Yield Gap Analysis of County Level Irrigated Wheat in Hebei Province, China

Yield gap analyses are useful for examining differences between potential yield (Yp) and actual yield realized in farmer fields. However, it is often difficult to estimate the attainable yields in smallholder farm agriculture. In this study, we estimated the yield gaps in irrigated wheat in the Hebei Province in China using data from farmer surveys and crop modeling. The EPIC (Environment Policy Integrated Climate) model was calibrated and evaluated for high-yielding wheat experiments in Hebei Province to estimate the Yp at the county level. The model was run for 10 yr (2005-2014) using county-level weather data, and the area-weighted average model-based estimate of Yp was 9.93 Mg ha(-1) across 116 counties in Hebei Province, which was higher than the estimate of approximately 9.0 Mg ha(-1) that was reported in previous studies. The attainable yield potential (Ya) during this period was defined as the mean yield of the top 5% of farmers, and the actual farm yield (Yf) in these counties was calculated based on a survey of 385,167 farmers. The area-weighted average Yf was 6.47 Mg ha(-1), corresponding to 65.2% of the model-based estimate of Yp. The total yield gap was high at 3.46 Mg ha(-1). The top-producing farmers achieved only 77% of the model-based Yp, which indicates that closing the yield gap remains a challenge. In the future, investments should be made in technology transfer for irrigated wheat production in China.