关中地区施氮量对小麦绿叶性状及产量的影响

Effect of Nitrogen Application Levels on Green Leaf Characters and Yield of Wheat in Guanzhong Area

以小偃22为供试品种,研究其在五个施氮水平下(B10 kg·hm^(-2)、B2120 kg·hm^(-2)、B3180 kg·hm^(-2)、B4240 kg·hm^(-2)、B5300 kg·hm^(-2))的绿叶性状及产量因子的差异。结果①各处理NDVI值均从花后7 d开始下降,但各施氮处理下降较慢,并且各施氮处理间差异不显著,适量施氮能延缓小麦植株的衰老,但过量施氮未能持续延缓植株衰老。②所有处理SPAD值在花后14 d内无明显差异,但未施氮肥的B1处理SPAD值下降早、下降速度快,各施氮肥处理SPAD值下降晚、下降速度慢,花后28 d后,所有处理叶片渐渐变黄,SPAD值降到较低水平,但各处理之间仍有一定差异,施氮量越多的处理SPAD值越高,施氮肥能明显延缓SPAD值降低时间和速度。③施氮量对出苗和冬分蘖没有显著影响;春分蘖、穗数、穗粒数均随施氮量增加,呈先升高后降低的趋势;千粒重随施氮量增加先减少后增加;产量随施氮量增加先升高后降低,B1处理产量最低,B3处理产量最高。

The effect of nitrogen application level on green leaf traits and wheat yield of‘Xiaoyan 22’was investigated,and five nitrogen fertilizer application levels of B1:0 kg·hm^(-2),B2:120 kg·hm^(-2),B3:180 kg·hm^(-2),B4:240 kg·hm^(-2),B5:300 kg·hm^(-2)were set up.The results showed that①NDVI values of all treatments decreased at 7 days after anthesis,but the decrease was slower among all nitrogen treatments,and the differences were not significant among all nitrogen treatments.Appropriate application of nitrogen fertilizer could delay the senescence of wheat plants,but abundant application of nitrogen fertilizer could not delay the senescence of wheat plants continuously.②SPAD values of all treatments showed no significant difference within 14 days after flowering,but SPAD values of B1 treatment without nitrogen fertilizer decreased earlier and faster,while SPAD values under treatment of nitrogen fertilizer decreased,postponed and slowed.After 28 days of flowering,the leaves of all treatments gradually turned to yellow,and SPAD value dropped to a lower level,but there were still some differences among treatments.The more nitrogen fertilizer was applied,the higher SPAD value was.Nitrogen fertilizer could significantly delay the time and speed of SPAD value reduction.③Levels of nitrogen fertilization had no significant effect on seedling emergence and tillering in winter;The number of spring tillers,spikes and grains per spike increased first and then decreased with the increase of nitrogen application level;the 1000-grain weight decreased first and then increased with the increase of nitrogen application rate;The yield first increased and then decreased with the increase of nitrogen application rate.The yield of B1 was the lowest,the B3 was the highest.