Exploring options for improving maize productivity for small farmers in the Loess Plateau

Millions of small farmers rely on maize (Zea mays L.) produced in the Loess Plateau of China. However, little has been reported on the effects of plastic mulch and maize cultivar on crop yield in the check dam environment. The objectives of this experiment were to determine the effects of maize cultivar and plastic mulch on photosynthetic characteristics and grain yield when grown in the check dam environment. Three maize cultivars were assessed with and without plastic mulch in 2016 and 2017 in Ansai County, Shaanxi Province, China. Results showed that mulch increased grain yield by 10.5% in 2016 and 11.3% in 2017 across all cultivars. Among all cultivars, ‘Xianyu335’ had the highest grain yield under both mulch and no mulch. Grain yield was significantly correlated with soil water content in the 0-20 cm layer. Soil temperature under mulch decreased with increasing soil depth. Averaged over soil depths, mulch increased soil temperature from 0.2 to 1.9 °C over the entire growing season. Maize cultivar directly determined photosynthetic characteristics. Grain yield was more closely related to photosynthetic rate in July than in August, and was significantly associated with stomatal conductance and transpiration rate. Our findings suggest that photosynthetic characteristics is an important index affecting maize grain yield for small farmers using check dams in the Loess Plateau.