EFFECT OF MEFLUIDIDE ON YIELD AND CHEMICAL COMPOSITION OF CRESTED WHEATGRASS IN EAST-CENTRAL SASKATCHEWAN

Abstract

Two experiments, each of two years duration, were conducted to examine the effect of the plant growth regulator, mefluidide (N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide), on yield and chemical composition of crested wheatgrass (Agropyron cristatum) (L.) Gaertn.). In exp. 1, 1986, high rates of mefluidide resulted in reduced (P < 0.05) dry matter yield (DMY) and growth was inhibited for longer periods of time at higher application rates. Mefluidide treatment reduced (P < 0.05) neutral detergent fiber (NDF) content, increased (P < 0.05) crude protein (CP), ash and in vitro digestible organic matter (IVDOM) contents and had no effect on acid detergent fiber (ADF) or lignin contents. In 1987, neither DMY nor chemical composition were affected by mefluidide treatment. There were no effects of mefluidide treatment on DMY of regrowth in either year. However, regrowth CP content in 1986 and IVDOM content in 1987 were increased (P < 0.05) by mefluidide treatment while other chemical fractions were unaffected. In exp. 2, conducted in both 1987 and 1988, mefluidide application reduced (P < 0.05) reproductive shoot densities (RS) and DMY in both years. However, in 1987, the reduction in DMY only became apparent at late harvest dates. There were no effects of mefluidide treatment on CP content in either year. The regrowth DMY was reduced (P < 0.01) by mefluidide treatment in 1988 but not 1987 and CP content was not affected in either year. In these experiments, mefluidide enhanced forage quality when environmental conditions were favorable but was not effective during periods of drought stress. The high probability of drought occurring on the Canadian prairies would appear to limit application of this technology to more mesic locations. Under dry growing conditions, improvements in forage quality appear to be obtained at the expense of reduced forage yields.Key words: Agropyron cristatum, plant growth regulators, forage quality, mefluidide, nutritional value