| Worldwide, the major regions of N deposition which cause by people is concentrated on North-America, Europe, East-Asia and South-Asia. More and more nitrogen is deposited to the most northern hemisphere by people's act. Forest has the most square which bear the N deposition directly. When the quantity of atmospheric N deposition exceed the load of the forest ecosystem, N deposition can leaching the nutrients and lead to leaf abscission earlier, also reduce the resistance of plant; N deposition can acidify the soil and leaching the exchangeable base cations.There are a lot of research on acid rain in China, but few on the relation of nitrogen deposition and forest. Fujian is a big forestry province which forest cover is about 60.52% is located on the southeast coast. There's an important significance of theory and reality to operate the research on the effect of nitrogen deposition to the forest ecosystem in fujian.The simulated elevated N depositions were equivalent to 0(N0), 60(N 1), 120(N2), 240(N3) kg.hm-2.yr-1N and began in Januray, 2004 each treatment set three repetition. We sprayed dissolved CO(NH2)2 once a month in the beginning of the month. This thesis studied the effects of N deposition on physical-chemical properties on soils and dynamics of carbon through stimulated N deposition in Minbei forest.The results obtained showed as the following: (1) N deposition increased the volume of soil, the three levels of deposition three levels had more than 2.55%,8.01%, 12.24% respectively compared with control level in the early period ,and 7.46%, 8.64%, 16.63% when the experiment near two years, the increased degree was positively with the N deposition level and deposition time. (2) N deposition led a decrease of soil pH, it is more sensitive on the layer of 0-20cm than 20-40cm and 40-60cm.The declining extent on soil pH is positively with N deposition. N3 turned out the minimal pH (4.31) lowed... |
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