The relationship between ground based multi-spectral radiometer sensor derived ndvi and agronomic variables of flue cured tobacco for in-season crop monitoring.

1Munyaradzi Shamudzarira, 2Ezekia Svotwa, and 3Walter Manyangarirwa

Abstract

 

 

Accepted 23^rd May, 2014

 

In-season tobacco crop status monitoring is used to evaluate the effect of cultural practices and environmental interactions that ultimately determine crop yield. In this experiment the relationship between hand-held Multispectral Radiometer (MSR 5) derived Normalized Difference Vegetation Index (NDVI) and tobacco biophysical parameters were established. From 100 Ha of tobacco crop, sampling sites were randomly selected for reflectance measurements and corresponding leaf length, leaf width, plant height, leaf number counts and above ground biomass. The biophysical parameters data was collected for 12 weeks from the age of 1 week after planting. The coefficients of determination between NDVI and leaf number (R2= 0.88), leaf length (R2 = 0.89), leaf width (0.82), plant height (0.86), Geometric mean length (0.863) and above ground dry mass (0.888) were high enough to allow for accurate assessment of crop health using NDVI. In-field variations in crop parameters were also observed on tobacco planted on different dates. Crop biophysical parameters are, hence, positively related to NDVI, and these results can be used in making in-season assessment of tobacco crop health, growth vigor and hence in yield estimation.

 

Keywords: Crop status monitoring, normalized difference, vegetation index, crop biophysical parameters, yield estimation 

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