Author(s): Deepak Khare, Prabhash Kumar Mishra, Arun Mondal, Sananda Kundu
Linked Author(s): DEEPAK KHARE
Keywords: NDVI, Kc map, ETc map, Tawa canal command, RS based crop identification
Abstract: To assess distributed crop water requirement in a canal command, identification of different crops becomes essential. This paper attempted to identify multiple crops grown in the Rabi season (Nov/Dec to Feb/Mar) in the Tawa canal command (Madhya Pradesh, India) utilizing temporal LISS III (24m x 24m) and AWiFS (60m x 60m) images. Initially, the interest class (irrigated agriculture) and non-interest class were segregated in developing land use land cover map. Then, irrigated crop pixels were masked prior to generating Normalized Difference Vegetation Index (NDVI) values of nine AWiFS images representing the Rabi crop season (23rd Oct�11, 11th Nov�11, 21st Nov�11, 10th Dec�11, 24th Dec�11, 12th Jan�12, 05th Feb�12, 20th Feb�12 and 10th Mar�12). Based on the NDVI profile and sample GPS points taken during field visits, four principal crops viz. wheat (74. 68%), chick-pea (14. 52%), sugarcane (2. 42%), linseeds (2. 32%) and others, mainly vegetables (6. 06%) were identified in the command. In the study, apart from identification of crops, assessment of water availability in the Tawa canal command has also been made, wherein distributed (pixel-wise) evapotranspiration (ET) approach has been applied to estimate the crop water requirement. Regression equations between the NDVI values and corresponding crop coefficient of identified crops taken from literature (FAO 56) for the six consecutive months were developed. The coefficient of determination (R2) obtained between Kc-NDVI relations were in the range of about 0. 65-0. 95. Using this empirical equation, pixel-wise crop coefficient values from the corresponding NDVI values for six months were computed, and represented as crop coefficient maps (Kc map). Daily reference evapotranspiration (ET0) values for the six months were calculated using the FAO-56 Penman-Monteith equation, and were multiplied by the pixel-wise crop coefficient values, and thus, corresponding crop evapotranspiration maps (ETc map) were generated for six different months
Year: 2017