Yagi Kazuyuki, Minami Katsuyuki
National Institute for Agro-Environmental Sciences (NIAES), 305-8604, Tsukuba, Japan.
Sci China C Life Sci. 2005 Sep;48 Suppl 2:928-36. doi: 10.1007/BF03187131.
Fertilizer N use in Japan has decreased by about 30% from 1960 to 2000, while keeping a little increase in cereal yields. This has resulted in a significant increase in apparent nitrogen use efficiency, in particular for rice. On the other hand, national N load on the environment associated with the production and consumption of domestic and imported agricultural products has almost tripled during this period, mainly due to the dramatic increase of imports of food and feedstuffs. The environmental problems, including water and air pollution, caused by the excessive loads of N are serious public concerns and there is an urgent need to minimize N losses from agricultural production. In order to meet the necessity for reducing the environmental impacts by excess N, political and technological measures have been taken at regional and country levels. In recent years, the Japanese government has embarked on a series of policies to encourage transition to an environmentally conscious agriculture. Promoting proper material circulation with reducing fertilizer impact and utilizing biomass and livestock wastes is emphasized in these policies. The effectiveness of environmental assessment and planning for reducing regional and national N load has been discussed. Implementation of environmentally friendly technologies and management, both conventional and innovational, have been developed and adopted in Japanese agriculture. The effectiveness of conventional technologies in reducing environmental reactive N has been re-evaluated. Innovative technologies, such as use of controlled availability fertilizers and livestock wastes compost pellets, are being investigated and extended. A comprehensive approach that applies political and technological measures with closer co-operation is necessary to control reactive N in the environment.
从1960年到2000年，日本的化肥氮用量减少了约30%，而谷物产量略有增加。这导致表观氮利用效率显著提高，尤其是水稻。另一方面，在此期间，与国内和进口农产品生产及消费相关的全国性环境氮负荷几乎增加了两倍，主要原因是食品和饲料进口量的急剧增加。氮过量负荷造成的包括水和空气污染在内的环境问题是严重的公共关切，迫切需要尽量减少农业生产中的氮损失。为了满足减少过量氮对环境影响的必要性，在区域和国家层面采取了政治和技术措施。近年来，日本政府已着手实施一系列政策，鼓励向环境友好型农业转型。这些政策强调促进适当的物质循环，减少化肥影响，利用生物质和牲畜粪便。人们讨论了环境评估和规划对减少区域和国家氮负荷的有效性。日本农业已开发并采用了传统和创新的环境友好型技术及管理方法。对传统技术在减少环境活性氮方面的有效性进行了重新评估。正在研究和推广创新技术，如使用控释肥料和牲畜粪便堆肥颗粒。需要采取一种综合方法，通过更密切的合作应用政治和技术措施来控制环境中的活性氮。
