EVALUATION OF IRRIGATION SCHEDULING TECHNIQUES: A CASE STUDY OF WHEAT CROP SOWN OVER PERMANENT BEDS UNDER SEMI-ARID CONDITIONS

Abstract

The present study was carried out at Water Management Research Centre (WMRC), University of Agriculture Faisalabad, Pakistan to optimize the water usage for wheat crop in water scare regions of the country. Two main irrigation scheduling approaches i.e soil-moisture-based and climatic based were adopted and compared. There were overall six treatments; three treatments were for testing of climatic approach of irrigation scheduling i.e. application of irrigations at 20 mm (TC1), 30 mm (TC2) and 40 mm (TC3) Cumulative Pan Evaporations (CPE), and three treatments were for soil-moisture-based approach of irrigation scheduling i.e. 30% (TS1), 45% (TS2) and 60% (TS3) of Management Allowable Depletion (MAD) levels, and one farmer’s practice (Fp). Another aspect of the study was to check the ability of an in-season Normalized Difference Vegetation Index (NDVI) measurements to predict wheat yield potential. Results showed that the soil-moisture-based treatments significantly increased wheat grain yields over climate-based treatments (TC2 and TC3) and non-significantly over TC1. Results of NDVI measurements showed that it can be used for accurate in-season wheat grain yield estimation with R², RMSE, C_v, ME, RE, Bias and NSE estimated 0.768, 17, 4.4, 0.07, 0.019, 0.073 and 0.84 respectively and can be used as a valuable crop management tool.