Abstract: To discover the effect of different planting densities and stubble heights on production performance of Jicao 1 and Jicao 2 Sorghum bicolor ? S.sudanense, a fieldplot experiment were conducted from 2008 to 2010 using a randomized block design. Plant height, the ratio of stem/leaf, tiller numbers, the ratio of fresh/dry and the total grass yield were investigated and analyzed. Results showed that plant height, the ratio of stem/leaf and grass yield had no significant difference between different planting densities, whereas the ratio of stem/leaf and population denisity had a significant difference between different treatments in the same cutting (P<0.05). There was no significant difference among different stubble heights during heading stage. Total grass yield had significant difference between 20 cm and 5cm stubble height when the height of plant was 1.5 m. Comprehensive analyses indicated that the planting density of 75~375 thousands plants穐m^-2 was suitable for all tested plants. The agronomic characters of the 2^nd had no significant difference between different treatments during heading stage. The optimum height of stubble should be 20 cm when the height of plant was 1.5 m.

Key words: Sorghum bicolor ? S. sudanense, Planting density, Stubble height, Production performance

摘要： 为揭示不同种植密度和留茬高度下高丹草(Sorghum bicolor×S. Sudanense)生产性能间的差异性,以国审冀草1、2号高丹草为试验材料,采用随机区组试验设计,于2008-2010年在海河低平原农区连续3年小区试验的基础上,比较分析了不同种植密度、留茬高度对冀草1、2号高丹草株高、茎叶比、群体密度、鲜干比以及草产量的影响。结果表明:不同种植密度(7.5~37.5万株·hm^-2)处理下,冀草1、2号高丹草的株高、茎叶比及总草产量无显著差异,而鲜干比和群体密度在相同茬次不同处理间表现出一定的显著性差异(P<0.05)。不同刈割时期(抽穗期刈割、株高1.5 m左右刈割)的留茬高度(5,10,15,20和25 cm)处理表明,抽穗期刈割时不同留茬高度下冀草1、2号高丹草各性状值间无显著性变化;而株高在1.5 m左右刈割时留茬高度为20 cm处理下冀草1、2号高丹草总鲜、干草产量显著高于留茬高度为5 cm的处理(P<0.05)。综合分析得出,海河低平原农区,抽穗期刈割时,冀草1、2号高丹草的种植密度在7.5~37.5万株·hm^-2均可,且不同留茬高度对2茬草的生产性能无显著性影响,而株高1.5 m左右刈割时,最佳留茬度应为20 cm。

关键词: 高丹草, 种植密度, 留茬高度, 生产性能