The herbicide 2,4,D, is applied to a golf course at a rate of 1.2 kg/ha. The organic matter content of the soil is 1%, bulk density is 1.3 g/cm3, and water content is 0.3.
(a) What fraction of the herbicide is adsorbed, and what fraction is dissolved?
(b) If the golf course is irrigated at a rate of 1.6 cm/day and the actual grass water use rate is 0.4 cm/day, how long will it take for the 2,4-D to reach the water table at a depth of 2 meters? Assume a constant and uniform soil water content of 0.3.
(c) How much (kg/ha) of the dissolved herbicide will remain when it reaches the water table? Use the decay constant for Ouachita soil and grass.
(d) By how much will the ground water concentration of 2,4-D increase if the herbicide mixes into 2 cm of saturated thickness with a porosity of 0.5?