关键词: 减氮, 覆膜, 黄土旱塬, 冬小麦, 产量, 养分吸收利用

Abstract:

【Objective】The Loess Plateau is an important wheat growing area in China, however the phenomenon of unreasonable fertilization and low yield is widespread. The aim of this study was to clarify the yield variation of winter wheat and the absorption and utilization of soil nutrients under long-term nitrogen reduction and quantitative monitoring of fertilization and mulching, so as to provide a recommendation for the scientific and rational fertilization of winter wheat and the increase of regional wheat production in the loess tableland. 【Method】 Based on the long-term positioning of the experimental land in the winter wheat growing area in the dry land of south Shanxi Province, three treatments were set up from 2012 to 2019, including farmer pattern (FP) , monitoring fertilization (MF) and monitoring fertilization plus ridge mulching-furrow planting (RFSF), to study the yield and composition of winter wheat, the absorption and utilization efficiency of nitrogen(N), phosphorus (P) and potassium (K) fertilizer, the transfer and absorption of nutrients before and after flowering and the N residue in the soil layer of 0-2 m .【Result】Compared with the FP, the total nitrogen application of MF decreased by 33.5% and balanced addition of phosphate and potassium fertilizer, while there was no significant difference in grain yield, biological yield and yield composition between FP and MP; the nitrogen uptake rate under MF was increased by 8.9%, and the apparent recovery rate of nitrogen fertilizer, phosphate fertilizer and nitrogen partial productivity under MF were increased by 7.6%, 2.7% and 55.0%, respectively; the transplanting amount of vegetative organs before flower under MF was 24.2% higher than that under FM, and the nitrogen uptake after flower was reduced. The total residual nitrate nitrogen in the soil layer of 0-2 m was 34.4% lower than that under the farmer model. Mulch was carried out on the basis of quantitative monitoring and fertilization of nitrogen reduction, grain yield and biological yield under RFSF increased by 24.3% and 25.5% than that under no mulch, respectively. The N, P and K uptake of grains increased by 20.9%, 35.0% and 33.1%, respectively. The apparent recovery and partial productivity of N, P and K fertilizer increased by 3.7%, 2.7%, 4.8% and 22.8%, 22.8%, 22.0%, respectively; nitrogen and phosphorus uptake increased significantly by 25.4% and 57.5% before flowering, respectively; the total residue of nitrate nitrogen in the 0-2 m soil layer was reduced by 25.1%.【Conclusion】On the premise of achieving stable winter wheat yield, the utilization efficiency of fertilizer could be improved and the residual amount of nitrogen in soil could be reduced by reducing the amount of nitrogen fertilizer and balanced application of phosphate fertilizer. Mulching on the basis of quantitative monitoring and fertilization of nitrogen reduction could increase the yield of winter wheat, further improve the utilization efficiency of fertilizer, and had a more significant effect on reducing environmental risks caused by nitrate nitrogen accumulation.

Key words: nitrogen reduction, film mulching, Loess Plateau, winter wheat, yield, nutrient absorption and utilization