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A profound consideration of soil organic carbon (SOC) and SOC pools as affected by the long-term use of fertilizer in a fixed crop sequence is essential to understand and maintain the health and productivity of soil. The dynamics of SOC pools, i.e. total soil organic carbon (TOC) and its different fractions under a rice-wheat cropping system subjected to various fertilizer management strategies over 42 years was investigated near Uttarakhand, India. The soil at the experimental site was an Aquic Hapludoll consisting of a poorly drained silty clay loam (1–1.5 m deep) overlying loamy to sandy sediments. Over 42 years, application of 100% NPK+ FYM (Farm Yard Manure) was the most effective management system in increasing organic C up to 0 to 60 cm soil depths under rice-wheat sequence. The combination of this integrated input application (100% NPK + 15 t ha−1 FYM) significantly built organic carbon fractions like total organic carbon, microbial biomass C (MBC), particulate organic C (POC), KMnO4 oxidizable C, Humic C, Fulvic C, Humin C, water-soluble carbon and hot water extractable carbohydrates at all four soil depths. Hence, application of FYM along with NPK resulted in a significant positive building up of all pools in the treatment at all four depths. Therefore, balance fertilization is panaceally important for sustaining improved soil health with balanced organic status and production potentiality of the soil for rice-wheat cropping sequence. [ABSTRACT FROM AUTHOR]

Incessant and disproportionate application of inorganic nutrients has deteriorated soil properties. An investigation was carried out to validate fertilizer requirement developed through soil test based crop response study to obtain desired yield of brinjal in Mollisol of Pantnagar during kharif season of 2019. The study revealed that maximum fruit yield, number of fruits per plants, fruit length and fruit diameter of brinjal was obtained under treatment with TY1 (250q ha−1) +10t ha−1 FYM (T6) (128:111:39 of N, P2O5, and K2O, respectively). In the initial phase of the investigation, experimental field was divided into three strip to which different doses of fertilizers were applied in low (no fertilizer application), medium (100:100:100 kg ha−1 of N, P, and K, respectively) and high (200:200:200 ha−1 of N, P, and K, respectively) proportion to create an artificial fertility gradient to bring heterogeneity in the experimental soil for the test crop. Further, in the second phase the response of brinjal to selected combinations through FYM, nitrogen, phosphorus and potassium in different soil fertility strips was also computed for spring and kharif seasons. With soil analysis, nutrient uptake studies, and yield the basic data for fertilizer prescription was worked out for both seasons. Further, using pooled data fertilizer prescription equation was generated for brinjal at different soil test values and yield targets. Response of brinjal in terms of growth, yield and nutrient uptake was studied to various soil test based fertilizer prescription at verification trial. The maximum microbial biomass carbon (427.29 μg g−1 soil), microbial biomass nitrogen (39.30 μg g−1), phosphates activity and dehydrogenase (150.36 µg TPF 24 h−1 g−1 soil) was reported under treatment TY2 (250q ha−1) +10t ha−1 FYM (T6) (128:111:39, of N, P2O5 and K2O, respectively). The balanced application of nutrients along with application of organic manure has ensured improvement in response of brinjal over general recommendation. [ABSTRACT FROM AUTHOR]