Atrazine leaching and its relation to percolation of water as influenced by three rates and four methods of irrigation water application

Leaching of atrazine and bromide or chloride was related to the amount of deep percolating water produced from irrigations. Atrazine is an herbicide and bromide and chloride are inorganic tracers that are used as surrogates for the measure of water movement in soil. Deep percolating water and subsequent solute movement were compared between four methods of water application: sprinkler, basin, furrow, and drip. In each method, three amounts of water were applied to bare soil which were calculated as 0.75, 1.25, and 1.75 frac-tions of reference evapotranspiration measurements (ETo). Water applications were based on ETo because the amount of infiltrated water from a treatment could be related to climatic conditions. ETo values were obtained from the California Irrigation Management Information System (CIMIS) weather station located at Fresno, California. Very little atrazine, bromide or chloride was recovered in soil sampled directly beneath drip emitters, precluding any comparison to the other irriga