Browsing by Author "Sumanta Kundu"

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Effect of long term application of organic and inorganic fertilizers on soil microbial activities in semi-arid and sub-humid rainfed agricultural systems
(International Society for Tropical Ecology, 2018) Cherukumalli Srinivasarao; Sumanta Kundu; Minakshi Grover; Mallappa Manjunath; Sudhakar Kasbe Sudhanshu; Jagannathbhai Jeevanbhai Patel; Shiv Raj Singh; Ram Pratap Singh; Madhanbhai Mohandas Patel; Ayyanadar Arunachalam; Sudhir Kumar Soam
A study was conducted to investigate the effect of chemical fertilizer, organic manure and two cropping systems viz., pearlmillet - clusterbean - castor rotation and upland rice - lentil sequence on microbial quotient (MQ), metabolic quotient, specific enzyme activity (dehydrogenase, arylsulfatase and urease) and microbial biomass carbon (MBC) in long-term (18-21 years) field experiments in Entisols of semi-arid region of Gujarat and Inceptisols of sub-humid region of Varanasi. Higher MQ values were recorded in Entisols than Inceptisols. MQ ranged from 4.00–5.08 and 1.00–1.85 % across soil layers in Entisols and Inceptisols, respectively. Metabolic quotient values ranged from 0.11–0.23 and 0.04–0.07 across soil layers in Entisols and Inceptisols respectively. The specific enzyme activity of dehydrogenase was maximum in Entisols, whereas, arylsulfatase and urease activity was recorded more in Inceptisols. Higher specific enzyme activity reflects greater microbial activity and microbial biomass turnover. Agro-ecosystem in sub-humid region resulted in 1.5 fold higher geometric mean of enzymes (GMea) than in semi-arid region. The application of 50% RDNF (recommended dose of N-fertilizer) + 50% RDN FYM (farm yard manure) in Entisols and 50% N (FYM) + 50% RDF in Inceptisols improved microbiological activities (GMea) at both the sites. The concentration of soil organic carbon (SOC) and MBC were significantly correlated with GMea in both agro-ecosystems. In conclusion, integrated sources of nutrients with inclusion of FYM and 50 % reduction of fertilizers improved the microbiological activities in both Inceptisols and Entisols. © International Society for Tropical Ecology.
Greenhouse gases emissions and agronomic productivity as influenced by varying levels of N fertilizer and tank silt in degraded semiarid Alfisol of Southern India
(John Wiley and Sons Ltd, 2023) Sharan Bhoopal Reddy; Cherukumalli Srinivasarao; Palli Chandrasekhar Rao; Rattan Lal; Suresh Rakesh; Sumanta Kundu; Ram Nagina Singh; Pradeep Kumar Dubey; Purushothaman Chirakkuzhyil Abhilash; Kondru Venkateswara Rao; Vikas Abrol; Jayaraman Somasundaram
The study aimed to assess the effects of combined application of urea nitrogen (N) and tank* silt (TS) on greenhouse gases (GHG) emissions [i.e., carbon dioxide (CO2) and nitrous oxide (N2O)] and agronomic productivity of maize-horsegram system. A factorial [urea (0, 60, 120, and 180 kg N ha−1)] and tank silt (0 and 30 t ha−1) replicated thrice randomized block design was employed for this investigation. Results of the study showed that maize grain yield was significantly influenced by the sole application of both N fertilizer and TS. When both the N fertilizer and TS were combined, the grain yield was significantly (p < 0.01) improved by 5% (4870 kg ha−1) over the highest yield observed under only N. We have noticed a significant (p < 0.01) residual effect of N and TS on horsegram straw yield during all the years of experimentation. With the increase in N-rate, there was an increasing trend in CO2 emission noticed in all the years including the pooled year data. Compared to CO2 emission, N2O emission was greatly influenced by nutrient management and amendment application. Among the seasons, the post-rainy season (Rabi) had a slightly lower emission trend of CO2, during all the years as compared to the rainy season (Kharif). The observed results marked the marginal increasing trend of cumulative CO2 (cCO2) emissions with regard to increasing doses of urea. Tank silt addition slightly favoured a CO2 emissions. The trend of cumulative N2O (cN2O) emission was greatly influenced by the dose of urea following the order of N180 > N120 > N60 > N0. However, N fertilizer application influenced the cCO2 emissions (r = 0.83), and significantly increased the cN2O emission (r = 0.99). Therefore, optimum and timely application of urea combined with TS is recommended as an effective strategy to combat GHG-based emissions (specifically N2O based) in semiarid rainfed regions. © 2022 John Wiley & Sons Ltd.
Integrated nutrient management improves soil organic matter and agronomic sustainability of semiarid rainfed Inceptisols of the Indo-Gangetic Plains
(John Wiley and Sons Inc, 2021) Ch. Srinivasarao; S.P. Singh; Sumanta Kundu; Vikas Abrol; Rattan Lal; P.C. Abhilash; G.R. Chary; Pravin B. Thakur; J.V.N.S. Prasad; B. Venkateswarlu
Background: Climate and management practices impact the soil organic carbon (SOC) stocks of agricultural soils. Especially under the semiarid climate of India, organic matter is rapidly decomposed, and imbalanced nutrient input further exacerbates its depletion, thus facilitating the decline in soil quality and crop yields. Improving SOC contents through integrated nutrient management (INM), that is, conjunctive use of organic and chemical sources of nutrients, could ameliorate soil health and sustain crop yields. Aim: To assess the potential of the INM approach to enhance the SOC status, soil quality, crop production, and drought adaptation of pearl millet under rainfed conditions. Methods: Nutrient inputs were supplied through mineral fertilizers, organic manures, and a combination of both. SOC sequestration, sustainable yield index, plant-available N, P, K, and water, bulk density, and KMnO4-oxidizable C were estimated. Results: Higher SOC sequestration rate (0.50 and 0.48 Mg ha−1 y−1 in 50% N (fertilizer) + 50% N (farmyard manure), and 50% N (fertilizer) + 50% N (crop residue), respectively) and significant increase in soil fertility were recorded in organically amended treatments. Improvement of 1 Mg ha−1 of SOC stock in the root zone (0.4 m depth) reduced the severity of drought and increased the yield by 38 kg ha−1. Plots under organic amendments suffered less yield losses under short-duration droughts, but this positive effect could only be exploited when the rainfall deficit was up to 25%. Conclusion: Managements that add up to 1.2 Mg ha−1 y−1 SOC are adaptive and climate-resilient strategies in dry semiarid degraded Inceptisols of the Indo-Gangetic Plains. © 2021 Wiley-VCH GmbH
Long-term effects of soil fertility management on carbon sequestration in a rice-lentil cropping system of the indo-gangetic plains
(2012) Ch. Srinivasarao; B. Venkateswarlu; Rattan Lal; Anil Kumar Singh; K.P.R. Vittal; Sumanta Kundu; S.R. Singh; S.P. Singh
Enrichment of soil organic carbon (SOC) stocks through sequestration of atmospheric CO 2 in agricultural soils is important because of its impacts on soil quality, agronomic production, and adaptation to and mitigation of climate change. In a 21-yr field experiment conducted under subhumid tropical conditions in India, the impacts of crop residue C inputs were assessed for the rice (Oryza sativa L.)-lentil (Lens esculenta Moench) cropping sequence. These impacts were evaluated in an experiment involving mineral fertilizers and manuring treatments on crop yield sustainability with reference to critical biomass requirements for maintenance of SOC in an Inceptisol. Application of farmyard manure (FYM) without and with mineral fertilizers increased C input and SOC concentration and stock. In comparison with the control, the 100% organic (FYM) treatment had significantly higher profile SOC (27.5 Mg ha -1), and more C build up (55.0%) and C sequestration (6.6 Mg C ha -1) to 1-m depth vis-à-vis the antecedent values in 1986. These parameters were also higher in 100% FYM treatment at a rate providing equivalent amount of the recommended dose of N followed by conjunctive use of FYM and mineral fertilizers. The SOC stock and rate of sequestration were positively correlated with cumulative C input, and with sustainable yield index (SYI) of upland rice and lentil. Higher grain yield (1.95 and 1.04 Mg ha -1 of rice and lentil, respectively) was obtained with the application of 50% organic (FYM)+50% recommended dose of fertilizer (RDF). In comparison, higher SOC sequestration rate was measured with the application of 100% organic (FYM). For every Mg increase in SOC stock in the root zone there was 0.16 and 0.18 Mg ha -1yr -1 yield increase of rice and lentil, respectively. For maintaining a stable SOC level (zero change due to cropping), a minimum quantity of 2.47 Mg C ha -1 yr -1 is required for this soil, climate, cropping system, and fertilization treatments. To achieve this quantity of C, 7.1 Mg of biomass is required to be produced every year vs. average rice and lentil yields of 1.6 and 0.7 Mg ha -1, respectively. The sole application of mineral fertilizers at 50 or 100% of the RDF did not maintain the SOC stock. Thus, application of FYM (or other organics) in conjunction with mineral fertilizers is essential to maintaining and enhancing the SOC stock in the rice-based cropping systems. © Soil Science Society of America.
Magnesium balance in four permanent manurial experiments under rainfed agro-ecosystems of India
(CSIRO, 2015) Ch. Srinivasarao; Sumanta Kundu; K.L. Sharma; Sharanbhoopal Reddy; A.L. Pharande; M. Vijayasankarbabu; A. Satish; R.P. Singh; S.R. Singh; G. Ravindra Chary; M. Osman; K.A. Gopinath; C. Yasmin
Magnesium (Mg) plays a vital role in photosynthesis, dry matter production and carbon partitioning in sink organs. Hence, four permanent manurial experiments (20-27 years of duration) under the auspices of All India Coordinated Research Project for Dryland Agriculture (AICRPDA) network centres across diverse agro-ecological regions were carried out to examine the soil exchangeable Mg (ex-Mg), crop uptake and overall Mg balance. Groundnut (peanut), finger millet, rice-lentil sequence and post rainy sorghum were the major crops or cropping systems followed in four permanent manure experiments at Anantapuram, Bengaluru, Varanasi and Solapur, respectively. Nutrient management in all experiments involved control (no addition of nutrients), 100% organic, 100% chemical, and integration of organic and chemical. Except in the finger millet-based system, mean ex-Mg status in the entire profile was higher than the sufficiency level (1.0cmol(+)kg-1 as a critical limit). Status of ex-Mg (cmol(+)kg-1 soil) in soil profiles was in the order: Solapur (3.80)>Varanasi (2.07)>Anantapuram (1.06)>Bengaluru (0.44). A uniform distribution of ex-Mg was observed in plots that received integrated application of organic and chemical fertilisers. In general, improved status of profile ex-Mg (cmol(+)kg-1) over the control was observed in soils under groundnut (0.19-0.78), finger millet (1.90-3.20), and post rainy sorghum (6.50-7.60, except 4.20 in 100% NPK) cropping. Overall, ex-Mg status and balance of different soil types under diverse crop production systems was influenced by several factors, some of which include soil type with varying mineralogy, particle size distribution, nutrient management strategies and rainfall. Significant positive relationships were observed between ex-Mg status and clay content (R2≤0.94), soil pH (R2≤0.92), cation exchange capacity (R2≤0.98) and mean air temperature (R2≤0.22), whereas a weak relationship was observed with rainfall (R2≤0.01). The study gives an account of Mg balance in major Indian soil types and recommends further attention on Mg nutrition in current intensive agriculture. © CSIRO 2015.
Soil potassium fertility and management strategies in South Asian agriculture
(Academic Press Inc., 2023) Ch. Srinivasarao; Sumanta Kundu; K.V. Rao; A.K. Shukla; A. Subba Rao; Patricia Imas; Nanthi S. Bolan; Rattan Lal; J.V.N.S. Prasad; P.C. Abhilash; G. Ranjith Kumar; R.S. Meena; G. Pratibha; G. Narayanaswami; S.K. Bansal; K.C. Nataraj; M. Jagadesh; K. Mrunalini; S. Jayaraman; M.L. Jat; S.N. Malleswari; Anthony Whitbread; B. Venkateswarlu
Almost one-fourth of the global population live in South Asia (SA) countries with 14% of cultivable land. Most of the countries in the South Asian region are facing multiple challenges like high population growth, declining farm land area, and low productivity in primary and secondary sectors leading to limited employment opportunities. Consequently, both availability and access to food are adversely affected. Regions exposed to natural disasters, tribal and the hilly regions of SA are amongst the most vulnerable in terms of food security. Accelerated efforts are required to ensure that conflicts do not exacerbate the already fragile food situation in SA. Despite recent strong gains in economic growth and agricultural productivity, food and nutritional security remains a major concern in SA. The region has the largest concentration of poverty and hunger in the world, with nearly 40% of the world's impoverished and 45% of the world's undernourished people. The enormity of malnutrition in SA can be gauged from the fact that it is the home to nearly two-thirds of the world's undernourished children. More than 56% of the world's low-birth-weight babies are born in SA. Furthermore, food and nutrition security remain major challenges with a large proportion of the world's poor living here and global hunger index (GHI) at 30.9. Overcoming these twin challenges require actions both at the national and regional level. Among production constraints and yield gaps, imbalanced nutrient use is a critical issue in many of the SA countries, with nutrient application focused mainly on nitrogen (N), leaving the possibility for other plant nutrient deficiencies including phosphorus (P) and potassium (K). In some cases, the use efficiency of N may be low due to losses in the form of N2O emissions, a potent greenhouse gas (GHG), or via leaching with the undesirable offsite effects. Among the primary nutrients, K is an essential nutrient for productivity, food quality and numerous functions in the plant system. It plays a major role in activating ∼60 enzymes, regulating stomatal functions, controlling water relations especially under rainfed crop production, influencing the water balance of plant systems, and underpinning agronomic productivity and sustainability. Negative K balance in soil under intensive cropping is reported because of low external input and large crop removal, leading to large scale K mining in soils. Declining yield trends were observed in several fertilizer experiments 30–40 years long with continuous application of either N alone or NP without K under both irrigated and rainfed crop production systems in the region. Recent K fertility analysis indicates widespread K deficiency in light-textured alluvial soils, red and lateritic soils beside acid soil types in India, Bangladesh, Sri Lanka, and Pakistan. The countries in SA depend largely on imported K fertilizers. Such imported fertilizer should be utilized most efficiently in the light of limited global K mineral reserves and 93% of world total K exports are from five countries viz. Canada (37.12%) followed by the Russian Federation, Belarus, Germany and Israel. Therefore, the current review addresses issues related to the K supplying capacity of soils in various crop production systems in SA, crop K responses, soil test methods followed, emerging issues in soil K fertility, K balance in major cropping systems and rationalizing K recommendations among crops, soil types and agro-ecological regions. The role of K in balanced nutrition, farm productivity, food and nutritional security in these countries is examined. The review also covers the critical role of K in climate change adaptation, mitigation of nitrous oxide (N2O) emissions and improving overall nitrogen use efficiency (NUE) in the SA region. © 2023 Elsevier Inc.