内蒙古东部线叶菊草地生物量与净第一性生产力的初步研究

RESEARCH OF BIOMASS AND NET PRIMARY PRODUCTIVITY OF FILIFOLIUM SIBIRICUM GRASSLAND IN EASTERN NEIMENGOU

线叶菊草地总地上生物量的增长规律符合 Logistic 增长,最大值出现在8月中旬,为198.15g/m^2。返青后,线叶菊较同群落内的禾草和杂类草提前达到其生物量最大值。线叶菊、禾草和杂类草的地上生物量的增长与降水量和≥5℃积温呈显著或极显著正相关。地下生物量的季节变化曲线大致为“U”字形,最低值出现在8月中旬,而在早春和秋末时期地下生物量基本相等。地下生物量最大值出现在10月中旬,为1608.5g/m^2(干物质)。该草地地上部分净第一性生产力为256.74gm^2·a,地下部分为599.51g/m^2·a(干物重计)。将生长季内以凋落物形式损失的生物量计算在内,得到的地上净第一性生产力比用极大现存量法估测的结果高出29.57%。

The growth dynamics of grass aboveground biomass(AB)of Filifolium si- biricum grassland was studied experimentally and shown to agree with Logistic growth with maximum value,occuring in the middle of August(198.15 g.m^(-2) DM).After germinating the herb F.sibiricum grew quickly,the growth time needed to reach the maximum AB were less than other forbs species.There was a significant or extremily significant positive correlation between precipitation, accumulated temperature(≥5℃)and the AB increase of F.sibiricium,grass and forbs. The seasonal variation of underground biomass(UB)generally showed a “U”form,the minimum UB occurred in middle of August,the maximum UB occurred in the middle of October(1608.2g.m^(-2)DM),and it was close to that in early spring.The net primary productivity of the aboveground part was 256.74g.m^(-2).year,and the underground 599.51g.m^(-2).year.If the litter in growing season was included,the net aboveground primary productivity was 29.57% higher than the result estimated with maximum standing crop method.