| The key problem for developing livestock production in Southern Xinjiang is the serious shortage of forages. Sweet sorghum has characteristics with high sugar content, biomass yield,good assistance, strong tillering ability and regenerating ability. Rational exploiting of sweet sorghum forage could alleviate the shortage of forage resources in Southern Xinjiang.Therefore, four experiments on agronomic traits, chemical composition, and microbial population of sweet sorghum varieties and corn and the silages made from them were carried out. The objective of this study was to select sweet sorghum adapting to environmental conditions in Southern Xinjiang, and to investigate the change of microbial population in silage process.In experiment 1, the main agronomic characters of 5 varieties of sweet sorghum and 1type of corn were tested. The result showed 1)sweet sorghum of Cowley, Rio, Tian-si No.1belongs to middle maturity varieties, Hunnigreen belong to extremely late variety, and X096 belong to early breed. 2)Height of Hunnigreen was the highest and stem diameter was the largest. 3) The differences of Brix in experimental varieties were significant. In milk stage,sugar brix of Rio reached 22.40%. Brix of BY02 had a minimum of 10.99%. 4)Hunnigreen had the largest leaf width, leaf length and other agronomic traits compared to BY02. and other sweet sorghum breeds. 5)Yield of Hunnigreen was 146 823.40 kg/hm2, and Rio had the lowest yield with 48 570.99 kg/hm2; comparing with other experimental planting varieties, the fresh weight, plant leaf weight, stem weight per plant and moisture content of Hunnigreen were the highest, and dry matter content was the lowest.In experiment 2, the the change trend of main nutritional components in silages made from different sweet sorghums and corn is basically consistent with that in the corresponding fresh materials. Protein and ether extrate have different levels of loss in the silage process, and the loss of protein in the corn silage process was largest. Cowley, Rio and Tian-si No1 with higher sugar content had the highest silage success rate(85%), higher protein and lactic acid content and lower fiber content, so obtained the best silage quality. Hunnigreen and X096 with lower sugar content had the lowest silage success rate, lower protein and lactic acid content and higher fiber content and pH value, so, obtained the worst silage quality. Corn silage success rate is middle with the highest protein content and lower fiber content, and its’ silage quality was also very good.In experiment 3 and 4, analysis of microorganisms in silage made from the experimental crops was carried out. The results showed: 1)the population of lactic acid bacterira in silages made from Cowley, Rio and Tian-si-No. 1 was much more than that in silages of Hunnigreen and X096, which had great number of yeast, fungi and aerobic bacteria.(2) 21 strains of lactic acid bacteria were separated successfully from the experimental silages. Silages made from Cowley, Rio and Tian-si-No.1 had lots of Lactobacillus, and Enterococcus faecium and Lactococcus lactis were not founded. The silages made from corn, Hunnigreen and X096 contained Enterococcus faecium and Lactococcus lactis.(3) Compared with other bacteria,Lactobacillus lactis had strong ability to produce acid and high rate of acid production.(4)The results of similar analysis of DGGE on silage lactic acid flora similarity showed that corn and sweet sorghum silage flora had 40% of similarity, bacteria group similarity between Hunnigreen and X096 was the highest, reached 92%, and bacterium group similarity between Cowley and Tian-si-No.1 reached 85%.In actual production, sweet sorghum of Cowley, Rio, Tian-si No.1 belongs to a high sugar content of plants; biological production of corn fairly and excellent quality silagesilage,Silage lactic acid bacteria content is high, abundant Lactobacillus; therefore, from silage quality perspective, Cowley, Rio, Tian-si No.1 suitable as feed crops cultivation in southern Xinjiang. However, biological yield higher of Hunnigreen can be found in biological yield performance; in production can be produced Hercules into hay or sweet sorghum varieties with high sugar mixed silage improve silage quality.Therefore, compared with BY02, all of Hunnigreen, Cowley, Rio and Tian-si NO.1 could be selected as sweet sorghum cultivars to utilize because of good performance in Southern Xinjing... |
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