Effect of phosphorus fertilization on tomato phosporous nutrition,yield and soil enzyme activities

Phosphorus(P)is one of the most important macronutrient elements for plant growth.High residual P in greenhouse soils was frequently found because P is relatively insoluble and has a long residence time in the soil.In order to find an optimal level of soil available phosphorus for tomato production,a pot experiment was conducted to investigate the effect of phosphorus(P_2O_5)on to tomoto yield,phosphorus partitioning in different organs of tomato,dry matter accu- mulation,soil available P and enzyme activities.The results showed that with the increase of P application rate,the con- tent of available P in soil and P content in all organs of tomato significantly increased.The tomato yield,signal fruit weight and dry matter accumulation reached maximum when P_2O_5 were 0.53 g/kg.The optimal content of soil available P was 60-77 mg/kg for tomato production.Excessive P application(0.53 g/kg)caused a high accumulated P in soil and plant,resulting in the salt toxicity,low soil enzyme activities,declined dry matter and low tomato yield.