Effect of water-saving irrigation and nitrogen reduction on grain filling and yield of spring wheat in the Yellow River irrigation areas in Ningxia
Li Hao
Tan Junli
Li Hong
Qian Zhijin
Wang Xina
Abstract：[Objective]Excessive irrigation and nitrogen fertilization in the Yellow River irrigation districts are a main source of environmental pollution,and improving water and nitrogen management is critical for sustainable agricultural production in these regions.This study aimed to experimentally investigate the effects of water-saving irrigation and nitrogen fertilizer reduction on grain filling and yield formation of spring wheat.[Method]The experiment was conducted in a spring wheat field with a water gradient(controlled by irrigation)and a nitrogen gradient(controlled by fertilization).During the experiment,we measured the spatiotemporal variations in soil water and mineral nitrogen,grain filling and grain yield.Key factors that affect yield formation were identified using correlation analysis and structural equation modeling.[Result]Nitrogen application significantly affected soil water content and mineral nitrogen content in the topsoil(0-40 cm)from the grain-filling stage to maturity stage.Soil water content in the no nitrogen treatment(CK)was much higher than that in the nitrogen-application treatments,being 24.11%higher than that in the conventional nitrogen treatment(NC)and 79.17%higher than that in the reduced nitrogen application treatment(NJ).NCW2 treatment increased soil moisture content by 83.95%compared with NJW2 treatment.The NC treatment had the highest soil mineral nitrogen content.In the water-nitrogen combined treatments,the 1 000-grain weight exhibited a'slow-fast-slow'increasing pattern as time elapsed during the grain filling process.When irrigation was the same,the NC and N0 treatments gave sharp and slender grain-filling rate curves,whereas the NJ treatment resulted in short and robust curves.The NJW1 treatment prolonged the active grain-filling period and rapid growth stage,increasing 1 000-grain weight by 2.25%-4.45%relative to the conventional treatment(NCWC).Furthermore,the optimized water-saving and nitrogen-reduction treatment increased grain yield by 1.72%compared with NCWC,due to the increased effective spike numbers and grain numbers per spike.Model analysis indicated that soil mineral nitrogen had a positive effect on 1 000-grain weight in the NJW1 treatment,while soil water exerted a negative regulatory effect on it.[Conclusion]Reducing irrigation by 20%and nitrogen application by 25%induced moderate crop stress tolerance,maintained effective soil nitrogen supply and optimized the grain-filling process,thereby increasing grain yield.This water-nitrogen optimization provides a feasible and efficient management strategy for high-yield and resource-saving spring wheat production in the Yellow River irrigation districts.
Keywords：spring wheatthousand grain weightLogistic modelgrain filling characteristicsyieldYellow River irrigation area
Publication Date：2026-07-31
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：8( 44-51 )