Fig. 1: The random forest (RF) model development.
From: China can be self-sufficient in maize production by 2030 with optimal crop management
a Study area and locations of experimental sites found in the literature. b Data distributions of OPDs and YieldOPD estimated from literature data with yield-density quadratic model. c Comparisons of the estimated OPD by RF model with observed OPD in 448 observations. The dashed line represents the 15% error line. d Linear-model for the relationship between OPD and YieldOPD. We find a similar performance in linear and quadratic fits for the relationship between the YieldOPD and OPD and the linear nature is applied. The solid line is the regression lines and the dashed line indicate the 95% confidence interval. Statistical significance in c and d is obtained with a two-tailed Student’s t test. Source data are provided as a Source Data file.
