Ecology, Environment and Conservation Paper

OPTIMIZING CHEMICAL FERTILIZER APPLICATION FOR ONION CROP UNDER DRIP FERTIGATION IN SANDY LOAM SOIL THROUGH SOLUTE TRANSPORT MODELING

G. Vijayakumar and P. Subramanian

Abstract

Field experiments were conducted at Excel Engineering College, Komarapalayam, Namakkal district, Tamilnadu during 2014 and 2015 to study the solute transport and moisture movement in sandy loam soil through validation of Hydrus-2D model in onion crop under drip fertigation. To economize the drip installation cost for onion crop, based on the wetting zone in the soil for 4 lph emitter, the spacing of lateral and spacing between emitters were selected as 1.5 m and 0.6 m respectively. A finite element model Hydrus- 2D was selected to simulate the moisture, N and K movement. Entire field was divided to identical volume with an emitter placed at the surface on the plane with radius ‘r’ as 40 cm and depth ‘Z’ as 60 cm. The observed and simulated moisture, N and K concentrations in the soil layers showed decrease in moisture content, N and K concentrations with increase in distances from emitter. Calibrated and validated results revealed that Hydrus-2D could be used for simulation of moisture, nitrogen and potassium distribution satisfactorily in onion under sandy loam soil condition for optimizing irrigation and fertilizer scheduling.