Study On Soil Properties And Construction Of The Urban Green Land In The West Of Xiangjiang, Changsha City

Urban soil is the important component of city ecosystem. Constructing theecology city and realizing its sustainable development, urban soil with finequality is necessary. The study on urban soil could conduct the afforestation ofcity, especially to the residential quarter green area directly.According to field study and soil samples analyzed in the laboratory, whichgathered in and around the Changtangshan residential district, the west bank ofXiangjiang River, soil properties and constructed ways of the main type of urbangreen land were evalutated. The results showed that:(1) The urban soil has bad physical and chemical character, compared withthe nature soil in the area, newly green land's soil has lower organism matter,lack of nutrient content, such as nitrogen, phosphorus, soil depletion. Also withthe pH values rising, the CEC is lower, the ability of supplying and preservingfertile is weakened.(2) The artificial effect is intense. Not only was the soil layer disturbed withlarge invasions, but also the percent of bricks is high, the soil texture is too sandyor clay to plant. Some urban soil with shallow layer, weaken ability of preservingmoisture and fertility, so the plant can't grow well on it.(3) The soil properties of different type and area in the urban variesconsiderably. The earth-excavation place is not the same as the landfill place, sodoes the urban soil constructed in the different period. The proper order of theafforested soil fertility in the investigation area is: the Yuelu Hill(the scenerywoodland)＞the older green land (the resource and environmental sciencecollege of Hunan Normal University, the library)＞the Xiangjiang Rivergreenbelt≥both sides of South-road of Lushan, YueLu public square(green land ofroad and pulic square)＞the Changtangshan residential district.(4) The constructing way of the affroested soil adapted now, removed thenature soil and backfilled other soil and rubbish, is unsuitable, which should beimproved. It not only seriously destroys the soil resources, add the costs, but alsocauses urban soil with poor fertility. Integrated planning should be done before development, the surface and subsurface layer of the nature soil should bepreserved during the developing period. In backfilled places, the tactics ofreducing the building rubbish in the beginning should be done. After beingsmashed and sifted out, the remains could be backfilled as afforested soil.(5) In accordance with the urban soil, we should improve soil structure,enrich the soil and raise public awareness about soil resources, then the city willmake step into the benign orbit of sustainable development.