Lowering soil greenhouse gas emissions without sacrificing yields by increasing crop rotation diversity in the North China Plain

Abstract

Intensive double cropping in the North China Plain has been challenged by serious environmental problems. Crop rotation is one of the important strategies for sustainable agriculture, which can reduce production risk and environmental impact. Yet, few studies have assessed enhanced crop rotation diversity on GHG emissions in the North China Plain. Carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) emissions and yields were measured from four cropping systems: (1) wheat ( Triticum aestivum L.)-maize ( Zea mays L.) double cropping (WM); (2) peanut ( Arachis hypogaea L.) and WM rotation (PWM); (3) ryegrass ( Lolium perenne L.)-cotton ( Gossypium hirsutum L.), peanut and WM rotation (RCPWM); and (4) continuous cotton (C), to determine if enhanced crop rotation diversity can reduce greenhouse gas (GHG) emissions and improve yields. The RCPWM, PWM and WM cropping system produced 11.9%, 15.7% and 32.4% higher net greenhouse gas emissions (GHGE), respectively, than the C cropping system each year by the soil-based method assessing the field productive process. From 2017 to 2018, in the same crop planting seasons, RCPWM had lower cumulative N 2 O and CO 2 emissions, and produced similar peanut, wheat, and maize yields when compared to PWM. In 2018, PWM had higher cumulative N 2 O than WM during the wheat period, and they had similar seasonal cumulative N 2 O emissions during the maize period. Meanwhile, PWM produced lower cumulative CO 2 emissions and higher wheat and maize yields. In 2019, RCPWM did not have significantly different seasonal cumulative N 2 O emissions and yield, but slightly higher soil CO 2 emissions than C during the cotton season. The GHG emission intensity (GHGI) of the same crops was lower in RCPWM than in PWM during the peanut, wheat, and maize period or slightly higher than in the C treatment during cotton period. The results demonstrate that RCPWM could reduce soil N 2 O emissions when the same crops in PWM were compared due to less soil CO 2 emissions that the previous cotton brought about. The RCPWM system did not show a lower soil organic carbon (SOC) sequestration rate than the PWM and C systems. Therefore, increasing cotton into the peanut and wheat-maize rotation system (RCPWM) for more diversified system can help reduce soil GHG emissions without sacrificing yields. • PWM, RCPWM and C cropping systems reduced indirect GWP compared to WM. • PWM did not decrease soil N 2 O emissions but improved wheat and maize yield. • The previous cotton lowered soil CO 2 and N 2 O emissions for next crop growing season. • Increasing crop species in rotation could reduce soil GHG emissions without sacrificing yields.