Integration of tillage and planting density improves crop production and carbon mitigation of maize/pea intercropping in the oasis irrigation area of northwestern China

Abstract

High yield is a benefit of production system with high input, but usually more CO2 emitted. It is unclear whether to integrate a multi-technology in the intercropping to achieve a high-yielding, low emission, and high efficiency agricultural integrated production system. In order to assess the crop production and carbon mitigation in integrated system, a field experiment of maize/pea intercropping was performed with two tillage (no-tillage and conventional tillage) and three maize plant density (low density-45,000, medium density-60,000, and high density-75,000 plants ha−1) in the oasis irrigation area of northwestern China during the 2016–2018. We found that no-tillage improved crop production and carbon mitigation, increasing maize density was able to improve yield in maize/pea intercropping, but increased the carbon emission. From the 3-year average, the integration of no-tillage and medium plant density (NI2) effectively increased the total grain yield (GY) by 14.5 %, reduced carbon emission by 3.5 % compared to conventional tillage with low maize density (CI1). Meanwhile, this integrated system had increased carbon emission efficiency (CEE) by 16.7 % compared to the CI1. For different crop components in maize/pea intercropping, no-tillage mainly reduced the carbon emission of the maize strip, but no significant effect of pea strip by increasing the maize plant density. In addition, this integrated system also increased net primary production (NPP), net ecosystem production (NEP) and carbon sequestration potential by 17.8, 19.9 and 21.8 % compared with CI1, while had highest economic benefits (average 3.1). Therefore, maize/pea intercropping compound production pattern integrated no-tillage and medium maize plant density (NI2) should be recommended as the high-efficiency model of farming system for resources saving and reducing carbon emission in oasis irrigation area of northwest China.