在内蒙古通辽市珠日河牧场沙化草地,通过苗期追施0、10.00、20.00、30.00、40.00 kg/hm2氮肥(纯N,下同)对沙地燕麦(Avena sativa)分蘖力、株高、茎粗、功能叶长度、植株重量及叶绿体色素含量的影响,分析沙地燕麦苗期追施氮肥的最佳用量.结果表明:苗期追施氮肥在10.00~40.00 kg/hm2燕麦生长指标均表现为先增加后降低的变化趋势,其中,分蘖率、株高、叶长、干重和鲜重值均在追施30.00 kg/hm2氮肥时达到最大,且均与对照差异极显著(P<0.01);茎粗则在追施20.00 kg/hm2氮肥时达到最大,且与对照差异极显著(P<0.01);苗期追施氮肥增加到40.00 kg/hm2时,燕麦各生长指标较追施30.00 kg/hm2氮肥降低,但差异均不显著;苗期追施10.00~40.00 kg/hm2氮肥均促进叶绿体色素合成,且叶绿素a、叶绿素b和类胡萝卜素含量均在追施30.00 kg/hm2氮肥时含量最高,并均与对照差异极显著(P<0.01).由此说明,在科尔沁沙地苗期追施30.00 kg/hm2氮肥,明显促进燕麦生长及叶绿素体色素合成.%The optimum nitrogen application rate for oat(Avena sativa) in seedling stage grown in steppe on Zhurihe Ranch,Tongliao City of Inner Mongolia Autonomous Region was studied through determining the tillering ability,plant height,stem diameter,leaf length,plant weight and chlorophyll content under the treatments of different nitrogen application rates (0,10,20,30 and 40 kg/ha) in 2016.The results showed that the nitrogen application in the range of 10 to 40 kg/ha in seedling stage promoted the growth of oat,and growth index showed an increasing and then decreasing trend.The tillering rate,plant height,leaf length,dry weight,fresh weight reached the maximum value at application rate of 30 kg/ha (P<0.01).The stem diameter reached the maximum at 20 kg/ha (P<0.01);While the nitrogen application rate was increased to 40 kg/ha,the growth indexes were lower than that at 30 kg/ha (P>0.05).The contents of chlorophyll a,chlorophyll b and carotenoid reached the highest at 30 kg/ha (P<0.01).The optimum nitrogen application rate was 30 kg/ha in research area.
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