Computing Spatio - Temporal Water Demand of Wheat Crop Using GIS and Remote Sensing - A Case Study of Faisalabad Irrigation District, Pakistan

Authors:

Arshad A*, Bakhsh A, Azzam A, Ali S and Awais M

DOI: 10.23880/oajar-16000178

Volume 3, Issue 6

Abstract

Water resources are considered to be finite and their management and judicious use is emerging as a big challenge in the

21st century due to high population growth rate and associated food security. For effective water management of water

resources, the assessment of evapotranspiration is necessary. GIS and RS is a best tool to estimate crop

evapotranspiration of agricultural crops. The aims and objectives of this study are to compute the real time spatially

distributed crop coefficient (Kc) and water demand of wheat crop grown in Faisalabad Irrigation District, Pakistan. In this

study monthly crop evapotranspiration for command area was computed using MODIS 13Q1 satellite imagery. The crop

evapotranspiration (ETc) was computed by pixel wise multiplication of crop coefficient (Kc) maps and the reference

evapotranspiration (ETo) in ERDAS Imagine Model Maker (EIMM). Kc maps were generated from MODIS 13Q1 satellite

imagery while reference evapotranspiration (ET0) was estimation using CROPWAT model which compute ETO based

FAO-24 modified Blaney-Criddle method using multi variables i.e., temperature, wind speed, sunshine, sun radiations and

relative humidity. It was observed that ETc value varied from 0.30-0.89, 0.52-1.47, 0.68-1.64, and 0.61-2.49 mm/day for

Dec, Jan, Feb and Mar respectively. Seasonal minimum and maximum value of ETc for wheat crop was 0.30 and 2.49

mm/day for whole command area. It was found that average ETc value for wheat was increased gradually from Dec to

Feb as 0.59 to 1.16 mm/days and then decreased to 1.05 mm/days in March. Seasonal crop water requirement of wheat

was varied from 265 mm to 665 mm with an average of 465 mm. Results of this study were very close to past studies

therefore, it can be concluded that remote sensing based computation of Kc is capable of estimating crop water

requirement of the command area satisfactorily for the wheat crop.

Keywords:

Evapotranspiration; NDVI; Kc; ETc

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