Soil Background Effects On Reflectance-Based Estimates of Leaf Area Index of Cotton.

Many of the precision agriculture applications use the widely used Normalized Difference Vegetation Index (NDVI) for assessing the crop growth.  The use of NDVI is usually accompanied by empirical relationships between NDVI and different factors of interest such as leaf area index (LAI).  Indices such as the NDVI rely on vegetation reflectance, while indices such as perpendicular vegetation index (PVI) rely on the distribution of soil and vegetation reflectance. Because NDVI values are based on the red and near infrared (NIR) reflectance characteristics of vegetation, the NDVI values depend on the sensor and location characteristics which make it site-specific. This site-specific dependence of NDVI with various crop growth factors necessitates tedious field scouting in many precision agriculture applications. In this poster soil background effects on NDVI and PVI-based estimates of LAI of Cotton is discussed in detail. The study was conducted in the agricultural fields in the Texas Rolling Plains.