Effects Of Lodging At Different Growth Stages On Yield Formation Of Summer Maize

This experiment was conducted in 2019-2020 at Huang-Huai-Hai Regional Maize Technology Innovation Center(36° 18’N,117° 12’E)of Shandong Agricultural University during the maize growing season.Laboratory analysis was conducted at the State Key Laboratory of Crop Biology.Summer maize variety Zhengdan 958 was used as experimental material.In the study,stabilization(S)and lodging non-stabilization(L)were set after four lodging stages: small trumpet stage(V9),large trumpet stage(V12),tasselling stage(VT),and 15 days after tasselling(VT+15).No lodging was taken as control(CK).The objectives of this study were to investigate effects lodging and centralization at different stages on dry matter accumulation and distribution and grain yield formation of summer maize by analyzing the differences of LAI,stem traits,root development quality,dry matter accumulation and distribution,mineral element accumulation and distribution,yield and yield components among different treatments.Then provided a theoretical basis for developing the technology of disaster reduction and stable yield of summer maize in the future.The main research results are as following:1.Effect of lodging on stalk traits of summer maize at different growth stagesThe stem puncture intensity and the cortex thickness of the basal third node of corn plants were increased with lodging at the small and big trumpet stage without straightening treatment.The stem puncture intensity was decreased with lodging at the tasselling stage and 15 days after tasselling,and straighten up could increase the puncture intensity of corn stalk of 13.83% and 5.97% under low density,16.01% and 5.78% under high density.Moreover,compared with the non-upright plants,the stem cortical thickness of the upright plants was significantly increased 17.98% and 9.63% under low density,and increased 6.87% and 7.26% under high density,respectively.2.Effect of lodging on root development of summer maize at different growth stagesAfter lodging at the small and large trumpet stages,compared with the not stabilization plants,the number of nodal root layers of the stabilization plants was average increased 2-4 layers,and the node length,area,volume and dry matter weight were significantly increased,which was beneficial to the growth and development of maize in later stage.There was no significant difference between the stabilization maize and CK.However,after lodging at tasseling stage and after lodging 15 days,the upper node number,length,area,volume and dry matter weight decreased with lodging.But stabilization measure can reduce the drop,which is beneficial to the transportation of water and nutrients in the later stage of maize and reduce the yield loss.3.Effects of lodging on dry matter accumulation and distribution in summer maize at different growth stagesThe total accumulation of dry matter declines with the prolonging of lodging stage.There is no significant effect on the dry matter distribution ratio of corn after lodging at the small and large trumpet stages.At tasselling stage and 15 days after tasselling,the proportion of stem and leaf dry matter had increased,and of grain had decreased.And the impact of no stabilization is most significant during the tasselling period.Compared with CK,under low density,the ratio of stalk and leaves dry matter increased by 9.89% and22.17%,the ratio of grains reduced by 14.06%.Under high density,the ratio of stalks and leaves increased by 26.40% and 23.32%,the ratio of grains decreased by 28.50%.And taking stabilization measures can greatly increase the distribution ratio of grains and decrease yield loss.4.Effects of lodging on nutrient accumulation and distribution in summer maize at different growth stagesThe accumulation of N,P and K was not significantly affected after lodging at the small and big bell stage,and were significantly decreased at tasselling stage and 15 days after tasselling.Not straighten up at tasselling period significant decreased the accumulation of N,P and K,compared with the CK,they were decreased by 27.68%,12.92% and 19.56% under low density,and decreased by 34.09%,27.08% and 17.81%under high density.Stabilization measures can effectively reduce nutrient and yield loss at tasselling stage and 15 days after tasselling.5.Effects of lodging on yield and yield components of summer maize at different growth stagesThe yield and yield components of summer maize were not significantly affected by straightening up at the small and big bell stage.Lodging at tasselling stage and 15 days after tasselling had significant effects on ear number per unit area and 1000-grain weight of maize.Not straighten up at tasselling stage had the greatest effect on ear number per unit area.Compared with the CK,it was reduced by 29.07% under low density and 39.2%under high density without stabilization.Lodging at 15 days after tasselling had the greatest effect on 1000-seed weight,which was reduced by 27.72% under low density and19.49% under high density.Taking stabilization measures can significantly reduce the yield decline.