Fig. 2
Overall, based on 148 observations, the mean effect value of yield under conservation tillage is 0.0443, with a 95% confidence interval (CI) from 0.0249 to 0.0636, indicating that crop yield can be increased by an average of 4.53% (2.52%-6.57%, P < 0.001) under different conservation tillage measures in NEC (Fig. 2). However, the large range in yield effect (-0.4073 to 0.4715), indicates that yield has responded differently in different studies, and that to apply conservation tillage practices appropriately it will be necessary to understand those conditions that effect the magnitude and direction of yield change.