Effects of Seven Diversified Crop Rotations on Selected Soil Health Indicators and Wheat Productivity

Diversified cropping systems can enhance soil condition and increase system productivity worldwide. To reduce the negative effects that accompany the continuous winter wheat-summer maize (WM) double-cropping in the North China Plain (NCP), diversified crop rotation (DCR) needs to be considered. The objective of this study is to evaluate the effect of DCR on soil health and wheat productivity as compared to a continuous WM double-cropping. A field experiment (37 degrees 41'N, 116 degrees 37'E) was established in the NCP including a traditional WM double-cropping as a baseline. During 2016/2017-2017/2018, the control is winter wheat-summer maize -> winter wheat-summer maize (WM -> WM) and seven DCRs as follow: fallow -> winter wheat-summer maize (F -> WM); spring maize -> winter wheat-summer maize (Ms -> WM); winter wheat -> winter wheat-summer maize (W -> WM); sweet potato -> winter wheat-summer maize (Psw -> WM); spring peanut -> winter wheat-summer maize (Pns -> WM); winter wheat-summer peanut -> winter wheat-summer maize (WPn -> WM) and potato-silage maize -> winter wheat-summer maize (PMl -> WM). Our results indicated that DCRs significantly changed certain soil health indicators in 2016/2017 compared with the control, where F -> WM rotation significantly decreased soil pH by 2.7%. The DCRs, especial Psw -> WM and Pns -> WM rotations showed a potential positive effect on soil health indicators at the end of the second year (2017/2018) compared with the control, where sweet potato increased soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP), urease activity (UA) and alkaline phosphatase activity (APA) in 2017/2018 by 5.1%, 5.3%, 13.8%, 9.4%, and 13.5%, respectively. With the spring peanut, TN, AP, and soil APA were increased by 2.1%, 13.2%, and 7.7%, respectively. Although fertilizer and irrigation input of DCRs were lower than the control, no significant decrease was observed on actual wheat yield as compared to the control (7.79 Mg/ha). The finding of this study highlights the value of DCRs, especially, Psw -> WM and Pns -> WM rotations over WM double-cropping in the NCP.