Effect of Organic Manure on the Status of Phosphorus in Greenhouse Soils

A field plot experiment was conducted in Shenyang suburb to study the effects of applying organic manure on the status of phosphorus in greenhouse soils.Three treatments(0,20,and 60 t hm-1 of organic manure) were installed in greenhouse fields with different soil fertility levels.The results showed that the contents of total P,available P in 0-20 cm soil layer increased with applying organic manure,being significant when the application rate was 60 t hm-1,while that in 20-40 cm soil layer had no significant difference among the treatments.Under the application of organic manure,the available P content in 0-20 cm soil layer increased before the stage of flowering and decreased then,while that in 20-40cm soil layer increased gradually from the beginning to fruiting stage.Applying 20 t hm-2 of organic manure could maintain the soil total P and available P level in middle fertility level and high fertility field,while higher application rates could induce the risk of soil P leaching.