Runoff and soil erosion as affected by plastic mulch patterns in vegetable field at Dianchi lake's catchment, China

Plastic mulching is an important agricultural practices used to improve crop productivity. Field experiments were conducted to determine the effect of plastic mulch patterns and crop rotations on runoff, erosion and soil physical properties in 2010 and 2011 growing seasons. The experiment was a randomized complete factorial design with two plastic mulch treatments (narrow vs. wide plastic mulch) and two rotation treatments (broccoli–zucchini–winter wheat vs. broccoli–zucchini–fallow). The wide-plastic-mulch treatment significantly (P<0.05) reduced runoff and soil loss compared to the narrow-plastic-mulch treatment, due to the better developed micro-basins found on the raised beds that enhanced infiltration in wide-plastic-mulch systems. Our results also indicated that inclusion of a winter wheat crop in the vegetable rotation did not alter the extent of runoff and soil loss from the vegetable field. Furthermore, we found that plastic mulch substantially accelerated runoff generation and soil erosion in vegetable seedling stages. There were significant correlations between soil loss and runoff volume (P<0.01) and rainfall intensity (P<0.01). The losses of total C, N and P were closely associated with that of the soil loss, and 82% of TC, 57% of TN and 75% of TP is entrained with sediment. After growing season, furrows without plastic mulch displayed lower total porosity and macroporosity (>60μm) that impeded infiltration in surface soil (0–5cm). Higher water stability of soil macro-aggregates >2mm were observed in plastic mulch ridges relative to the furrows after rain season. The results obtained in this study have practical implications for soil and water conservation in vegetable culture.