Effects of ridge-covering mulches on soil water storage and maize production under simulated rainfall in semiarid regions of China

The ridge furrow rainwater harvesting (RFRH) system with different ridge covering materials as mulch for collecting runoff water is a valuable technique for enhancing seed filling rates and maize productivity. Therefore, a field experiments were conducted during 2 consecutive years in 2014-15, under large mobile rain-proof shelter at the Institute of Water Saving Agriculture in Semi-Arid Areas of China. Objectives of this study were enhancing soil water storage, promoting seed filling and yield of maize, with following two planting models: (i) traditional flat planting (CK); (ii) ridges covered with different mulching material (plastic film (PM), biodegradable film (BM), soil crust ridges (SC)); and two simulated rainfall levels: 320 mm and 430 mm rainfall. Results of this work revealed that mulching material on ridges had distinct effect on soil water storage in the 200 cm depth of soil at the middle of furrows and in the order of PM430 ≈ BM430 > SC430 > PM320 > BM320 > SC320, compared to CK320 and CK430, respectively. The average seed yield increased by 27%, 23% and 17% for PM320, BM320, and SC320, compared to CK320, and increased by 30%, 25% and 12% for PM430, BM430 and SC430 as compared to CK430 over 2 consecutive years, respectively. Average WUE significantly improved by (P < 0.05) in PM430 and PM320, BM430, BM320, SC320, and SC430 were 32.8%, 29.7%, 24.8%, 24.2%, 17.6% and 8.5% over 2 years compared to CK320 and CK430, respectively. The effect of RFRH system on maize seed filling was significantly related to the simulated rainfall levels and the position of the seeds on the ear. Both PM320 and BM320 significantly (P < 0.05) promoted the seed filling rates of the superior, middle and inferior seeds. Seed-filling rates of the superior, middle and inferior seeds at the PM430 were also significantly increased. Our results suggested that PM430 and BM430 both significantly increased the SWS during the seed-filling process; which resulted higher grain yield and might have potential for reducing maize productivity risk under dry-land farming system.