Sankhyan, N. K.PATIAL, DISHA2022-02-052022-02-052021-10-28https://krishikosh.egranth.ac.in/handle/1/5810181764The present investigation was carried out in an on-going long-term fertilizer experiment, initiated during 1972 at experimental farm of Department of Soil Science, CSK HPKV Palampur, to study the long-term effect of fertilizers and amendments on soil aggregate stability and carbon dynamics in an acid Alfisol under maize-wheat cropping system. The experiment consisted of eleven treatments. The soil of the experimental site was silt loam and classified taxonomically as “Typic Hapludalf” (Subgroup). Soil samples were collected from surface (0 - 0.15 m) layer after the harvest of wheat (rabi, 2019-20) and were analyzed for different physical and chemical soil parameters. Long-term use of integrated nutrient management practices significantly improved the available N, P and K as compared to control. Effect of long-term application of inorganic fertilizers and amendments on soil aggregate distribution, aggregate stability and aggregate associated different carbon pools were studied. Application of inorganic fertilizers along with FYM increased the WSA, MWD and GMD over control thus, enhanced aggregate stability of soil. MWD and GMD were higher in FYM amended plots than unfertilized control plots. The addition of FYM enhanced the macroaggregates (>0.25 mm) as compared to microaggregates (<0.25 mm). Incorporation of FYM alone or in combination with chemical fertilizers enhanced the accumulation of different C pools in all aggregate fractions over unfertilized control. Among the macroaggregates, 1-0.5 mm fraction had the higher TOC, OC, LC and NLC as compared to microaggregates. 100 per cent NPK + FYM amended plots recorded highest productivity of wheat. Different aggregate fractions of TOC, OC, LC and NLC were found to be positively and significantly correlated with available N, P and K and negatively and significantly correlated with BD whereas, positively and non-significantly correlated with soil pH and EC. Different aggregate fraction of TOC, OC, LC and NLC were positively and significantly correlated with grain and straw yield of wheat.EnglishThesis