Evolution Rule Of Korean Pine Plantation Soil Quality

The study has compared and analyzed the soil quality of 6 pieces of forest type, including different development stages of Korean pine plantation and the mixed forest of Korean pine, secondary natural forest in mountain region of the Northeastern China, discussed the evolution rules of soil quality of different age stages of the plantation and the relationship between soil quality and its forest productivity through the combined method of typical sample investigation, sample collection and measurement as well as Multiple statistical analysis. The results showed as follows:(1) From 25 year-old to 45 year-old of Korean pine plantation, organic matter hydrolysable N in soil decreased, available P, rapidly available K in soil increased, soil moisture and soil porosity decreased, soil bulk density and soil acidity increased; From 45 year-old to 58 year-old of Korean pine plantation, soil organic matter and hydrolysable N increased, soil available P decreased significantly and rapidly available K decreased too, soil moisture and soil porosity still decreased, soil bulk density and soil acidity increased; From 58 year-old to 68 year-old of Korean pine plantation, soil organic matter and hydrolysable N, rapidly available K decreased, but available P increased. Therefore, we can draw the conclusions: Soil acidity of Korean pine plantation increased, soil physical properties deteriorated and soil partial nutrient contents decreased as stand age accrued.(2) Organic matter and hydrolysable N, rapidly available K in rhizosphere soil and non-rhizosphere soil of Korean pine plantation decreased as compared with those in the mixed forest of Korean pine and secondary natural forest soil; soil acidity and soil bulk density increased, soil physical property worsen, the quantity of bacterium and three major kinds of microbe in soil diminished. This result demonstrated that after establishment of Korean pine pure plantations, as compared with the mixed forest of Korean pine and secondary natural forest, physical and chemical property in soil worsen, the biochemical activity in soil declined.(3) The undergrowth vegetation biomass in Korean pine plantations declined over years and was less than that of the mixed forest of Korean pine and secondary natural forest at all age stages.(4) Comprehensive evaluation on forest soil quality was done by using principal component analysis. The result showed that comprehensive score decreased in the order as follows: the mixed forest of Korean pine, 45 year-old, 68 year-old, 25 year-old, and then 58 year-old. Soil quality of mixed forest of Korean pine is the best, and that of 58 year-old Korean pine plantation is the worst.