Carbon sequestration and soil quality index under different cropping systems in tarai region of Uttarakhand
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Date
2019-05
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
A field experiment was conducted during the crop season, 2016-17 and 2017-18 at two different sites of GBPUA&T, Pantnagar, in the first site i.e. Norman E. Borlaug Crop Research Centre, four treatments were taken in an ongoing Long Term Fertilizer Experiment, and the second site was Agroforestry Research Centre, where two treatments were taken from poplar and eucalyptus based agroforestry systems and analyzed in
randomized block design with four replication. Continuous application of inorganic fertilizers alone or integration with any of the organics did not influence soil pH. The highest soil organic carbon, N, P, K, S, Ca, Mg and DTPA extractable micronutrient (Zn, Cu, Fe and Mn) recorded under treatment T3-100 % RDF + FYM (LTFE) at surface and sub surface soil during both the year after kharif and rabi. The soil organic carbon and plant essential nutrients were decreased with increase in soil depth which may be assigned to the addition of FYM and crop residues on the soil surface. However, the highest EC was recorded under treatment T5-Poplar based agroforestry. The highest microbial count, dehydrogenase activity, was found in 100 % RDF + FYM treated plot (T3) followed by T5 and T4 whereas, the lowest value was observed in control plot. The lowest bulk density and particle density at surface and sub surface soil was recorded in 100% NPK + FYM @ 15 t ha-1 treated plot (T3), whereas, the highest value was observed in the control plot (T1). The highest mean weight diameter of soil aggregates, hydraulic conductivity and water holding capacity at surface and sub surface soil was observed in FYM along with 100% NPK fertilizer treated plot (T3). The inorganic fertilizers with organic manure maintained or improved soil quality and soil health in comparison to application of NPK fertilizers alone. A
marked increase in the active and passive carbon fractions was noticed in all the treatment except NPK treated plot and unfertilized plots. Carbon sequestration was observed to be highest order in NPK+FYM treated plots followed by poplar based cropping system. Correlation studies revealed that carbon fractions of soil (active and passive fractions) helps in nutrient release, restoration and transformation. It is concluded that continuous application of inorganic fertilizers alone could not sustain the soil fertility status and productivity. Therefore, integrated nutrient management in continuous cropping system and agroforestry based cropping systems proved effective for sustainability of soil on long term basis.