Abstract:

In order to provide the basis for using MODIS vegetation index to monitor wheat growth and estimate yield, the variance analysis of growth characteristic, yield and yield components of two varieties of spring wheat was carried out by using the observation data of two varieties of spring wheat from 1994 to 2012 in Yongning Agrometeorological Experiment Station of Ningxia, then the samples with no significant difference between the two varieties of spring wheat were selected to establish the relationship between LAI at different growth stages and plant height, density, yield, panicle number per unit area, grain number per spike and 1 000 grain weight.   The results show that LAI could reflect the changes of the plant height, density and the number of panicles per unit area at different development stages. The plant height could be estimated by using LAI from the heading to milking stage, the plant density could be monitored by LAI from the trefoil to milky stage, and the monitoring effect was best from the jointing to milking stage. The number of effective panicles per unit area could be estimated by LAI from the heading to milking stage, which was best at heading stage. LAI from the heading to milking stage could reflect the change of wheat yield better. The vegetation index, which can be constructed by wheat canopy hyperspectral measurement value or by MODIS Terra/Aqua data, could be used to estimate LAI, and then the yield could be estimated by the relationship between LAI and yield. The wheat growth could be monitored by the relationship between LAI and plant height and  density of wheat if LAI was estimated by remote sensing vegetation index at different growth stages. LAI retrieved from MODIS vegetation index was relatively stable during the heading to early filling stage and it could be used to estimate the wheat density, yield and yield components.

Key words: wheat, LAI, growth characters, yield, yield components, vegetation index

摘要：

利用宁夏永宁农试站1994—2012年2个品种小麦观测资料，对2个小麦品种的生长性状、产量和产量结构进行方差分析，然后选取2个品种间差异不显著的样本，建立小麦不同发育期叶面积指数（LAI）与株高、密度、产量、穗粒数、结实小穗数及千粒重的关系。结果表明，不同发育期的LAI能反映小麦株高、密度和单位面积结实穗数。抽穗至乳熟阶段的LAI可估测株高，三叶至乳熟阶段的LAI均可监测同期密度，以拔节至乳熟阶段最好。抽穗至乳熟阶段的LAI可估测单位面积有效穗数，以抽穗期效果最好。抽穗至乳熟阶段LAI能较好地反映小麦产量的变化，可利用小麦冠层高光谱测定值构建的植被指数或MODIS植被指数反演LAI，利用LAI与产量的关系估产。如果在小麦不同生育阶段用遥感植被指数估测LAI，就可通过LAI与小麦株高、密度的关系监测小麦长势。抽穗至灌浆前期的LAI相对稳定，利用MODIS植被指数反演的LAI可估测小麦密度、产量和产量结构。

关键词: 小麦, 叶面积指数, 生长性状, 产量, 产量结构, 植被指数