Reduce carbon footprint without compromising system productivity: Optimizing crop rotation in the North China plain

Abstract

The North China Plain (NCP) serves as a crucial production base for wheat and maize in China. However, the intensive winter wheat-summer maize (WM) cropping system has also led to high carbon emissions. It is imperative to optimize crop rotations to reduce greenhouse gas (GHG) emissions while ensuring food security. Thus, we conducted a 6-year field experiment in the NCP to evaluate the productivity, carbon footprint (CF), and sustainability of the five rotation systems. These included four 2-year rotation systems: spring maize → WM (WMME), spring millet → WM (WMML), spring peanut → WM (WMMP), and spring soybean→ WM (WMMS), with WM serving as the control. Our results indicated that the 2-year rotation systems significantly reduced GHG emissions and improved agricultural sustainability. Wheat yield following the spring crops was 38.6%–47.5% higher than that following summer maize. The energy use efficiency, energy productivity, maize economic equivalent yield (MEEY), and net income in WMMP were higher by 9.7%, 51.8%, 4.4%, and 15.5%, respectively, compared to WM. This was mainly attributed to the high yield, price, energy equivalent coefficient, and pre-crop effect of spring peanut. The reduction of N and electricity inputs in the 2-year rotation systems reduced on-farm N2O emissions and indirect emissions by 39.0%–56.2% and 41.9%–42.9%, respectively, thus lowering CF per unit area by 25.7%–36.6% compared with WM. WMMP demonstrated a 38.2% reduction in CF per kg MEEY, 16.1% reduction in CF per unit net energy, and 44.1% reduction in CF per unit net income, while increasing the sustainable evaluation index by 42.9% compared to WM. In conclusion, the 2-year rotation systems can reduce carbon footprint and improve agricultural sustainability in the NCP, among which the introduction of spring peanut into winter wheat-summer maize rotation can simultaneously enhance system productivity.