Determination of suitable mixture ratios of some warm season perennial grasses with alfalfa (Medicago sativa L.) in order to artificial pasture and hay production under Çukurova

In this study, it was aimed to determine the appropriate mixing ratios of two different perennial warm season grass forage species, common dallisgrass (Paspalum dilatatum Poir.) and Rhodes grass (Chloris gayana Kunth) mixed intercropped with alfalfa (Medicago sativa L.) under Mediterranean climate conditions. In two separate trials, the performance of seven different mixture ratios of "common dallisgrass + alfalfa" (for pasture establishing) and "Rhodes grass + alfalfa" (for hay production) was determined. Intercrop of Rhodes grass + alfalfa were cut as to imitate hay production, and intercrop of common dallisgrass + alfalfa were cut as to imitate grazing. The experiments were carried out under irrigated conditions in the Eastern Mediterranean Agricultural Research Institute (Adana, Turkey) between 2018 and 2020, according to the randomized complete blocks design with 4 replications. In the study, it was observed that the performances of the examined species and intercrops changed significantly based on years. It was determined that the yield of intercrops were higher than the sole plantings, and the highest values were obtained in 2019 (second year of the study) in both trials. As the ratio of alfalfa species increased in the applications, the quality values of the grasses in the mixture were also increased. In the mixtures of common dallisgrass + alfalfa (CD+A), the highest green grass yield (69.8 t ha-1) was obtained with "80% CD + 20% A"; the highest dry matter (16.4 t ha-1) and digestible dry matter yield (9.9 t ha-1) was obtained with "70% CD + 30% A"; the lowest ADF (34.8%) and NDF ratios (47.1%) was obtained with "sole alfalfa"; the highest crude protein yield (2,4 t ha-1) was obtained with "60% CD + 40% A"; the highest relative feed value (RFV) (123.2), crude protein ratio (19.8%) and digestible dry matter ratio (61.2%) were obtained with "sole alfalfa"; and the highest land equivalent ratio (1.27) was obtained with "80% CD + 20% A" and "70% CD + 30% A" applications. Second highest crude protein ratio (15.7%) and RFV (100.3) following "sole alfalfa" application were determined "50% CD + 50% A", where alfalfa species was existing in the mixture at the highest rate. The ratio of alfalfa in the botanical composition by weight was high in the first year (52.0%) and low in second year (30.3% and 25.0%, respectively). The proportion of alfalfa species in the botanical composition by weight was decreased by the shift from the first year to the second year. The most well balanced mixing ratio was determined as "70% CD + 30% A" and "60% CD + 40% A" applications. In the mixtures of Rhodes grass + alfalfa (RG+A), the highest green grass (89.9 t ha-1), dry matter (19.6 t ha-1), digestible dry matter yield (11.5 t ha-1) and land equivalent ratio (1.31) was obtained with "60% RG + 40% A"; the lowest ADF ratio (37.1%), the highest crude protein yield (2.3 t ha-1) and digestible dry matter ratio (59.3%) was obtained with "15% RG + 85% A"; the lowest NDF ratio (48.7%) were obtained from "sole Rhodes grass"; the highest crude protein ratio (15.6%) and RFV (115.2%) were obtained from "sole alfalfa" applications. Following "sole alfalfa" application, the second highest crude protein content (12.5%) and RFV (100.5) were obtained with "15% RG + 85% A" application in which alfalfa was included in the mixture at the highest rate. While the ratio in the average botanical composition of the Rhodes grass species was highest in first year (78.6%), it decreased in the following two years (62.5% and 56.7%, respectively) compared to the first year. The most well balanced mixing ratio was determined with "75% RG + 25% A" and "60% RG + 40% A" applications.