Scheduling Irrigation Using Automatic Tensiometers for Pea Crop
Recent technological advances have made soil water sensors available for efficient and automatic operation of irrigation systems. Automatic soil water sensor-based irrigation seeks to maintain a desired soil water range in the root zone that is optimal for plant growth. Automatic tensiometers were buried at 30 cm depth under the sandy soil surface of Nubaria experimental station of NRC, subjected to drip irrigation system to automatically schedule irrigation for pea crop. Soil moisture potentials 70, 75 and 85 kPa, represented 3 irrigation treatments and 3 Potassium treatments 50, 75 and 100% of 100 kg fed.-1, the officially recommended amount of Potassium fertilization for a pea crop by the ministry of agriculture in Egypt for sandy soils, were scheduled and added with the drip irrigation portions. The obtained results revealed that using soil moisture potentials 70, 75 and 85 kPa were equivalent to 85, 75 and 60% of the field capacity of the soil, respectively. The average crop factor (Kc) was calculated for each growth stage and the water applied according to the depletion percentage for each water treatment. All the applications were adjusted on control panel which was connected to an electric valve for each treatment. Water use efficiency, productivity, growth parameters, K use efficiency were calculated for each treatment. Automatic scheduling of drip irrigation at 85% F.C. using irrometer tensioner and 75% K fertilizers led to saving 16% to 35% of supplied irrigation water compared to uncontrolled drip irrigation method, with an increase in the yield of the crop estimated by 20%.
Keywords: automatic irrigation, scheduling irrigation, automatic tensiometer, potassium fertigation, drip irrigation.