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.
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.
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.
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.
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.
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.
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.
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.
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), ‘as’ (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 ‘ßs’ (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’ (two-constant rate); ‘kp’, ‘k/p’, ‘k//p’ and higher value of rate constant ‘as’ (associated with lowest value of zinc desorption constant ‘ßs’) 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.
Arbuscular mycorrhizal fungi (AMF) play a vital role in enhancing plant growth and soil health through symbiotic nutrient exchange. This study evaluated the effects of vesicular-arbuscular mycorrhizal (VAM) inoculation on the growth and physiological responses of Sorghum bicolor (L.) Moench under controlled greenhouse conditions at Tokai University, Japan, from August to September 2025. A completely randomized design with three treatments comprising commercial AMF inoculum, sterilized inoculum, and non-inoculated control was applied to plants grown in sterilized Andosol soil mixed with vermiculite. Growth parameters, including plant height, stem diameter, chlorophyll content, and soil electrical conductivity (EC) were measured weekly. Biomass traits and soil bulk density were assessed at harvest. Microscopic analysis confirmed AMF colonization through the presence of hyphae, spores, and vesicles. Data were analyzed using ANOVA and Tukey’s test at a 5% significance level. Results showed no significant differences in early vegetative traits; sterilized inoculum slightly enhanced plant height, reaching 61.5 cm, representing a ~4.8% increase compared to the non-inoculated treatment (58.7 cm). Root biomass was also higher under sterilized inoculum, with fresh root weight reaching 12.1 g, approximately 27% greater than the non-inoculated treatment (9.5 g). Soil EC remained low and stable (0.062-0.086 dS m-1), while bulk density was significantly lower in the non-inoculated treatment (0.290 g cm-3) compared with inoculated treatments (0.650-0.652 g cm-3). These findings suggest that while physiological responses were initially uniform, specific treatments influenced vertical growth and soil structure, highlighting the potential of AMF in sustainable sorghum cultivation.
A field experiment was conducted during kharif 2021 at CCS HAU, Regional Research Station, Bawal on loamy sand soil to study the performance of potassium levels and foliar applications on soil properties yield and quality of cluster bean. Integrating soil potassium fertilization with foliar nutrient applications can enhance soil status in cluster bean cultivation. The treatment involving 30 kg K2O ha-1 with foliar sprays of 2% urea and 2% multiplex nutrient at pre-flowering and pod formation stages (T9) resulted in the highest availability of nitrogen (146.7 kg ha-1), phosphorus (15.9 kg ha-1) and potassium (188.7 kg ha-1) in the soil after post-harvest of the crop. Crop yield, both seed (17.9 q ha-1) and stover (45.8 q ha-1) along with yield attributes, increased significantly with higher potassium levels and foliar application of 2% urea plus 2% Multiplex nutrient (a water-soluble micronutrient fertilizer that corrects deficiencies and enhances plant growth, flowering, quality, and yield). The highest values were recorded under the T9 treatment (30 kg K2O ha-1 + 2% urea spray + 2% Multiplex nutrient spray), outperforming both the control and sole potassium application. Also, significantly maximum numbers of nodules and their fresh weight per plant (18.9 and 0.06 g at 40 DAS and 20.92 and 0.070 g at 60 DAS) were recorded under T9. The highest protein content and gum content (23.9 and 28.9%) were observed under treatment T9 (30 kg K2O ha-1 + 2% urea spray + 2% multiplex nutrient spray) followed by T7 (30 kg K2O ha-1 + 2% multiplex nutrient spray). Higher net monetary returns (Rs. 102240 ha-1) with B:C (1.82) obtained under T9. The present study concludes that application of 30 kg K2O ha-1 at sowing time and foliar spraying of 2% urea along with 2% multiplex at pre-flowering and pod formation stage proved to be economically beneficial while achieving optimum nutrient status and yield under clusterbean cultivation.
Seven typical pedons representing major land forms namely plains and uplands originated from granitegneiss parent material in semi-arid eco-system of Vedurukuppam mandal under varying land uses in Chittoor district of Andhra Pradesh were studied for their morphological characteristics, physical and chemical properties and soil genesis. These soils were slightly acidic to slightly alkaline (pH 6.12 to 7.83) in reaction, non-saline (0.06 to 0.40 dS m-1), shallow to very deep and had isohyperthermic temperature and ustic soil moisture regime. Texture, organic carbon, cation exchange capacity and base saturation of the soils were found to vary from sandy loam to clay loam, 0.9 to 7.3 g kg-1, 15.35 to 32.53 cmol(p+)kg-1 soil and 70.96-89.52 per cent, respectively. Soils were low to medium in available N (87.80 to 188.16 mg kg-1), high in available P2O5 (14.36 to 36.64 mg kg-1) and medium to high in available K2O (61.15 to 240.36 mg kg-1) and sufficient in available sulphur (17.50 to 72.50 mg kg-1). The DTPA extractable Zn was found to be deficient to sufficient (0.52 to 1.54 mg kg-1) whereas DTPA extractable Fe (6.32 to 24.02 mg kg-1), Cu (0.60 to 2.68 mg kg-1) and Mn (4.40 to15.86 mg kg-1) were sufficient. The pedon 7 grouped under Entisols due to absence of sub-surface diagnostic horizon and was classified as Lithic Ustorthents whereas pedons 1, 2 and 4 were grouped under Inceptisols due to presence of cambic (Bw) sub- surface diagnostic horizon and classified as Typic Haplustepts, Lithic Haplustepts and Typic Haplustepts, respectively. Pedons 3 and 6 and 5 were grouped under Alfisols due to the presence of argillic (Bt) sub-surface diagnostic horizon and classified as Typic Haplustalfs and Typic Rhodustlafs. All soils of the study area fall in cultivable land under land capability sub-classes viz., IIIs, IIIw and IVes. On the basis of major soil constraints and potentials, suitable land use plan for Vedurukuppam mandal was suggested.
We investigated the effect of rock phosphate enriched compost with microbial inoculants on phosphorus (P) fractions in soil and how these forms affect the bioavailability of P to wheat. Phosphorus was applied through rock phosphate enriched compost, P solubilizer and mobilizer and compared with conventional Pfertilizer i.e. single superphosphate. Chemical P- fractions through a sequential fractionation scheme, biomass production, and P concentrations in plant parts were measured to estimate the plant P uptake. Yield, yield attributes and P uptake in straw and grain were significantly affected by the synergistic application of P- enriched compost along with 50% recommended dose for P with the microbial inoculants, compared to absolute control. The percentage contributions of different fractions to the total P content in soil after wheat harvest were in the order of labile P< Fe/Al-P< Ca-P < residual.
A comparative study was conducted at the experimental field of Tocklai Tea Research Institute, Jorhat, India to determine the effects of organic (OFS) and conventional farming (CFS) systems on soil chemical and biochemical properties of tea leaf. A part of the field under CFS was converted to organic in 2008 by using eleven different combinations of organic manures. After four years of conversion process, chemical properties of the soil samples such as soil-organic carbon, available N, available P, available K as well as caffeine and catechin contents of the leaf samples were quantified. OFS resulted in significantly increase in soil organic carbon (8.8%) and cation exchange capacity (28.4%). On the other hand, CFS resulted in significantly higher levels of available potash and nitrogen contents in soil. The estimates of leaf biochemical contents resulted in up to 43% increase in leaf proline and 27% increase in catechin contents in tea leaves under OFS, although there was upto 22 percent reduction in tea yield due to conversion from conventional to organic farming practices. The present study provides information on soil nitrogen and potash level as well as leaf proline and catechin content in tea leaves under OFS and CFS in North east India.
In a range of cadmium (Cd) spiked soil the effects of soil moisture regimes, amendments and ageing on Cd availability were assessed. A sandy loam soil was spiked with Cd @ 0, 10 and 25 mg kg-1 soil through its nitrate solution. Lime (5%), farmyard manure (20 t FYM ha-1) and zinc (25 mg Zn kg-1) were added as amendments. The treated soil samples were incubated at 35 °C for 1, 45 and 90 days at field capacity and submerged soil moisture regimes. Available Cd was extracted with 0.005 M DTPA extractant and determined by ICP-AES. The results revealed that there was a temporal decrease in the available Cd with ageing and was in the order of 90 days > 45 days > 1 day. The magnitude of decrease in Cd availability was higher with the addition of amendments in the order of lime > FYM > Zn > unamended soil. The decrease in available Cd was further pronounced under submerged moisture regime than under field capacity. An overall reduction in the per cent recovery of DTPA-Cd was observed under submergence compared to field capacity moisture regime in lime, FYM, Zn amended soils and unamended soil. Least percent recovery was obtained under submergence combined with lime amendment at 90 days of incubation. The results enable us to understand the effect of ageing coupled with different amendments under various moisture regimes on Cd availability.
The present investigation is aimed at determination of various pedogenic indices to understand soil maturity in catenary sequence of varying physiographic confluences of Easternghats of Odisha occurring on Sambalpur and Koraput districts. Important pedogenic indices (PI) including redness rating (RR), relative profile development (RPD), relative horizon distinctness (RHD), sand/ silt, silt/ clay, CEC/ clay, index of weathering (Iw), exchangeable aluminium percentage (EAP) and ratios of dithionite-citrate extractable iron (Fed) and ammonium oxalate extractable iron (Feo) were used to assess soil maturity. Hierarchical clustering was employed to unfold varying degree of pedogenic processes across the geomorphic situations of the state. The physiographic confluence of Easternghats, Gahrjat Hills and Mahanadi Basin (Sambalpur district) represents formations of red ferruginous Alfisols in foot hills and uplands of granite-gneissic, quartzite and Khondalite (Typic Rhodustalfs) and in uplands of charnockite landscapes (Rhodic Paleustalfs) with high RR, RPD, RHD, EAP, (Fed-Feo)/ Fed and low sand /silt, silt/ clay, Iw and Feo/Fed attributing to rapid rate of pedogenesis with higher degree of maturity of soil profiles indicating to their relict nature i.e. paleoformations through progressive pedogenesis. Soils on inter-hill valleys, valleys and plains of any geologic formation revealed stagnated rates of pedogenesis indicated by gleyization with formations of Aquic Rhodustalfs, Aquic Haplustalfs, Oxyaquic Haplustalfs and Typic Endoaqualfs with low RPD, RHD, EAP and high Iw and Feo/Fed. Such an occurrence represents regressive pedogenic process under reduced conditions. Soil quality index (SQI) showed inverse relationship to pedogenic indices. Valleys and plains support promisingly crop diversification with high SQI and low PI, whereas, uplands and foot hills, representing the inverse characteristics, are being better promoted for agri-horticulture, agro-forestry and horti-silvicultural practices. The current research endeavor put an ample scope to upscale its inventory in similar physiographic and agro-climatic regions of the country.
