Cropping System Impacts on Carbon Fractions and Accretion in Typic Ustochrept Soil of Punjab, India

Abstract

Implementation of best management practices (BMPs) to increase crop productivity by intensive cultivation on marginal/fallow lands has positive impact on soil organic carbon (SOC). Because of difference in BMPs, impact of cropping system (CS) on SOC is not similar across soil types. Therefore, this study evaluated the relative influence of 10 different CSs on important SOC fractions and accretion in Typic Ustochrept of Punjab, India. Conversion of fallow lands to agricultural systems for eight years significantly increased SOC concentration in 0–15 cm layer. However, keeping the field fallow for the same period decreased SOC concentration by 24% from antecedent level of 3.8 to 2.8 g C kg−1. Among different CSs, significant differences in SOC concentration was recorded in crops amended with farmyard manure (FYM). All maize (Zea mays L.)-based CSs contained significantly higher SOC concentration as compared with that in rice (Oryza sativa), cotton (Gossypium hirsutum), and groundnut (Arachis hypogaea)-based CSs except for the groundnut-potato (Solanum tuberosum)-bajra (Pennisetum glaucum), which also received FYM. While comparing three important CSs of the region, maize-wheat cropping system had 5.6% higher labile carbon (LC) than for cotton-wheat, and was 7.3% higher in rice-wheat system. On an average, among different CSs, maize-based CSs had the maximum SOC pool, followed by that in groundnut, cotton, and the minimum in rice (31.3 Mg C ha−1)-based CS in 0–60 cm soil profile. The rice equivalent yield ranged between 6.9 Mg ha−1 to 38.6 Mg ha−1 under different CSs.