Response of old world bluestem (WW 517) and Ermelo weeping lovegrass to fertilization, irrigation, and defoliation



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Texas Tech University


The potential of old world bluestems and weeping lovegrass as forages on the Southern Great Plains is recognized. Management practices to maximize forage productivity and animal performance are currently being developed. In this study, two experiments were conducted to evaluate the effect of fertilization, irrigation, and defoliation on productivity, water use efficiency, forage quality, and carbohydrate reserves of old world bluestem (WW 517) (Bothriochloa intermedia var. indica) and Ermelo weeping lovegrass (Eragrostis curvula). An individual plant experiment evaluated single plant response to treatment and was conducted at Lubbock, TX. A microplot experiment was conducted on established stands of the grasses at Brownfield, TX. This experiment determined the response of plants to treatment application in a field situation. In the individual plant experiment fertilization and irrigation at weekly intervals increased root production above that of unfertilized plants. Maximum root production of WW 517 was achieved by weekly irrigation. Defoliation reduced root weights of fertilized and weekly-irrigated WW 517 and Ermelo by 25 and 36%, respectively, when compared to undefoliated plants. Regrowth production was greater for defoliated plants when compared to undefoliated plants. Regardless of species, water use efficiency of fertilized and weekly-irrigated plants exceeded that of plants treated differently. In the microplot experiment undefoliated WW 517 produced more than defoliated plants, with the exception of plants defoliated at 45-day interval. Production of undefoliated Ermelo was less than that of plants defoliated at 45-day intervals. In both experiments leaf crude protein content was increased following fertilization. Jji vitro digestible organic matter of WW 517 was not affected by fertilization while that of Ermelo was increased. Defoliation of plants in the individual plant experiment had no effect on forage quality. Forage quality of undefoliated plants from the microplot experiment was lower than defoliated plants. At the end of the growing season roots of WW 517 and crowns of Ermelo were primary carbohydrate storage organs. This study investigates short term responses of WW 517 and Ermelo to various treatments. Knowledge of these responses should aid development of more effective pasture management practices.