[Effects of cultivation patterns on wheat yield and grain nutrient concentration 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 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.