不同氮肥水平下大豆叶片光谱反射率与叶绿素含量的相关性研究

用Unispec光谱分析仪和SPAD-502叶绿素仪测定不同生育时期不同氮肥水平大豆叶片光谱反射率及叶绿素含量,并分析了光谱植被指数与叶绿素含量的相关性。结果表明:不施氮肥处理光谱反射率高于施氮处理,随着施氮量的增加,大豆叶片光谱反射率下降,并初步断定结荚期是大豆氮素光谱营养诊断的敏感时期;随着氮肥水平的提高叶绿素含量增加;整个生育时期,除鼓粒期不施氮处理外其它处理的植被指数mND705与叶绿素含量均呈极显著正相关;在花期和结荚期,各处理的mSR705与叶绿素含量呈极显著正相关,PSSRc与叶绿素含量呈极显著负相关。

Correlation between Spectrum Reflectance and Chlorophyll Content of Soybean Leaves under Different Nitrogen Level

Field trail with four nitrogen level of 0,30,60 and 90 kg·ha-1(N0,N1,N2 and N3)was conducted,the leaf chlorophyll content and spectral response at flowering,podding and seed-filling of soybean were measured by Unispec pectrometer and SPAD-502 chlorophyll meter,respectively.Leaf spectral reflection declined with the increasing of applied N,and podding period of soybean was diagnosed as N sensitive stage by spectral reflection.Leaf chlorophyll content increased as the increasing of applied N.Vegetation index mND705 showed significant positive correlation with chlorophyll content under all treatments,except that of N0 at seed-filling.mSR705 significant positively correlated with,while PSSRc significant negatively correlated with chlorophyll content under four N levels at flowering and podding.Results suggest that vegetation index mSR705,mND705 and PSSRc could be used as predictors for soybean leaf chlorophyll content and N levels.