Mulch covered ridges affect grain yield of maize through regulating root growth and root-bleeding sap under simulated rainfall conditions

- Simulated rainfall 430 mm significantly improved the root growth and increased grain yield.
- Plastic mulching regulating root growth distribution and root bleeding sap rate.
- Plastic mulching with 430 mm rainfall enhanced characteristics of ear and grain yield.

Application of various ridges covering mulch materials with ridge-furrow rainfall harvesting (RFRH) system are the principal agricultural technique for enhancing characteristics of ear and grain yield through regulating root growth distribution across the rooting zone. Therefore, at the College of Life Science in Semi-Arid Regions of China in Ningxia University, Yinchuan, and Ningxia Province， during 2014-15. The objectives of this research work were to enhance characteristics of ear and grain yield through regulating root growth and root bleeding sap flow, with following two planting models: (i) traditional flat planting (CK); (ii) ridge covered with different mulches materials (plastic film (PM), biodegradable film (BM), soil crust ridges (SC)); and two simulated rainfall levels: 320 mm and 430 mm rainfall. Finding of the current research work indicated that ridge covering mulch materials under simulated rainfall had significantly improved characteristics of ear which led to distinct effect on grain yield as compared with flat planting. The average grain yield increased by 30%, 25% and 12% for PM430, BM430 and SC430 as compared to CK430 over 2 consecutive years, respectively. RFRH system significantly enhanced the rooting systems on the top 50 cm soil profile which was attributed to enhancing the grain yield. Root length density (RLD) and root surface area density (RSD) were significantly higher under PM430 (plastic film mulch with 430 mm rainfall) and BM430 (biodegradable film mulch with 430 mm rainfall) in the uppermost soil profile layer of 10-50 cm as compared with flat planting, but there was no significant difference in RLD and RSD among all the treatments at the deeper soil profile below 60 cm. The effect of RFRH system on root dry weight (g plant−1) and bleeding sap of root is significantly related to the simulated rainfall levels. PM430 and BM430 significantly improved the root dry weight (g plant−1) and rate of root bleeding sap in the different growth stages in both study years. Our results suggested that PM430 and BM430 is an effective, modern cultivation mode for maize productivity in semi-arid areas due to enhanced characteristics of ear, root spatial and temporal distribution of rooting systems across the root zones at different soil profiles, as a result in higher grain yield and reducing maize productivity risk under dry-land farming system.