基于水稻冠层植被指数的龟裂碱土盐碱化信息预测研究

土壤盐碱化是危及农业生产的重大生态环境问题,遥感技术可以通过植被冠层光谱来估测土壤的盐碱化程度。试验结果表明:土壤pH与ESP(exchangeable sodium saturation percentage)之间有极显著相关关系;随着生育期的推移,水稻冠层NDVI逐渐增大,RVI逐渐减小,孕穗期水稻冠层NDVI值最高,RVI值最低。从拔节期到乳熟期的水稻冠层NDVI和RVI与相应时期的土壤pH和ESP都有较好的相关性,而且随着作物生长期的延伸,NDVI估测土壤pH和ESP的准确性有增加的趋势;返青期和分蘖期相关性不稳定。NDVI和RVI对pH和ESP估测的精度无显著性差异,但NDVI对ESP的估测效果更好一些。所以,从拔节期到乳熟期,通过水稻冠层植被指数可以较准确地预测龟裂碱土的碱化程度。

Prediction of the salinity information of Takyr Solonetzs based on the spectral characteristics of rice Canopy Indexes

Soil salinization-alkalization is a crucial issue of agricultural environment.Remote sensing is an important and effective technical method to predict the degree of soil salinization through monitoring the crop.The results showed that there was significant relationship between soil pH and ESP;canopy NDVI increased and RVI decreased with the rice growth,there was the highest NDVI and the lowest RVI in booting stage.Predicted values by NDVI and RVI were well related with measured values of soil pH and ESP at corresponding stages,and the correlation coefficients were higher at later stage of rice growth.There was an increasing tendency of accuracy of NDVI predicted values for pH and ESP along the rice growth,however,the relationships between estimated values by NDVI or RVI and actual values of soil pH or ESP were unstable at returning green stage and tilling stage.There was no significant difference of accuracy for estimating pH and ESP between NDVI and RVI,but the estimation of ESP by NDVI was better than RVI.Therefore,we could predict the degree of salinization of Takyr Solonetzs through measuring the canopy reflectance of rice from jointing to filling stage.