With increasing demand for vegetables and horticultural products, the greenhouse cultivation area is expanding at an unimaginable rate. According to Ministry of Agriculture and Rural Affairs, PRC, the total area of planting facilities, mainly plastic greenhouses, solar greenhouses and terraces, will be stabilized at more than 2 million hectares by 2025, which was just 20 thousand hectares in 1980.However, under such special conditions as higher temperature, humidity, evaporation, planting intensity, multiple cropping index, and large amounts of fertilizer application, lack of rainwater leaching and so on, greenhouse soils are susceptible to degradation characterized by deteriorated physical properties, secondary salinization and acidification [1], imbalance of soil nutrients and microbial flora, increased crop diseases and insect pests, etc [2,3].