Intensifying crop rotations with pulse crops enhances system productivity and soil organic carbon in semi-arid environments

Abstract

Pulse crops are commonly rotated with cereals to reduce nitrogen fertilizer use and increase economic returns while offering plant-based protein premium. However, it is unclear how pulse crops might affect soil quality, considering their low residue return to the soil. This study determined soil organic carbon, crop productivity, and system stability in intensified pulse-wheat (Triticum aestivum L.) rotations. Chickpea (Cicer arietinum L.)- wheat, lentil (Lens culinaris Medik.)-wheat, pea (Pisum sativum L.)-wheat, and wheat monoculture were studied over four cycles at two field sites. Across four rotation cycles, pea-wheat increased protein-based system yields by 22–82, 9–26 and 26–66% compared with chickpea-wheat, lentil-wheat, and wheat monoculture, respectively. Pea-wheat had the smallest variation in protein-based system yield and was most responsive to environments. Soil mineral N to the 60-cm depth was not different among the rotations involving pulse crops, but was higher than wheat monoculture. After eight years of rotations, soil organic carbon increased to 11.2 g kg−1 from the baseline soil of 10.3 g kg-1, but there was no difference among rotation systems. The integrated assessment of yield, soil organic carbon and system stability indicate that pulse crops-based rotations perform superior than wheat monoculture and pea-wheat system provides a paradigm of sustainable crop intensification.