Effect of full substituting compound fertilizer with different organic manure on reactive nitrogen losses and crop productivity in intensive vegetable production system of China

How substituting compound fertilizer with organic manure affects crop productivity and reactive nitrogen (Nr) losses from vegetable production system during the cradle-to-gate life cycle is not well understood. We thus investigated the impact of substituting compound fertilizer with various organic manures (stored solid manure and composted manure) on spinach productivity, Nr losses (e.g. NH3, N2O, NOx, N-leaching) and yield-based Nr losses in Changsha, Hunan, China. We found that the application of stored solid manure and composted manure decreased the total Nr losses by 58.1% and 75.0%, respectively, compared with compound fertilizer, but the spinach productivity was also decreased by 27.9% and 16.4%. Overall, substituting compound fertilizer with organic manure decreased yield-based Nr loss by 41.9-70.1%. These results highlight that substituting compound fertilizer with organic manure, particularly composted manure, may be beneficial to the environment at the expense of vegetable productivity. Strategies should be developed to decrease Nr losses from N input without compromising productivity in intensive vegetable production system.