不同刈割时期和留茬高度紫花苜蓿品质动态研究

Study on the dynamic of Medicago sativa quality in different cutting period and cutting height

为了探讨紫花苜蓿的最佳刈割模式,本研究在紫花苜蓿返青后采用裂区试验设计,对不同刈割时期和留茬高度下紫花苜蓿的生物产量和营养品质动态进行研究,结果表明:(1)现蕾期和初花期具有较高的粗蛋白质和较低的中性洗涤纤维和酸性洗涤纤维含量,其相对饲喂价值较盛花期分别提高了12.57%和15.66%(P<0.05);(2)随着留茬高度的增加,紫花苜蓿干物质产量下降但营养品质增加,在7.5 cm和10.0 cm显著高于5.0 cm和2.5 cm,前二者相对饲喂价值分别较2.5 cm提高了5.84%和8.16%(P<0.05);(3)无论是现蕾期、初花期还是盛花期刈割苜蓿,不同的茬次之间品质差异均较大,其中以第一茬苜蓿品质最佳;(4)结合产业化对紫花苜蓿产量和品质的要求,以现蕾期5.0 cm留茬和初花期7.5 cm留茬较合理。

Cutting management is important for the yield and quality of M.sativa.In order to explore the optimal cutting model of M.sativa,the study analyzed the biological yield and nutrition of M.sativain the different cutting period and cutting height using the split plot experiment.The results showed that:(1)Comparing with full-bloom stage,there were higher crude protein and lower neutral detergent fiber(NDF)and acid detergent fiber(ADF) in M.sativa under budding stage and early-flower stage,thusthe relative feeding value(RFV) of the two stages increased 12.57% and 15.66% respectively(P < 0.05);(2) With the increasing of cutting height,the dry yield decreased while the nutrition increased,the nutrition of M.Sativa under the 7.5 cm and 10.0 cm were significantly higher than 5.0 cm and 2.5 cm,comparing with 2.5 cm,the RFV under 7.5 cm and 10.0 cm enhanced 5.84% and 8.16% respectively(P < 0.05);(3)There were significant difference between the different cuts in all the three cutting period including budding,early-flower,and full-bloom,of which the first cuts showed the best quality;(4)Combined with the requirements of Alfalfa industrialization on yield and nutrition,it was more reasonable that cutting at budding stage with 5.0 cm stubble or cutting at early-flower stage with 7.5 cm.