年际间周年覆盖保水对旱地小麦植株氮素利用的调控研究

A Study on the Effects of Interannual Mulching on Nitrogen Utilization of Dryland Wheat in Different Precipitation Years

为深入探索旱地小麦覆盖保水、增产、高效栽培技术途径,于2011—2014年在山西农业大学闻喜试验基地,以夏季覆盖渗水地膜与不覆盖为主区,以生育期膜际条播、常规条播为副区,研究年际间周年覆盖对麦田土壤水分运行和植株氮素积累、利用及氮效率的影响。结果表明:夏季覆盖提高播前3m内土壤水分,其保水效果可至孕穗期,且采用膜际条播效果更佳。夏季覆盖提高各生育时期植株氮素积累量,丰水年效果显著,提高27~31kg/hm^2,且采用膜际条播,夏季覆盖条件下欠水年提升空间较大,提高2~8kg/hm^2。夏季覆盖促进丰水年花前叶片和穗中氮素运转,促进平水年和欠水年茎秆+茎鞘中氮素运转,提高花前氮素运转量及对籽粒的贡献率,尤其欠水年;且采用膜际条播促进平水年茎秆+茎鞘和欠水年叶片中氮素运转,提高花后氮素积累量及对籽粒的贡献率。夏季覆盖提高氮素利用效率和氮素生产效率,欠水年采用膜际条播氮素吸收效率效果更佳;且采用膜际条播提高氮素吸收效率,欠水年夏季覆盖条件下氮素生产效率影响较大。结果还表明,夏季覆盖后,丰水年和平水年单位花后氮素积累量的增产效果较好,每增加1kg/hm^2可增产176~224kg/hm^2,而欠水年单位花前氮素运转量的增产效果较好,每增加1kg/hm^2可增产142~185kg/hm^2;采用膜际条播较常规条播,丰水年和平水年单位花前氮素运转、单位花后氮素积累的增产量均较大,欠水年夏季覆盖条件下采用膜际条播单位花后氮素积累量的增产量较大,每增加1kg/hm^2可增产234kg/hm^2。总之,周年覆盖有利于植株氮素吸收、运转,实现旱地小麦高产高效。

In order to explore the ways of water-conserving, yield-increasing and mgh-elIlclency cultivation technology of dryland wheat, a field experiment was carried out at the Wenxi Experimental Base of Shanxi Agricultural University during 2011 to 2014. Taking the summer mulching with water-permeable plastic film and non-mulching as the main plots, and sowing patterns, i.e. inter-mulching drilling （FM） and conventional drilling （CD） as sub-plots, the effects of interannual mulching in different precipitation years on soil water movement, plant nitrogen accumulation and utilization, and nitrogen efficiency in dryland wheat field were studied. The results showed that soil water content in the first 3 m soil layer before sowing could be improved by summer mulching, and the effect of water conservation could last to the booting stage, with FM having better effects. Summer mulching increased N accumulation of plants at different growth stages, the effect was significant in humid years, in which N accumulation was increased by 27 kg/hmz to 31 kg/hmz, and the FM under summer mulching could increase N accumulation significantly, i.e. by 2 kg/hmz to 8 kg/ hmZin dry years. Summer mulching could promote N mobilization in leaves and spikes in humid years, promote N mobilization in stems q- sheaths in normal years and dry years, and increase N mobilization andtheir contributions to grain before anthesis, especially in dry years. Summer mulching could also promote N mobilization in stems＋sheaths in normal years and in leaves in dry years, increase N mobilization and their contributions to grain after anthesis by using FM. Nitrogen use efficiency and nitrogen production efficiency were improved by summer mulching, and nitrogen absorption efficiency was better under FM in dry years; nitrogen absorption efficiency was increased by FM, and summer mulching had greater impact on nitrogen production efficiency in dry years. The results also showed that after summer mulching, the yield of N accumulation per unit after anthesis was significantly higher in humid and normal years, an 1 kg/hm2 increase of N accumulation could increase yield by 176 kg/hm2 to 224 kg/hrn2. The yield of N accumulation per unit before anthesis was larger in dry years, with the yield being increased by 142 kg/hmz to 185 kg/hmz. Compared with the CD, the yield of N mobilization per unit before anthesis and N accumulation per unit after anthesis were higher than those under FM in humid and normal years, the yield of N mobilization per unit after anthesis was higher under summer mulching condition with FM in dry years, an 1 kg/hm2increase of N accumulation could increase the yield by 234 kg/hm-. In conslusion, interannual mulching is beneficial to nitrogen absorption and mobilization by plants, and high yield and high efficiency of dryland wheat.