Soil water and potassium dynamics simulation under drip fertigated Kinnow mandarin in sandy loam soils

Abstract

The availability of water and nutrients in the root zone of the crop is very important for improving agricultural production. Studies on water and nutrient distribution in the crop root zone are essential for the appropriate design of drip fertigation systems. In the present study, water and potassium (K) dynamics under drip fertigated Kinnow mandarin in the sandy loam soil were studied. To simulate the water and potassium dynamics in the soil, HYDRUS 2D model was calibrated and validated. The results revealed that the HYDRUS-2D model was able to simulate both water and solute dynamics with R2 values ranging from 0.90-0.95 for soil water and 0.92-0.95 for potassium. The moisture content in the active root zone was near field capacity at 24 and 48 h after irrigation but significantly declined after 72 h. Potassium concentration was found higher in the upper layers of the soil (0-30 cm) and lower in deeper layers (30-60 cm) at 24, 48 and 72 h after fertigation. The results indicated that soil moisture and potassium were efficiently utilized by Kinnow trees with 4 Lh-1 dripper without much wastage, as the active root zone of the Kinnow was found between 15-30 cm depth. Thus, 4 Lh-1dripper was the optimum discharge size for drip fertigation in sandy loam soils. This information can be helpful for designing of drip fertigation system for citrus crop under sandy loam soils for improving productivity.