生长季降水量和刈割强度对羊草群落地上生物量的影响

Influence of rainfall in growing season and clipping intensity on aboveground biomass of Leymus chinensis steppe

对不同降水量和刈割强度下的羊草Leymus chinensis、南牡蒿Artemisia eriopoda、糙隐子草Cleisto-genes squarrosa和群落总地上生物量的变化规律进行了研究,结果表明:降水量减少50%(R1)的处理中南牡蒿、糙隐子草的生物量和总生物量显著降低(P<0.05),羊草生物量变化不明显;降水量增加50%(R3)的处理中南牡蒿和糙隐子草的生物量呈增加的趋势,羊草生物量和总生物量呈减少趋势(P>0.05);随刈割次数的增加,羊草和南牡蒿的生物量与总生物量都呈增加趋势,南牡蒿的生物量和总生物量增加程度达显著水平(P<0.05);丰雨年(2006年,311mm),南牡蒿和糙隐子草的生物量与总生物量显著高于少雨年(2005年,216mm)(P<0.05),羊草的生物量差异不明显;生长季前期干旱的丰雨年(2007年,290mm),羊草和糙隐子草的生物量与总生物量显著低于2006年(P<0.05),羊草的生物量甚至也低于生长季前期不干旱的2005年。糙隐子草、南牡蒿、羊草和总生物量的变异系数分别为85.2、58.3、36.0和16.5,彼此之间差异达到显著水平(P<0.05)。

The study on the biomass change of Leymus chinensis, Artemisia eriopoda, Cleistogenes squarrosa and community of L. chinensis grassland under different rainfall conditions by using rainfall shelter and irrigation to adjust natural rainfall and using clip frequency to adjust clipping intensity was conducted from 2005 to 2007. The result showed that the biomass of A. eriopoda , C. squarrosa and the community except L. chinensis were significantly decreased in Rt treatment （rainfall was reduced by 50%, P〈0.05）. In R3 treatment （rainfall was increased by 50%）, the biomass of A. eriopoda and C. squarrosa performed an increasing tendency, however both L. chinensis and community showed a decreasing tendency （P〉0.05）. In Cz treatment （clipping frequency was increased）, the biomass of L. chinensis, A. eriopoda and the community showed the significant increasing tendency （P〈0.05）. In 2006 （rainfall was 311 mm）, the biomass of A. eriopoda, C. squarrosa and the community except L. chinensis increased significantly compared to that in 2005 （rainfall was 216 mm, P〈0.05）. In 2007 （rainfall was 290 mm, drought in spring）, the biomass of L. chinensis and C. squarrosa decreased significantly compared to that in 2006 （P〈0. 05）, the biomass of L. chinensis was even lower than that in 2005. The coefficient of variation （CV） on biomass of C. squarrosa, A. eriopoda, L. chinensis and the community was 85.2, 58.3, 36.0 and 16.5 respectively and the difference was significant.