Effects of Combined Application of Organic Manure and Chemical Fertilizers on Yield and Quality of Tomato and Soil Nitrate Leaching Loss Under Greenhouse Condition

Recently,the excessive use of chemical fertilizer,especially nitrogen and phosphorus fertilizers,and unreasonable application of organic manure led to degradation of soil fertility,alarming environmental risk of fertilization and decreasing safety of vegetable products in main vegetable production regions in China.This study was conducted to determine the effects of combined application of organic manure and chemical fertilizers on yield and quality of tomato,and accumulation and leaching loss of soil nitrate under greenhouse condition.The field experiment consisted of six treatments of 1(No N),2(4/4 CN,all nitrogen in chemical fertilizer),3(3/4 CN+1/4 ON,ON denotes nitrogen in organic manure),4(2/4 CN+2/4 ON),5(1/4 CN+3/4 ON),and 6(CF,conventional fertilization).Equal NPK was designed for treatments 2,3,4,and 5.Rates of P2O5 and K2O application were respectively equal for each of treatments 1,2,3,4 and 5.The results showed that:(1) compared with the conventional fertilization with much higher rates of N,P2O5 and K2O,there were not significant differences of tomato yields under the different combined application patterns of organic manure and chemical fertilizers with proper rates of N,P2O5 and K2O.The average income of the combined application patterns of organic manure and chemical fertilizers was significantly increased by 19 127 RMB yuan·hm-2,with the highest income for the combined application pattern of 3/4 N in chemical fertilizer and 1/4 N in organic manure.(2) Compared with two treatments of the all NPK applied with chemical fertilizer and the conventional fertilization,the combined application patterns of organic manure and chemical fertilizers respectively decreased nitrate contents in fruit of tomato by 5.4% and 7.0%.Whereas the combined application patterns of organic manure and chemical fertilizers increased Vc contents in fruit of tomato by 9.4% than that in treatment of all NPK applied with chemical fertilizer.(3)Soil nitrate contents generally tended to increase in surface soil layer(0~20 cm) and decrease in deep soil layer after tomato harvest compared with the stage before tomato planting.Soil nitrate content in each soil layer for treatments of the combined application patterns of organic manure and chemical fertilizers were significantly lower than that in corresponding soil layer for conventional fertilization treatment.(4)Compared with the chemical fertilizer application pattern and the conventional fertilization,the NO-3-N leakage rates in the leakage water significantly decreased by 35.5% and 55.1% under the combined application patterns of organic manure and chemical fertilizers.The proper pattern of combined application of organic manure and chemical fertilizers based on yield,income and environment was the pattern of combined application of 3/4 N in chemical fertilizer and 1/4 N in organic manure under this experimental condition.