Effect of plastic mulch and winter catch crop on water availability and vegetable yield in a rain-fed vegetable cropping system at mid-Yunnan plateau, China

• We assessed water availability and yield in a rain-fed vegetable cropping system under different plastic mulch and rotation systems.
• The wide-plastic-mulch practice increased soil moisture storage in upper 60 cm layer and fruits yields and WUE of vegetables.
• The broccoli–zucchini–winter wheat rotation treatment did not decreased available soil water at broccoli transplanting.

The fluctuation of rainfall is the primary limiting factor for sustainability of rain-fed vegetable cropping systems in mid-Yunnan plateau. Our objectives were to evaluate effects of an alternative plastic mulching practice (narrow vs. wide plastic mulch) and an additional catch crop (broccoli–zucchini–winter wheat vs. broccoli–zucchini–fallow) on the soil moisture status, crop yield and water use efficiency (WUE) in the rain-fed vegetable cropping systems. Rainfall was much low and erratic during the entire experiment period compared with the long-term average (1971–2000). The 0–60 cm soil water storage (113 mm) of growing season was significantly higher under wide plastic mulch plots than narrow plastic mulch plots (99 mm). Fruit yield and water use efficiency of broccoli and zucchini were enhanced with wide plastic mulch during growing season in the three years experiment. Compared with the broccoli–zucchini–fallow plots, the broccoli–zucchini–winter wheat rotation treatment did not significantly decrease available soil water at broccoli transplanting stage. This implicated that the addition of winter wheat in the vegetable cropping system would not pose serious consequences for water storage. The results obtained in this study have practical implications for sustainability of the rain-fed vegetable culture.