紫花苜蓿与草地早熟禾轮作牧草的养分变化特征

Forage nutrients variation of alfalfa/Poapratensis rotational pasture

摘要:

以甘农9号紫花苜蓿(Medicago sativa cv.Gannong No.9)和海波草地早熟禾(Poa pratensiscv.Haibo)为材料,设置草地早熟禾-紫花苜蓿(PA)、紫花苜蓿-草地早熟禾(AP)轮作处理,以草地早熟禾-草地早熟禾(PP)、紫花苜蓿-紫花苜蓿(AA)为对照,进行了建植第2年的观察试验,测定粗蛋白含量(CP)、中性洗涤纤维含量(NDF)和酸性洗涤纤维含量(ADF),计算相对饲喂价值(RFV),研究紫花苜蓿与草地早熟禾轮作的养分变化特征。结果表明:在PA 模式下1~4茬紫花苜蓿的CP含量平均值和RFV 平均值分别较AA 模式高12.80%、21.59%,而NDF含量平均值和ADF含量平均值分别较AA模式低9.05%、17.33%;在AP模式下1~3茬草地早熟禾的CP含量平均值和RFV 平均值分别较PP模式高25.36%、15.73%,而NDF含量平均值和ADF含量平均值分别较PP模式低11.22%、7.49%。不同处理下第2茬和第3茬的紫花苜蓿CP含量和RFV 值均高于第1茬和第4茬,而第3茬高于第2茬,NDF含量和ADF含量均表现为与其相反;在不同处理下草地早熟禾的CP含量和RFV 排序由高到低均为,第1茬>第2茬>第3茬,而NDF含量和ADF含量均表现为与其相反。因此,在牧草生产实践中应该广泛的实施轮作方式,抓好第1茬和第4茬紫花苜蓿以及第3茬草地早熟禾的田间管理,是获得最优质牧草的关键。

Abstract:

The forage nutrients variation of rotational pasture of Medicago sativa cv.Gannong No.9 andPoa pratensis cv.Haibo was studied in order to provide theoretical basis for reasonable rotation and high qualityforage production.Four treatments were designed (P .pratensis-alfalfa,PA;alfalfa-P .pratensis,AP;P .pratensis-P .pratensis,PP;alfalfa-alfalfa,AA) and the contents of crude protein (CP),neutral detergent fiber (NDF)and acid detergent fiber (ADF) were measured,and the relative feed value (RFV) was estimated in second yearafter planting.The results showed that the average CP content and RFV of 4 cuttings of alfalfa in PA treatmentwere 12.80% and 21.59% higher than those of AA treatment respectively,but the average NDF and ADF contentsin PA treatment were 9.05% and 17.33% lower than those of AA treatment respectively.The average CPcontents and RFV of P .pratensis of 3 cuttings in AP treatment were 25.36% and 15.73% higher than those inPP treatment respectively,but the average NDF and ADF contents in AP treatment were 11.22% and 7.49%lower than those in PP treatment respectively.The CP content and RFV of alfalfa of second and third cuttingswere higher than those of first and fourth cuttings in all treatments,while the third cutting was higher than thesecond cutting.And the contents of NDF and ADF were opposite to CP content.The order of CP content andRFV of P .pratensis in all treatments were as follows:first cutting>second cutting>third cutting,while the orderwas opposite to CP content.Therefore,the crop rotation should be widely utilized in forage production,andthe field management during first and fourth cuttings for alfalfa and third cutting for P.pratensis is the key toobtain the high quality forage.