New crop coefficients estimate water use of vegetables, row crops

To estimate the water use of vegetable and row crops, crop coefficients were developed using portable Bowen ratio instruments that were constructed and tested against lysimeters. These instruments measured evapotranspiration (ET) in fields of vegetable and row crops at various developmental stages. The crop coefficient was calculated at different percentages of ground cover using a direct ratio between the ET of the crop and that of a reference grass, which was calculated using meteorological data calculated from local CIMIS weather stations. The crop coefficients for most of the crops increased as the percentage of ground cover increased.