[Effects of cultivation patterns on wheat yield and soil fertility in dryland].

A field experiment was conducted to examine the effects of plastic film mulching (PM), straw retention (SR), and planting green manure (GM) on winter wheat grain yield and soil fertility. The results showed that PM did not have consistently positive effect on the grain yield, when compared to the traditional patterns (TP). No difference of average grain yield was observed between them over three years. Soil total nitrogen (N), available phosphorus (P), potassium (K), sulfur (S), zinc (Zn) and manganese (Mn) were decreased in 20-40 cm layer in PM than those in TP, while no difference was observed for soil organic matter, nitrate (NO3--N), available iron (Fe) and copper (Cu). The mean grain yield of three years decreased by 12.1% in SR than that in TP treatment. At maturity stage of winter wheat, soil total N and available Cu was increased by 5.8% in 0-20 cm and 6.2% in 20-40 cm layer, respectively, while soil available P and Mn were decreased by 36.1% and 10.2%, respectively. No difference was observed between SR and TP treatments for soil organic matter, NO3--N, available K, S, Zn and Fe at anthesis and maturity stages. Compared to the TP treatment, the mean grain yield was decreased by 12.1% in GM treatment. Soil pH, available P and S were decreased, while the soil organic matter, total N, NO3--N, and available Zn and Mn were increased. No difference was observed for soil available K, Fe and Cu. In conclusion, the PM and SR were not beneficial for the improvement of soil fertility, and thus inhibited the grain yield increase in dryland with low soil fertility level. The GM has greater potential to increase soil nutrients, but it should be paid more attention to the risk of grain yield reduction due to insufficient annual precipitation.通过田间试验,研究地膜覆盖、秸秆还田和种植绿肥对冬小麦籽粒产量和土壤肥力的影响.结果表明: 与传统模式相比,地膜覆盖并不总能提高旱地小麦产量,3年平均产量无显著变化,但降低20～40 cm土壤全氮、有效磷、速效钾、有效硫、有效锌和有效锰含量,对土壤有机质、硝态氮、有效铁和有效铜含量无显著影响.秸秆还田的小麦产量3年平均降低12.1%,收获期0～20 cm土层全氮提高5.8%,20～40 cm土层有效铜含量提高6.2%,而有效磷和有效锰分别降低36.1%和10.2%,对开花期和收获期土壤有机质、硝态氮、速效钾、有效硫、有效锌和有效铁无显著影响.种植绿肥的籽粒产量降低12.1%,同时土壤pH、有效磷和有效硫含量降低,有机质、全氮、硝态氮、有效锌和有效锰均增加,对土壤速效钾、有效铁和有效铜均无显著影响.综上,在旱地土壤肥力较低的条件下,地膜覆盖和秸秆还田不利于土壤肥力的提升,使小麦增产受到限制;种植绿肥培肥效果最好,但应考虑区域降水情况,注意其带来的减产问题.