金沙江干热河谷山地草地封育过程中土壤种子库时空特征

The Soil seed bank’s temporal and spatial characteristics in the enclosed process of the mountain-grassland

2006年和2007年,分别选择放牧、封育1年、封育2年和封育3年的退化山地草地,采用土壤种子库萌发法对土壤种子库的时间、空间分布进行测定,旨在揭示金沙江干热河谷退化山地草地在封育过程中,土壤种子库的时间、空间以及时间序列上的空间变化特征。结果表明,(1)随封育年限的推移土壤种子库密度显著增加(F=73.107;P=<0.001)。植物种群土壤种子库密度随封育年限的推移,多年生植物种群土壤种子库密度显著增加(P=<0.001),一年生植物种群土壤种子库密度显著现降低(P=<0.01)。(2)土壤种子库的空间分布特征为0～5cm土壤层(含凋落物层)>5～10cm土壤层>10～15cm土壤层,种子密度呈自上而下减少的趋势。(3)土壤种子库时间序列上的空间分布特征为,0～5cm土壤层中种子库密度随封育时间的推移呈显著下降趋势(F=43.758;P<0.01),5～10cm土壤层中种子库密度随封育时间的推移呈显著增加趋势(F=6.435;P<0.05),10～15cm土壤层中种子库密度随封育时间的推移呈显著增加趋势(F=6.620;P<0.05)。

The experiment was conducted in 2006 and 2007 to investigate temporal and spatial distribution of soil seed bank in degeneration mountain grassland by using germination characteristics of the soil seed bank. Four type treatments are the mountain grassland opened, enclosed one year, enclosed two years and enclosed three years in the jin-Sha River Hot-Dry valley. The results showed that： 1.The soil seed bank density increase significantly （F = 73.107; P = 〈0.001） with the raising of year when grassland enclosed. In the process of mountain grassland enclosed, the perennial herbage population density in soil seed bank increased significantly （P = 〈0.001） while that of annual herbage decreased significantly （P = 〈0.01）. 2. The soil seed bank density decrease from top to bottom in the spatial： 0-5 cm soil layer （including litter layer） 〉 5-15 cm soil layer 〉 5-15 cm soil layer. 3 With the process of the mountain grassland enclosed, the soil seed bank density in the 0-5 cm soil layer was significant decreased with the raising of year when grassland enclosed（F=43.758 ; P 〈 0.01 ） ,while that in the 5-10 cm soil layer（F=6.435; P〈 0.05） and in 10-15 cm soil layer （F=6.620; P 〈 0.05 ） both significant increased.