地膜覆盖与氮肥配施对玉米生长及氮素利用的影响

Effects of plastic film mulching combined with different nitrogen fertilizer levels on maize growth and nitrogen utilization

覆膜栽培是旱区农业常用的种植技术。为探究滴灌水肥一体条件下,覆盖生物降解膜后,配施氮肥对玉米生长和氮素利用的影响,从而减少农田残膜污染和过量施氮等问题。于2020和2021年在宁夏旱作节水灌溉区设置两类地膜[Ⅱ类环境生物降解膜(S)和普通地膜(P)]和4个氮素水平裂区试验,探究滴灌条件下降解膜覆盖配施氮肥对膜下滴灌玉米生长和氮素吸收利用的影响。结果表明:S与P覆盖下对滴灌玉米出苗率和出苗期影响效应一致,且在玉米苗期保温效果相当,无显著性差异;S覆盖下,随着施氮量的增加,滴灌玉米干物质累积量、氮素吸收利用、穗数、籽粒重和产量均表现为先增加后降低的趋势,在施氮量为240 kg·hm^(-2)时最佳,且与P覆盖下无显著性差异,这表明生物降解地膜可替代普通地膜投入到农业生产中去;建立膜下滴灌玉米施氮量与产量、吸氮量、氮素利用效率的多元回归曲线得到S和P膜覆盖下的最大产量(13338、13806 kg·hm^(-2))对应的施氮量均为240 kg·hm^(-2),两种地膜覆盖下的最大产量较施氮量360 kg·hm^(-2)(N3)时分别提高6.8%和6.1%,氮肥农学效率和氮肥偏生产力分别提高63.8%、45.2%和58.7%、59.8%。降解膜在促进作物出苗、前期增温、氮素吸收利用和产量等方面与普通地膜一致,施氮量为240 kg·hm^(-2)时在促进作物干物质累积、氮素吸收利用和作物增产增效等方面达到最佳。因此,S覆盖下配施氮肥240 kg·hm^(-2)可作为西北灌区滴灌玉米适宜的种植措施。

Mulching is a common planting technique in dryland agriculture.Under the condition of drip irrigation with the integration of water and fertilizer,the effects of mulching of biodegradable film with different levels of nitrogen(N)fertilizer on maize growth and nitrogen utilization were investigated,thus reducing the problems of residual film pollution and excessive nitrogen application in farmland.Two types of mulch[Class II environmental biodegradable film(S)and common film(P)]and four nitrogen levels split plot experiments were set up in 2020 and 2021 in dry farming water-saving irrigation area of Ningxia.The results showed that the effects on seedling rate and emergence stage of drip-irrigated maize under S and P cover were the same,and the insulation effects were comparable at the maize seedling stage without significant differences.Under S cover,with the increase of N application,the accumulation of dry matter,N uptake and utilization,number of ears,seed weight and yield of drip irrigated maize showed a trend of increasing first and then decreasing,and was best at 240 kg·hm^(-2) N application,and it was not significantly different from P cover,which indicated that biodegradable mulch could be put into agricultural production instead of common mulch.Multiple regression curves were established between N application and yield,N uptake and N use efficiency of maize under drip irrigation,and the maximum yield(13338 and 13806 kg·hm^(-2))was obtained under S and P cover,and the both corresponding N application was 240 kg·hm^(-2).The maximum yields under both mulches were 6.8%and 6.1%higher than those at 360 kg·hm^(-2) N(N3)application,and the nitrogen fertilizer agronomic efficiency and nitrogen fertilizer bias productivity were 63.8%,45.2%and 58.7%,59.8%higher,respectively.The degradation film was consistent with common mulch in promoting crop emergence,preliminary warming,nitrogen uptake and utilization,and yield,etc.The best application of N at 240 kg·hm^(-2) was achieved in promoting crop dry matter accumulation,nitrogen uptake and utilization,and crop yield and efficiency.Therefore,the application of 240 kg·hm^(-2) of N fertilizer under S cover can be a suitable planting practice for drip-irrigated maize in the northwest irrigation area.