CROP WATER REQUIREMENTS AND IRRIGATION SCHEDULING FOR SUPPLEMENTAL IRRIGATION FOR WHEAT CROP IN POTOHAR REGION

Abstract

Supplemental irrigation (SI) schedules as a value-added management practice for a rainfed region have become necessary to avoid massive production-cum economic losses. This study aimed to design the supplemental irrigation schedules for wheat crops in the Potohar region using the CROPWAT model under silt clay loam (SCL) soil conditions. The climate data were obtained from the nearest weather station installed at National Agricultural Research Centre (NARC) Islamabad. This experiment was divided into five treatments with three replications of each and was laid out within the randomized complete block design (RCBD). Before sowing the seeds, the soil samples were collected from 0 to 15, 15 to 30, and 30 to 45 cm for physical and chemical properties and during the growing season for moisture determination at an interval of 7 days. The treatments were no SI (T0), SI at soil moisture depletion of 60% (T1), 70 % (T2), 80% (T3), and SI on the predicted date by the CROPWAT model (T4). The net irrigation applied in T1, T2, and T3 treatment was 44.8, 52.2, and 59.7 mm, respectively. The Net Irrigation Requirement (NIR) predicted by the CROPWAT model was 130 mm, with different application amounts in subsequent growth stages. T4 treatment was observed with maximum grain yield (4.645 tons/ha) and minimum yield in T0 (3.40 tons/ha). The grain yield under T1, T2, and T3 treatment was observed as 3.86, 3.69, and 3.55 tons/ha, respectively. There is an immersive impact of supplemental irrigation on crop production in the Potohar region.