种植密度对高丹草农艺性状及饲用品质的影响

摘要

选择光周期不敏感型冀草1号、光周期敏感型冀草2号高丹草(Sorghum bicolor×S.sudanense)为研究对象,通过设置不同种植密度处理,分别于抽穗期、开花期、乳熟期分析了高丹草农艺性状及饲用品质指标的变化规律.结果表明,抽穗-乳熟期,低密度(6.0万~7.5万株·hm-2)处理下,冀草1号、冀草2号高丹草的主茎直径显著高于高密度处理(30.0万~37.5万株·hm-2)(P<0.05),但其它农艺性状无显著差异(P>0.05).乳熟期,不同种植密度对冀草1号高丹草的干草产量无显著影响(P>0.05),但15.0万株·hm-2处理下的粗蛋白含量和相对饲用价值显著高于7.5万株·hm-2处理(P<0.05);种植密度在30.0万株·hm-2处理下,冀草2号高丹草的干草产量显著高于12.0万株·hm-2处理(P<0.05);但12.0万株·hm-2处理下的饲用品质指标与其它处理无显著差异(P>0.05).综合得出,海河平原区,乳熟期刈割时,光周期不敏感型高丹草适宜种植密度为15.0万株·hm-2,光周期敏感型高丹草适宜种植密度为12.0万株·hm-2.%This study aimed to discover the differences in agronomic traits and forage quality at different plant densities of Sorghum bicolor×S.sudanense.A field small-plot experiment was conducted in the Haihe lowland plain,in which ''Jicao 1'' and ''Jicao 2'' were used for photoperiod insensitivity and photoperiod sensitivity of the experimental material,respectively.These correlative characteristic indexes,including the agronomic traits and forage quality,were analysed at different plant density treatments during the individual stages of heading,flowering,and milk.These results showed that the stem diameters of ''Jicao 1'' and ''Jicao 2'' at the low plant density(60 000~75 000 plant·ha-1)were significantly higher than the high plant density(300 000~375 000 plant·ha-1)from the heading to the milk stage(P<0.05),whereas there was no significant differences in the plant height,leaf number,ratio of stem∶leaf,and dry matter content(P>0.05).There was no significant differences in the dry yield of ''Jicao 1'' under different treatments(P>0.05),but the content of crude protein and the relative feed value of ''Jicao 1'' at the 150 000 plant·ha-1 were significantly higher than at 75 000 plant·ha-1 during the milk stage(P<0.05).The hay yield of ''Jicao 2'' at the 300 000 plant·ha-1 was significantly higher than at 120 000 plant·ha-1(P<0.05),but there was no significant differences between the treatment of 120 000 plant·ha-1 and other treatments on the content of forage quality for ''Jicao 2'' during the milk stage.According to the comprehensive analysis,the suitable plant density of the photoperiod insensitive Sorghum bicolor×S.sudanense was 150 000 plant·ha-1,and the photoperiod sensitive variety was 120 000 plant·ha-1 when cutting during the milk stage in the Haihe lowland plains.