Effect of ridge-covering mulching materials on hormonal changes, antioxidative enzyme activities and production of maize in semi-arid regions of China

The objectives of this study was to investigate the effect of different ridges covered mulching materials on maize production under different simulated rainfall levels and the relationship with anti-oxidant enzyme activities in leaves and hormonal changes in grains. In the present study, conventional fiat cultivation (CK) was compared with several ridge covered mulching materials (PM: plastic film, BM: biodegradable film, SC: soil crust ridges) under 320 mm and 430 mm simulated rainfall levels. The results clearly indicated that the effect of ridge covering mulching materials on antioxidant enzyme activities and hormonal changes of maize were significantly related to precipitation levels. At 430 mm rainfall level, PM significantly promoted indole-3-acetic acid, zeatin + zeatin riboside and abscisic acid contents and decreased ethylene, and gibberellic acid contents in superior, middle and inferior seeds as compared with CK430 treatment. At 430 mm rainfall level, PM significantly increased soil water storage, characteristics of ear, antioxidant enzyme activities in leaves, hormonal changes in seeds and reducing lipid peroxidation which led to increased (43.1%) grain yield of maize than that of CK430 treatment. At 430 mm rainfall level and ridges covered with plastic film significantly increased the activities of peroxidase (33.5%), catalase (76.0%) and superoxide dismutase (43.6%) at grain filling stage, while activity of malondialdehyde (MDA) concentration in leaves significant rise and reached up to maximum (16.7 mu mol g(-1) FW) value at maturity stage under conventional flat planting. Based on these results, we conclude that the PM treatment with 430 mm simulated rainfall significantly increased the soil water storage, adjusting antioxidant enzyme activities in leaves, debasing lipid peroxidation and balance of hormones in the grains as a result improve maize productivity under semi-arid regions of China.