限量补灌与追氮对陕北糜子干物质及氮素积累转运的影响OA

Taking'Yumei 2'as the experimental material,supplementary irrigation and fertilization were car-ried out at the booting and the filling stage of the broomcorn millet.Three total nitrogen application levels(N1:200 kg·hm-2,N2:150 kg·hm-2,N3:100 kg·hm-2)and three supplementary irrigation water levels(W1:30 mm,W2:22.5 mm,W3:15 mm)were set up to study the effects of limited supplementary irrigation and nitrogen application at key growth stages on the growth characteristics,dry matter pre-flowering translocation and post-flow-ering accumulation,water and nitrogen use efficiency,and yield of broomcorn millet.The results showed that ap-propriate water and nitrogen supply impacts broomcorn millet growth.The leaf area index of N1W1 treatment in-creased by 6.00％-68.35％at heading stage,and the crop growth rate and photosynthetic potential from heading and flowering stage to filling stage increased by 4.08％-64.58％and 6.12％-64.18％,respectively.The application rate of nitrogen and irrigation water significantly affected the dry matter and nitrogen accumulation and translocation of broomcorni millet(P＜0.05).The N1W1 treatment increased dry matter accumulation during maturity,pre-flow-ering translocation,and post-flowering accumulation by 5.94％-40.12％,11.96％-102.83％,and 1.00％-25.87％,respectively.Nitrogen pre-flowering translocation and post-flowering accumulation increased by 7.93％-103.75％and 3.89％-41.52％,respectively.Post-flowering dry matter and nitrogen accumulation contributed 73.21％-81.49％and 65.95％-73.6％to grain yield,respectively,both significantly higher than the pre-flowering transport contribution rate.When the application rate of nitrogen reached 150 kg·hm-2,the dry matter accumula-tion in grains,the pre-flowering translocation rate and the post-flowering accumulation of dry matter would no longer increase significantly.The pre-flowering translocation and post-flowering accumulation of dry matter and nitrogen were significantly positively correlated with grain yield,and the correlation coefficient between post-flowering dry matter accumulation and grain yield was the highest(R2=0.98).Grain yield increased with the increase of nitrogen application rate and irrigation water,with the N1W1 treatment yielding the highest(at 7 139.69 kg·hm-2),show-ing no significant difference from the N2W1 treatment.Water use efficiency peaked under the N1W1 and N2W1 treatments.The partial factor productivity of nitrogen decreased by 20.68％-79.27％with the increase of nitrogen application but increased by 5.31％-25.95％with the increase of irrigation water.The N2W1 treatment exhibited relatively high nitrogen fertilizer partial productivity.Therefore,based on the conditions of this experiment,consid-ering the water and nitrogen use efficiency and reducing nitrogen input,the N2W1 treatment(total nitrogen appli-cation:150 kg·hm-2,supplementary irrigation:30 mm)is more suitable as a supplementary irrigation and fertili-zation model to increase the yield of broomcorn millet in northern Shaanxi.