Effects of combined application of organic manure and chemical fertilizers on yield and quality of celery and soil nitrate leaching under greenhouse condition

This study was conducted to determine the effects of combined application of organic manure and chemical fertilizers on yield and quality of celery, and accumulation and leaching of soil nitrate under greenhouse condition. The results show that compared with the conventional fertilization with much higher rates of N, P2O5 and K2O, there are not significant differences of celery yields under the different combined application patterns of organic manure and chemical fertilizers with proper rates of N, P2O5 and K2O. The average output of the combined application patterns of organic manure and chemical fertilizers is significantly increased by 22306 RMB Yuan/ha, with the highest income for the combined application pattern of 3/4 N in chemical fertilizer and 1/4 N in organic manure. Compared with the chemical fertilizer application pattern and the conventional fertilization, the nitrate contents in edible celery parts are decreased by 16.7% and 26.1%, while the Vc contents in edible celery parts are increased by 36.8% and 112.2% under the combined application patterns of organic manure and chemical fertilizers. There are significant accumulations of soil nitrate at depths of 6080 and 80100 cm after celery harvest under the conventional fertilization, whereas no significant accumulations of soil nitrate at depths of 6080 and 80100 cm after celery harvest are observed for the combined application patterns of organic manure and chemical fertilizers. Compared with the chemical fertilizer application pattern and the conventional fertilization, the NO3--N leakage rates in the leakage water are significantly decreased by 57.5% and 61.9% under the combined application patterns of organic manure and chemical fertilizers, with the lowest NO3--N leakage rate for the combined application pattern of 3/4 N in chemical fertilizer and 1/4 N in organic manure. The proper pattern of combined application of organic manure and chemical fertilizers based on yield, income and environment is the pattern of combined application of 3/4 N in chemical fertilizer and 1/4 N in organic manure under this experimental condition.