Effect of different harvest stages on some silage quality characteristics of sweet sorghum (Sorghum bicolor (L.) Moench var. Saccharatum) and bean (Phaseolus vulgaris) mixtures

This study was conducted to assess silage and forage values of sweet sorghum (Sorghum bicolor var. saccharatum) silage when ensiled with different proportions of bean [Phaseolus vulgaris]. Rio cv. of sweet sorghum and Noyanbey-98 cv. of bean were used as crop material. Sweet sorghums were cut 3 different harvesting stages (panicle emergence, anthesis and doughy) and were mixed with bean at sorghum crop:bean ratios of 100:0, 75:25, 50:50, 25:75, and 0:100% on dry matter bases. All crops were chopped using a conventional chopper, and for each mixture 500 g of fresh material was vacuum sealed in a plastic bag and fermented for an average of 40 days, four bags per mixture. Dry matter (DM) yield and some silage quality parameters were tested such as pH, ME, relative forage value in the experiment. There were significant differences between harvest stages and mixture rates. Delaying harvest stage affected positively DM yield but not silage quality. Crude protein (CP) increased as proportion of bean increased in the mixture. In addition, pH and AA increased when bean was added. Silage with 100% bean without sweet sorghum had the highest pH and lowest AA concentration. It was concluded that mixing bean (25%) with sweet sorghum for silage increased CP concentration of the mixture.