Vol5 No.2: 130-139
【Title】Evaluation of nitrogen cycling associated with agricultural production and environmental load in a mountain region, in Hokkaido, Japan
【Author】LIANG Lei, JIN Datian, HU Ning
【Addresses】Faculty of Environment, Liaoning University, Shenyang, 110036, China
【Citation】LIANG Lei, JIN Datian, HU Ning (2008) Evaluation of nitrogen cycling associated with agricultural production and environmental load in a mountain region, in Hokkaido, Japan. JOURNAL OF MOUNTAIN SCIENCE 5(2):130-139. DOI: 10.1007/s11629-008-0027-x
【Abstract】This study examined the nitrogen cycling associated with agricultural production and environmental load in central Hokkaido. The nitrogen (N) budget analysis model offers a new set of tools for evaluating N cycling in agro-ecosystems. The cycling index (CI) is a useful tool for estimating optimal N flows in farmlands. The fertilization index (FI) is a useful indicator for characterizing the N flows related to farms. Using these parameters, we analyzed all farm systems to estimate the optimal N cycling for minimizing N pollution in groundwater and maximizing agricultural production in mountain regions of Japan. The results showed that the critical N application rate (chemical fertilizer + manure) was 143.3 kg N ha-1 y-1. The critical inter-system input (chemical fertilizer N, imported food and feed N, and natural supplied N) was 169.2 kg N ha-1 y-1.
【Keywords】cycling index; mountain agro-ecosystem; N cycling; N load; N management; Hokkaido; Japan