Effect of different organic fertilizers application on growth and environmental risk of nitrate under a vegetable field.

The effect of chicken manure after different disposal methods (water-logged composting, GOF; anaerobic digestion, BR; thermophilic composting, ROF) on vegetable growth and environmental risk was investigated under the tomato-celery-tomato field. Results showed that organic fertilizers significantly increased vegetable yield and quality, but with inappropriate application may cause serious environmental risk such as nitrate pollution. Maximum vegetable yield of 80.9, 68.3, 112.7 t·ha-1 (first, second and third rotation crop, respectively) with best vegetable quality was obtained in ROF treatment. The highest N use efficiency with the least nitrate enrichment in soil was also found in ROF treatment. Moreover, under this fertilization way, nitrate concentration in soil leachate dropped to 6.4 mg·L-1 , which satisfied the threshold (<10 mg·L-1 ) for drinking water set by the US Environmental Protection Agency. Thus, ROF was suggested to be the optimal fertilizer with the best yield, quality and the least environmental risk under the" tomato-celery" rotation system.