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Long-term impacts of land-use change on dynamics of tropical soil carbon and nitrogen pools
Abstract： Land-use changes, especially the conversion of native forest vegetation to cropland and plantations intropical region, can alter soil C and N pools and N availability for plant uptake. Deforestation, followed by shiftingcultivation and establishment of rubber tree plantation, is a common land-use change in Xishuangbanna, southwestChina. However the influence of this kind of land-use change on soil C and N dynamics in this region remains poorlyunderstood. This study was conducted to assess the effects of land-use change on soil C and N pools. Soil sampleswere collected on five adjacent plots, which belong to three land-use types including secondary forest-an acuminatebanana( Musa itinerans) secondary forest and a male bamboo( Dendrocalamus membranaceae) secondary forest,shifting cultivation, and rubber tree ( Hevea brasiliensis (H. B. K. ) Muell. Arg. ) plantation (one plot is 3-year-old,and another is 7-year-old). We measured soil bulk density (BP), pH value, moisture content and concentrations ofsoil organic carbon(SOC), total soil nitrogen(TSN), and inorganic N(NO-3 -N and NH~ -N) at 0-3, 3-20, 20-40and 40-60 cm depths, and calculated C and N pools in 0-20, 20-40, 40-60, and 0-60 cm soil layers.Compared with the adjacent secondary forests, shifting cultivation and establishment of rubber tree plantationsresulted in significant decline in concentrations and stocks of SOC and TSN in 0-20 and 0-60 cm soil layers, andincrease in pH and bulk density at 0-3, 3-20, and 20-40 cm depths. Soil moisture content decreased only in 0-20 cm surface soils in shifting cultivation and plantations. The dynamics of mineral N was much more complex,which had different trends among depths and ecosystems. Compared with the secondary forests, SOC stocks in 0-20 cm surface soils in shifting cultivation and rubber tree plantations(3-year-old plantation and 7-year-old plantation)decreased by 34.0%, 33%, and 23%; and TSN stocks decreased by 32.2%, 20.4%, and 20.4%, respectively,whereas the decreases of SOC and TSN stocks in 0-60 cm soil layers were much less. The results indicated that Cand N losses were mainly occurred in 0-20 cm surface soil, followed by 20-40 cm layer. 作 者： YANG Jing-Cheng HUANG Jian-hui PAN Qing-min TANG Jian-Wei HAN Xing-guo 作者單位： YANG Jing-Cheng,HUANG Jian-hui,PAN Qing-min,HAN Xing-guo(Laboratory of Quantitative Vegetation Ecology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China)TANG Jian-Wei(Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, China)
期 刊： 環(huán)境科學(xué)學(xué)報(英文版) ISTICSCI Journal： JOURNAL OF ENVIRONMENTAL SCIENCES 年，卷(期)： 2004, 16(2) 分類號： X14 X13 Keywords： soil organic carbon (SOC) total soil nitrogen (TSN) inorganic nitrogen land- use change tropical soil Xishuangbana【Long-term impacts of land-use change】相關(guān)文章：
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