Boron Transport within an Agricultural Field: Uniform Flow versus Mobile-immobile Water Model Simulations

THERE is a restricted range of boron concentration in soil water that is beneficial to plants. At lower concentrations, plants exhibit boron deficiency, whereas at higher concentration, phytotoxicity occurs. The specific range of favorable response varies by species but has been characterized as 0.028 to 0.093 mmol L 1 for sensitive crops and 0.37 to 1.39 mmol L 1 for tolerant crops (Keren and Bingham, 1985). Plants respond to soil water boron concentrations rather than to adsorbed concentrations (Keren et al., 1985). Thus, development of management practices should consider maintenance of beneficial boron concentration in soil water. In California, the total yearly discharge of boron from water districts utilizing the San Joaquin river as the ultimate collector of drainage water is regulated; hence, another goal is reduction of boron disTECHNICAL ARTICLES