Characteristics of Available Nutrients Distribution and Accumulation in Greenhouse Soil Profile

In order to know the characteristics of available nutrients distribution and accumulation in greenhouse soil profiles,available nutrients in different soil layer in greenhouse with different planting years were measured.The results showed that nitrate nitrogen content in greenhouse soil profile distributed like an inverse trapezoid,total content of nitrate nitrogen accumulation in 0-100 cm in greenhouse soil profile with 5,10 and 14 planting years were 4.3,5.8 and 7.1 times greater than that in neighboring field.Available phosphorus in topsoil was over 200 mg kg-1 in greenhouse after planting 5,10 and 14 years in greenhouse,available phosphorus accumulation in 0-100 cm soil profile were 6.2,13.2 and 18.0 times greater than that in neighboring field respectively.Contents of available potassium in 5,10 and 14 year-planted greenhouse were over 300 mg kg-1,and distributed like an inverse trapezoid.The total concentrations of available potassium accumulated in soil profile were 1.8,2.9 and 4.4 times greater than that in neighboring field.Distribution of water-soluble phosphorus in 5 year-planted greenhouse was a T-bar and an inverse triangle after 10 years planting,and then developed to an inverse trapezoid gradually.Distribution of water-soluble potassium was an inverse trapezoid after different planting years in greenhouse.Accumulation rates of different soil available nutrients displayed as available P nitrate nitrogen available K.Available nutrients accumulated at surface layer in low-aged greenhouse,and the proportion of nutrients accumulation increased in deep soil layer in old-aged greenhouse.