Effects Of Sowing Date On Stalk Development And Lodging Resistance Of Maize

Aiming at the serious lodging problem of maize in Huang-Huai-Hai Plain,in order to study the effects of different sowing dates on internode development and lodging resistance,and to explore the relationship between meteorological factors at different growth stages and lodging resistance indexes of stalks,this study was conducted at Qingyuan Test Station of Agricultural University of Hebei.Zhengdan 958(ZD95 8),Xianyu 335(XY335)and Jinhai 5(JH5)were used as experimental materials,and the planting density was 67,000 plants·hm-2.In 2019,three sowing dates of spring sowing S1(April 21),late spring sowing S2(May 19)and summer sowing S3(June 17)were set,and in 2020,four sowing dates of spring sowing S1(May 1),late spring sowing S2(May 22),early summer sowing S3(June 6)and summer sowing S4(June 13)were set,with spring sowing S1 as the control.On each processing stage swig(V12),spinning(RI),milk stage(R3)and the base of the mature period(R6)3-4 internode stem lodging resistance index were measured and compared under the condition of different sowing date stem growth,internode storage material and lodging resistance,analysis of meteorological factors on the fertility during growing period stem lodging resistance.The results were as follows:(1)With the delay of sowing date,the duration from sowing to jointing of maize was significantly shortened,which shortened the whole growth period,and there was little difference in the grain filling time of maize at different sowing dates;During the growth period of maize sown in late April and early May,rainfall distribution was uneven,which made maize susceptible to drought stress during stalk development.The effective accumulated temperature in maize growth period decreased with the postponement of sowing date and the shortening of growth period.(2)Early summer sowing and summer sowing maize plants while the plant height,ear position,center of gravity and the highest high coefficients,but the enlargement of basal internode elongation and 3-4 growth speed is reasonable,intemode length thick difference than smaller,higher dry matter accumulation,internode bending force,hard skin tissue puncture strength is higher,stem lodging resistance is stronger,late spring sowing times,poor spring sowing.(3)With the delay of sowing date,the thickness of cortex and sclerothelial tissue in basal 3-4 intrnodes increased,and the number of large and small vascular bundles decreased.Before silking,the contents of soluble sugar,starch,potassium and nitrogen in the basal internodes of maize decreased with the delay of sowing date.To some extent,the increase of accumulated precipitation during the growing period of maize had a positive effect on the lodging resistance of stalks,while the higher average daily temperature and the more accumulated sunshine hours during the growing period were more adverse to the lodging resistance of stalks.In conclusion,compared with spring sowing,delaying sowing date increases the temperature,light and water resources in early growth period of maize,thus shortening the growth process before silking,and shortening the growth period of maize.In the Huang-Huai-Hai Plain,precipitation and high temperature were the main meteorological factors affecting the growth and lodging-resistance of corn stalks.