Response of maize yield and water use to different green manure utilization patterns in arid oasis irrigation area

With the aim of long-term continuous cropping of wheat and maize in arid oasis irrigation areas, the fallow-period after wheat harvest is long and the utilization efficiency of light, heat, and water resources is relative low; thus, it is important to study the effects of different green manure utilization patterns on maize yield and water use characteristics. In the Shiyang River basin, the effects of different green manure utilization patterns on the yield formation and water use characteristics of maize were studied through a field experiment on the wheat-green manure-maize rotation system. Different green manure utilization patterns included tillage with full quantity of green manure incorporated in the soil (TG), no-tillage with full quantity of green manure mulched on the soil surface (NTG), above ground green manure harvested and tillage with root incorporated in the soil (T), no-tillage with above ground green manure harvested (NT), and conventional tillage without green manure (CT) as the control. The results showed that the average maize grain yield for treatments of NTG and TG reached 14 274.9 kg·hm^-2 and 14 687.5 kg·hm^-2, respectively, which was 18.2% and 20.4% higher, respectively, than that of CT. This is mainly due to the fact that the number of ears, seed number per ear, and seed weight of maize for NTG were 5.4%, 9.6%, and 20.8% higher, respectively, than those of CT, and the effect was significantly higher than that of root utilization patterns (treatments T and NT). Meanwhile, TG and NTG treatments significantly increased maize leaf area index, dry matter accumulation, and average net assimilation rate. The average water use efficiency of the NTG treatment reached 24.4 kg·hm^-2·mm^-1, which was 29.9% higher than that of CT, which significantly increased the soil water storage before maize sowing to 26.9%, with an average of 280.7 mm. In addition, under NTG treatment, the water consumption of maize during the whole growth period was significantly lower than that of the other green manure treatments. Under the conditions of green manure root utilization (treatments T and NT), the water use efficiency of maize was 16.7% and 16.0% higher, respectively, than that of CT. Therefore, in the arid oasis irrigation area, for the wheat-green manure-maize rotation system, employing no-till with full quantity of green manure mulched on the soil surface achieves high yield of maize while achieving efficient use of water resources.