含水量和混播比例对青南牧区燕麦-箭筈豌豆/毛苕子混播青贮品质的影响

Effects of moisture content and sowing-mix ratio on the quality of baled oat and common vetch/hairy vetch silage mixtures in the pastoral area of southern Qinghai

将青南牧区燕麦和箭筈豌豆或毛苕子以不同的混播比例(18∶2、17∶3、16∶4、15∶5)、原料含水量(40%~70%)和青贮方式(整株与切短青贮)青贮并评价发酵品质,筛选出最佳的加工利用模式。参照德国农业协会青贮饲草评分标准,70个青贮处理中品质等级1级的35个,占总数的50.0%;品质等级2级的18个,占25.7%;品质等级3级的15个,占21.4%;品质等级4级的2个,占2.9%。总体上看:含水量50%~60%切短青贮感官评定得分较高。实验室化学测定结果表明,从pH值、乳酸含量、粗蛋白含量和氨态氮占总氮比值4个指标比较,h1t2s50、h1t2s55、h1t2s60、h1t2s65和h4t2s50、h4t2s55、h4t2s60、h4t2s65等8个处理综合表现较好。综合现场感官评定、实验室化学检测以及饲草产量,建议在青南牧区采用h4t2s50处理方式进行牧草生产与青贮。

In order to provide an optimum reference for local forage production,this experiment evaluated the silage quality of oat-vetch and oat-hairy-vetch sown with different mix ratios and produced with different moisture contents and silage methods in the pastoral area of southern Qinghai.An initial comparison of forage production indicated that mixes of Denmark No.444 oat＋Ximu333 vetch and Denmark No.444＋hairy-vetch performed the best as silage raw materials.The test was located in the Henan Mongolian Autonomous County（elevation 3600 m,longitude and latitude 34°45′N,101°34′E）of Qinghai Province.The trial design included different sowing mix ratios（18∶2、17∶3、16∶4、15∶5）,moisture contents（40%,45%,50%,55%,60%,65%,70%）and different silage methods（whole silage,chopped silage）.Oat-vetch and oat-hairy-vetch seeds were mixed and sown on 20 May 2015.The sowing ratio of 15∶5 oat-vetch produced the highest yields at12525 kg·ha-1.The oat and vetch forages were harvested at the milk stage,then wilted and their primary moisture contents tested,with the forages then sprayed to obtain the target moisture contents.Two silage methods were tested-long silage,in which whole plants were baled and ensiled,and short silage,with the forage cut to 3-5 cm before ensiling.All treatments had 6 replicates.Bales were sampled at 150 days after ensiling.Based on the DLG silage evaluation system,there were 35 treatments with sensory scores in the range20-16（Quality-level 1）,accounting for 50.0% of the total treatments.There were 18 treatments with scores15-10（Quality-level 2,25.7% of the total）,15 treatments with scores 9-5（Quality-level 3,21.4% of the total）and 2 treatments with scores 4-0（Quality-level 4,2.9% of the total）.Of all the 70 treatments,the chopped silage sensory score was at the highest level when the raw material moisture content was in the range of 50%-60%.Silage quality was also evaluated using four indexes：pH value,lactic acid content,crude protein content and AN/TN ratio.The results indicated that in terms of yield,sensory and chemical evaluation,the treatment with sowing mix ratios at 15∶5,moisture contents at 50%and chopped silage,produces the best quality forage.