Combined impact of organic and mineral nitrogen fertilization on water and salt dynamics and yield of winter wheat in saline-alkaline soils in the Yellow River Delta

XU Jiayi; YANG Yun; SUN Chitao; WANG Xiaohan; ZHU Hai; ZHANG Junpeng; BAO Jianping; WEN Yanchen

doi:10.13522/j.cnki.ggps.2025158

Abstract：[Objective]Soil salinity and alkalinity is an abiotic factor affecting crop growth in the Yellow River Delta,and various methods have been developed to improve its fertility.This paper experimentally investigates the influence of combination of organic and mineral nitrogen fertilizations on water and salt dynamics,as well as the yield of winter wheat in this type of soil.[Method]The experiment was conducted in a wheat field.It consisted of two organic fertilization treatments:0 kg/hm2(F0)and 75 kg/hm2(F1);each treatment had three mineral nitrogen applications:180 kg/hm2(N1),225 kg/hm2(N2)and 270 kg/hm2(N3).During the experiment,we measured soil water and salt distribution along the soil profiles,as well as grain yield of the wheat.[Result]① During wheat growth period,average soil water content in the 0-40 cm soil layer in the F1 treatment was higher than that in the F0 treatment,and soil water content in both F treatments increased as nitrogen application increased.Over the whole wheat growth period,soil salinity,especially in the 0-40m soil layer,in the F1 treatment was lower than that in the F0 treatment.At harvest stage,F1N3 reduced soil salinity in the 0-40 cm layer and the 0-100 cm layer by 45.65％and 29.16％,respectively,compared F0N3.② Compared to F0,F1 increased maximum plant height,leaf area,dry matter accumulation,and contribution of post-anthesis dry matter accumulation to grains by 15.42％,3.80％,19.54％and 17.70％,respectively.F1N3 increased grain yield and its components significantly,compared to other treatments;its harvest index was 45.07％and partial factor productivity of nitrogen fertilizer was 34.11 kg/kg,lower only than that in F1N2.③ Correlation analysis showed that soil salinity was negatively correlated with plant height and grain yield,while grain yield was positively correlated with dry matter accumulation and spike numbers per unit area,both at significantly levels.Comprehensive evaluation analysis indicated that F1N3 was optimal among all treatments.[Conclusion]Applying 75 kg/hm2 of organic fertilizer as base fertilization combined with topdressing 270 kg/hm2 of nitrogen fertilizer can effectively reduce soil salinity and increase yield of winter wheat in the saline and alkaline soil in the Yellow River Delta,despite its partial factor productivity of nitrogen fertilizer tending to decrease.These results provide guidance for improving winter wheat production in this region.