The Effect Of Prescribed Burning To The Mixed Coniferous And Broad-leaved Forest Soil Physical And Chemical Property And Microbial Density

The effect of fire to the forest ecosystems is very complex. Select three different standard plot, which is coniferous and broadleaved mixed forest, in MeiLing National Forest Park, and make prescribed burning every two month that the firing time is0min,10min.30min. and60min each. Take soil sample and experimental analysis, after the last burning, to find out the effect of prescribed burning to soil physical properties, soil chemical properties and microbe density. The results are as follows:According to the variance analysis, the connections between fire interval and soil bacteria, fungi, actinomycetes, living bacterial counts, soil water content, soil PH, soil available nitrogen content and soil organic matter content have a significant difference, however connection between soil saturated moisture, soil bulk density, soil total nitrogen content, soil available P content and soil available K content shows otherwise. The connections between fire duration time and soil bacteria, fungi, living bacterial counts, soil available P content, soil available K content, soil bulk density and soil available nitrogen content have a significant difference, however connection between actinomycetes number, soil water content, soil saturated moisture, soil organic matter content, soil pH and soil total nitrogen content shows otherwise.Soil water content drops dramatically and soil saturated moisture increase after the fire, and the magnitude of coil water content drops is proportional to time duration. The soil water content restore before fire after four month. And when fire duration time is10min. it recovered more quickly. When10min and30min. soil bulk density drops however60min, soil bulk density increase with time.Soil pH, soil organic matter and soil total nitrogen content increases after the fire, and soil pH is proportional to time duration. When duration time is10min. soil organic matter and soil total nitrogen content increases with time, when30min and60min, it increase first and then decrease. Soil available nitrogen content shows increase first then decreases however it always higher than before fire. Soil available P content variation varies with fire duration time, when duration time is lOmin, it shows a continuous increasing trend, and30min and60min it shows decreases first then increases, and30min, it recovered more quickly. The soil available K content shows increase tendency when duration time is1Omin, and30min and60min it shows increase first then decrease tendency.Fire is vital to soil microorganism, so the soil microorganism content drops after fire and it is proportional to time duration. However the recovery rate is inverse proportion to time duration. When time duration is10min, the content of bacteria, fungi and actinomycetes recovered in the shorter time and the number is bigger than the fire.