Understanding yield gap and production potential based on networked variety-density tests and Hybrid-Maize model in maize production areas of Inner Mongolia

Exploitation of yield gaps in current maize production was needed for increasing grain yields to meet future food requirements. The quantification of yield gap and production potential by scientific method was critical for rational planning of production and development of maize industry in Inner Mongolia. This study combined cultivar and density network test data with Hybrid-Maize model simulation, and used data of recorded the highest yield since 2006, the average yield of the farmers in different ecological regions in Inner Mongolia to analyze the yield gap and production potential of Inner Mongolia and its six ecological regions. Based on the modeled yield potential, the highest recorded yield, experimental yield and farmers’ yield generally increased from the east to the west of Inner Mongolia. Maize yield potential in Inner Mongolia was 14.9 thm^-2, with the highest recorded yield of 14.4 thm^-2 and experimental yield of 11.1 thm^-2. Farmers’ yield reached 49% of the modeled yield potential, 51% of the highest recorded yield and 66% of the experimental yield. Yield gap based on the modeled yield potential (YGM), the highest recorded yield (YGR) and experimental yield (YGE) was 7.5 thm^-2, 7.0 thm^-2 and 3.8 thm^-2, respectively. Based on YGE, the short-term production potential in Inner Mongolia was 3 525.2×10⁴ tons (which was 1.6 times of the current maize production) and the short-term production gap was 1 191.9×10⁴ tons. In the short-term, the four eastern regions (including Hulunber, Xing’an, Tongliao and Chifeng) contributed 61% to the production potential of the whole Inner Mongolia, while the western regions (including Hohhot and Bayannur) contributed only 16%. The main factor of high YGE was inefficient cultivation management practice. To address this challenge, the countermeasures were recommended, such as comprehensive improvement of cultivation management practices, simplification of agronomic techniques easily adopted by farmers, for to gradually narrow YGE.