Influence Of Sonneratia Apetala Buch-ham On Changing Of Soil Factors Of Spartina Alterniflora Loisel Lawn

Spartina alterniflora Loisel produced in the US North Atlantic Ocean coast mutually, is one kind of the plant being suitable grows in the beach tidal zone and bearing the salt and floods. In the 1970s,it invasive into our country, which has already proliferated the southeast coast at present and caused the coastal shallow seas and tidelands soil physics and chemistry nature to drop and dropped the soil fertility in the south of our country. Simultaneously it also gives the coastal mangrove forest the renewal to reproduce, the tidal zone species to multiplicity, the river course to be unimpeded as well as the shallow seas and tidelands fish breeding and poultry raising brings the serious negative influence. Included in 2003 the first batch external invasion species name list which the State Environmental Protection Agency announces, that is regarded as studying the biological invasion ecology and the genetics characteristic pattern plant. In the Qiao island of city Zhuhai between 2000-2008, the Chinese Science Academy of Foresty Tropics Forestry Research Institute mangrove forest topic-based group used the fast-growing mangrove Sonneratia apetala Buch-Ham controlling the damage caused by weeds of Spartina alterniflora Loisel succeefully, and caused the Spartina alterniflora Loisel lawn soil various nutritive elements content distinct enhancement mutually, improved the coastal shallow seas and tidelands soil structure effectively, enhanced the soil fertility. In order to verify its control mechanism, the experiment using the shady net simulation vegetation to provide the shade studies the influence of shade to the exotic species which mutually Spartina alterniflora Loisel grew and Spartina alterniflora Loisel lawn different age of forest non-petal sea Sang Duihu the Spartina alterniflora Loisel soil changed factor influence. The result indicated:1,Along with the Sonneratia apetala Buch-Ham closing forest, the nutritive elements of soil has the slight change tendency in the forest, the changing of soil physical property is not obvious. And the organic matter, the effective nitrogen's content shows the little trendency of declining, but the effective phosphorus and the effective potassium's content presents the obvious riseing (, when Sonneratia apetala Buch-Ham age of forest amounts to above ten years, in forest the content of various nutritive elements is much higher compared to the forest-grass lawn, pure lawn, light beach). The soil PH value also decreases along with the age of forest, the soil assumes the acidity, the soil fertility obtains the enhancement if the cover of Sonneratia apetala Buch-Ham in the forest is elimination.2,Provide shade to Spartina alterniflora Loisel,the growth have the very tremendous influence, under the different shade intensity to Spartina alterniflora Loisel, the growth condition, photosynthesis ability and the biomass mutually and so on has the remarkable difference. Under the condition of in two Pieces of shady net to provide shade, Spartina alterniflora Loisel is emaciate, the single seedling's stem leaf dry weight and the gross dry weight obviously reduce, seedling's 12 phases obviously reduce the growth rate and the mortality rate is obviously bigger than one that provide one piece of shady net and no providing shade. Which provides three nets dies completely one month later. The experiment proved that the growth have the remarkable inhibitory action mutually if provides shade to Spartina alterniflora Loisel. From this we can infers the Sonneratia apetala Buch-Ham successfully controlling the Spartina alterniflora Loisel is mainly through mutually the forest crown's camouflage crucial role.3,The demand of the light resources of Spartina alterniflora Loisel exist marginal value. Because this experiment supposes the gradient to be big, it only obtains the preliminary result and that is namely 65.8% transmittances. Spartina alterniflora Loisel grow extremely slow down if it is lower than this transmittance and the adult plant is more emaciated.And also the transmittance is lower, its growing trend is worse until dies completely. When the parts on the grand of Spartina alterniflora Loisel are died completely, there still had certain root system underground. Show that even Spartina alterniflora Loisel is controlled effectively, it will very possibly to sprout again mutually if removes provided shade.