Abstract: Four kinds of mulching film biodegradable film S1 which is made of starch and polycaprolactone, S2 which is made of polylactic acid and poly (butylene adipate-co-terephthalate), S3 which is made of poly (butylene adipate-co-terephthalate) and common mulching film P which is made of polyethylene) and 4 nitrogen application levels (0, 120, 240 and 360kg · ha⁻¹) were set. Under the condition of drip irrigation water and fertilizer integration, maize field experiment was conducted to investigate the effects of different types of film mulching combined with nitrogen fertilizer application on maize yield, soil moisture, temperature, nitrogen fertilizer use efficiency and economic benefits, so as to screen out the degradable film mulching and the suitable combined application amount of nitrogen fertilizer for maize planting in Ningxia irrigation area. The results showed that under different film mulching, the soil water content, yield, nitrogen use efficiency, nitrogen partial productivity and economic benefit under biodegradable film mulching S2 treatment increased by 1.15%, 13.15%, 2.38%, 11.69% and 19.03% respectively compared with S1 treatment, and there was no significant difference between biodegradable film mulching S2 treatment and common mulching film P treatment; there was no significant difference in 5−25cm soil average temperature between S2 and S1 treatments; the soil water content, nitrogen fertilizer use efficiency and nitrogen fertilizer partial productivity of 0−100cm layer under N2 treatment decreased by 2.31%, 4.59% and 38.15% respectively, while the maize yield and economic benefit increased by 62.22% and 108.69% respectively compared with N0 treatment; nitrogen fertilizer application had no significant effect on soil temperature in 0−25cm. The results showed that degradable film mulching S2 and nitrogen fertilizer application with 240kg · ha⁻¹ could effectively improve soil moisture and temperature, increase maize yield and nitrogen use efficiency, and increase net income in arid agricultural areas of Ningxia.

Key words: Maize, Biodegradable film, Soil moisture, Soil temperature, Yield, Nitrogen use efficiency