杂交狼尾草生长过程中营养成分含量与生物量变化规律的研究

Studies on the Changes of Nutrient Contents and Biomass of Pennisetum Hybrid during Growing Period

本试验研究了杂交狼尾草在北京地区从春季萌发到7月17日100d生长时间内营养成分含量、瘤胃降解率和生物量的变化规律及刈割次数(1次或2次)与刈割时间对营养物质含量、瘤胃降解率和生物量的影响。试验结果表明:随着生长时间的延长,杂交狼尾草水会和粗蛋白含量大体上逐渐下降,NDF和ADF含量大体上逐渐上升,干物质48h瘤胃降解率逐渐下降;对于第一次刈割或第二次刈割杂交狼尾草鲜草亩产、干草亩产、有机物亩产、粗蛋白亩产和瘤胃48h可降解干物质亩产大体上逐渐上升。特别是第一次刈割杂交狼尾草瘤胃48h可降解干物质亩产在达到一定的生长时间后不再升高,甚至出现随生长时间的延长而下降的趋势。刈割次数和刈割时间均对100d生长时间的总生物量有较大影响。总鲜草亩产以第二期生长时间最长者为最高。粗蛋白总亩产大体上随第一次刈割时间的后延而逐渐降低。以单位土地面积收获反刍动物可消化干物质的最大量为衡量指标,杂交狼尾草在100d的生长时间内,以6月17日和7月17日各刈割一次为最佳选择,第一阶段的生长时间为70d,第二阶段的生长时间为30d。

This Experiment studied the changes of nutrient contents, degradability and biomass of Pennisetum Hybrid during about 100 growth days from spring germination to July 17 in Beijing area. The effect of mowing frequency and mowing date on nutrient contents, degradability and biomass were also determined. The results showed that： with extension of the growing period, moisture and crude protein percentage basically decreased; NDF and ADF percentage basically increased; dry matter 48-hour rumen degradability decreased. For the first mowing or the second mowing as the growing period extended, the biomass production of per unit land, such as fresh grass yield, hay yield, organic matter yield, crude protein yield and 48-hour rumen degradable dry matter yield basically increased. Especially, after reaching the highest point at a certain growth stage, the 48-hour rumen degradable dry matter yield did not go up anymore, even presented a down trend with the continues extension of growing period. If the Pennisetum Hybrid was moved one time or two times during the 100 growth days, the total fresh grass production of per unit land of the twice harvests was maximum when the second growing time was longest. The total yield of crude protein basically reduced with extension of the first time cutting. With the largest amount of rumen digestible dry matter yield on a unit land as a measure indicator, the Pennisetum Hybrid should be harvested twice within 100 growth days, at June 17 and July 17 respectively. The first growth phase was 70 days, and the second growth phase was 30 days.