休闲期深翻覆盖对旱地小麦水氮利用效率和产量的影响

Effects of deep plowing and mulching in summer fallow period on dryland wheat yield and water-and nitrogen use efficiency

采用大田试验研究了旱地小麦休闲期不同时间深翻、不同材料覆盖对植株氮素吸收和转运分配、水分和氮利用效率的影响。结果表明:前茬小麦收获后45d深翻覆盖较15d提高了拔节期、孕穗期、成熟期植株含氮率,提高了各生育时期植株氮积累量和各生育阶段氮吸收速率,提高了花前氮素转移量、转移率,提高了液态地膜覆盖和不覆盖条件下花前氮素转运对籽粒氮的贡献率,提高了籽粒氮积累量及其所占的比例,降低了叶片、茎秆、颖壳+穗轴中氮积累量所占的比例,且均以采用渗水地膜覆盖效果较好;前茬小麦收获后45d深翻覆盖较15d增加了产量和水分利用效率,提高了氮素吸收效率、氮素生产效率。总之,休闲期等雨后深翻覆盖有利于植株氮素吸收、积累,有利于花前植株中贮存氮素向籽粒的转移,促进籽粒中氮素积累,降低其他器官中的氮素,最终提高产量、水分利用效率、氮素吸收效率及氮素生产效率,且以渗水地膜覆盖效果较好。

A field experiment was conducted to stufly the effects of deep plowing at different time and of mulching with different materials in summer fallow period on the nitrogen absorption, translocation, and allocation, and on the water- and nitrogen use efficiency of dryland wheat. As compared with the deep plowing and mulching after 15 days of previous wheat harvest, the deep plowing and mulching after 45 days of previous wheat harvest improved the plant nitrogen content at elongation, booting, and mature stages, increased the plant nitrogen accumulation and nitro- gen uptake at each growth stage, increased the nitrogen transfer amount and transfer rate in pre- ant]hesis, increased the contribution rate of nitrogen transfer to grain nitrogen in pre-anthesis un- der liquid film mulching and no-mulching, and increased the accumulation amount and rate of grain nitrogen while decreased the accumulation rate of nitrogen in leaf, steam, and glume ＋ spike stem, with the better effects under seepage plastic mulching. Deep plowing and mulching after 45 days of previous wheat harvest, as compared with that after 15 days of previous wheat harvest, increased the yield and water use efficiency and the nitrogen uptake efficiency and pro- duetion efficiency. In sum, deep plowing and mulching after rain in fallow period increased the plant nitrogen uptake and accumulation, and was conducive to the transfer of pre-anthesis stored nitrogen to grain, increased the accumulation of grain nitrogen, decreased the nitrogen accumula- tion of vegetative Organ, and ultimately, improved the yield, water use efficiency, nitrogen up- take efficiency, and nitrogen production efficiency. Among the mulching measures, seepage plas- tic mulching had better effects.