Authors: Ahmet GÖKKUŞ, Ali KOÇ
Abstract: This study was conducted on the natural meadows of Atatrk University in 1988-90 in order to determine the effects of three herbicides (2,4-D, picloram and 2,4-D + picloram) applied in three times (20 April, 30 April and 10 May) on the hay and crude protein (CP) content and yield, and botanical composition. The research was established in split plot design with 4 replicates. According to three years averages. There was no significant difference between herbicides in terms of hay yield and crude protein content. Yields were generally lower in 2,4-D sprayed plots than in other plots. Hay and crude protein yields were not affected significantly by the time of herbicide applications increasing gradually with years. Crude protein percentages were generally lower in herbicide sprayed plots with the application dates having no significants effect. However, an insignificant but gradually increased in protein percentages occured with years. The percentage of grasses in botanical composition increased gradually, but that of forbs including legumes and Ranunculus kotschyii decrased. The rate of Hordeum nodosum, Poa pratensis and Alopecurus pratensis was inconsistant. The rate of grasses in control plots was found to be lower than in sprayed plots, but forbs including R. kotschyii and legumes were higher. The rate of A. pratensis increased when herbicides were applied. Neither the effect of different herbicide use nor the time of application on the botanical composition was significant.