Effects of Mix Cropping of Alfalfa and Annual Ryegrass on Forage Production

Mix cropping of alfalfa (Medicago sativa) and annual ryegrass (Lolium rigidum) may improve forage production in the rangeland and field conditions, especially in spring after the establishment year. In this study, the effects of different sowing rates of alfalfa and annual ryegrass seeds in the replacement and additive series of mix cropping were evaluated on forage yield in first year after the establishment in Shahrekord, Iran. Treatments included 100-0, 80-20, 60-40, 40-60, 20-80, 0-100, 100-25 and 100-50 percent of alfalfa (A) and annual ryegrass (R) seeds, respectively. Results showed that the highest total annual forage Dry Matter (DM) yield was obtained from A80R20 with the average value of 13900 kg ha-1 that had no significant difference with pure alfalfa. DM yield was reduced when seed rate proportion of ryegrass increased from 60 to 100% in the replacement series and the least DM yield was obtained from pure ryegrass. There were no significant differences between the additive series (A100R25 and A100R50) and many replacement series treatments (A80R20, A60R40 andA40R60). Number of alfalfa stems as one of the yield components was reduced by increasing the ryegrass seed rate proportion in A80R20 to A20R80 and A100R50. The lowest number of alfalfa stems in cuts 3 and 4 was obtained for A20R80. In general, total DM yield and number of alfalfa stems in A80R20 and A60R40 of the replacement and in A100R25 of the additive series were similar as compared with pure alfalfa, particularly in cuts 3 and 4. Since alfalfa and ryegrass are perennial and annual crops respectively, it is reasonable that less ratio of ryegrass may be used in mix cropping for the stability of forage production in subsequent years.