The Characteristics Of Soil Seed Bank In Aerially-seeded Pinus Massoiana Plantations

The soil seed bank was a part of the plant community, which can be used as the material basis for the update and restore of vegetation. It was also of great importance to the restoration of ground vegetation cover. The paper took middle-aged aerially-seeded Pinus massoiana plantations in south of Jiangxi province as the research object, it discussed the characteristics of soil seed bank, the relationship of the soil seed bank, soil properties and the existing vegetation, the potential of soil seed bank update natural vegetation by the methods of typical sample survey, identification of soil seed bank and determination of soil physical and chemical properties. It provided scientific evidence for tree species structure adjustment, undergrowth vegetation restoration and effective management of aerially-seeded Pinus massoiana plantations in south of Jiangxi province. The main results were as follows:(1) The relationship between the total soil seed bank and germination time was showed double “S”, in other word, the trend was “flat-rise-flat-rise-flat”. The average density of soil seed bank was just 9.8×102 seed/m2. The density of the soil seed bank in different slope positions showed that: downhill>middle slope>total slope>uphill slope, which density respectively were 12.3×102 seed/m2, 10.3×102 seed/m2, 8.8×102 seed/m2 and 7.7×102 seed/m2. The seeds of 0-5 cm soil slope positions were accounted for more than 65% of the total number of 0-10 cm soil seed, but the soil seed bank density in 0-2 cm were less than 2-5 cm at downhill and middle slope, uphill and slope were opposite.(2) The herbaceous plant of Gramineae and Cruciferous played important roles in the 23 species which belonging to 17 families. Species richness index of lower slope and middle slope were larger for 12 and 10. The diversity index and evenness index of lower slope were largest, which were 1.729 and 0.880. The Dicranopteris linearis rhizome length of per unit area(1 m2) increased with the change of uphill slope, middle slope, downhill and total slope, taproot length of the stem significantly greater than the lateral root stalk.(3) The soil non-capillary porosity, soil moisture, organic matter, total nitrogen and total phosphorus had great influnce on soil seed bank. The average similarity coefficient in different slope positions was 0.15, the middle slope was the largest and the total slope was the minimum, they were respectly 0.19 and 0.11. On the whole, the restoration potential of vegetation of aerially-seeded Pinus massoiana plantations was at low level.