Soil organic carbon dynamics and crop yields of maize (Zea mays)–black gram (Vigna mungo) rotation-based long term manurial experimental system in semi-arid Vertisols of western India

Abstract

Achieving sustainable crop productivity and maintenance of concurrent soil organic carbon (SOC) at desired levels in cereal-based cropping systems in relatively, poorly fertile Vertisols in semi-arid rainfed ecosystem is challenging task for dryland researchers. Diferent soil fertilization practices can contribute to carbon (C) sequestration, which requires a detailed knowledge of SOC dynamics in soil profle (0–1.0 m). We conducted a feld experiment for 6 years to study the efect of applying mineral fertilizers and organic amendments (FYM, compost, green leaf and crop residue) on profle SOC stocks, C sequestration, SOC sequestration rate, C buildup rate and sustainable yield index (SYI) of maize and blackgram crops in dry semi-arid Vertisols of western India. The study encompasses diferent nutrient management viz., 100% recommended dose of fertilizer (RDF) of NP, 25 kg ha−1 N (FYM)+25 kg N (Urea)+30 kg P ha−1, 25 kg ha−1 N (Compost)+25 kg N (Urea)+30 kg P ha−1, 25 kg ha−1 N (Crop residue)+25 kg N (Urea)+30 kg P ha−1, 15 kg ha−1 N (FYM)+10 kg N (Crop Residue)+25 kg N (Urea)+30 kg P ha−1, 15 kg ha−1 N (FYM)+10 kg N (Compost)+25 kg N (Urea)+30 kg P ha−1, 15 kg ha−1 N (FYM)+10 kg N (Green Leaf)+25 kg N (Urea)+30 kg P ha−1, 100% recommended N (urea) without P and unfertilized control. Randomized Complete Block design was used wherein all the treatments were replicated thrice. Application of 15 kg ha−1 N (FYM)+10 kg N (Crop Residue)+25 kg N (Urea)+30 kg P ha−1 signifcantly improved the SOC concentration of the soil profle (0–1.0 m) than unfertilized control and treatments receiving solely mineral fertilizers. Highest SOC profle stock, C sequestration with concomitant C buildup was obtained with 15 kg ha−1 N (FYM)+10 kg N (Crop Residue)+25 kg N (Urea)+30 kg P ha−1. A positive correlation is observed between total C input and profle mean SOC content (R2=0.74), profle C stock (R2=0.76), C sequestration (R2=0.76), C sequestration rate (R2=0.76) at P values