variations in soil resistivity due to iron and moisture content might help optimise irrigation techniques.
Sewage Sludge and Inorganic Chemical Fertilization Modulate Rhizosphere Microbial Activity and Diversity in Kale and Spinach Cropping Systems
Sewage sludge is widely explored as an organic nutrient source, but its ecological effects on soil microbial communities remain context dependent. This study evaluated the effects of sewage sludge and NPK fertilizers on soil microbial populations associated with kale (Brassica oleracea L. cv. ‘GM Dari’) and spinach (Spinacia oleracea L. cv. ‘Shalimar Green’). A two-season field experiment (rabi and kharif) was conducted at the Experimental Farm, Wadura Campus, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, using a randomized complete block design with nine treatment combinations and three replications. Results showed that sewage sludge amendments significantly increased the abundance and diversity of soil microorganisms compared to control and solely chemical fertilizer treatments. Rhizospheric soils of kale and spinach contained Flavobacterium, Bacillus, and Alcaligenes species, while fungal genera such as Aspergillus, Trichoderma, Mucor, and Paecilomyces were predominant in sludgeamended soils. The highest bacterial counts (39.30 × 10x CFU g-1 for kale and 39.25 × 10x CFU g-1 for spinach) and fungal counts (16.70 × 10t CFU g-1 for kale and 16.39 × 10t CFU g-1 for spinach) were recorded under 100% sewage sludge, followed closely by the combined treatment of 75% sludge + 25% NPK, whereas the control plots exhibited the lowest microbial abundance. The findings demonstrate that sewage sludge effectively enhances soil microbial activity and diversity, improving soil biological fertility. Partial substitution of mineral fertilizers with sludge (75% sludge + 25% NPK) appears optimal for maintaining microbial health and supporting sustainable vegetable production in the Kashmir Valley.
Microbial Decomposers-Mediated Changes in Soil Biological Properties, Organic Carbon Fraction and Wheat Yield Under Rice Residue Retention in Indo Gangetic Plains
A field experiment evaluated the effects of tillage, rice residue management, and microbial decomposers on soil biological properties, carbon dynamics, and wheat productivity. Seven treatments were tested in a randomized block design. The treatment T7 (zero tillage + 70% residue retention + fungal–bacterial consortia @ 250 ml ha-1) significantly (p<0.05) outperformed the residue burning treatment T2. Soil pH decreased from 7.87 (T2) to 7.57 (T7), while oxidizable organic carbon increased from 0.49% to 0.59%. Microbial biomass carbon under T7 reached 297.50 and 288.53 μg g-1 soil at flowering and harvest, showing a 22.0–24.1% increase over T‚ . Dehydrogenase activity also improved markedly (46.57 and 41.67 μg TPF g-1 soil h-1 at flowering and harvest) compared to T2. Populations of bacteria, fungi, and actinomycetes increased by 86.1, 71.0 and 72.9%, respectively. Carbon fractions, including very labile, non-labile, active, and passive pools, were significantly higher under T7. Consequently, grain and straw yields were maximized (41.03 and 51.09 q ha-1), with increases of 18.8% and 15.1% over T2. Overall, residue-retained zero tillage combined with microbial consortia enhances soil health, carbon sequestration, and wheat productivity sustainably.
Soil Nutrient Dynamics Following Conversion of Long-term Poplar Based Agroforestry to Rice-Wheat Rotation
Different land use systems lead to variation in soil properties and nutrient status of soil. A study was conducted to observe the changes in soil pH, EC, organic carbon, available macronutrients (N, P and K) and DTPA extractable micronutrients (Zn, Fe, Mn and Cu) on the sites where poplar based agroforestry system (AFS) was being raised for the last 35 years, sites with rice-wheat rotation for last 35 years, sites converted to rice-wheat rotation after 30 years of poplar based AFS and sites with no plants (control) at Khera bet village, Ludhiana, Punjab. Soil samples were analyzed under these four land use systems in four soil depths (0-15, 15-30, 30-45 and 45-60 cm). The rice-wheat system showed the lowest pH (7.09-7.30), while EC values were comparatively higher in this system. The soil OC content was highest in poplar based AFS followed by converted sites, rice-wheat rotation and control. Available N was statistically at par in poplar based AFS and rice-wheat rotation. Available P was significantly higher in rice-wheat rotation and available K in poplar based AFS in various depths than the other land use systems. Average DTPA extractable Zn, Mn and Cu contents were significantly higher in poplar based AFS (2.29, 5.49 and 1.27 mg kg-1) than rice-wheat rotation whereas Fe was statistically at par between these two systems (12.39 and 12.81 mg kg-1, respectively). The converted sites had lower values of macro and micronutrients than poplar based AFS. Soil OC and all the macro and micronutrients were higher in surface depth than the lower depths. Thus, the greater micronutrient availability under poplar based AFS highlights its importance in maintaining long-term micronutrient balance and soil health.
Depth-wise Distribution of Soil Nutrients under Different Cropping Systems in Eastern Rajasthan, India
The availability of nutrients for crops is significantly impacted by various cropping systems and nutrient management techniques. Ten common cropping systems—pearl millet-wheat, pearl millet-mustard, pearl millet-chickpea, sesame-chickpea, pearl millet-fennel, groundnut-wheat, maize-chickpea, maize-wheat, tomato-cabbage, and sesame-mustard—were thoroughly evaluated in four districts (Karauli, Sawai Madhopur, Bharatpur, and Dholpur) in Eastern Rajasthan, a semi-arid region of India. In order to measure depthwise differences in soil macronutrients (N, P, K, S) and micronutrients (Zn, Cu, Fe, Mn), 360 soil samples (12 per system over three depths: 0–15, 15–30, and 30–45 cm) were taken in April 2024 after Rabi crop harvest. The Maize-Chickpea) system had the highest available nitrogen (N) 432.75 kg ha-1, 373.80 kg ha-1 and 277.48 kg ha-1 at 0-15 cm, 15-30 cm and 30-45 cm depth, while both the groundnut-wheat (27.70 kg ha-1) and maize-chickpea (25.25 kg ha-1) systems had higher available phosphorus (P) levels compared to pearl millet–fennel (14.56 kg ha-1). Nutrient concentrations generally declined with depth, yet legumebased systems excelled: maize-chickpea and groundnut-wheat achieved peak available N and P, driven by biological N fixation and enhanced organic matter turnover. Pulse-based systems substantially outperformed cereal based systems rotations in nutrient retention and SOC buildup. These findings underscore crop diversification—especially legume integration—as vital for boosting soil fertility in semi-arid agroecosystems, supporting sustainable agriculture.
Effects of Irrigation Regimes and Residue Management Practices on Soil Organic Carbon and Physical Properties under Rice-based Cropping System
Soil organic carbon and physical properties have the immense importance in relation to crop growth and productivity. The effect of different residue management practices (rice straw @6 t ha-1 and mungbean residue @ 2.5 t ha-1) and irrigation regimes on soil organic carbon and physical properties was studied under rice–based cropping after four years of the start of experiment. There were three irrigation regimes in rice (CF– Continous flooding, 2–D- irrigation applied after 2 days of drainage of ponded water and 4–Dirrigation applied after 4 days of drainage of ponded water) and six residue management practices viz., R0– Residue removal, R0+M– only mungbean residue incorporation, RRR– rice residue surface retention, RRR+M– rice residue surface retention + mungbean residue incorporation, RRI– rice residue incorporation and RRI+M– rice + mungbean residue incorporation. The soil organic carbon concentration increased by 22, 18, 16, 14% in RRI+M, RRI, RRR+M and RRR in comparison to R0 in 0–15 cm soil layer. Soil bulk density of surface layer was lower in RRI+M, RRI, RRR+M and RRR than R0 plots. However, there was an increase in soil porosity and mean weight diameter of soil aggregates in plots with RRI+M, RRI, RRR+M and RRR residue management practices than R0 plots in 0–15 cm soil layer. Pooled rice yield was similar under CF and 2–D irrigation regime but significantly higher than 4–D irrigation regime. The impact of residue management practices was evident in both rice and wheat crop with higher yield under in–situ residue management practices in comparison to residue removal. Thus, residue management practices viz. incorporation or retention improved the crop productivity, soil physical properties and soil organic carbon of surface soil layer in the sandy loam soils under rice–based cropping system.
Soil Quality Assessment in Major Mango-Growing Regions of Southern Karnataka, India
The Soil Quality Index (SQI) is a vital tool for crop-specific land-use planning aimed at sustaining productivity and long-term soil health. This study identified key soil indicators that influence soil quality across two major mango-growing belts in southern Karnataka. Soils were sampled from the Central Mango Belt (Davangere, Chikmagalur, Shivamogga, Chitradurga, Mandya, and Mysuru) and the Southern Mango Belt (Kolar, Tumakuru, Chikkaballapura, Bengaluru Rural, Ramanagara, and Bengaluru Urban), representing diverse agro-climatic conditions. Soils samples were collected from the horizons of 15 representative pedons and analysed for their physico-chemical properties. Principal Component Analysis (PCA) was used to derive a Minimum Data Set (MDS) of key soil indicators, and the Soil Quality Index (SQI) was subsequently computed using additive and weighted approaches with both linear (LSF) and non-linear (NLSF) scoring functions. In SMB, Bangalore North, Hoskote, Chintamani, and Srinivasapura taluks showed high to very high SQI, whereas Mulabaghilu exhibited low SQI (0.38–0.43) due to high sand content and exchangeable sodium. Similarly, in the CMB, Tarikere and Hunsur Taluks showed high to very high SQI, while Nagamangala recorded a low SQI (0.36), constrained by a shallow effective soil depth. Yield–SQI relationships showed that NLSF captured soil functional variability more effectively than LSF, while weighted indexing outperformed the additive approach, particularly in semi-arid red ferruginous soils. The findings highlight the importance of incorporating inherent soil quality into land-use planning for perennial crops. These results offer a robust basis for region-specific, crop-optimized land use planning in comparable agro-climatic environments.
Terai, a Rich Hub of Soil Carbon Storage: A Case Study from Bihar
Five typical pedons representing the Terai regions of the middle Indo–Gangetic plain of Bihar under different landforms and land uses were studied with reference to their soil carbon storage. These soils have been developed from the recent tertiary deposits of alluvial parent materials under sub humid climate. Soils are very deep, olive brown to grey in colour, silt loam to silty clay loam in texture and are frequently flooded. The soils are slightly to moderately alkaline (pH 7.5 to 8.8), medium to high in organic carbon content, low in cation exchange capacity (CEC) and high in base status. The soils are highly calcareous in nature, and the CaCO3 present in these soils are mostly geogenic rather than pedogenic. This region is characterized by marshy land at the foothills of the Himalayas. The biomass of these soils in the Terai is produced under a cool and humid climate with luxuriant vegetation growth, with an enhanced regeneration rate, which supports low rate of decomposition of organic matter. Further, the soil inorganic C pool carried by the runoff water from hills as CaCO3 also gets deposited in these Terai regions through the dissolution, transportation and reprecipitation of dissolved ions as carbonate nodules/powder. The high slopes of the northern hills, laden with eroded surface soils rich in organic, inorganic matter and other nutrients, continuously replenish the foothill soils, making it a rich hub of soil carbon storage. The Terai soils are fertile in terms of nutrient reserve and are highly productive. Farmers should protect these precious natural resources and use them judiciously, not only to increase crop production but also to maintain the ecosystem in this fragile environment.
Soil Health in the Age of The Kali Yuga : Anthropocene and Technosphere
Anthropocene, the era in which impact of human activity is as big as any geological event to transform planetary processes, called ‘Kali Yuga’ in the Vedic philosophy, is characterized as technosphere since the mid 20th century and which is adversely affecting all other ecospheres (i.e., hydrosphere, biosphere, atmosphere, and geosphere). The adverse effects of the Technosphere are related to growing demands for new materials and incomplete or no recycling of the residues (crop residue burning) including the greenhouse gases or GHGs, materialism and excessive use of resources. Thus, Technosphere is “the global, interconnected assemblage of human-created, nonliving artifacts—such as buildings, dams, machines, infrastructure, and computers—that now acts as a significant component of the Earth system (Galbrith et al. 2025). Indeed, humanity has become a new and aggressive agent of transformation of planetary processes. Thus, Anthropocene is now defined as the formative epoch of human development because of its impact on planetary processes (Conte and Bates 2024). In addition to or in conjunction with the use of fossil fuel since circa 1750, dietary preference of increasing and growingly affluent humanity is the driving force of the Anthropocene or ‘Kali Yuga’. The dietary preferences at present have long lasting impact on sustainable planetary processes adversely affecting nature and jeopardizing human wellbeing. It is pertinent, therefore, to consider human diets to address the Anthropocene epoch as well as resolve current issues such as public health, climate change and related environmental crisis, and socioeconomic political challenges of the 21st century (Mazac and Tuomisto 2020). Regionally, diverse approaches, based on social and cultural parameters are needed to understand and address the complexity of the technosphere-driven Anthropocene (Peša 2022).
Nitrogen and Phosphorus Mineralization Pattern and Microbial Count in Phosphate Rich Organic Manure (PROM) Amended Soil
Comparative Assessment of Integrated Fertilization Approaches on Finger Millet Quality and Soil Properties in North-Western Himalayas
Climate change induced soil degradation and progressive nutrient depletion are emerging as critical constraints for global food security, particularly in hill agroecosystems. In this context, integrated nutrient management (INM) offers a holistic and ecologically sustainable strategy to improve crop productivity and soil fertility. Therefore, a field experiment was laid out during kharif 2024 (one year) on finger millet as the test crop to evaluate the effect of INM practices on primary macronutrients’ content, uptake and soil chemical properties. The study included nine nutrient management practices (T1: FYM @ 5 t ha-1, T2: N40P20K0 + FYM @ 5 t ha-1, T3: N40P20K20 + FYM @ 5 t ha-1, T4: N60P30K20 + FYM @ 5 t ha-1, T5: N40P20K0 + FYM @ 5 t ha-1 + Azospirillum, T6: N40P20K20 + FYM @ 5 t ha-1 + Azospirillum, T7: N60P30K20 + FYM @ 5 t ha-1 + Azospirillum, T8: natural farming practices, T9: organic farming practices) which were replicated thrice in a randomized block design. The results revealed that conjoint application of N60P30K20 + 5/ t/ ha-1 FYM + Azospirillum (T7) recorded the highest content of nitrogen (N) (1.34%), phosphorus (P) (0.27%) and potassium (K) in grains and total uptake of N, P and K (55.66, 11.31 and 94.78 kg ha-1, respectively) by finger millet. Further, similar treatment recorded maximum soil available P (29.58 kg ha-1). Subsequently, organic practices (T9) significantly improved bulk density. Correlation analysis revealed significant and positive relationship between N, P and K uptake with available N and P, while available K showed nonsignificant relationship. Soil pH exhibited a significant negative correlation with nutrient uptake. Overall, the findings emphasize that combined use of fertilizers, FYM and Azospirillum is an effective strategy for enhancing nutrient uptake and productivity of finger millet under hill conditions.
Agronomic Performance of Tomato to Calcium and Magnesium Sulphate Amendments under Alluvial Plains of Punjab
Punjab region’s crop productivity potential and soil health has been compromised through the continual NPK and imbalance secondary nutrients application. Decreased application of secondary and micronutrients have resulted in severe nutritional deficiencies in crop and soil, and therefore, lowered the overall crop productivity. For investigation, open field experiments were conducted during 2022-23 and 2023-24 under randomized block design (RBD) at research farm, UIAS to evaluate the tomato growth performance and nutrients uptake to varying levels of CaSO4 (75 and 150 kg) and MgSO4 (50 and 100 kg) amended with NPK sources (Urea, SSP and MOP). Nine treatments with three replications comprised of varying Ca and Mg levels along with NPK sources have been selected and tested for two years. Results showed that the Ca and Mg based treatments showed high vigor in improving the crop growth and improved the soil nutrients pool. T5 (100% RDN NPK + Mg @ 100 kg ha-1) showed its supremacy over the other treatments with maximum plant height of 199.73 cm at maturity, fruit/plant (27.64 and 28.51 kg), yield/plant (2.64 and 2.99 kg) and fruit yield/100 m2 (1056.96 and 1081.29 kg). Similar treatment (T5) significantly improved the leaf and fruit NPK content over the sole NPK based treatment. Data on leaf and fruit Ca and Mg content revealed that maximum leaf Ca (2.27 and 2.29%) in T4, fruit Ca (2.16 and 2.18%) in T3, leaf Mg (1.26 and 1.29%) and fruit Mg (0.41 and 0.45%) was recorded under T7 treatment. Moreover, T7 treatment also showed its potential with highest Ca and Mg accumulation of 491.42 and 253.98 ppm in soil in respective years. Therefore, the study identified the T5 and T7 treatments as potent returning higher crop production and quality indices and also restored the soil with balanced Ca: Mg ratios along with other nutrients.
Unraveling the CO2–Microbe Nexus: A Conceptual Framework for Nitrogen Fixation Efficiency in Legume–Rhizobium Systems
Elevated atmospheric CO2, a principal driver of anthropogenic climate change, imposes emerging constraints on symbiotic nitrogen fixation (SNF), particularly within legume–Rhizobium systems. This study critically assesses the impact of CO2 enrichment on nitrogen fixation efficiency (NFER) in Rhizobium spp., a microbial process essential for sustainable crop productivity. Literature search across Scopus and ScienceDirect identified 2,066 peer-reviewed articles, of which 39 met rigorous inclusion criteria focused on plant–microbe interactions under elevated CO2 conditions. To mechanistically synthesize current understanding, we propose a conceptual framework defining NFER as a function of three core parameters: nodule formation and development rate (N), symbiotic connection efficiency (S), and genetic expression and regulation (G). Evidence from the reviewed studies indicates that elevated CO2 can reduce nodulation efficiency by up to 30%, disrupt symbiotic signaling pathways, and impair transcriptional regulation critical for effective nitrogen fixation. These interlinked perturbations contribute to a systemic decline in NFER, threatening agroecosystem resilience and global food security under projected climate scenarios. This synthesis highlights key vulnerabilities in legume–Rhizobium symbioses and delineates strategic knowledge gaps, providing a foundation for targeted quantitative research into microbial adaptation under atmospheric CO2 enrichment.
Effect of Potassium Fertilization on Quality of Potato (Solanum tuberosum L.)
A screen house was conducted to evaluate the effect of applied potassium (K) (0 and 60 kg K2O ha-1) on potato quality parameters planted on 30 different surface (0-15 cm) soils. The field experiments including five levels of K (0, 15, 30, 45, 60 and 90 kg K2O ha-1) were also conducted at four field sites to validate the results obtained from the pot study. Tuber yield, uptake and quality parameters include tuber size, reducing sugars content, tuber color and specific gravity were studied. The results from pot study showed that the tuber yield and uptake increased significantly with addition of 60 kg K2O ha-1 in one-third and one-fourth of the 30 soils whereas tuber size did not show significant increase with the K application of 60 kg K2O ha-1 compared to no K. The reducing sugar content of tubers also showed inconsistent significant decrease with K application. The one-third samples showed negative impact of applied K on the reducing sugars. The reducing sugar weakly but significantly correlated with tuber K uptake (R2=0.141). Tubers received K application were significantly lighter (L) in colour compared with tubers without K. The inconsistent significant effect of K application on specific gravity in all soils were reported. In field experiments, similar inconsistent response of K on plant indices and quality parameters were measured. The results suggest that K addition in soils with low, medium and high exchangeable K causes negative influence on crop yield and its quality.
Effect of Organic Manures and Fertilizers on Potassium Fractions in Coastal Saline Soil under Rice
A field experiment was carried out with no manure, farmyard manure, Glyricidia sepium, Sesbania aculeata, Thespesia populnea, no fertilizers, the recommended dose of fertilizers, Konkan Annapurna briquettes, and urea-diammonium phosphate briquettes in coastal saline soils of Maharashtra during kharif season 2023 to examine how different nutrient management practices influence the availability of potassium with rice as test crop. Results indicated that the maximum (100.33 mg kg-1) water-soluble K+ was observed with treatment receiving recommended dose of fertilizers + 10 t Glyricidia ha-1 at tillering stage, however, the highest exchangeable K+ (579 mg kg-1) was recorded with the integration of Glyricidia and Konkan Annapurna briquettes @ 170 kg ha-1 at panicle initiation stage. The significantly highest non-exchangeable K+ (1056 mg kg-1) was observed at harvest stage with Urea-Diammonium Briquettes (UB-DAP) which was placed without manure. There was significantly higher lattice K+ (9117.00 mg kg-1) with UB-DAP @ 170 kg ha-1 along with Thespesia @10 t ha-1 during harvest stage. The data showed that the water-soluble and exchangeable K got declined from tillering stage to harvest stage and the available K was low during tillering and panicle initiation but increased at harvest of the crop. Non-exchangeable K increased from tillering to harvest stage, however, lattice K and total K were declined from tillering to harvest stage. The sequence of K+ fractions followed the order as: total K+ > lattice K+ > non-exchangeable K+ > exchangeable K+ > water-soluble K+. The combination of Gliricidia sepium and Sesbania aculeata with chemical fertilizers was effective in sustaining the elevated potassium levels and reducing the decline of reserve soil K, particularly in the early and mid-growth phases of rice crop in saline coastal soils.
Influence of Organics and Inorganics on Microbial Population and Enzyme Activities in the Rhizosphere of Kiwifruit (Actinidia deliciosa) in Western Himalayas
Very limited information is available on how different nutrient management practices influence soil microbial populations and enzyme activities (dehydrogenase and acid phosphatase), especially in the lower Himalayan soils of India. To address this gap, we evaluated three nutrient management approaches—Subhash Palekar’s Natural Farming System (SPNFS), an Organic Farming-Based System (OFBS), and a Chemical Fertilizer- Based System (CFBS) using six-year old kiwifruit (Actinidia deliciosa cv. Allison) as test crop at Dr. Y.S. Parmar University of Horticulture and Forestry, Solan, Himachal Pradesh during 2018–19 and 2019–20. Here three nutrient management systems were tested to assess the changes in soil microbial populations and enzyme activities in the surface (0–15 cm) and sub-surface soil (15-30 cm) soil layers. The SPNFS-based treatment having 30 L Jeevaamrit, 3 kg Ghana Jeevaamrit, and 40 kg FYM per vine, recorded the highest biological activity (pooled analysis) and had bacterial, fungal, and actinomycetes populations of 200 × 105, 25 × 10³, and 22 × 10³ cfu g-¹ soil, respectively. Correspondingly, dehydrogenase activity increased to 35.8 μg TPF g-¹ h-¹ and acid phosphatase activity reached to 119.8 μg PNP g-¹ h-¹. The treatment having 100% recommended dose of N through vermicompost + poultry manure on 50:50 basis + 40 kg FYM resulted in bacterial, fungal and actinomycetes populations to the tune of 166 × 105, 19 × 10³ and 13 × 10³ cfu g-¹ soil, respectively, along with dehydrogenase activity of 34.6 μg TPF g-¹ h-¹ and acid phosphatase activity of 116.5 μg PNP g-¹ h-¹, wherein lowest values were observed in T1 (800 g N, 600 g P2O5, 800 g K2O and 40 kg FYM. There was a strong positive association between acid phosphatase activity and bacterial population (r=0.934**), fungal population (r=0.807**), and actinomycetes population (r=0.786**). Acid phosphatase activity was highly correlated with dehydrogenase activity (r=0.894**), suggesting that improved microbial abundance directly enhances the soil enzymatic activity in the rhizosphere of kiwifruit.
Fertilizer Prescriptions Equation for Targeted Yield in Onion under Integrated Plant Nutrient Management System in an Inceptisol
A field experiment was conducted on onion under soil test crop response correlation studies in Varanasi region of Utter Pradesh during rabi 2024-25. Multiple regressions have been calibrated for predicting onion yield through soil and fertilizer nutrients and their interactions. The models were found to have a high and significant predictability value. Using the data, fertilizer adjustment equations have also been developed for prescribing optimum fertilizer doses for attaining different yield targets. Soil test data, bulb yield and NPK uptake by onion were used for achieving four important basic parameters, viz., nutrients required (NR) to produce one quintal of onion bulb contribution of nutrients from fertilizers (% CF), contribution of nutrients from soil (% CS) and contribution of nutrients from organic matter-FYM (% COM). It was found that 0.35, 0.10 and 0.25 kg of N, P2O5 and K2O, respectively were required for producing one quintal onion bulb yield. The per cent contribution of nutrients from soil, fertilizer and FYM were 27.70, 62.37 and 22.08 for N; 12.76, 46.36 and 31.98 for P2O5 and 7.72, 4.80 and 6.79 for K2O, respectively. By using these basic parameters, ready reckoner of fertilizer doses was prepared for varying soil test values and desired bulb yield targets of onion using NPK alone and NPK with FYM.
Behaviour of Biochar as an Amendment for Soil Physico-chemical and Biological Properties in Acidic Soil of West Bengal
A 60-days laboratory incubation study was carried out after applying bamboo biomass-derived biochar to an acidic soil of West Bengal. The results showed that the application of 5, 10, 15, and 20 g kg-1 of soil (w/ w basis) of bamboo biochar significantly affected the physical (particle density, porosity, water holding capacity) and chemical (pH, EC) properties of the soil as well as the enzymatic activities (dehydrogenase, acid phosphatase, and cellulase). As the amount of biochar increased, an increase trend in pH was observed. In comparison to treatments B15 (BioC @ 15 g kg-1 of soil), B10 (BioC @ 10 g kg-1 of soil), B5 (BioC @ 5 g kg-1 of soil), and B0 (control), the EC of soil for B20 (applied BioC @ 20 g kg-1 of soil) was 19.67, 36.06, 46.62, and 52.45% higher, respectively. For every incubation period, a decrease in particle density was followed by an increase in the amount of biochar applied. Following incubation, treatment B20 had the maximum porosity (46.74%), which was statistically higher than all other treatments. For every incubation phase, raising the WHC was followed by raising the biochar levels. In comparison to all other treatment levels B5, B10, and B15, treatment B0 had the lowest dehydrogenase activity in the soil. According to our findings, adding biochar as an amendment to acidic soil promoted a healthy physical, chemical, and biological environment, all of which improved the soil’s quality.
In-depth Insights into Zinc Desorption Kinetics from Inceptisols Using Mathematical Models
Four mathematical models viz. simple Elovich, two-constant rate, parabolic diffusion and parabolic double diffusion adequately described zinc desorption kinetics by DTPA from 10 selected Inceptisols from two watersheds of Gaya district, Bihar, for extraction periods from 0.083 h to 48 h and were evaluated for determination of rate constants of the respective models. The mean values of initial Zn desorption rate constant ‘a’ (two-constant rate), ‘αs’ (simple Elovich), diffusion rate constant ‘kp’ (parabolic diffusion), first diffusion rate constant ‘k/ p’ and second diffusion rate constant ‘k//p’ (parabolic double diffusion) were 10.82×10-2 (mg kg-1s-1) b, 96.46×10-4 (mg Zn kg-1 s-1), 1.17×10-3 (mg kg-1)-0.5, 2.67×10-3 (mg kg-1)-0.5 and 0.73×10-3 (mg kg-1)-0.5, respectively. The mean values of desorption rate coefficient ‘b’ (two-constant rate) and zinc desorption constant ‘βs’ (simple Elovich) were 0.19 (mg Zn kg-1 s-1) and 15.92 (mg Zn kg-1 s-1), respectively. The desorption rate for all the soils included an initial short-term fast reaction followed by a long-term slower continuing reaction. Soil sample S8, having highest values of rate constants ‘ab’ (twoconstant rate); ‘kp’, ‘k/ p’, ‘k//p’ and higher value of rate constant ‘αs’ (associated with lowest value of zinc desorption constant ‘βs’) indicated highest rate of Zn desorption, among the studied soils. Correlation coefficients between rate constants and soil properties revealed oxalate extractable Fe (Feo), representing poorly crystalline or amorphous iron oxides, to be the most important soil factor controlling Zn desorption from the Inceptisols under investigation. The data generated from this study might be crucial for informed decisions towards optimizing nutrient management and reduced environmental impact.
Spatial Variability of Soil Physicochemical Properties in the Mid-Central Table Land Zone of Odisha: A Geostatistical Approach
Soil is a dynamic body exhibiting spatial variability both at micro- and macro-levels. Spatial distribution maps of various physicochemical soil properties, generated using geostatistical tools, are considered more effective for soil management than traditional methods. The objectives of the present study were to assess the spatial variability of different physiochemical properties of soil viz., sand (%), silt (%), clay (%), water holding capacity (WHC) (%), bulk density (BD) (Mg m-3), pH, and electrical conductivity (EC) (dS m-1) of Tangi-Choudwar block situated in the Mid-Central Table Land of Odisha, India and prepare spatial variability map for the region. Total of 193 soil samples were collected from sampling grids spaced 200 meters apart, from a depth of 0 to 15 cm using a GPS device to record the coordinates. Statistical and geostatistical analyses were performed to characterize the spatial distribution of soil physicochemical properties using various kriging models. The results revealed considerable variability among the properties, particularly for sand, silt, clay, and water holding capacity (WHC), with coefficients of variation (CV) of 143, 47.53, 75.82, and 61.04%, respectively. In Semivariogram analysis properties namely, sand, WHC, pH, and EC fitted well with the Gaussian model Instead, the variability of silt, clay and BD were well explained by exponential and spherical models. Apart from water holding capacity (WHC), all properties exhibited moderate spatial dependence, with nugget-to-sill ratios ranging from 29 to 70%. The regionspecific soil maps will be beneficial to both farmers and policymakers, as they will facilitate the adoption of precision agriculture through site-specific nutrient management and ensure the efficient allocation and application of inputs.
Geostatistical Estimation and Mapping of Surface Soil Properties using Ordinary Kriging Approach in the Middle Indo-Gangetic Plains of India
The point measurement of common soil properties and their use in fertilizer predictions over an area in India has often backfired due to large existent spatial variability. Mapping of soil properties with acknowledge of its spatial variability has widespread applications in environmental modelling, precision farming and sustainable agriculture. Hence a study was carried out in the middle Indo Gangetic plain zone of India to map the spatial variability of some important soil properties that are used in fertilizer predictions. A total of 280 surface soil samples from the plough layer (0–15 cm depth) were collected and analyzed for pH, electrical conductivity, organic carbon, available P, available K, sand, silt and clay. The values of these properties ranged from 5.12 to 9.20, 0.01 to 1.71 dS m-1, 1.2 to 8.70 g kg-1, 8.27 to 24 kg ha-1, 114.9 to 277.8 kg ha-1, 19.0 to 58.0%, 13.7 to 56.0 % and 12.5 to 52.5%, respectively following non-normal distribution for electrical conductivity and normal distribution for rest of the parameters. The coefficient of variation was highest for organic carbon (43.7%) and lowest for soil pH (0.15%), suggesting that use of arithmetic mean and standard deviation would serve as a poor estimator of these parameters for unknown locations. Geostatistics revealed that Gaussian model best fitted the experimental semi-variogram for pH and sand content; exponential model for organic carbon, available P, available K, silt and clay content and spherical model for electrical conductivity. The nugget/sill ratio indicated that all the studied soil properties were strongly spatially dependent except pH and sand content, which were moderately spatially dependent. Cross validation statistics showed that the surface soil maps prepared by ordinary kriging were robust and would sever much better when predicating values of the soil parameters in unsampled locations, often need in modelling at the landscape scale, and could serve as a primary guide for identifying management zones for precision farming and region-specific nutrient management and designing future soil sampling strategies in the intensively cultivated soils of the middle Indo Gangetic plains of eastern India.
A large proportion of soils of agroecosystems of India are degraded and depleted of their soil organic carbon (SOC) stock. Soils of arid and semi-arid regions have a relatively higher soil inorganic C (SIC) content. Whereas SOC content decreases with plowing, crop residues removal or burning and intensive grazing, SIC stock is vulnerable to acidification by use of nitrogenous fertilizers. Thus, degraded and depleted soils of India have a large soil C deficit and a high soil C sink capacity. Land use and agricultural practices which enhance SOC content are conservation agriculture, residue retention, elimination of in-field burning of residues, controlled grazing and use of organic amendments. Increasing SOC content in the root zone has a positive impact on crop yield and increase in over all agronomic productivity, and sequestering C through sustainable soil management can be a solution to climate change mitigation. However, gain in SIC content may have a little if any impact on crop yield. Farmers can be incentivized for enhancing soil C stock through payments for ecosystem services (PESs) at the rate of US $50 per credit (INR ~4600) or an appropriate social value of soil C. There is a strong need for Soil Health Act at district, state and national level. The Bharat Soil Protection Policy (BSPP) being developed by ICAR is a useful start in promoting carbon farming and recarbonization of soils of India.
Honorary Members of the Indian Society of Soil Science
Honorary Members & Fellows of the Indian Society of Soil Science
Effect of Sulfur and Zinc on Soil Health Parameters and Yield of Rice (Oryza sativa L.) in Alluvium of Prayagraj, India