Evaluation of Nitrogen Cycling in a Basin Associated with Forest, Grassland and Animal Husbandry, Hokkaido, Japan

日本北海道与森林、草原和畜牧业相关的盆地的氮循环评估

基本信息

批准号：
11460028
负责人：
HATANO Ryusuke
金额：
$ 9.6万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

Expansion of N cycling in ecosystems with increase of human activity impacts on not only regional environments but also global environments. Global warming with increasing emission of N2O, acidification with increasing of NH3 deposition, water pollution with NO3 leaching, degradation of bio-diversity with N load are the problems associated with N cycling in ecosystems. This report discussed about optimum N cycling in agro-forested ecosystems. In order to evaluate optimum amount of N cycling in agro-forested ecosystems, we studied following topics: 1) Impact of N cycling in basin ecosystem complexes on stream water quality; 2) Impact of atmospheric N deposition on forest soil ecosystems; 3) Green house effect gas fluxes in basin ecosystem complexes. Surplus N in agricultural lands and disposal N in regions are major factor determining stream water quality. N flow model was crucial for their evaluation. Unique N load was shown in each land use structure in a basin ecosystem complex. Most … More N load occurred during rainfall and snow melt season. In agricultural land, chemical fertilizer N, which was supplied to the fields within a 10-day before rain, was mainly discharged to the stream. Although animal and human excreta produced with the consumption of feed and food can be used as manure, inadequate composting process resulted in water pollution. Ammonium volatilization induced acidification of forest soils and stream N discharge induces eutrophication of coastal ecosystems. However they depended on soil quality. Acidification was controlled by exchangeable Ca in soils and eutrophication was controlled by Si supply from soils. Soil forming process, which releases both Ca and Si from primary rock minerals to soil solution, was quite important factor for occurrence of both acidification and eutropication. Hokkaido was the specific area in the world for occurrence of large N2O emission from agricultural fields. Denitrification was major process for large N2O emission. Conversion of forested land to crop land increased global warming effect of the land. However, N2O emission through water discharge from agricultural fields was smaller than the values reported previously. According to the above results, it is necessary for us to evaluate optimal N cycling with scenario analysis using N cycling model to describe numerically N flow associated with production and consumption of food and feed in basin ecosystem complex. Less

随着人类活动的增加，生态系统中氮循环的扩大不仅影响区域环境，而且影响全球环境：N2O排放增加导致全球变暖，NH3沉降增加导致酸化，NO3浸出导致水污染，N导致生物多样性退化。负荷是与生态系统中氮循环相关的问题。本报告讨论了农林生态系统中的最佳氮循环。为了评估农林生态系统中的最佳氮循环量，我们进行了研究。以下主题：1）流域生态系统复合体中的氮循环对河流水质的影响；2）大气氮沉降对森林土壤生态系统的影响；3）流域生态系统复合体中的温室效应气体通量和处置氮。流域生态系统中每个土地利用结构的独特氮负荷是决定河流水质的主要因素。大多数氮负荷发生在农业中。土地、化肥 N，雨前 10 天内供应到田间的氨氮主要排入河流，虽然动物和人类消耗饲料和食物产生的排泄物可以用作肥料，但堆肥过程不充分导致水体氨挥发导致酸化。森林土壤和溪流氮排放导致沿海生态系统富营养化，但它们取决于土壤质量，酸化受土壤中交换性钙的控制，而富营养化则受土壤中硅供应的控制。土壤形成过程将原生岩石矿物中的钙和硅释放到土壤溶液中，是酸化和富热带化发生的重要因素，北海道是世界上农田反硝化大量排放的地区。林地转为农田增加了土地的全球变暖效应，但农田排水造成的 N2O 排放量低于之前报告的数值。必要的让我们通过情景分析来评估最佳氮循环，使用氮循环模型以数字方式描述与流域生态系统复合体中食物和饲料的生产和消费相关的氮流量。