Distinguishing between yield advances and yield plateaus in historical crop production trends.

The following criteria were used to identify the best-fit model for each crop–region yield trend: highly significant (Student’s t -test; P <0.01) model parameters, highest r 2 and lowest r.m.s.e. compared with other models, and independent, normally distributed yield residuals with homogenous variance and unbiased distribution when residuals were plotted against year ( Fig. 4 ).

also in 132,142 other papers

Although the yield residual versus time relationship of the linear model exhibited a strong trend, there was no detectable pattern in the yield residuals of the LUP or LLP models, with the only exception of maize in West Africa where there was no detectable trend in both linear and LLP models.

also in 5,725 other papers