Influence of Organic Manure Fertilization on Nitrate Accumulation under Protected Cultivation Condition

An experiment was conducted in Xinmin suburb to study the influence of different planting years and organic manure rate on nitrate accumulation by collecting soil samples(0 ～10、10 ～20、20 ～40cm) planted with cucumber in greenhouse soil.The results showed that the accumulation characteristics of nitrate in soil were affected by the different planting years and the rate of organic manure. The nitrate contents of soil were increased all along with planting years and organic manure rates,between different planting years the difference was significant(P0.05) ,especially the soil of 0～ 10cm. When the amount of organic fertilizer was the highest(M4) ,the content of nitrate had conspicuous accumulation(P0.05) . In addition,the highest content of nitrate in soil was 96.54 mg/kg after 2 years,there were different levels about nitrate accumulation in the mid and late time of cucumber;but when the quantitative of organic manure was lower,although the content of nitrate in soil was higher than comparison,the difference was insignificant.