关键词: 养分资源管理, 效率, 养分流, 玉米, 生产- 消费体

Abstract: The method that linked material flow with nutrient flow was adopted in this article in order to study nitrogen and phosphorus nutrient flows in the whole process from the fertilizer input to the consumption of corn.Nutrient flow model was firstly established in corn productionconsumption system.Taking the year 2004 for example, in which the characteristics of nitrogen and phosphorus in maize ( including straw) and the efficiency of resources utilization were estimated.In 2004, 5.496×106 tons of nitrogen (N) and 2.112×106 tons of phosphorus ( P2O5) were applied into corn field in the form of chemical fertilizers; and 3.429×106 tons of nitrogen (N) and 1.394×106 tons of phosphorus ( P2O5) were harvested, in which 75%(N) and 68%( P2O5) were consumed.Corn was used for making staple feed.The total amount of N and P2O5 that came into the families, including directly by plant products and industrial products, and indirectly by animal products, occupying 22.8% and 13.6%, respectively.The ratio of returning straw to the field was quite low—phosphorus was about 80%, higher than that of nitrogen, which was 47%.So the returning straw to the field was regarded as an effective measure for phosphorus utilization. Nutrient flow began with the input of resource in the corn production-consumption system, but the utilization efficiency of resources was very low.Lots of resources were consumed by corn production, while 1 ton of nutrients in corn was produced, nitrogen and phosphorus which were consumed in the form of fertilizer were equal to 5.2 tons of coal and 12.1 tons of phosphorite, respectively.Therefore, optimizing nutrient flow in the entire corn production-consumption system was vital to the improvement of efficiency of nutrient resources and minimization environmental pollution.

Key words: nutrient management, efficiency, nutrient flow, maize, production-consumption
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