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.
