Fig. 4: Soil health assessment for different rotation systems.
a Principal component analysis (PCA) for eigenvalues of the ten key soil properties, including soil organic carbon (SOC), dissolved organic carbon (DOC), total nitrogen (TN), NO3–-N, available P (AP), pH, microbial biomass N (MBN), microbial biomass carbon (MBC), bulk density (BD), and soil water content (SWC). Each soil property was normalized as an individual CSHA (Cornell Soil Health Assessment) contributor to the overall soil health score. b CSHA score for each rotation. In b, the whiskers in each column represent the standard deviation of three replications; circles are the corresponding data points for the bar chart, n = 3. One-way ANOVA with two-sided and post-hoc test was conducted for the significance test among different treatments. Different lowercase letters denote significantly different groups of crop rotations at P < 0.05. The red dashed line with red percentages is the baseline of the WM rotation. The black dashed line with black percentages is the baseline of 2016. Treatment abbreviations: WM winter wheat–summer maize (control case), SpWM sweet potato→winter wheat–summer maize rotation, PWM peanut→winter wheat–summer maize rotation, SWM soybean→winter wheat–summer maize rotation, SmWM spring maize→winter wheat–summer maize rotation, RSWM ryegrass–sorghum→winter wheat–summer maize rotation. Source data are provided as a Source Data file.
