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1.
中国滇池流域土地利用方式对土壤侵蚀和养分状况的影响   总被引:2,自引:0,他引:2  
Soil erosion and loss of soil nutrients have been a crucial environment threat in Southwest China. The land use and its impact on soil qualities continue to be highlighted. The present study was conducted to compare soil erosion under four land use types(i.e.,forestland, abandoned farmland, tillage, and grassland) and their effects on soil organic carbon(SOC), total nitrogen(TN) and total phosphorus(TP) in the Shuanglong catchment of the Dianchi Lake watershed, China. There were large variations in the erosion rate and the nutrient distributions across the four land use types. The erosion rates estimated by137 Cs averaged 2 133 t km-2year-1under tillage and abandoned farmland over the erosion rate of non-cultivated sites, and the grasslands showed a net deposition. For all sites, the nutrient contents basically decreased with the soil depth. Compared with tillage and abandoned farmland, grassland had the highest SOC and TN contents within 0–40 cm soil layer, followed by forestland. The significant correlations between137 Cs, SOC and TN were observed. The nutrient loss caused by erosion in tillage was the highest. These results suggested that grassland and forestland would be beneficial for SOC and TN sequestration over a long-term period because of their ability to reduce the loss of nutrients by soil erosion. Our study demonstrated that reduction of nutrient loss in the red soil area could be made through well-managed vegetation restoration measures.  相似文献   

2.
This paper introduces and illustrates the concepts of geoecological process combinations and geographical or landscape dimensions by outlining the methodology of a Sino-German cooperative project in Southeast China and presents the first results of the modelling process for the catchment scale. The project equipped a catchment in subtropical Southeast China from plot scale to catchment scale in order to study the hydrological and soil erosion processes. Distinct spatial differences in principal water and soil material fluxes were quantified. Deep drainage peaks occurred in May, June and July and even in August and November. Measurements in erosion plots as well as sedimentary deposits revealed that there was soil erosion connected with overland flow. Consistent with the results from the regular catenary variations of soil colors, textural stratification and hydrograph analysis, there was also a clear indication of interflow from measured soil moisture data. The experimental set up has the potential to further deepen the understanding of small-scale processes involved in lateral water fluxes and soil erosion. The expected results and interpretations will lead to a further integration of the collected data. In the future, to understand matter transfer in and between landscape ecological units, agricultural influence on nutrient status and flux data will be incorporated.  相似文献   

3.
The Wangdonggou Watershed on the Loess Plateau in China was selected as the study area to develop a model for soil erosion assessments. Using the data collected at 20 sampling sites all tentatively selected indicators were assessed against their corresponding erosion intensity through a correlation analysis. Eight highly correlated indicators were then chosen for the soil erosion assessment. In addition, threshold limits to delineate the class size for these indicators and weights to rank them were determined. Next, a grading model incorporating the selected indicators class rating and their associated weights was developed and verified by an on site evaluation of the soil erosion intensity in the study area. Results of the verification showed that the overall accuracy of the indicator system for assessing soil erosion in the Loess Plateau gully regions could reach 85%.  相似文献   

4.
天然载体控释氮肥研究初探   总被引:2,自引:0,他引:2  
The Wangdonggou Watershed on the Loess Plateau in China was selected as the study area to develop a model for soil erosion assessments. Using the data collected at 20 sampling sites all tentatively selected indicators were assessed against their corresponding erosion intensity through a correlation analysis. Eight highly correlated indicators were then chosen for the soil erosion assessment. In addition, threshold limits to delineate the class size for these indicators and weights to rank them were determined. Next, a grading model incorporating the selected indicators class rating and their associated weights was developed and verified by an on site evaluation of the soil erosion intensity in the study area. Results of the verification showed that the overall accuracy of the indicator system for assessing soil erosion in the Loess Plateau gully regions could reach 85%.  相似文献   

5.
Soil erosion gradation is a robust and objective quantitative indicator of soil erosion intensity. Recent applications of soil erosion gradation have focused on monitoring soil erosion with models or simulation of soil erosion through gradation trends. However, soil erosion simulation accuracy is generally being reduced due to the rare consideration of the relationship between soil erosion gradation and erosion evolution. In this study, we investigated different soil erosion intensity grades to demonstrate their sensitivity to types and rates of erosion. Specifically, the objective was to define the relationship between soil erosion gradation and soil erosion evolution in Changting, an undeveloped area in Fujian Province, China, for four time intervals (1975, 1990, 1999, and 2006). The time series of erosion gradation were developed by modeling analysis with integration of several erosion indicators, and the relationships between the erosion grades and evolution types and rates were quantified. Comparison of the collapsing forces with natural and restoring forces based on human activity demonstrated that there existed an obvious spatial uncertainty in the erosion evolution types, both positive and negative succession coexisted, and the evolution rates were mostly influenced by the force of policy orientation. The impacts of these driving forces were eventually reflected in the erosion intensity gradation and erosion evolution. The correlation between the negative succession rate and erosion intensity gradation was weak and showed a poor contribution to the average succession rate, while the negative correlation between the positive succession rate and erosion intensity gradation would be increasingly clear as time passed.  相似文献   

6.
印度热带森林干旱扰动土壤的微生物碳, 氮, 磷的研究   总被引:1,自引:0,他引:1  
Variations in microbial biomass C (MB-C),N (MB-N) and P (MB-P) along a gradient of different dominant vegeta- tion covers (natural forest,mixed deciduous forest,disturbed savanna and grassland ecosystems) in dry tropical soils of Vindhyan Plateau,India were studied from January 2005 to December 2005.The water holding capacity,organic C,total N,total P and soil moisture content were comparatively higher in forest soils than in the savanna and grassland sites.Across different study sites the mean annual MB-C,MB-N and MB-P at 0-15 cm soil depth varied from 312.05 ± 4.22 to 653.40 ± 3.17,32.16 ± 6.25 to 75.66 ± 7.21 and 18.94 ± 2.94 to 30.83 ± 23.08 μg g ?1 dry soil,respectively.At all the investigated sites,the maximum MB-C,MB-N and MB-P occurred during the dry period (summer season) and the minimum in wet period (rainy season).In the present study,soil MB-C,MB-N and MB-P were higher at the forest sites compared to savanna and grassland sites.The differences in MB-C,MB-N and MB-P were significant (P 0.001) among sites and seasons.The MB-C (P 0.0001),MB-N (P 0.001) and MB-P (P 0.0001) were positively correlated with organic C,while the relationship between soil moisture and MB-C,MB-N and MB-P (P 0.001,P 0.01 and P 0.0001,respectively) was negative.The decreasing order of MB-C,MB-N and MB-P along study ecosystems was natural forest mixed deciduous forest savanna grassland.The results suggested that deforestation and land use practices (conversion of forest into savanna and grassland) caused the alterations in soil properties,which as a consequence,led to reduction in soil nutrients and MB-C,MB-N and MB-P in the soil of disturbed sites (grassland and savanna) compared to undisturbed forest ecosystems.  相似文献   

7.
Evaluation of soil erosion in agricultural fields is valuable to develop conservation practices for reducing agricultural nonpoint source pollution.Soil erosion rates were quantified using the fallout radionuclide tracer technique in Mojiagou Basin located on the outskirts of Changchun in Northeast China.The calculated soil erosion rates in the study area were 1.99 and 1.85 mm year-1 using 137Cs and excess 210Pb(210Pbex)measurements,respectively.Both fallout radionuclides showed a similar tendency at downslope sites.All measured sites have experienced net erosion during the past 50 to 100 years.137Cs and 210Pbex measurements were useful to quantify soil erosion rates on field and small basin scales.At this rate of erosion,the current fertile topsoil layer would be entirely removed within 70 years.  相似文献   

8.
树的年轮和土壤中元素含量的长期分布情况   总被引:19,自引:0,他引:19  
Soil erosion accelerates soil degradation. Some natural soils and cultivated soils on sloping land in southern Jiangsu Province, China were chosen to study soil degradation associated with erosion. Soil erosion intensity was investigated using the ^137Cs tracer method. Soil particle-size distribution, soil organic matter (OM), total nitrogen (TN) and total phosphorus (TP) were measured, and the effects of erosion on soil physical and chemical properties were analyzed statistically using SYSTAT8.0. Results indicated that erosion intensity of cultivated soils was greater than that of the natural soils, suggesting that cultivation increased soil loss. Erosion also led to an increase of coarser soil particle proportion, especially in natural soils. In addition, silt was the primary soil particle lost due to erosion. However, in cultivated fields, coarser soil particles over time were attributed not only to soil erosion but also to mechanical eluviation as a result of farming activities. Moreover, erosion caused a decrease in soil OM, TN and TP as well as thinning of the soil layer.  相似文献   

9.
中国东南部红壤地区不同植被对土壤侵蚀和土壤养分的影响   总被引:31,自引:0,他引:31  
The effect of different vegetation systems including bamboo plantation (BP), forest ecosystem (CF), citrus orchard (Ctr) and farmland (FL) on erosion and nutrients of red soil were investigated in hilly region of southeastern China to find effective control measures for soil erosion. The results showed that all the vegetation systems could significantly reduce soil erosion and nutrient losses compared to bare land (Br). The ability of different vegetation systems to conserve soil and water was in the order of Ctr > BP > CF > FL > Br. Vegetation could also improve soil fertility. The soil organic matter, total N and total P contents were much higher in all the vegetation systems than in bare land, especially for the top soils. Vegetation systems improved soil physical properties remarkably. Compared to the bare land, soil organic matter, TP, TK and available K, especially soil microbial biomass C, N and P, increased under all the vegetation covers. However, they were still much lower than expected, thus these biological measurements are still needed to be carried out continuously.  相似文献   

10.
运用红边参数估算叶片叶绿素含量   总被引:4,自引:0,他引:4  
Soil samples collected from several sites along an altitudinal transect on the eastern slope of the Tibetan Plateau were analyzed for hexachlorobenzenes(HCHs) and dichlorodiphenyltrichloroethanes(DDTs).The results showed that HCHs and DDTs were found in the soil samples from the remote high altitude areas away from source regions,which confirmed the long-range atmospheric transport phenomenon of these organochlorine pesticides(OCPs) insecticides.The OCP concentrations in the soils had a significant negative correlation with altitude;they showed a trend to increase with decreasing altitude,but the increase was not continuous,being interrupted at some moderate-altitude sites on the transect.The distances from the source region,landforms,soil properties,and physical-chemical properties of OCPs were more important than total organic carbon content to the distribution of OCPs in soils disturbed by human activities.An analysis of the compositions of HCH isomers and DDTs revealed predominantly low ratios of α-HCH to γ-HCH,ranging from 0.06 to 4.79,which suggested current lindane inputs.On the other hand,low p,p-DDT/p,p-DDE and o,p-DDT/p,p-DDT ratios were observed,indicating mainly aged historical DDT residues in the study area.  相似文献   

11.
结合森林资源二类调查,以立地因子为依据,运用数量化回归方法,建立一系列方程,对广西林朵林场的林地进行杉木立地类型的划分和立地质量评价研究.结果表明:海拔、坡向、坡位和土层厚度是影响杉木生长的主导因子。所建立的方程具有较高的评价精度,可根据具体情况及对精度要求,选用适当方程.  相似文献   

12.
大庆盐碱地立地质量评价   总被引:6,自引:0,他引:6       下载免费PDF全文
根据盐碱地土壤性质与植物的生态关系,调查分析植物群落种类、生物量与土壤理化性质(pH值、有机质、水解氮、有效磷、速效钾、阳离子交换量、交换性钠和水溶性总盐含量)之间的相互关系。利用多元统计分析的因子分析和聚类分析方法,以盐碱地土壤理化性质为分类依据,以地上草本植物群落生物量为验证标准,进行立地分类和立地质量评价,将大庆市盐碱地分为高生物量轻度盐碱地、高生物量中度盐碱地、中生物量中度盐碱地、低生物量中度盐碱地和重度盐碱地5种立地类型。研究结果可为恢复植被,提高土地资源生产力提供科学参考。  相似文献   

13.
北京山区河岸植被恢复立地类型划分   总被引:1,自引:1,他引:0  
[目的]对北京山区不同立地条件下的河岸带进行立地类型分类,为山区河岸带的植被恢复工作提供理论依据。[方法]以北京市怀柔区怀九河河岸60个80m长的样地为基础,进行野外实地观测调查,并确定了土壤层厚度、坡面组成物质、坡度、硬化面积、坡长5个因子为河岸立地类型划分的主导因子。[结果](1)怀九河河岸带的立地类型可划分为3个立地类型区,9个立地类型组,15个立地类型。(2)加杨、旱柳、荆条、胡枝子等作为适宜当地生长的优势植物种,在进行植被恢复时可结合其它适生物种进行合理的配置。[结论]北京山区河岸带多以短坡薄土层为主,边坡坡面砾石裸露严重,表现为严重的人为干扰,应加快河岸边坡生态环境安全建设。  相似文献   

14.
水土保持监测点是全国水土保持监测网络的重要组成部分,是全国水土保持监测网络和信息系统二期工程建设的一项重要内容,同时也是整个监测网络和信息系统建设的基础,关系到能否及时准确地获取信息的重要工作.科学的选址、合理的规划、标准化的建设是开展本项工作的基础,只有在这些基础工作完善、科学合理的选址布设的基础上,才能研发监测点的设施设备以及监测管理手段,搞好数据化处理与传输和信息化建设,为发挥整个水土保持监测点的作用提供有效的监测作用.从水土保持监测点建设的作用和几个约束条件探讨入手进行了简要探索,仅供参考.  相似文献   

15.
贵州陡坡退耕地立地分类系统研究   总被引:8,自引:2,他引:8  
按逐级控制、逐级分类、全覆盖及主导因子原则,将贵州省陡坡退耕地以大地貌及气候条件分6个类型区,以岩组性质分5个类型小区,以坡度等为2个类型组。在非可溶岩分布区按土层厚度分3个类型,喀斯特地区按土被连续性分4个类型。共形成30个常态地貌区的类型组合及喀斯特地貌区的8个类型组合。为贵州陡坡退耕地水土保持工程建设提供规划依据。  相似文献   

16.
国内立地质量评价研究浅析   总被引:10,自引:0,他引:10  
立地是林木生长的基础,立地质量评价是适地适树、合理高效用地、改善生态环境的重要保证。该论文通过对国内外大量文献资料的综合分析,介绍并评价了国内目前立地质量评价研究的主要内容、途径和方法,并提出了未来立地质量评价研究的发展趋势。  相似文献   

17.
采用野外人工模拟降雨试验方法,对神府东胜煤田开发建设中原生和扰动地面的产流、产沙规律进行了研究。结果表明,扰动地面径流起始时间是原生地面的1.8~11.7倍,径流率比原生地面小5%~54.4%;初始径流含沙量是原生地面的1.1~5.8倍,径流含沙量是原生地面的1.2~6.3倍,产沙量是原生地面的2~12.7倍。由于扰动地面质地疏松,孔隙度大,入渗率大,与原生地面相比,一般在强降水条件下才产流并发生侵蚀。扰动地面临界抗剪力较小,侵蚀一旦发生,在相同降水条件下,更易发生侵蚀,且其侵蚀强度更大。通过回归分析,得出两种下垫面产沙量与水流剪切力呈线性相关。  相似文献   

18.
论文以稻作梯田农业文化遗产地——广西龙脊平安寨为个案,采用田野调查、调查问卷和统计分析方法,通过测算案例地居民对社会文化变化的态度值,探讨了农业文化遗产地类型旅游地居民对旅游开发引起的社会文化变化的感知及其对旅游发展的影响。结果表明,旅游开发使农业文化遗产地的社会文化发生较大变化,且总体上呈正向发展。不同特征居民对社会文化的态度存在差异,但总体上对变化持积极态度。家庭收入、旅游移民、社会治安、建筑服饰等文化因素的变化将直接影响居民对当地未来旅游发展的态度。只要能正确引导、调控和疏导其变化方向,旅游地社会文化变化的负面影响可以减少乃至消除,并促进旅游地更好的发展。论文还针对遗产旅游地的社会文化负面影响,提出了针对各级政府管理部门及专业机构、旅游企业及投资商、旅游者和当地居民的社会文化影响调控建议。  相似文献   

19.
Preventing the off‐site effects of soil erosion is an essential part of good catchment management. Most efforts are in the form of on‐site soil and water conservation measures. However, sediment trapping can be an alternative (additional) measure to prevent the negative off‐site effects of soil erosion. Therefore, not all efforts should focus solely on on‐site soil conservation but also on the safe routing of sediment‐laden flows and on creating sites and conditions where sediment can be trapped. Sediment trapping can be applied on‐site and off‐site and involves both vegetative and structural measures. This paper provides an extensive review of scientific journal articles, case studies and other reports that have assessed soil conservation efforts and the sediment trapping efficacy (STE) of vegetative and structural measures. The review is further illustrated through participatory field observation and stakeholders' interview. Vegetation type and integration of two or more measures are important factors influencing STE. In this review, the STE of most measures was evaluated either individually or in such combinations. In real landscape situations, it is not only important to select the most efficient erosion control measures but also to determine their optimum location in the catchment. Hence, there is a need for research that shows a more integrated determination of STE at catchment scale. If integrated measures are implemented at the most appropriate spatial locations within a catchment where they can disconnect landscape units from each other, they will decrease runoff velocity and sediment transport and, subsequently, reduce downstream flooding and sedimentation problems. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

20.
本文通过对11个草本(丝茅、黄茅)生物量样方的测定表明:丝茅生物量为14.26t/ha,黄茅生物量为9.16t/ha。并应用数量化理论的方法,建立了草本生物量的预测方程。  相似文献   

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