Role of Geospatial Technology in Crop Growth Monitoring and Yield Estimation

Abstract

Assessing crop growth during the growing period and the prediction of crop productivity is gaining importance for the estimation of seasonal production prior to crop harvest. Reliable and timely estimates of crop production in the face of different types of abiotic or biotic stresses or climatic aberrations, namely heat stress, drought or pest infestation, etc., are particularly important for those countries where agriculture contributes substantially to the economy. Advance warnings of adverse effects of such disastrous events can be of great help for strategic planning and the use of measures to avoid any consequent food shortages in the future. Satellite remote-sensing platforms can be applied quite effectively for real-time crop condition assessment and yield predictions, as satellite systems can provide continuous data on variable spatio-temporal scales, with timely availability and global coverage. These data are also inexpensive and readily available at various online portals and archives. Several studies conducted so far have either derived vegetation indices from remote-sensing data or have coupled remote-sensing data with crop simulation models for crop yield prediction. The coupling of remote-sensing data with crop simulation models has shown a significant improvement in yield prediction. Among spectral indices, Normalized Difference Vegetation Index (NDVI) has been shown to be quite effective for predicting crop yield, but detection of the anomalies from historical values of NDVI needs the availability of NDVI at the temporal scale for predicting the crop yield of the current season. Obtaining biophysical parameters (leaf area index, soil moisture, evapotranspiration, etc.), derived from satellite imagery at the appropriate stage of crop growth, is required for robust prediction of crop yield at the regional level. Yield estimates at regional level can provide important information for agricultural planning and can enable policy makers to frame import or export plans, determining prices on one hand, and can enable farmers to plan their marketing strategies on the other hand, while ensuring food security.