Studies On Improving The Fermentation Quality Of Mixed Silages Of Crop Straw And Tall Fescue Or Perennial Ryegrass In Tibet

This studies was carried out to find the optimal mixture rates and evaluate the dynamic fermentation quality of both the mixed silage of wheat straw (Triticum aestivum Linn.) or oat straw (Avena sativa L.) with tall fescue (Festuca arundinacea Schreb.) and perennial ryegrass (Lolium perenne L.) and different additives of enzymes (cornzyme, E), molasses (molasses, M) and Lactic acid bacteria (lactobacillus, F). In the assay, there are mainly three experiments in the following study, for rational it is supposedly to provide theoretical support and technical basis for rational use of the crop stalks with tall fescue and perennial ryegrass of Tibet.1. Studies on the fermentation characteristics of wheat and/or oat straw and tall fescue and perennial ryegrass mixed silage.Wheat straw and oat straw respectively mixed with tall fescue were at the proportion of100:0(C),80:20(WT20, OT20),60:40(WT40, OT40) and40:60(WT60, OT60); oats straw and perennial ryegrasswere mixed at the proportion of100:0,85:15(OP15),65:35(OP35) and45:55(OP55). Silos were opened after7,24,45and60days of ensiling and the fermentation quality was analyzed. The results indicated that, compared with oat straw or wheat straw control group, the content of lactic acid and water soluble carbohydrate in silage which mixed with tall fescue were significantly increased, and the values of pH were reduced. The content of lactic acid and water soluble carbohydrate in silages which mixed oat straw with perennial ryegrass were significantly improved, and the values of pH were reduced. With the proportion of perennial ryegrass increasing, the ammonia nitrogen/total nitrogen values showed a gradual decline in silages. Within the three experiments, the contents of total volatile fatty acids of treatments were all lower than those of control groups. Through comprehensive consideration, that fermentation qualities of mixed silage of WT60, OT60, and OP55groups were better than those of their corresponding straw ensiled alone, it suggests that ensiling the wheat straw or oats straw mixed with tall fescue or perennial ryegrass improve the fermentation quality, but considering the indexes of lactic acid, values of pH and ammonia nitrogen/total nitrogen and so on, the treatments did not reach the standards of high-quality silage. Therefore, based on the results of this experiment, we need to further improve the fermentation quality of mixed silage by addtions.2. Effect of cornzyme and lactobacillus inoculant on fermentation quality of wheat and/or oat straw and tall fescue and perennial ryegrass mixed silage.Based on the first experiment, wheat straw and oat straw were both mixed with tall fescue at the proportion of40:60, and mixed ration of oat straw and was45:55, and then ensiled with cornzyme (E,2.5ml kg-1FW) or lactobacillus (F,2g kg-1) or cornzyme+lactobacillus (EF,2.5ml kg-1FW+2g kg-1). The silos were opened after7,24,45and60days of ensiling and analyzed for the fermentation quality of silages.The results indicated that, when adding cornzyme or lactobacillus, pH values were lower than those of control groups during the whole fermentation progress, while the contents of lactic acid were on the contrary. After24days of ensiling, the fermentation became stable. The content of lactic acid in oat straw silage which treated with E+F groups was lower than that of the cornzyme treatments. The contents of acetic acid were higher in cornzymeand E+F treatmentsthan control groups. Compared with control groups, the contents of total volatile fatty acids in each treatment were higher. According to comprehensive consideration, it suggests that fermentation quality of the silage treated with F should be better than that of E and E+F treatments.3. Effect of molasses and lactobacillus on fermentation quality of wheat and/or oat straw and tall fescue and perennial ryegrass mixed silage.In this part, the ensiling materials and methods were the same as the part two,while the treatments were M and M+F. The results indicated that, after60days of ensiling, both additives of M and MF, sped up the pre-silage of fermentation rate.24days later, the fermentation became stable. The content of lactic acid, water soluble carbohydrate and acetic acid of each treatment were significantly higher than control groups (P<0.05), and pH values were below4.2. The rate of ammonia nitrogen/total nitrogen(42.25～52.23) of OTM was significantly higher than control group (36.97)(P<0.05), while those of WTM and OPM treatments were on the contrary.Compared with other treatments, M+F treatments decreased the values of pH and ammonia nitrogen/total nitrogen in silage, and corresponding improved the content of lactic acid and water soluble carbohydrate. Addition of MF effectively inhibited the degradation of protein in silage. There was additionaleffect with F+M on promoting silage fermentation. According to the comprehensive evaluation, for mixed silage of crop straw and grass, the M+F treatments are more efficient than M or C treatments.