Effect Of Different Age Popar Plantations On The Micro-environment Of The Soil

Poplar (Populus) belongs to salicaceae, mainly distributed in China, Asia, North America's temperate and boreal regions, Mediterranean countries and the Middle East. It is widely used not only for the timber, but also for timber processing industry, including synthesis of plywood and fiberboard, papermaking, matchmaking, disposable chopsticks manufacturing and packaging. By 2007, the total area of poplar plantations in China has reached 7 million square hectares, which ranks first in the world.For a long time, we used to implement a continuous short cycle and pure stand business model, which initiated that the whole tree or the all trees forest utilization while reducing investment in forest land. The results directly affect the effective use of land resources and sustainable development of forest resources.This study analyzed the soil physical properties, chemical properties,microbial and enzyme activity of the different ages poplar plantations. The purpose of this study is to explore the different ages poplar plantations impact on soil environment, As well as to provide a scientific basis for sustainable management of a large area of poplar plantation.The results are as follows:(1) Poplar forest contents organic matter of the surface 0-20cm higher than the non-forest land. In 0-60cm layer of soil, 5 years and 28 years old poplar forests content available phosphorus lower than non-forest land by 32.05% and 29.79%, while available K content were 13.36% and 43.90% higher than the non-forest land. It is suggests that poplar forest needs to strengthen the facilities of the phosphate,but no potassic.To micronutrient, 5 years and 28 years old poplar forests in 0-60cm layer of effective iron content lower than non-forest land by 30.31% and 31.79%. In addition, Zn content were lower than non-forest land by 24.48% and 26.50%. Therefore, it should be noted of iron and Zinc fertilizer in the production. (2) In the range of 0-60cm layer of poplar forest, the soil structure tends to be favorable for the plant growth. For 5 years and 28 years old poplar forests, field moisture capacity, saturation moisture content and capillary porosity were all higher than no-forest land, but volume weight was lower than no-forest land by 3.12% and 6.24%.(3) The number of the soil microbes was directly associated with soil organic matter and water content. Compared with non-forest land, soil bacteria and soil actinomycetes of 5 years old poplar forest in 0-40cm layer were 35.56% and 25.08% lower, while 28 years were 12.10% and 8.71% higher.This reflects the correspondence between soil organic matter content and the comparison organic matter content.(4) Soil enzyme activity reflects the soil organic matter content and soil structure. Compared with non-forest land,5 years and 28 years old poplar forest in 0-40cm layer of soil catalase activity were increased by 61.35% and 60.74%, while of soil protease activity were increased by 14.77% and 30.17%. This is consistent with the views of many studies.Both for 5 years and 28 years old poplar forest, soil urease activity and soil polyphenol oxidase activity in 0-40cm layer were all higher than non-forest land, these results may related with the soil permeability.