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1.
Daisuke Hattori John Sabang Sota Tanaka Joseph Jawa Kendawang Ikuo Ninomiya Katsutoshi Sakurai 《Soil Science and Plant Nutrition》2005,51(2):231-241
In order to provide appropriate soil information for the rehabilitation of tropical rainforest ecosystems, we examined the soil morphological, physico-chemical, mineralogical properties and charge characteristics in a degraded mixed dipterocarp forest with three type of vegetation, namely grassland, secondary forest, and remnant forest in Japan Sarawak Friendship Forest, Sarawak, Malaysia. We compared the soil properties at six representative locations differing in topography and vegetation types, with special reference to the effect of anthropogenic activities on the catenary sequence. All the soils were acidic or weakly acidic. Contents of clay, exchangeable Al, Alo, Ald and Fed and the values of the cation exchange capacity and Al saturation increased with depth. The clay mineral composition was dominated by kaolin minerals. The value of point of zero salt effect ranged from 3.0 to 4.0, indicating that the soil was not yet strongly weathered. A catenary sequence of the soils was observed; softer in soil hardness, higher contents of total exchangeable bases in the lower slope plots than in the upper slope plots and higher values of Feo/Fed in the surface horizon in the lower slope plots than in the upper slope plots. However, the effect of anthropogenic activities was observed; higher contents of total exchangeable bases in the grassland than in the other vegetation types. Based on the stable condition on weathering and erosion, the upper slope plot of the remnant forest exhibited a thicker O horizon, lower Feo/Fed values and a relatively high amount of chlorite. Soil variability should be taken into account for appropriate management of rehabilitation in tropical rainforests. 相似文献
2.
Irving Uriel Hernández Gómez Edward A. Ellis 《Land Degradation u0026amp; Development》2023,34(14):4456-4471
Evaluation and monitoring of forest biomass are important to help combat global warming and conserve biodiversity. Above ground biomass (AGB) mapping has been effectively used to assess forest loss, degradation, and recovery in the tropics. In this study, temporal (2007, 2010, and 2015) AGB maps were developed for the Mayan Zone of the Yucatan Peninsula, México integrating vegetation data from the National Forest Inventory (NFI) with synthetic aperture radar (SAR) image data (ALOS PALSAR). We assess if degradation could be attributed to the land use categories present in the study area: selectively logged forest, shifting agriculture, permanent commercial cultivation, and conservation forest. Spatial autoregressive models are applied to determine differences in AGB dynamics between land use categories, compared to baselines of mature conserved forest. We find that forest biomass remains stable in the study area. AGB does not differ in selectively logged areas compared to conserved mature forests. Biomass losses are observed due to deforestation for commercial cropping and pasture. AGB in shifting agriculture areas, however, fluctuates and shows a slight gain from 2007 to 2015. AGB mapping using NFI data and SAR imagery has the potential for monitoring forest loss and degradation on the Yucatan Peninsula. 相似文献
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Zhenchao Zhang Tianyu Zhan Yanpeng Li Yi Wang Ting Yu Juan Sun 《Land Degradation u0026amp; Development》2023,34(2):353-361
Grassland degradation is commonly thought to cause soil organic carbon (SOC) change, and the response of SOC stock to degradation is highly dependent on grassland type. However, the effects of grassland type on changes in SOC stocks with grassland degradation over broad geographic scales remain unclear. Here, we explored the probably different responses of SOC stocks to grassland degradation for alpine meadows and alpine steppes based on 58 peer-reviewed publications regarding the Qinghai-Tibetan Plateau. The results showed that SOC stock consistently decreased with increasing degradation levels in both alpine meadows and steppes, whereas the magnitudes of reduction of SOC stock in alpine meadows were significantly larger than those in alpine steppes (p < 0.05). The variations in SOC stock were significantly positively correlated with variations in aboveground biomass in the alpine steppes only (p < 0.05) but were significantly positively correlated with variations in belowground biomass in both alpine meadows and alpine steppes (p < 0.01). The relationships between change rates of SOC stock with initial SOC stock and mean annual precipitation were both significantly negative during the lightly and moderately degraded stages, while the negative relationship became nonsignificant for the heavily degraded stage (p > 0.05). These findings suggest that soil organic carbon stock responded more sensitively to degradation in alpine meadows with higher initial SOC stock and annual mean precipitation than in alpine steppes. Our study might have significant implications for future sustainable management practices for carbon sequestration of alpine grasslands on the Qinghai-Tibetan Plateau. 相似文献
4.
Gaurav Mishra Rossana Marzaioli Krishna Giri Rinkumoni Borah Antara Dutta R.S.C. Jayaraj 《Archives of Agronomy and Soil Science》2017,63(10):1355-1368
The study aimed to evaluate the impact of shifting cultivation on soil quality, in Wokha district of Nagaland, using weighted soil quality index (SQIw). Four forest sites and three sites under shifting cultivation were selected and physical (texture and bulk density) and chemical (pH, electrical conductivity, cation exchange capacity, organic carbon, available N, P, K, exchangeable cations) parameters were analyzed. The SQIw was calculated on a minimum data set selected by principal component analysis, followed by varimax rotation algorithm and through subsequent normalization of the parameters using the linear scoring function. Significant (P < 0.05) variations in SQIw were found across the depth of the soil and land use according to severity of factors associated with land use. Three different classes of soil quality were also identified: high quality (SQIw > 0.70) for two forest soils (FS1 and FS2) and land under shifting cultivation (JH1), low quality (SQIw < 0.50), only to FS3, and intermediate quality (0.50 < SQI < 0.70) in all other soils. The approach used in this study proved to be sensitive to evaluate the soil quality, however further research is required to better understand the sustainability of shifting cultivation by including more physical, biological and chemical indicators. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(5):495-500
Abstract Regression equations for the relationship between Walkley‐Black carbon and carbon by dry combustion in a tropical humic brown clay soil were variable in four different vegetation regimes. In one case, statistically different correlation coefficients were obtained for grassland surface and the corresponding subsurface soils. Calibration of the Walkley‐Black method against dry combustion carbon is recommended for each treatment in soil fertility studies as soil organic matter might have a different composition and hence carbon recovery value because of treatment. 相似文献
7.
To evaluate soil erodibility under different land uses and to study the applicability of nomograph for estimation of soil erodibility a field experiment was conducted under both natural and simulated rainfall conditions under four land uses viz. barren, cultivated, grassland, and forest in the sub‐mountainous tract of Punjab (India). Measured soil erodibility (K) values varied from 0·33 to 0·67 under natural rainfall conditions and from 0·23 to 0·40 under simulated rainfall conditions. Among different land uses, measured K was in the order of barren > cultivated > grassland > forest soils. The values of the K estimated by nomograph were very low as compared to the observed values. The trends were also in contrast to these observed values of K under simulated and natural rainfall conditions. To modify nomograph equation, different ranges of aggregate sizes were correlated with soil loss. It was observed that water stable aggregates (WSA) <2 mm size had a significant correlation with soil loss under both natural (r = 0·88) and simulated (r = 0·76) rainfall conditions. So the nomograph equation was modified to include the M parameter based on WSA <2 mm size. The value of K estimated from the modified nomograph had a significant correlation with measured values of K under both the natural and simulated rainfall conditions. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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森林和草地是陆地生态系统的重要组成部分,研究整合基于涡度相关法观测碳通量的已发表文献,共选取东亚地区40个拥有1年以上数据的通量站(森林26个,草地14个),分析碳利用效率(CUE)以及净生态系统生产力(NEP)、总生态系统生产力(GEP)、生态系统呼吸(RE)的空间变异特征及其影响因素。东亚地区的森林和草地为碳汇,且森林的碳汇显著高于草地(p0.001),其NEP分别为328.64±256.46gC/(m~2·a),63.43±42.99gC/(m~2·a)。森林和草地的CUE分别为0.21,0.20,影响森林CUE变化的因素主要是林龄,呈线性负相关关系(p0.001)。影响草地CUE的因素主要是年均降水量(MAP),呈线性负相关关系(p0.05)。森林和草地的GEP,RE均是随纬度的升高而线性降低,NEP与纬度呈现二次函数关系,随纬度升高而先升高后降低。森林和草地的GEP,RE都与MAP呈线性正相关关系,且NEP与MAP呈先升高后降低的二次函数关系,其中森林和草地的饱和降水量大约为1 300mm和390mm。森林的GEP,RE与年均温(MAT)呈现线性正相关关系。森林和草地的GEP,RE与增强型植被指数(EVI)呈线性正相关关系。 相似文献
10.
The proportional differences in soil organic carbon (SOC) and its fractions under different land uses are of significance for understanding the process of aggregation and soil carbon sequestration mechanisms. A study was conducted in a mixed vegetation cover watershed with forest, grass, cultivated and eroded lands in the degraded Shiwaliks of the lower Himalayas to assess land‐use effects on profile SOC distribution and storage and to quantify the SOC fractions in water‐stable aggregates (WSA) and bulk soils. The soil samples were collected from eroded, cultivated, forest and grassland soils for the analysis of SOC fractions and aggregate stability. The SOC in eroded surface soils was lower than in less disturbed grassland, cultivated and forest soils. The surface and subsurface soils of grassland and forest lands differentially contributed to the total profile carbon stock. The SOC stock in the 1.05‐m soil profile was highest (83.5 Mg ha−1) under forest and lowest (55.6 Mg ha−1) in eroded lands. The SOC stock in the surface (0–15 cm) soil constituted 6.95, 27.6, 27 and 42.4 per cent of the total stock in the 1.05‐m profile of eroded, cultivated, forest and grassland soils, respectively. The forest soils were found to sequester 22.4 Mg ha−1 more SOC than the cultivated soils as measured in the 1.05‐m soil profiles. The differences in aggregate SOC content among the land uses were more conspicuous in bigger water‐stable macro‐aggregates (WSA > 2 mm) than in water‐stable micro‐aggregates (WSA < 0.25 mm). The SOC in micro‐aggregates (WSA < 0.25 mm) was found to be less vulnerable to changes in land use. The hot water soluble and labile carbon fractions were higher in the bulk soils of grasslands than in the individual aggregates, whereas particulate organic carbon was higher in the aggregates than in bulk soils. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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Soil management systems can have great effect on soil chemical, physical and biological properties. Conversion of forest to grassland and cropland can alter C and N dynamics. The objective of this study was to evaluate the changes in aggregate‐associated and labile soil organic C and N fractions after conversion of a natural forest to grassland and cropland in northern Turkey. This experiment was conducted on plots subject to three different adjacent land uses (forest, grassland and cropland). Soil samples were taken from 0–5, 5–15 and 15–30 cm depths from each land use. Some soil physical (soil texture, bulk density), chemical (soil pH, soil organic matter, lime content, total organic C and N, inorganic N, free and protected organic C) and biological (microbial biomass C and N, mineralizable C and N) properties were measured. The highest and lowest bulk densities were observed in grassland (1.41 g cm−3) and cropland (1.14 g cm−3), respectively. Microbial biomass C and total organic C in forest were almost twice greater than grassland and four‐times greater than cropland. Cultivation of forest reduced total organic N, mineralizable N and microbial biomass N by half. The great portion of organic C was stored in macroaggregates (>250 µm) in all the three land uses. Free organic C comprised smaller portion of soil organic C in all the three land uses. Thus, this study indicated that long‐term conversion of forest to grassland and cropland significantly decreased microbial biomass C, mineralizable C and physically protected organic C and the decreases were the greatest in cropland. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
12.
Hilary Ford John R. Healey Bid Webb Tim F. Pagella Andrew R. Smith 《Soil Use and Management》2019,35(4):576-584
Hedgerows have the potential to influence ecosystem function in livestock‐grazed pasture. Despite this, they are often ignored when quantifying farmland ecosystem service delivery. In this study, we assess the contribution of hedgerows to the ecosystem function of carbon (C) storage, with a particular emphasis on soil organic carbon (SOC). We measured SOC stock (kg C m?2), on an equivalent soil mass basis, at 0–0.15 m depth in pasture adjacent to 38 hedgerows (biotic) and 16 stone walls or fences (abiotic controls) across ten farms in the county of Conwy, Wales, UK. Pasture SOC stock (~7 kg C m?2) was similar adjacent to biotic and abiotic field boundaries, positively associated with soil moisture and negatively with soil bulk density (BD). For biotic boundaries, two further variables were significantly associated with SOC stock, distance from hedgerow (decrease in SOC stock) and slope orientation (upslope SOC stock greater than downslope). For pasture adjacent to hedgerows, a model combining the aforementioned variables (BD, soil moisture, distance from hedgerow, slope orientation) explained 78% of variation in SOC stock. This study demonstrates that whilst hedgerows do have subtle positive effects on SOC stock in adjacent pasture, SOC storage adjacent to field boundaries is influenced more by soil moisture content and BD than field boundary type. 相似文献
13.
浅析我国设施农业发展的若干问题 总被引：13，自引：0，他引：13
设施农业是运用现代工业技术成果和方法为农产品生产提供可以人为进行控制和调节的环境和条件,使植物和动物处于最佳的生长状态,使光、热、水、土地、气等资源得到最充分的利用形成农产品的工业化生产和全年生产,从而更加有效地保证农产品的发展供应,提高农产品质量、生产规模和经济效益,促进农业现代化. 相似文献
14.
不同水土保持耕作措施对径流泥沙与土壤碳库的影响 总被引：4，自引：3，他引：1
为了研究南方红壤坡地不同水土保持耕作措施的蓄水保土和固碳减排效应,通过江西省水土保持生态科技园5a的定位观测资料,对3种耕作措施（横坡间作,纵坡间作和果园清耕）条件下坡面产流产沙及土壤碳库的变化进行了分析。结果表明：（1）与裸露对照相比,3种耕作措施均具有一定的蓄水减流和保土减沙效应,其减流率在21.16%～75.32%,减沙率在38.08%～80.57%,红壤坡地不同耕作措施的蓄水保土效应从优至劣排序为：横坡间作〉纵坡间作〉果园清耕;（2）与裸露对照相比,3种耕作措施均具有提高土壤有机碳质量分数和增加土壤碳库的作用,其表层土壤总有机碳质量分数增加幅度为37.24%～66.34%,土壤碳储量增加幅度为35.23%～55.34%,红壤坡地各项耕作措施实施5a后的表层土壤碳库指数和土壤碳储量大小排序均为：纵坡间作〉横坡间作〉果园清耕;（3）间作措施的蓄水保土和固碳减排效益优于清耕措施,适宜在红壤坡地推广。 相似文献
15.
不同松栎混交林土壤溶解性有机碳氮的差异分析 总被引：1，自引：0，他引：1
为揭示北亚热带地区不同林分类型的土壤活性碳氮分布特征,在驻马店市南部山区选取4处具有代表性的松栎人工混交林为研究对象,对其0-20 cm土壤的溶解性有机碳（DOC）,溶解性有机氮（DON）等组分进行研究。结果表明:4种林型土壤DOC的含量为麻栎纯林 > 湿地松麻栎混交林 > 火炬松麻栎混交林 > 马尾松麻栎混交林,DON的含量为马尾松麻栎混交林 > 麻栎纯林 > 湿地松麻栎混交林 > 火炬松麻栎混交林,不同林分类型间整体上差异性显著（p<0.05）;在垂直剖面上,4种林型土壤DOC和DON均随土层深度的增加而显著性下降（p<0.05）。4种林分类型DOC/SOC,DON/TN,DOC/DON分别以麻栎纯林、马尾松麻栎混交林、麻栎纯林最高,在垂直空间分布上,差异性整体上不显著。土壤DOC和DON与土壤含水率、土壤硬度、速效钾、全氮均呈显著（p<0.05）或极显著（p<0.01）相关性。 相似文献
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Farmers in Ghana use a variety of soil‐fertility management practices to optimize the benefits of shifting cultivation and/or to intensify their production. The research question was to analyze the relationship between these practices and the availability of the production factors land, labor, and capital. A farm survey along a gradient through SW Ghana showed that there is only a weak link between the intensification of traditional farming systems, population pressure, and reduced fallow periods as long as shifting cultivation is possible and common. Even where fallow periods reach a cut‐off point, farmers might look for land in remoter areas or invest in off‐farm activities. Only where market proximity supports the production of high‐value crops, investment flows are used to maintain continuous cultivation on favorable production sites, especially those with water access. The results verify the validity of the framework of agricultural‐systems dynamics in W Africa, developed by the International Institute of Tropical Agriculture (IITA) and the importance to distinguish between population‐driven and market‐driven situations. Both meet in periurban areas, which make them hot spots for research and development, while support for intensification is likely to fail where markets are far and shifting cultivation still an option. 相似文献
17.
亚热带2种针叶林土壤碳氮磷储量及化学计量比对混交的响应 总被引：3，自引：0，他引：3
针叶林混交阔叶树是改善土壤肥力、增强林地养分循环的重要措施,而混交效应受到针叶树种自身特性的影响,马尾松(Pinus massoniana)和湿地松(P.elliottii)是亚热带地区广泛种植的针叶树种,但目前2种针叶林对阔叶树混交的响应特征还不清楚。选取马尾松、湿地松纯林以及木荷(Schima superba)补植后形成的马尾松—木荷和湿地松—木荷混交林为研究对象,采集剖面土壤样品,测定土壤容重、有机碳(OC)、全氮(TN)和全磷(TP)含量,计算碳氮磷储量及化学计量特征,比较不同森林类型间的异同。混交阔叶树显著增加了马尾松林0—60cm各土层OC含量,而湿地松纯林与其混交林间OC含量无显著差异。同时,混交增加了2种针叶林土壤TN含量。马尾松林混交后0—60cm土层碳储量显著增加95.8%,而混交阔叶树对湿地松林土壤碳储量无显著影响。混交阔叶树后马尾松和湿地松林0—60cm土壤总氮储量分别增加了15.8%和28.4%,但混交对土壤磷储量无显著影响。混交显著增加了马尾松林0—40cm各土层C/N,而降低了湿地松林0—10cm土层C/N。混交阔叶树后马尾松林0—20cm土层C/P和0—10cm土层N/P显著增加,而混交仅增加湿地林0—10cm土层N/P。混交阔叶树增加了针叶林土壤氮储量,但对磷储量无显著影响,同时混交改变了土壤碳氮磷生态化学计量特征。与湿地松林相比,马尾松林土壤养分含量、储量及其化学计量特征对混交的响应更敏感。 相似文献
18.
《Land Degradation u0026amp; Development》2017,28(5):1626-1640
Development of rural areas needs information about sustainable use of the land. The main objective of this research is to study the spatial distribution pattern of different field types in the traditional agricultural landscape in the Central Spanish Pyrenees (flat fields, four different terrace fields, sloping field and shifting agriculture) related to different geoecological variables: slope, exposition, altitude, distance to the villages, rainfall (intensity and volume), lithology and demographic pressure. Agricultural land patterns were mapped in five valleys in the Central Pyrenees from aerial photographs (1957). These maps were digitised and implemented in a Geographic Information System on a scale 1:50,000. We determined the influence of different geoecological variables in the spatial distribution of land agricultural patterns at local and regional valley using statistical analysis. The results showed that the agricultural area occupied a large extension, despite physical environment limitations, extending even in marginal slopes, with little agricultural skills, creating a complex landscape with different field patterns. At the local scale (valley), slope and distance are the more influence variables to explain the spatial distribution of the different field types. At the regional scale, in the Western valleys, sloping fields and shifting agriculture predominate, while terraces dominate in the Eastern valleys. Distance to the village and rainfall intensity is the more determinant factors in the spatial distribution. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
19.
Koosha Parsamehr Mehdi Gholamalifard Yahya Kooch Hossein Azadi Jürgen Scheffran 《Land Degradation u0026amp; Development》2023,34(10):2763-2779
Reducing emissions from deforestation and forest degradation (REDD+) is way key to reduce the emission of greenhouse gases (GHGs) while also protecting vulnerable forest ecosystems. The purpose of this study was to recognize suitable areas for REDD+ Programme projects and calculate the reduction in CO2 emissions through the prevention of forest cover degradation in the Central Hyrcanian forests. For this purpose, the cover changes of the Central Hyrcanian forests were assessed using LANDSAT satellite images. Applying the voluntary carbon standard (VCS) methodology and the calibration period 1984–2014 (30 years), forest cover changes were predicted. The results showed that under the business-as-usual scenario, 155,698 ha of Central Hyrcanian forests will be declined by 2044. In general, the REDD+ Programme project implementation will prevent the release of 1,209,231 tCO2e. Based on the social cost of carbon (SCC) approach, the REDD+ Programme project implementation can save 12,092,310 US$. In addition, this approach can be used for the project design document (PDD) of the forest development mechanism. 相似文献