Normalized Difference Vegetation Index as a Tool for Wheat Crop Coefficient and Evapotranspiration Estimation: A case study of Nankana Sahib District Pakistan

Abstract

Pakistan is an agricultural country and major part of its economy is also based on agriculture and among all crop wheat is most preferable in Pakistan to grow according to its climate condition and natural resources, but due to abrupt changes in climate, the agriculture sector is adversely effecting and water scarcity is the biggest part of this issue which is also being increased day by day, rapidly increasing in population rate is also affecting water resources. In Pakistan, almost all farmers use flood irrigation to fulfil their crop water requirement. A large portion of water is applied to the field used by evapotranspiration and only a very small quantity of water is used by plants for their growth, metabolism and other activities, etc. Therefore, this has been needed to calculate the crop water requirement at the field level and for this purpose, remote sensing is one of the best technique which calculates the crop coefficient KC and evapotranspiration Etc at field level and also helps to efficient use of water for crops. Normalized difference vegetation index (NDVI) is used as a tool for the calculation of crop coefficient and Evapotranspiration by using the following formula N = (Ndvi Landsat-bare soil Ndvi)/(Maximum Ndvi-bare soil Ndvi) Where KC=N 2 and the calculated crop coefficient was 0.28 to 1 and Evapotranspiration 0.9mm/day to 3.33 mm/day from January to April respectively.