| Single grain crop production for long time leads to serious environental problems,such as inefficient use of water and soil pollution in inland arid areas.Changing using style of small grains from the traditional food production into forage production and planting new varieties forage grass at the same time,could develop sown grassland-livestock comprehensive production system,which will improve the economic benefits and ecological benefits of agricultural systems.Therefore,we studied the effects of traditional small grains and varieties forages on digestility,metabolism and emission of greenhouse gas（GHG）of sheep,evaluated the quality of forages with conventional nutrient,in order to provide theoretical and technical basis for feeding grain reform and adjustment of agricultural structure.1Under simulation rotational grazing,the hay yield of rye,barley and wheat reached 9.2 t/ha and 8.5 t/ha and 6.4 t/ha.The crude protein（CP）content of these forageswere 12.6%,13.3%and 12.0%,and the protein productionwere 1.16 t/ha and1.13 t/ha and 0.76 t/ha,respectively.whencrops were used for production of seeds,dry matter production of the seeds were 4.0 t/ha,4.9 t/ha and6.2 t/haandstrawyield were 4.1 t/ha,6.4 t/ha,5.1 t/ha and the yield of CP were 0.69t/ha、0.90t/ha and0.72t/ha,respectvely.Choosing6 months Small-tailed Han sheep（♀）x Hu sheep（♂）hybrid generation rams and three small grain forages in filling stages,we conducted the tests and the results showed that,dry matter digestibility of wheat,rye and barley grass were 76.5%,77.8%and 72.6%,which were significantly higher than that of the wheat straw（50.2%）（P<0.05）.Furthermore,among three species of small grains,protein digestion rate of barley is the highest,at 86.33%,and that of rye is the lowest,at78.22%（P<0.05）;acid detergent fiber（ADF）and acid detergent fiber（NDF）digestibility of wheat,rye and barley were 77.1%,76.5%,76.1%and 77.1%,72.2%,71.2%,and all of them were significantly higher than those of wheat straw,whichwere 59.2%and41.5%（P<0.05）.There is potentialapplication forfeeding grain reform of barley,rye and wheat.2 The digestibility test of sheep for Yucao（Y）,Sorghum Hybrid Sudangrass（G）,Y/Vicia sativa（J）（2:1）,G/J（2:1）showed that,the dry matter digestibility of Y,G,Y/J,G/J were 67.87%,62.50%,61.31%and 47.13%,respectively.The digestibility of ADF and NDF were 69.81%,62.09%,69.07%,50.47%and 67.68%,60.58%,64.72%,51.45%for the former combinations,and both of them were the least in group G/J（P<0.05）.The digestibility of CP were 82.46%,60.20%,78.8%and 66.08%,respectively;and the digestibilityof CP of single grasseswere higher than it mixing with Vicia sativa（P<0.05）.Emissions of methane/intake of Y/J was the least,at 15.7L.kg-1（P<0.05）andemissions of methane/metabolic weight of G/Jwas the least,at1.55L.kg-0.75（P<0.05）.3Sheep digestion and metabolism tests of barley grass and hay of Vicia sativa80:20（DJ1）and 60:40（DJ2）two annual forage mixed groups,alfalfa and tall fescue（MG）amixture of two perennial forage grass.The results showed that the dry matter digestibility of DJ1,DJ2 and MG were 62.95%,59.76%and 54.99%,respectively,and the digestibility of CP were 74.97%,67.58%and 68.88%,respectively.Both indexes were significantly higher inbarley grass and green hay of Vicia sativa80:20 group（P<0.05）.Methane emissions/metabolism weight of MG was the least,at1.19L.kg-1 and theemissions methane/metabolic weight of MG was the least at 1.19L.kg-0.75.Furthermore,the Respiratory quotient（RQ）of two types of mixed forages（DJ1 and DJ2）were significantly higher than that of MG in（P<0.05）.To sum up,there is potential for transforming from grain to forage among barley,rye and wheat in inland arid area;which are uesed as mowing forages or grazing forage.There are better for livewight gain and less GHG emission for store lamb by using Y/J（2:1）and barley/J（8:2）. |
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