Investigating optimum number of irrigations for wheat under raised bed technology in semi-arid climate

Water conservation technologies like furrow irrigated raised bed planting are the need of day to improve water productivity and to get more crop production from the available limited water supplies. The present study was conducted at the experimental area of Water Management Research Centre, University of Agriculture, Faisalabad, to perform irrigation scheduling and investigate optimum number of irrigations for wheat under flat sowing and raised bed planting in a semi-arid climate of Faisalabad. Soil type of the area was sandy loam with bulk density of 1.55 g/cm3. The experiment was designed in Randomized Complete Block Design with five replicates and three treatments viz. T1: Flat sowing with irrigation at 50% MAD, T2: Bed planting with irrigation at 50% MAD, and T3: Bed planting with irrigation on the same day as in T1. Regular check of soil moisture status was performed and irrigations were applied in first two treatments at about 50% depletion of available water. The irrigations in T3, however, were applied on the same day as in T1, even if the soil moisture content went far below 50% of available water, to check the impact of water stress on crop, if any, under raised bed technology. In this way, four irrigations were applied to T1 and T3 on same dates, whereas five irrigations were applied in T2 throughout the season. The impacts of increasing number of irrigations in wheat bed planting were evaluated statistically to check the changes in yield and irrigation water productivity. Grain yields under two bed planting treatments were found significantly higher as compared to T1, but at par with each other, while the water saving in comparison to flat sowing decreased from 47.43% in T3 to 35.74% in T2 due to an extra irrigation in T2. Highest irrigation water productivity (1.32 kg/m3) was achieved in T3, followed by 1.12 kg/m3 in T2 and 0.54 kg/m3 in T1. It was concluded that application of an extra irrigation in bed planting resulted in non-significant increase in yield in comparison to bed planting with normal four irrigations, but in a highly significant decrease in irrigation water productivity, indicating that there is no need to apply extra number of irrigations in bed planted wheat in comparison to conventional method.