Effects of carbon and nitrogen amendment on soil carbon and nitrogen mineralization in volcanic immature soil in southern Kyushu, Japan
Effects of carbon and nitrogen amendment on soil carbon and nitrogen mineralization in volcanic immature soil in southern Kyushu, Japan
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DOI：
10.1007/s10310-011-0272-7
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发表时间：
2011-08
影响因子：
1.5
通讯作者：
A. Yamasaki;R. Tateno;H. Shibata
中科院分区：
文献类型：
--
作者：
A. Yamasaki;R. Tateno;H. Shibata
土壤氮素矿化受微生物生物量和呼吸作用的影响，而微生物生物量和呼吸作用又受到有效C和N的限制。为了研究土壤微生物C和N动态与N动态的关系，我们进行了C和N改良后的长期室内培养(150天)，并测定了整个培养期间C和N矿化、微生物量C和溶解C和N的变化。研究土壤为来自日本南部的火山未成熟土壤，与其他日本森林土壤相比，其C和N含量较低。尽管如此，该地区仍被发达的天然林和人工林所覆盖。碳素改良导致微生物生物量和呼吸作用增加，净氮素矿化减少，这可能是由于微生物固定化程度增加所致。相比之下，施氮降低了土壤微生物的呼吸作用，增加了土壤中N的净矿化作用，这可能是由于微生物的固氮量减少所致。C和N的同时添加对微生物生物量和呼吸作用没有影响，但净N矿化略有增加。结果表明，碳素利用率越高，氮肥对微生物呼吸的抑制作用越小。因此，土壤有效碳可能会限制这种火山未成熟土壤的微生物生物量和呼吸作用。即使在C和N底物较低的未成熟土壤中，土壤C，如植物根分泌物和地上和地下死亡生物的物质，也可能有助于维持本研究地点的微生物活性和N的矿化。
Soil N mineralization is affected by microbial biomass and respiration, which are limited by available C and N. To examine the relationship between C and N for soil microbial dynamics and N dynamics, we conducted long-term laboratory incubation (150 days) after C and N amendment and measured changes in C and N mineralization, microbial biomass C, and dissolved C and N throughout the incubation period. The study soil was volcanic immature soil from the southern part of Japan, which contains lower C and N compared with other Japanese forest soils. Despite this, the area is covered by well-developed natural and plantation forests. Carbon amendment resulted in an increase in both microbial biomass and respiration, and net N mineralization decreased, probably due to increasing microbial immobilization. In contrast, N amendment resulted in a decrease in microbial respiration and an increase in net N mineralization, possibly due to decreased immobilization by microbes. Amendment of both C and N simultaneously did not affect microbial biomass and respiration, although net N mineralization was slightly increased. The results suggested that inhibitory effect on microbial respiration by N amendment should be reduced if carbon availability is higher. Thus, soil available C may limit microbial biomass and respiration in this volcanic immature soil. Even in immature soil where C and N substrate is low, soil C, such as plant root exudates and materials from above- and belowground dead organisms, might help to maintain microbial activity and N mineralization in this study site.