Effect of pyrazon on water-use efficiency of sugarbeets (Beta vulgaris L.).

Abstract

This study was conducted in a greenhouse at Tucson, Arizona to determine the water••use efficiency of sugarbeets, when treated with soil-incorporated pyrazon and grown under a low and high soil-moisture regime. During the first two weeks, measurements were taken to determine if pyrazon had any significant effect on growth and development of sugarbeets from germination to the cotyledon stage. No significant differences were found among treatments for germination and emergence, but significant differences were found in survival of the seedlings among herbicide rates. Pyrazon did not significantly affect the water-use efficiency of sugarbeets; however, the quantity of soil moisture present was a significant factor in the water requirement of beets. The treatment with the best water-use efficiency for the total plant was the 1.12 kg/ha rate of pyrazon under low soil-moisture. Plants receiving pyrazon treatments under low soil moisture transpired significantly less water than those receiving corresponding treatments under high soil-moisture; however, no significant difference was observed between controls for high and low soil-moisture. The 2.24 kg/ha rate of pyrazon was the only treatment in which root and total dry weight were significantly higher under high soil-moisture than under low soil-moisture. Transpired water and dry weight production were correlated with top, root, and whole plant efficiency to determine if these factors significantly influence the water requirement of sugarbeets.