We tried to compare the soil and water conservation effects of plastic film mulching with some traditional measures for controlling the soil and water erosion in economic forest

such as green manure mulching

grass coverage

biological hedge

and paraquat application. We tried to explore the feasibility of plastic film mulching on preventing soil and water erosion in Castanea henryi plantation

using erosion needles and observation in runoff plots at the same time. The results showed that the soil erosion and nutrient loss of 5 different treatments were all significantly less than the control treatment as the extension of processing time. The liquid runoff of green manure mulching and paraquat application measures were both less than the other 3 treatments. The liquid runoff of plastic film mulching was more than the other measures when soil loss was the least for low level of rainfall infiltration

and soil loss of paraquat application was less than the other traditional measures. We also analyzed the spatial heterogeneity of soil erosion on the slopes. We found that net sediment on the slopes of green manure mulching

biological hedge and paraquat application reduced gradually as the extension of processing time. But all the different slope positions of grass coverage and plastic film mulching showed net deposition obviously. On the other hand

so much liquid runoff of plastic film mulching did not take too much nutrient away because the mulch could separate nutrient from rainfall. Only the content of total phosphorus

total potassium and ammonium nitrogen in liquid runoff in May and June were more than the control treatment when the liquid nutrient loss were less than the control treatment significantly from July to October. The soil nutrient loss of plastic film mulching was also less than the other measures. Moreover

plastic film mulching could reduce the labor costs by reducing the time to harvest. Therefore

we think that plastic film mulching had significant effect in reducing slope soil erosion and nutrient loss

and it had certain superiority in soil and water conservation of Castanea henryi. But it had a tendency to increase erosion for liquid runoff on the film

so practical use of this measure should be restricted. In our opinion

we can set up the proportion of mulch

using a porous membrane or micro-engineering on slopes to reduce liquid runoff

to achieve the best effect of plastic film mulching.