不同盐碱地紫花苜蓿及其青贮品质的研究

Study on the quality of alfalfa from different saline-alkali lands and its quality after silage

为了研究不同盐碱地紫花苜蓿营养品质及其青贮后的营养品质和发酵品质的差异性,试验按照土壤含盐量设置NS(含盐量≤1 g/kg)、LS(含盐量>1~≤2 g/kg)、MS(含盐量>2~≤4 g/kg)、HS(含盐量>4 g/kg)处理,每个处理3个重复,苜蓿刈割后分别青贮发酵30 d和60 d,并分析苜蓿原料及青贮后的干物质(DM)、粗蛋白(CP)、非结构性碳水化合物(NSC)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF),以及青贮后的DM、CP、ADF、NDF、NSC、pH值、乳酸(LA)、乙酸(AA)含量。结果表明:盐碱化程度对苜蓿原料营养品质有较大影响,HS处理的苜蓿原料DM含量最高,NS处理的苜蓿原料DM含量最低。LS处理的苜蓿原料CP含量最高。分别在青贮发酵30天和60天时,4个处理间的青贮苜蓿DM含量均差异显著(P<0.05),随着盐碱化程度的增大,青贮饲料的CP含量逐渐降低,且HS处理的苜蓿青贮CP耗损量最小。在发酵60天时,各处理组pH值从大到小排序为NS>LS>HS>MS。分别在青贮发酵30天和60天时,MS处理的青贮苜蓿的LA含量显著高于其他处理(P<0.05)。不同盐碱化苜蓿在青贮发酵过程中,LS、MS、HS的青贮苜蓿在发酵前后营养物质的耗损量均较小。说明中度盐碱地(MS)苜蓿原料营养品质最佳,NSC和CP含量较高,充足的营养物质可以提供足够的发酵底物。且青贮发酵60 d后,中度盐碱地苜蓿青贮营养品质最佳。

To study the differences in nutrient quality and fermentation quality of alfalfa from different saline-alkali land in silage process, NS(saltness≤1 g/kg) and LS(saltness 1~≤2 g/kg),MS(saltness >2~≤4 g/kg), HS(saltness>4 g/kg) treatments were set according to soil salt content in this experiment. Each treatment was repeated 3 times.After harvesting, and dry matter(DM), crude protein(CP), non-structural carbohydrate(NSC), neutral detergent fiber(NDF), and acid detergent fiber(ADF) of alfalfa were analyzed, and the content of DM, CP, ADF, NDF, NSC, pH value, lactic acid(LA), and acetic acid(AA) were analyzed at 30 and 60 d of silage.The results showed that the salinization stress had a greater impact on the nutrient quality of raw alfalfa. The raw alfalfa of MS treatment had the highest DM content, and the raw alfalfa of NS treatment had the lowest DM content. The CP content of LS treatment raw alfalfa was highest. At 30 d and 60 d of silage fermentation, the DM content of alfalfa silage was significantly different(P<0.05). With the increase of salinization, the CP content of silage gradually decreased, and the CP content of HS treatment silage got the minimal losses. At 60 d of fermentation, the pH value of each group was sorted from high to low as NS>LS>HS>MS. At 30 d and 60 d of fermentation, the LA content in MS treanment was significantly higher than that in other treatment(P<0.05).During the ensiling process of alfalfa, the nutrient consumption loss of LS, MS, HS silage alfalfa was relatively small before and after the fermentation. The results indicated that nutrient quality of MS treatment raw alfalfa was the best, and the content of NSC and CP was higher, and its sufficient nutrients could provide enough fermentation substrate. And after 60 days of fermentation, the nutritional quality of alfalfa silage was the best in MS treatment.