IMPROVED GROUND SAMPLING AND CROP YIELD ESTIMATION USING SATELLITE DATA

The existing procedures for crop yield estimation involve Crop Cutting Experiments (CCEs) conducted during harvesting time in the plots sele cted based on a pre-designed sampling scheme using available ground da ta. These ground sampling designs do not consider the crop condition w hich is directly related to the yield during the season, for stratific ation and subsequent sample selection leading to biased distribution o f plots. Moreover these experiments are capable of providing estimates only at larger areal units such as the total command area. Hence ther e is a need to improve the sampling design to achieve more accurate es timates. An alternate methodology exploiting the information on crop a rea and crop condition, derived from satellite remote sensing data on near real-time basis, for improving the ground sampling design has bee n proposed in this paper. The methodology is demonstrated in the Davan gere and Malebennur divisions of the Bhadra project command area to es timate the average yield of paddy during Rabi 1992-93. The results obt ained from conventional methodology and the improved procedure showed that the latter has increased the accuracy of estimates. The yield val ues obtained from CCE plots have been regressed with corresponding Nor malized Difference Vegetation Index (NDVI) statistics and thus the der ived paddy yield model is capable of providing the yield estimates at smaller area I units, such as within distributary command.