一年一作旱地麦田休闲期地膜覆盖保水对植株氮素利用的影响

Effects of film mulching in fallow period on water conservation and nitrogen utilization of dryland wheat in the winter-summer fallow cropping system

[目的]探究一年一作旱地小麦休闲期地膜覆盖保水提高底墒基础上对植株氮素利用、氮效率的影响,寻求实现水氮高效利用的最佳地膜覆盖方式。[方法]开展全膜覆盖、起垄半覆盖、不起垄半覆盖、不覆盖4种覆盖方式下对水分和氮素利用影响的大田试验研究。[结果]休闲期地膜覆盖后,播种至孕穗期0~1m土壤蓄水量显著提高,采用全膜覆盖和起垄半覆盖较不起垄半覆盖、不覆盖显著提高播种期土壤蓄水量,分别达14 mm、42 mm和12 mm、40mm,提高水分利用效率,且以全膜覆盖效果较好。休闲期地膜覆盖后,各生育时期植株氮素积累量提高,尤其中后生育阶段,有利于花前贮存氮素的运转,籽粒氮素积累增加,提高氮素吸收效率9%~32%、氮素收获指数2%~10%、氮素生产效率11%~30%,且以全膜覆盖效果较好。[结论]休闲期地膜覆盖有利于蓄积降雨,提高底墒,全膜覆盖更有利于水分利用效率、氮素吸收效率、氮素生产效率的提高,实现水氮耦合。

[Objective]To study the effects of plastic film mulching during fallow period with great soil water storage be- fore sowing on nitrogen （N） utilization and N use efficiency of dryland wheat conventionally cultivated as a single crop every year, and to seek the best film mulching to achieve water and nitrogen use efficiency. [Methods]The field experi- ment was conducted at Qiujialing village, Wenxi County, Shanxi Province from 2011 to 2012, under the conditions of full mulching （FM）, ridge half mulching （RM）, no ridge half mulching （NRM）, no mulching （NM）, to study the effects of different mulching modes on soil water and nitrogen utilization, l-Results]After plastic film mulching durir-g fallow period, the soil water storage from sowing to booting stage in 0- 1 m soil layer significantly improved. Com- pared with NRM and NM treatments, FM and RM could improve soil water storage at sowing stage significantly, reac- hing 14 mm, 42 mm and 12 mm, 40 ram, respectively, and water use efficiency also increased, and FM was better. After plastic film mulching during fallow period, N accumulation amount in plant at different growth stages increased, especially middle and late stages, it was also conducive to N translocation amount before anthesis （NTBA） to N in grains to promote the grain N accumulation, and which increased N uptake efficiency, N harvest index and N produc- tive efficiency reaching 9 M - 32 M, 2 % - 10 % and 11% - 30 %, respectively, and FM was better. [Conclusion] Plastic film mulching during fallow period was conducive to store precipitation into the soilresult ing in the increase of soil wa- ter storage before sowing. Full mulching had better effects on promoting water use efficiency, N uptake efficiency and N productive efficiency.