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Soil Carbon Stock and Flux in Plantation Forest and Grassland Ecosystems in Loess Plateau, China 被引量:3
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作者 HU Chanjuan LIU Guohua +3 位作者 FU Bojie CHEN Liding LYU Yihe GUO Lei 《Chinese Geographical Science》 SCIE CSCD 2014年第4期423-435,共13页
Carbon sequestration occurs when cultivated soils are re-vegetated. In the hilly area of the Loess Plateau, China, black locust (Robinia pseudoacacia) plantation forest and grassland were the two main vegetation typ... Carbon sequestration occurs when cultivated soils are re-vegetated. In the hilly area of the Loess Plateau, China, black locust (Robinia pseudoacacia) plantation forest and grassland were the two main vegetation types used to mitigate soil and water loss after cultivation abandonment. The purpose of this study was to compare the soil carbon stock and flux of these two types of vegetation which restored for 25 years. The experiment was conducted in Yangjuangou catchment in Yah'an City, Shaanxi Province, China. Two adjacent slopes were chosen for this study. Six sample sites were spaced every 35-45 m from summit to toe slope along the hill slope, and each sample site contained three sampling plots. Soil organic carbon and related physicochemical properties in the surface soil layer (0-10 cm and 10-20 cm) were measured based on soil sampling and laboratory analysis, and the soil carbon dioxide (CO2) emissions and environmental factors were measured in the same sample sites simultaneously. Results indicated that in general, a higher soil carbon stock was found in the black locust plantation forest than that in grassland throughout the hill slope. Meanwhile, significant differences in the soil carbon stock were observed between these two vegetation types in the upper slope at soil depth 0-10 cm and lower slope at soil depth 10-20 cm. The average daily values of the soil CO2 emissions were 1.27 μmol/(m2·s) and 1.39 μmol/(m2·s) for forest and grassland, respectively. The soil carbon flux in forest covered areas was higher in spring and less variation was detected between different seasons, while the highest carbon flux was found in grassland in summer, which was about three times higher than that in autumn and spring. From the carbon sequestration point of view, black locust plantation forest on hill slopes might be better than grassland because of a higher soil carbon stock and lower carbon flux. 展开更多
关键词 soil organic carbon soil carbon dioxide co2 emissions vegetation restoration Loess Plateau
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Variation in Total Soil Organic Carbon Stocks in Relation to Some Land Use Systems in the Bamenda Highlands, Cameroon
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作者 Christian Tegha Kum Aaron Suh Tening +1 位作者 Martin Ngwabie Cornelius Tsamo 《Journal of Geoscience and Environment Protection》 2021年第9期150-165,共16页
Climate change and food security are among the pressing challenges facing humanity in the 21</span><sup><span style="font-family:Verdana;">st</span></sup><span style="fo... Climate change and food security are among the pressing challenges facing humanity in the 21</span><sup><span style="font-family:Verdana;">st</span></sup><span style="font-family:Verdana;"> century. Soil organic carbon (SOC) stocks, total nitrogen (TN), texture, and bulk density (BD) are important soil properties, which control climate change. Three land use systems (smallholder </span></span><span style="font-family:Verdana;">farmlands</span><span style="font-family:Verdana;">, grazing land</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">, and forest lands) that coexist in the </span><span style="font-family:Verdana;">Bamenda Highlands (BH) influence ecosystem</span><span style="font-family:Verdana;"> services and induce soil degradation with the loss of SOC. The objective of this study was to evaluate the variation of SOC and some soil physicochemical properties as affected by the three land use systems (LUS). A total of 21 composite soil samples collected from 7 microclimatic zones of BH following “S” shape plots to the depth of 0 - 30 cm, were analysed for moisture content (MC), SOC, TN, BD, available phosphorus (Av.P), pH and texture. The results revealed that grazing land had the lowest mean sand content (40.79 ± 4.07). Mean MC, TN</span><span style="font-family:Verdana;"> and</span><span style="font-family:Verdana;"> SOC (%) content were significantly higher </span><span style="font-family:""><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> < 0.05) </span></span><span style="font-family:Verdana;">in forest land than those </span><span style="font-family:Verdana;">in</span><span style="font-family:Verdana;"> the grazing land </span><span style="font-family:Verdana;">and smallholder farmlands</span><span style="font-family:Verdana;">. Conversely, BD and Av.P were significantly higher</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">(</span><i><span style="font-family:Verdana;">p</span></i><span style="font-family:Verdana;"> < 0.05)</span></span><span style="font-family:""> </span><span style="font-family:Verdana;">in smallholder farmlands than grazing and forest lands probably due to different</span><span style="font-family:Verdana;"> litter accumulation and agricultural practices. </span><span style="font-family:""><span style="font-family:Verdana;">Moisture content and TN revealed positive significant correlations (</span><i><span style="font-family:Verdana;">p</span></i></span><span style="font-family:""> </span><span style="font-family:Verdana;"><</span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">0.05) with SOC, while BD and Av.P revealed negative significant correlations (</span><i><span style="font-family:Verdana;">p</span></i></span><span style="font-family:""> </span><span style="font-family:Verdana;"><</span><span style="font-family:""> </span><span style="font-family:Verdana;">0.05)</span><span style="font-family:Verdana;">. Mean SOC density in </span><span style="font-family:Verdana;">smallholder farmlands (132.91 ± 9.48 tC/ha)</span><span style="font-family:Verdana;"> was </span><span style="font-family:Verdana;">the </span><span style="font-family:""><span style="font-family:Verdana;">lowest among the three land use types. Losses in CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> equivalence, as a result of land use change </span></span><span style="font-family:Verdana;">from forest lands to smallholder farmlands</span><span style="font-family:Verdana;"> w</span><span style="font-family:Verdana;">ere</span><span style="font-family:Verdana;"> 137.33 t/ha while that from </span><span style="font-family:Verdana;">grazing lands to smallholder farmlands were</span><span style="font-family:Verdana;"> 109.13 t/ha. </span><span style="font-family:""><span style="font-family:Verdana;">Total organic carbon (TOC) stocks differed significantly (</span><i><span style="font-family:Verdana;">p</span></i></span><span style="font-family:""> </span><span style="font-family:Verdana;"><</span><span style="font-family:""> </span><span style="font-family:Verdana;">0.05) from smallholder farmlands (10.73 Mt) to forest lands (91.13 Mt)</span><span style="font-family:Verdana;">. A sustainable farming</span><span style="font-family:""><span style="font-family:Verdana;"> technique that enhances SOC sequestration and minimizes soil CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> emissions is therefore recommended to replace tillage ridges formation commonly practiced by smallholder farmers. 展开更多
关键词 soil soil Organic Carbon Land Use Systems Bamenda Highlands soil co2 emissions
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Soil Respiration of Biologically-Crusted Soils in Response to Simulated Precipitation Pulses in the Tengger Desert, Northern China 被引量:3
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作者 LI Xiaojun ZHAO Yang +2 位作者 YANG Haotian ZHANG Peng GAO Yongping 《Pedosphere》 SCIE CAS CSCD 2018年第1期103-113,共11页
Soil respiration(SR) is a major process of carbon loss from dryland soils, and it is closely linked to precipitation which often occurs as a discrete episodic event. However, knowledge on the dynamic patterns of SR of... Soil respiration(SR) is a major process of carbon loss from dryland soils, and it is closely linked to precipitation which often occurs as a discrete episodic event. However, knowledge on the dynamic patterns of SR of biologically-crusted soils in response to precipitation pulses remains limited. In this study, we investigated CO_2 emissions from a moss-crusted soil(MCS) and a cyanobacterialichen-crusted soil(CLCS) after 2, 4, 8, 16, and 32 mm precipitation during the dry season in the Tengger Desert, northern China.Results showed that 2 h after precipitation, the SR rates of both MCS and CLCS increased up to 18-fold compared with those before rewetting, and then gradually declined to background levels; the decrease was faster at lower precipitation amount and slower at higher precipitation amount. The peak and average SR rates over the first 2 h in MCS increased with increasing precipitation amount, but did not vary in CLCS. Total CO_2 emission during the experiment(72 h) ranged from 1.35 to 5.67 g C m-2 in MCS, and from 1.11 to3.19 g Cm^(-2) in CLCS. Peak and average SR rates, as well as total carbon loss, were greater in MCS than in CLCS. Soil respiration rates of both MCS and CLCS were logarithmically correlated with gravimetric soil water content. Comparisons of SR among different precipitation events, together with the analysis of long-term precipitation data, suggest that small-size precipitation events have the potential for large short-term carbon losses, and that biological soil crusts might significantly contribute to soil CO_2 emission in the water-limited desert ecosystem. 展开更多
关键词 biological soil crusts C cycling co2 emission desert ecosystem precipitation amount soil water content
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