不同降水年型地膜覆盖及秸秆覆盖提高小麦产量和氮素利用的效应

  【目的】  地膜和秸秆覆盖是提高西北旱地小麦产量和氮素利用率的有效措施，本研究比较了两种覆盖方式在不同降雨年型的效果，为小麦高产、氮素高效利用和可持续发展提供技术支撑。  【方法】  于2012—2020年在陕西省咸阳市永寿县御驾宫村旱地进行8年大田试验，试验期间有3个丰水年、1个平水年和4个干旱年。试验设无氮对照、常规播种、全膜穴播和秸秆覆盖共4个处理，其中3个施氮肥处理为施纯氮150 kg/hm2。调查了小麦产量、产量三要素、生物量、氮含量、吸氮量，计算了氮肥表观利用率和氮肥农学利用率。  【结果】  与常规播种相比，在丰水年、平水年、干旱年和8年平均值中，全膜穴播和秸秆覆盖产量分别提高9.9%和6.8%、15.0%和12.8%、16.3%和15.2%、13.0%和10.9%；穗数分别提高15.1%和10.9%、4.4%和13.2%、3.3%和8.7%、9.0%和10.4%；地上部吸氮量分别提高14.2%和15.4%、2.1%和5.8%、6.4%和8.5%、9.6%和11.5%；籽粒吸氮量分别提高7.0%和9.8%、4.0%和5.4%、6.5%和9.2%、6.4%和9.1%；氮肥表观利用率分别提高23.0%和24.9%、3.0%和8.1%、10.4%和14.0%、15.3%和18.2%；氮肥农学利用率分别提高20.4%和13.8%、25.1%和21.5%、34.5%和31.8%、26.2%和21.9%。与秸秆覆盖相比，8年试验期间全膜穴播产量提高0.9%～2.9%，氮肥农学利用率提高2.1%～5.9%；与全膜穴播相比，秸秆覆盖地上部吸氮量提高1.0%～3.6%，籽粒吸氮量提高1.4%～2.7%，氮肥表观利用率提高1.5%～4.9%；在丰水年，全膜穴播穗数比秸秆覆盖提高3.9%，在其它年型，全膜穴播穗数降低1.2%～7.8%。  【结论】  无论降雨多寡，全膜穴播和秸秆覆盖均有蓄水保墒，提高小麦产量和氮素利用率的效果；且全膜穴播与秸秆覆盖的效果相当。综合考虑经济和环境效益，建议尽可能使用秸秆覆盖。

Effects of plastic film mulching and straw mulching on wheat yield and nitrogen utilization during different precipitation years

  【Objectives】  Plastic film mulching and straw mulching are widely used in wheat production in northwest dryland area. We compared the effect of the two mulching methods under different precipitation years, to provide support for efficient and sustainable wheat production.  【Methods】  A field experiment was conducted from 2012 to 2020 in dryland of Xianyang City, Shaanxi Province. According to the annual precipitation, there were three rainy years, one normal year and four dry years during the experimental period. Randomized complete block design was adopted for the study with four treatments: no-N application control, conventional mode, plastic film mulching and straw mulching. Except control, all the plots received N 150 kg/hm2. The wheat grain yield, yield components, N uptake, and the N use efficiency were determined.  【Results】  Compared to the conventional mode, plastic mulching and straw mulching increased wheat grain yields by 9.9% and 6.8%, 15.0% and 12.8%, 16.3% and 15.2%, 13.0% and 10.9% during the rainy, normal, dry years, and 8-year cumulative mean, respectively. Number of spikes increased by 15.1% and 10.9%, 4.4% and 13.2%, 3.3% and 8.7%, 9.0% and 10.4%, respectively. The aboveground N uptake increased by 14.2% and 15.4%, 2.1% and 5.8%, 6.4% and 8.5%, 9.6% and 11.5%, respectively. The grain N uptake was increased by 7.0% and 9.8%, 4.0% and 5.4%, 6.5% and 9.2%, 6.4% and 9.1%, respectively. The N apparent use efficiency was enhanced by 23.0% and 24.9%, 3.0% and 8.1%, 10.4% and 14.0%, 15.3% and 18.2%, respectively. The N agronomic efficiency increased by 20.4% and 13.8%, 25.1% and 21.5%, 34.5% and 31.8%, 26.2% and 21.9%, respectively. Compared with straw mulching in the 8-year study, the wheat grain yield of plastic film mulching increased by 0.9%?2.9%, the N agronomic efficiency increased by 2.1%?5.9%; compared with plastic film mulching, the aboveground N uptake of straw mulching increased by 1.0%?3.6%, the grain N uptake increased by 1.4%?2.7%, the N use efficiency increased by 1.5%?4.9%. Compared to straw mulching, number of spikes with plastic film mulching increased by 3.9% during rainy years, and decreased by 1.2%?7.8% during the normal and dry years.  【Conclusions】  Regardless of the amount of precipitation, both the plastic film mulching and straw mulching had markedly and similarly improved water storage, moisture retention, wheat yield, and N utilization. By comprehensively considering the economic and environmental benefits, it is recommended to use straw mulching in sustainable wheat production.