Effects of Water and Nitrogen Coupling on Photosynthetic Fluorescence Characteristics and Yield of Millet

Feng Liling; Guan Yan'an; Qin Ling; Li Feifei; Yang Yanbing; Du Jinzhe; Chen Erying

doi:10.14083/j.issn.1001-4942.2025.11.007

Abstract：In order to explore the effects of different nitrogen fertilizer levels and coupled with water on photosynthetic fluorescence characteristics and yield of millet,a two-factor experimental design was adopted with five water treatments,namely normal water(CK,60%～70%of field water capacity),drought at booting stage(W1,30%～40%of field water capacity),drought at early filling stage(W2,30%～40%of field water capacity),drought at middle filling stage(W3,30%～40%of field water capacity),drought at late filling stage(W4,30%～40%of field water capacity),and two nitrogen treatments including normal nitrogen(N150)and no nitrogen(N0).The effects of different water and nitrogen treatments on net photosynthetic rate,fluo-rescence characteristics,chlorophyll content and yield of millet Jigu 20 were studied by pot method.The re-sults showed that compared with N0,N150 treatment significantly increased the chlorophyll content,photosyn-thetic rate and fluorescence parameters of millet leaves,and increased the accumulation and yield of assimila-ting substances.Under CK and drought treatments,the increase of yield after application of nitrogen fertilizer was 49.0%and 54.5%to 65.3%,respectively,and that under W1 N150 treatment was the highest in the drought treatments.Compared with CK,drought treatments at different stages significantly decreased the chlorophyll content,net photosynthetic rate and fluorescence parameters of leaves,reduced the accumulation of assimila-ting substances and thus the yield.Under both N0 and N150 treatments,W2 treatment decreased the yield the most(33.3%and 30.8%),followed by W3(32.4%and 29.9%)and W4(23.1%and 16.9%)treatments,and W1 treatment decreased the yield the least(14.5%and 5.2%).In conclusion,the yield of millet under different drought treatments could be increased by nitrogen application,but the yield decreased under drought stress in different periods,and drought at the early stage of grouting had the greatest effect.There was a cou-pling effect of water and nitrogen treatments on millet,and nitrogen application could alleviate the effect of drought stress on yield reduction,and the alleviating effect was the largest when drought stress was at booting stage.Therefore,reasonable water and fertilizer management measures should be formulated in millet produc-tion to improve yield and utilization rate of water and fertilizer.