不同施氮水平下净、套作大豆茎秆特征比较研究

在"玉/豆"模式下,研究了不同施氨水平和套作条件下大豆的茎秆特征.结果表明:套作大豆主茎高度显著高于净作大豆,而茎粗和主茎节数差异不显著.净、套作大豆各节间长度呈"降-升-降"的趋势,套作大豆最长节间出现在第9节,比净作大豆最长节间节位点低了2节.与净作大豆相比,套作大豆第7节间长度增加最大,为2.2 cm(F=240...

Characteristics of Stem between Sole-cropping and Relay-cropping Soybean under Different Nitrogen Applied Levels

Soybean is prone to lodging and overgrowth in the "maize/soybean" relay-cropping pattern.The characteristics of soybean stem is studied by creating high nitrogen and shaded environment using different nitrogen levels(0、40、60、80、120 and 160 kg·ha-1) and intercropping conditions,which is relatively easy to result in overgrowth and lodging.The results indicated that the stem height of relay-cropping soybean(RCS) was significantly higher than that of sole-cropping soybean(SCS),but no significant differences between the stem diameter and the main stem node number were observed.Whether SCS or RCS,in the direction of morphology,the length of nodosity stem showed as "down-up-down",the longest nodosity stem of RCS appeard in the 9th section,which was two sections lower than that of the SCS.Compared with the SCS,the largest increase of nodosity stem of RCS appears at the 7th section,as 2.2 cm(F=240.56**,P=0.0001),the increase extent reaches up to 61.24%.With gradually increase of nitrogen levels,the nodosity stem showed as "down-up-down",and no changes were found at the positions of longest nodosity stem.It indicated that the reason why RCS was easier to lodge than SCS was that length of nodosity stem increased significantly and the longest nodosity stem moved downward.Although N is a factor to influence soybean nodosity stem,the reason for the change of the longest nodosity stem positions was in the "maize/soybean" relay-cropping pattern.The best time to control the overgrowth and stem lodging of RCS was before the 7th nade period.