休闲期耕作对旱地麦田土壤水分与小麦植株氮素吸收、利用的影响

Effects of Tillage in Fallow Period on Soil Water and Nitrogen Absorption and Utilization of Dryland Wheat

于山西农业大学闻喜试验示范基地采用大田试验连续3年研究休闲期深翻、深松对0-300cm土壤水分、植株氮素吸收和运转特性、氮效率的影响。结果表明:休闲期耕作有利于蓄积休闲期降水,提高底墒,欠水年、平水年,休闲期深翻分别提高播种前0-300cm土壤蓄水量26.98%,15.67%,较深松更有利于蓄积休闲期降水,且欠水年蓄水保墒效果可延续整个生育时期,而丰水年,休闲期深松效果更佳,可提高12.25%。休闲期耕作有利于植株氮素吸收积累,欠水年、平水年,休闲期深翻更有利于氮素吸收,可延续至开花期,且欠水年效果更佳;丰水年,休闲期深松更有利于氮素吸收,可延续至生育后期。结果还表明:休闲期耕作显著提高欠水年、平水年花前氮素运转量,且深翻效果较好;丰水年,休闲期深松较深翻可显著提高花后氮素积累量及其对籽粒的贡献率。休闲期耕作可显著提高成熟期籽粒氮素积累量,显著降低平水年茎秆氮素积累量及其占整株比例,显著降低丰水年茎秆、颖壳+穗轴氮素积累量占整株比例。最终,休闲期耕作可显著提高不同降水年型氮素生产效率,且欠水年、平水年休闲期深翻较深松有利于提高氮素吸收效率,丰水年休闲期深松较深翻有利于提高氮素吸收效率、氮素生产效率。总之,休闲期耕作有利于蓄积休闲期降水,提高土壤水分贮备水平,尤其是欠水年;有利于促进植株氮素吸收,可延续至生育后期;有利于促进茎秆、颖壳+穗轴中贮存的氮素向籽粒运转,提高籽粒氮素积累量;最终,休闲期合理耕作有利于提高氮素吸收效率、氮素生产效率,且欠水年、平水年以深翻效果更佳,丰水年以深松效果更佳。

The field test was carried out in Wenxi experimental base of Shanxi Agricultural University for 3 years to study the effect of deep plowing or subsoiling on soil water storage, nitrogen distribution and nitrogen use efficiency in 0--300 cm soil layer in fallow period. The results showed that tillage in fallow period could benefit the accumulation of rainfall, and improve soil moisture, deep plowing in fallow period could improve the soil water storage of 0--300 cm before sowing by 26.98% and 15.67% in dry and normal years respectively, the effects of water retention in dry years could be extended to the whole growth period, however in humid years, subsoiling in fallow period had better effects, it could rise by 12.25%. Tillage in fallow period could improve nitrogen absorption and accumulation, and deep plowing in dry and normal years could make the absorption of nitrogen better, which could go down to the anthesis stage, especially in dry year, while subsoiling had better effects in humid year which could go down to the growth anaphase. The results also showed that tillage in fallow period could improve nitrogen translation amount of accumulated before Anthesis（NABA） in dry and normal year, and deep plowing had better effects, compared with deep plowing, subsoiling could significantly improve nitrogen accumulation amount after anthesis（NAAA） and contribution of NAAA to N in grains in humid year. Tillage in fallow period could significantly improve grains nitrogen accumulation amount at maturity stage, and greatly decrease the rate of nitrogen accumulation amount of tem in normal year, and significantly decrease the rate of nitrogen accumulation amount of stem and glume＋spike stem in humid year. At last, tillage in fallow period significantly improved nitrogn productive efficiency （NPE） in different precipitation years, and deep plowing could improve the nitrogen uptake efficiency（NUPE） more in dry and normal year, while subsoiling in fallow period in humid year was more conducive to improve NUPE and NPE. In a word, tillage in fallow period was conductive to conserve rainfall in fallow period, improve soil water reserve level, especially in dry year, and was beneficial to improve the absorption of nitrogen until growth anaphase, it could also improve the stem and glume＋spike stem NABA to nitrogrn in grains. All in all, reasonable tillage in fallow period could improve NUPE and NPE and deep plowing had better effects in dry and normal year, while subsoiling had better effects in humid year.