华北地区紫花苜蓿适宜刈割物候期及留茬高度的研究

Study on mowing Phenophase and Stubble Height of Alfalfa Hay in north China

研究不同物候期及不同刈割留茬高度下对紫花苜蓿生产性能指标、营养成分指标及根系生长指标的影响,可为优质苜蓿青干草的适时刈割及奶业安全、高效生产的技术指标的确定提供有效依据。在不同的物候期,即现蕾期(50%植株现蕾),初花期(10%植株开花)和盛花期(50%植株开花),刈割频率分别为3次、2次、1次,刈割留茬高度分别为2-5cm,5-8cm,8-10cm情况下对试验地苜蓿进行刈割,每个试验组均设置3个重复。综合考虑苜蓿的生长特性、营养指标及根系生再生情况,在刈割物候期为现蕾期时苜蓿鲜草产量达最大,平均值为52216.51kg·hm-2;初花期苜蓿全年干草产量达最大,平均值为11630.84kg·hm-2;在不同刈割频率下,其CP含量、CP产量在现蕾期达到最大,分别为20.37和163.4kg·hm-2,而RFV现蕾期比盛花期高出11.12个百分点;在留茬高度为5-8cm时,苜蓿全年干草产量最高(P>0.05),为16279.95kg·hm-2,再生相关系数最大出现在留茬高度为8-10cm时,为0.9401。紫花苜蓿的最适刈割物候期为现蕾期至初花期,刈割频率以3次为宜,留茬高度为5-8cm,末次刈割时留茬高度为8-10cm时有利于其安全越冬及有效增加其分枝数。

This experiment was designed to explore the effect of mowing phenophase and mowing stubble height of alfalfa in the district of main production in Chifeng, China , in order to provide the appropriate time of high--quality alfalfa green haythe safety of dairy industry and the efficient production of technical indexes. In dif- ferent phenologieal phase, namely the budding stage （50 % plant budding）, initial bloom stage （10% plant flowering）, full--bloom stage （50% plant flowering） and pod-setting stage （50% plant podding）, mowing frequency respectively 4, 3, 2, 1, mowing stubble height respectively 2 5 cm, 5- 8 cm, 8-10 cm cases to mowing the tested alfalfa, each group were set up three repetition. Considerate the growth characteristics, nutritional indices and root regeneration, in mowing phenological period for budding period when the alfalfa grass yield reaches maximum, with a mean of 52216.51 kg/hm2 ; the largest throughout the year was reached in Early flowering period , with a mean of 11630.84 kg/ hmz ; Under the different mowing frequency, the maximum of CP content, CP yield was reached in budding period, respectively 20.37 kg/ hm^-2 and 163.4 kg/hm^-2 , and the RFV of budding period was 11.12% higher than the coated; the highest alfalfa hay yield throughout the year was reached in the stubble height is 5 --8 cm, with a mean of 16279.95 kg/ hm^2 （P〉 0.05）, and the renewable correlation coefficient of the largest in stubble height of 8 to 10 cm, with a mean of 0. 9401. The appropriate time of high--quality alfalfa is the budding period to the early onset of flowering, mowing frequency with 3 advisable, stubble height is 5- 8 cm, at the end of the time when mowing stubble height of 8--10 cm for its safety overwintering and have to increase its number of branches in north China.