渭北旱塬区不同栽培模式对小麦产量与土壤水分及硝态氮累积的影响

摘要

渭北旱塬小麦生产中需要克服的主要限制因子是水分不足,寻求合理的栽培措施以提高天然降水的利用率对于产量提高具有重要意义.本试验通过2a大田试验,研究了不同栽培措施对冬小麦产量及0～200 cm土层水分与硝态氮累积的影响.结果表明:(1)推荐施肥+垄上覆膜+沟内覆草(NP+ PF+ S)与推荐施肥+垄上覆膜(NP+ PF)两种垄沟栽培模式,虽然单位面积穗数明显降低,但由于穗粒数、千粒重显著高于其它栽培模式,因此产量和水分利用效率在所有模式中为最高.(2) NP+ PF+S和NP+ PF模式在小麦生育期内明显增加了土壤储水量,尤其在冬小麦易遭水分胁迫的时期(3-5月),其土层中储水量要明显高于其他模式.(3)土壤中硝态氮的累积主要集中在60cm以上,随着土壤深度的增加,累积量逐渐减少.在第二季,塬面冬小麦NP+ PF+S处理的硝态氮累积显著高于其它处理.在梯田,NP+S处理出现明显累积.由此可见,推荐施肥+垄沟栽培模式虽然促进土壤中氮素的累积,但是显著提高降水的有效贮蓄,是渭北旱塬区雨养农业条件下维持冬小麦高产的合理栽培模式.%Water shortage was the key factor of restraining winter wheat yield in Weibei Loess Plateau, so it was meaningful to search reasonable cultivation models to improve water use efficiency and yield of winter wheat. A two-year field experiment was conducted to investigate the effect of different cultivation modes on soil water dynamic variation and N03 - N accumulation in soil layer of 0 - 200 cm. The results showed that recommended fertilization + plastic mulch on soil ridges + straw mulch in furrow (NP + PF + S) treatment and recommended fertilization + plastic mulch on soil ridges ( NP + PF) treatment significantly increased 0 ~ 2 m soil water storage during the growing season, especially in the second year. The water storage under 100 cm soil increased obviously in the two ridge cultivation modes, so enough soil water was provided for winter wheat growth during the dry spring season, especially in the critical water demand stage. The water use efficiency of the two ridge cultures were the highest among all the treatments. In the CK2 treatment, NO3 - N was significantly accumulated in soil layer of 0 ~ 200 cm. More fertilizer application involved more NO3 - N residue in the soil. In the second season of Yuan surface, the accumulation below 100 cm soil was bigger in the CK2 and NP + S treatments, and in the terrace, the biggest accumulation appeared in the NP + PF + S. Compared to the other treatments, spike per mu in NP+ PF + S and NP + PF was lower, however, the other yield component factors were higher, especially the grain per spike and spike length. In conclusion, NP + PF + S and NP + PF was suitable to the agricultural development in the rainfed region of Weibei Loeass Plateau.