Growth and yield responses of crops and macronutrient balance influenced by commercial organic manure used as a partial substitute for chemical fertilizers in an intensive vegetable cropping system

A long-term field experiment was conducted with an annual rotation of tomato–radish–pakchoi to assess the effects of a commercial organic manure (COM) used as a partial substitute for chemical fertilizers on crop yield and nutrient balance in an intensive vegetable cropping system. Four treatments as chemical fertilizers (T1), chemical fertilizers + lower rate of COM (T2), chemical fertilizers + medium rate of COM (T3), and chemical fertilizers + high rate of COM (T4) were designed in the present experiment. The supplied doses of N, P, and K were equal for all treatments. Results showed that there were no significant differences in shoot biomass and market yields of tomato, radish and pakchoi among treatments (P > 0.05). It was found that positive P and K balance existed in the tomato–radish–pakchoi cropping system of all treatments. Compared with no manure treatment (T1), application of medium rate of COM (T3) decreased N, P runoff losses, increased N, P, K contents in crop tissues except N, P in pakchoi shoot, and lessened P, K accumulation in soils, accordingly, improved the efficiency of macronutrient. It was concluded that appropriate COM used as a partial substitute for chemical fertilizers could not only meet the crops’ nutrient requirement, but also improved the efficiency of macronutrient and remained positive balance of P and K in the intensive tomato–radish–pakchoi cropping system, which can be regarded as an effective measure for a contribution towards sustainable agriculture and a control pathway for reducing the potential risk of castoff to water environment.