Influence of Long-term Fertilization on Productivity and Organic Carbon under Rice-rice System in Inceptisols of Eastern India
Rajaram Satapathy
Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Science, SOA (Deemed University), Bhubaneswar, Odisha, India.
Manisha Das
Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Science, SOA (Deemed University), Bhubaneswar, Odisha, India.
Samanyita Mohanty *
Department of Soil Science and Agricultural Chemistry, Odisha University of Agriculture and Technology, OUAT, Chiplima, Odisha, India.
Asit Kumar Pal
Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Science, SOA (Deemed University), Bhubaneswar, Odisha, India.
*Author to whom correspondence should be addressed.
Abstract
A field experiment was conducted for eighteen consecutive years (2005-06 to 2021-22) at the Central Farm, OUAT, Bhubaneswar, Odisha, under AICRP on LTFE to assess productivity and soil organic carbon fractions in a rice-rice cropping system under long-term fertilisation. Soil samples were collected from two depths (0-0.15 m and 0.15-0.3 m) under different nutrient management treatments [T1: control, T2: 100% N, T3: 100% NPK, T4: 150% NPK, T5: 100% NPK along with FYM, T6: 100% NPK along with FYM + Lime, T7: 100% NPK along with Boron + Zinc, T8: 100% NPK + Sulphur + Zinc] in a randomised block design (RBD) with three replications. Results revealed significant differences in rice grain and straw yields among the treatment combinations, with grain yield ranging from 1.69 to 5.19 t ha-1. Application of 100% NPK along with FYM and lime produced the highest grain and straw yields of rice. The contributions of different soil organic carbon pools (VLC, LC, LLC and NLC) to TOC were 27.7%, 24.6%, 27.0%, and 20.8% at 0–0.15 m, and 19.5%, 22.8%, 32.4%, and 25.0% at 0.15–0.30 m soil depth, respectively. The carbon pool index (CPI), lability index (LI), carbon management index (CMI), and carbon sequestration (CS) were highest in the treatment receiving integrated nutrient sources. Judicious application of NPK fertilisers and organic sources (FYM), alone or in conjunction with lime, is necessary for maintaining soil organic carbon fractions and nutrient turnover to ensure sustainable crop productivity in a long-term rice-rice cropping system.
Keywords: Soil organic carbon, carbon pools, carbon management index, carbon sequestration, integrated nutrient management, farmyard manure, lime, rice–rice system, long-term fertilisation, Inceptisols