Clearly, minimizing N fertilizer overuse at the end of the chain is vital. This would not only enhance N fertilizer efficiency and lower emissions in fertilized fields but, more importantly, decrease the total amount of N fertilizer demand. The latter means emission reductions involving the entire N fertilizer chain. Various factors contribute to the excessive N use in China. First, fertilizers have been kept at artificially low prices through heavy government subsidies (31), which obscure the financial burden resulting from excessive N use. Second, there is the absence of an effective and functional extension system that can reliably and systematically deliver science-based recommendations and techniques to hundreds of millions of farmers, although such recommendations have been developed for all major crops and cropping systems in China (33