A field experiment was conducted to examine the effects of plastic film mulching (PM), straw retention (SR) and planting green manure (GM) on grain yield and nutrient concentrations of winter wheat. Compared to the traditional pattern (TP), plastic film mulching showed no significant effect on the average yield over the three years but increased the average phosphorus (P) uptake and concentration in grain by 8.4% and 13.0%, respectively. The average uptake of nitrogen (N), sulfur (S) and iron (Fe) was decreased by 12.6%, 15.0% and 11.1%, and the corresponding concentration was decreased by 12.1%, 12.9% and 10.1%, respectively. There was no significant effect on grain zinc (Zn) concentration. Straw retention decreased grain yield by 12.1%, reduced the average uptake of N, S and Fe decreased by 22.5%, 21.0% and 19.8%, and their corresponding concentration by 10.1%, 9.4% and 3.8%, respectively. The average uptake of P in grain was decreased by 9.8% with straw retention, while the P concentration was increased by 5.0%. There was no significant effect of straw retention on Zn concentration in grain. Planting green manure decreased the grain yield by 12.1%. It had no significant effect on the average uptake of N and Zn, but increased the grain N and Zn concentration by 12.1% and 12.6%, respectively. It showed no impact on P, S and Fe concentration in grain. The discordance between variation of grain yield and its nutrient uptake under different cultivations was the key reason for the changes of their nutrient concentration. Considering the potential adverse effects of plastic film mulching and straw retention on the quantity and quality of grain yield, suitable N fertilization should be applied to ensure the nutrient requirement for grain yield and regulate the uptake and utilization of N, S and Fe for improving the grain quality. Planting green manure could improve soil fertility and increase grain N and Zn concentration, but the yield reduction deserves more attention.
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籽粒养分含量的影响.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,但籽粒磷吸收量却增加8.4%,磷含量平均提高13.0%;籽粒氮、硫和铁吸收量分别降低12.6%、15.0%和11.1%,含量分别降低12.1%、12.9%和10.1%,锌含量无显著变化.秸秆还田使小麦籽粒产量下降12.1%,籽粒氮、硫和铁吸收量分别降低22.5%、21.0%和19.8%,含量分别降低10.1%、9.4%和3.8%;磷吸收量降低9.8%,含量却增加5.0%,锌含量亦无显著变化.种植绿肥的小麦籽粒产量降低12.1%,籽粒氮和锌吸收量无显著变化,含量分别增加12.1%和12.6%,对磷、硫和铁含量无显著影响.可见,旱地条件下,不同栽培模式引起的籽粒产量增减与其养分吸收量变化不一致是养分含量变化的主要原因.在旱地小麦生产中,需注意地膜覆盖和秸秆还田的减产风险及对籽粒养分的不利影响,适当调控氮肥用量,保证小麦产量形成的养分需求,协调氮、硫、铁养分的吸收利用.种植绿肥能培肥土壤,提高籽粒氮和锌含量,但也应注意其减产问题.
Keywords: dryland; nutrient concentration; planting green manure; plastic film mulching; straw retention; winter wheat; yield.