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1.
对轻、中、强等不同侵蚀程度和长期封禁的林地芒箕生长和土壤微生物区系进行调查分析的结果表明：芒箕的盖度、密度、高生长、生物量等都随着侵蚀程度的加重而呈下降趋势,长期封禁林地的芒箕生长最好,盖度达96％,密度为452株／m^2,平均高86cm,生物量10577kg／hm^2,较轻度、中度、强度侵蚀地增加了0．5—2．3、1．4～7．1、0．8～2．0、2．3～7．4倍,强度侵蚀地芒箕生长差,盖度仅29％,密度56株／m^2,平均高18cm。生物量为1256kg／hm^2。土壤侵蚀程度增加,芒箕地上部分生物量比例降低,根量和根冠比增大,土壤微生物数量减少。侵蚀地土壤细菌占43．0％-45．6％,真菌28．3％-35．2％,放线菌21．0％-26．4％,氨化、亚硝化、硝化细菌少,有一定数量的纤维分解菌和磷细菌,好气性自生固氮菌多。不同侵蚀土壤中的微生物组成和数量的变化与相应林地的芒箕生长变化趋势一致。 相似文献
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中国荒漠化评价指标体系 总被引：9，自引：0，他引：9
根据《联合国防治荒漠化公约》对于荒漠化所作的定义 ,该文首先介绍了中国荒漠化现状 ;其次介绍了中国荒漠化评价指标体系 ,其中包括 :(1)荒漠化气候区划 ;(2 )中国土地利用类型划分 ;(3)中国荒漠化成因类型 ;(4)荒漠化程度分级指标 ,其中包括风蚀、水蚀、土壤次生盐渍化以及草原退化 ;最后 ,从理论及经济可行性观点出发 ,详细讨论并列出了可用于荒漠化评价的相关指标 相似文献
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遥感数据分析林区的植被和土壤侵蚀特征 总被引：2，自引：0，他引：2
以大兴安岭根河林业局潮查林场为试验区,选择合适时间和空间分辨率的卫星遥感TM数据,从中提取植被类型等有关特征及其空间分布等信息,并将有关的信息转化为通用水土流失方程(USLE)中的地面覆盖因子,计算试验区的土壤侵蚀量,进行侵蚀强度区分,生成土壤侵蚀强度图.结果表明:试验区的水土流失主要受坡度的影响.土壤侵蚀强度图与林相图进行空间叠加分析,获得土壤侵蚀严重的小班分布,从而为试验区的水土保持和流域管理提供依据. 相似文献
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对半干旱黄土丘陵沟壑区不同植被类型径流、侵蚀效应进行长期观测.研究结果表明:不同植被产流和侵蚀次数效应为:坡耕地＞牧草地＞乔木林地＞天然草地＞灌木林地;不同植被类型之间径流量和侵蚀量差异较大,其大小次序为:坡耕地＞牧草地＞乔木林地＞天然草地＞灌木林地;灌木林地的减流率和减沙率均在较高的水平,具有良好的水土保持效应;天然草地由于其独特的功能,水土保持效应较好;乔木林地和人工草地除了乔木林地减蚀效应较好外,减流效应较差;坡耕地的累积径流量及侵蚀量最大,而累积减沙率和减流率最低,水土保持效应最差. 相似文献
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GIS支持下滇池流域生态环境敏感性评价 总被引：2，自引：1，他引：2
针对滇池流域存在的主要生态环境问题,选取坡度、地形起伏度、土地利用类型、土壤侵蚀强度和磷矿污染程度共5类关键性因子作为评价指标,运用GIS技术进行生态敏感性综合评价.结果表明,滇池流域生态敏感性在空间分布上呈显著差异性,低敏感区主要分布在昆明市周边西山区、五华区、盘龙区和官渡区及嵩明县部分地区,土地面积约为1062 km2,约占流域总面积的36.39%,土地利用类型多为林地、草地,生态环境较好;滇池湿地生态服务功能不明显,基本符合滇池污染严重的现状,中敏感区土地面积约为1374 km2,约占流域总面积的47.05%;高敏感区的分布主要受到磷矿、采石场等污染源的影响,土地面积约为484 km2,约占流域总面积的16.56%. 相似文献
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P. R. Bird D. Bicknell P. A. Bulman S. J. A. Burke J. F. Leys J. N. Parker F. J. Van Der Sommen P. Voller 《Agroforestry Systems》1992,20(1-2):59-86
The purpose of this review is to examine the current knowledge of the role of trees in providing shelter for pastures, crops, and livestock, for controlling erosion of soils and improving productivity and sustainability of agricultural production in Australia — and the extent to which this knowledge has been applied.Land degradation — tree loss and associated soil salinity, water and wind erosion, soil acidification, soil structural decline and nutrient degradation — is evidence that our primary production systems are not sustainable. We have sought increased production without proper consideration of the ecological context of that system. About half of Victoria's crop and pasture lands are affected or at risk, and in Western Australia about 25% of the cleared agricultural land is wind-eroded and 60% is potentially susceptible, salinity affects 0.43 m ha and half of the divertible surface water is affected by salinity. Similar problems occur in other States. At least 43 m ha or 13% of our rangelands are seriously degraded by wind erosion caused by overgrazing, often coinciding with drought or a run of drier years.Minimum tillage and stubble management for erosion control in cropping has been a major extension and research activity in Australian agriculture. Severe weather, combined with imperfect adoption of appropriate grazing and crop management systems, shows the weakness of complete reliance on these methods of erosion control. An effective system must accommodate the impact of extreme events, which are the most damaging. However, the complementary use of windbreaks to reduce soil erosion is rare, and their establishment has not been promoted, despite the wide-spread adoption of this technology by other countries.In the cropping and higher rainfall grazing areas, the systematic planting of 10% of the land in a net of shelterbelts/timberbelts/clusters could achieve a 50% windspeed reduction; this would substantially improve livestock and pasture production in the short and long-term. Wind erosion could be dramatically reduced and crop production probably increased by the use of windbreaks. Wheat and oat yield at Rutherglen (Victoria), and lupin yield at Esperance (Western Australia), were increased in the sheltered zone by 22% and 47%, and 30%, respectively.In semi-arid and dry temperate areas, planting of 5% of the land to shelter could reduce windspeed by 30–50% and soil loss by up to 80%. This planting would also contribute substantially to achieving other objectives of sustainable agriculture. Agroforestry — particularly timberbelts applications — will be important in the long-term strategy for achieving revegetation. If some of the trees yield a marketable product then the adoption of the system will be more readily achieved.In the arid (pastoral) areas there is an urgent need to promote the ethic that preservation and improvement of the perennial grass and shrub vegetation is critical for the protection of the soil and maintenance of land capability. Control of animal grazing remains the sole means of preventing erosion in much of this zone. While satellite imagery allows us to assess the condition of leasehold lands, we have failed to achieve stocking policies that will halt the degradation of our rangelands. 相似文献
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基于福建安溪官桥生态茶园2017年度自然降雨数据及园区5种铁观音茶树水土流失治理模式的坡面产流、产沙情况的观测数据,系统研究了不同治理模式下铁观音茶树坡面水土流失对引起侵蚀的降雨的响应机制。结果表明:(1)降雨集中于4~8月份,引起侵蚀频次最多的是5~6月份;(2)根据降雨量与最大30 min降雨强度I 30,可以将侵蚀性降雨分为Ⅰ~Ⅴ种类型,其中,Ⅰ雨型的降雨是当地发生频率最多的侵蚀性降雨,雨量最大的Ⅴ雨型平均产流量最大,雨强最大的Ⅳ雨型平均产沙量最大,发生频率较高的Ⅲ雨型产流总量最大,Ⅱ雨型产沙总量最大。(3)5种铁观音茶树水土流失治理模式在不同降雨类型下的水土保持效应不同,其中采取“梯田+自然留草”的治理模式在各雨型条件下的减流率和减沙率均优于其他模式。研究结果对山区茶园水土保持及提升茶产量有重要的参考价值。 相似文献
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Soil erosion by wind is a persistent problem in central Wisconsin. The extent and effectiveness of windbreaks in erosion-prone
areas are unknown. We investigated the potential effectiveness of windbreaks established for soil erosion control in Portage
County, Wisconsin. Our objectives included quantification of their extent and condition, development of a routine method for
field assessment, and compilation of a reference database of windbreak information. We used aerial photographs to identify
the windbreak population, and a two-stage, stratified random sampling technique to obtain samples for field evaluation. Variables
and attributes examined included species, number of gaps, height, width, porosity, spacing, live crown ratio, crown condition,
and a condition rating. Methods included simple photo-interpretation techniques, field measurements, optical scanning techniques,
and data manipulation in geographic information systems. We identified over 2600 windbreaks comprising a total extent of 834
km; only a small proportion of this may offer effective protection at critical periods. Collectively, field windbreaks protect
a very small proportion only of the county‘s agricultural land area from wind erosion. These results imply a need for increased
planting rates, explicit maintenance or renovation of existing barriers, and windbreak designs that are both sustainable and
compatible with current agricultural production efforts.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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全球荒漠化防治现状及发展趋势 总被引：8，自引：2，他引：8
文章在讨论了荒漠化定义的基础上,介绍了全球荒漠的分布状况和因荒漠化引起的经济损失情况,论述了荒漠化的主要危害,并针对干旱地区的不同地类,如旱作农地、灌溉农地、草地、林地分别提出了相应的荒漠化防治对策。 相似文献
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The threshold wind velocity of a number of variables was studied in four different land-use types: farm land, forestland,
wild grassland and a flood plain in the Yongding River sandy land in Beijing. The variables studied were transport of sand,
underlying surface roughness, windblown sediment, wind-sand flow structure, soil mechanical composition and amount of wind
erosion. The following conclusions were drawn: 1) The order of decreasing threshold of wind speed for sand displacement and
surface roughness were forestland, wild grassland, farm land, sparse wild grassland and flood plain. 2) There were significant
differences in sand flux among different ground covers. At a height of 0–20 cm, the height increased while the sediment discharge
percent of sand flux decreased; there were significant differences in the sand flow formation under different land-use types.
3) The mechanical composition of sand particles consisted mainly of silver sand in the flood plain and sparse wild grassland,
and of silver sand, particle silver sand and floury sand in other land-use types. 4) The amounts of wind erosion and sand
sediment were different among different land-use types. Increased vegetation cover and change in farming techniques were suggested
to prevent and control wind erosion of sand and soil.
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Translated from Scientia Silvae Sinicae, 2005, 41(4) [译自: 林业科学, 2005, 41(4)] 相似文献
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[目的]充分发挥海岸带木麻黄林地的生产潜力,为福建木麻黄人工林林分质量精准提升提供理论基础.[方法]基于福建省平潭岛海岸带木麻黄林样地调查和土壤分析,通过文献查阅,结合相关性分析筛选出影响木麻黄树高的主要养分因子,利用主成分分析方法对各样地多种土壤养分指标进行降维综合评价,并用聚类分析对所选样地土壤进行分级,最后结合立... 相似文献
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Agroforestry and its application in amelioration of saline soils in eastern China coastal region 总被引：2，自引：0，他引：2
Some environmental problems, especially soil salinity hinder the regional sustainable development of eastern China coastal region. Salinity mainly comes from tide weave, seawater flooding and seawater intrusion. Over exploitation of groundwater,which is the result of unfitful land use systems, leads to seawater intrusion and salt concentration increase. Agroforestry systems can enrich soil fertility and prevent soil salinization, furthermore help maintain biodiversity and enhance productivity. For the intergrated multiple ecosystems the most critical issue is to select optimum tree species and rationally arrange these plants. The basics of this multiple ecosystem is that different plants will occupy variable ecological niches within an area, both in space and in soil depth.Shelterbelts and trees intercropping with agricultural crops are major types of the multiple ecosystem. Shelterbelts can reduce wind speed and consequently lessen evaporation and erosion of the soil, increase pasture growth by up to 60% on exposed sites, increase crop yields by up to 25%. Besides intercropping with jujube, other agroforestry multiple ecosystem such as forestry plus agriculture,forestry plus agriculture plus fishery, and forestry plus animal husbandry are the most appropriate ways to utilise land resource in this region. 相似文献
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吴起县地处黄土高原北部,毛乌索沙漠南缘的农牧过渡地带,陕西省的西北部位.属于黄土高原梁状丘陵沟壑区,系干旱半干旱气候.由于长期的掠夺式利用森林资源和过度放牧、开垦利用,天然植被消失殆尽,植被群落退化严重,是黄土高原生态环境脆弱和水土流失最严重的县份.退耕还林工程实施后,植被得到迅速恢复,林地面积迅速扩增,环境气候条件得到明显改善.为巩固退耕还林的成果,本文阐述了吴起目前林地资源利用情况,分析了林地利用的特点,剖析了林地利用中存在主要问题,提出了吴起县今后林地保护利用的对策. 相似文献
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Effect of conversion of farmland to forest or grassland on soil erosion intensity changes in Yanhe River Basin, Loess Plateau of China 总被引：2，自引：0，他引：2
Dynamic changes of soil erosion affected by conversion of farmland to forest or grassland in the Yanhe River Basin were analyzed
based on the revised universal soil loss equation (RUSLE). The RUSLE variables were selected and calculated reasonably using
the GIS technique. Results show that: 1) After the conversion of farmland to forest or grassland, soil erosion decreased greatly.
Compared with soil erosion in period of 1986 to 1997, the soil erosion amount had been reduced on the average by 30.6% by
2000; 2) Of the different land uses, slope farmland, especially the steep slope land had the greatest impact on soil erosion.
The conversion of forest or grassland was the main driving force for the reduction of soil erosion; 3) In the short term,
soil erosion was mainly controlled by C-factor, implying that the adjustment of land use structure might be an effective approach to reduce soil erosion.
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Translated from Science of Soil and Water Conversation, 2007, 5(4): 27–33 [译自: 中国水土保持科学] 相似文献
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In Pakistan, particularly in Punjab Province, it is difficult for agrofarmers to combine their indigenous knowledge and modern scientific methods to evaluate existing traditional farming systems and forestry practices. This requires an evaluation of indigenous soil classification in simple terms along with knowledge of the local flora, especially trees. This study focuses on land suitability classification for trees in the Attock District of Punjab, Pakistan. A survey was conducted which included interviews of local agrofarmers as well as standard soil analyses including both chemical and physical determinations of local soil types. An evalu- ation of soil types for cultivation of various crops was carried out given its total extent, component soil series and their proportions, spotting characteristics of each soil series and their major limitations/hazards for trees/crops. These would lead to the identification of various tree species according to soil characteristics. Then, according to the soil types and species, a land suitability map was obtained for the choice of tree species by using geographic information system (GIS) software. Land suitability classification will help local agroforesters/agrofarmers in matching suitable agricultural trees/crops properly for different soils in the area. 相似文献
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The beneficial effect of organic matter on soil aggregate stability is well documented. Alley cropping has been suggested as a possible alternative to maintain soil organic matter content in cropping systems without fallowing the land. The objective of this study was to asses the effect of alley cropping on dry and wet soil aggregate stability on land degraded by shifting cultivation. The aggregate size distribution by dry sieving, aggregate stability by wet sieving, soil organic Carbon content and soil bulk density were measured following two and three years of alley cropping with Gliricedia (Gliricidia sepium) and Pigeon pea (Cajanas cajan) in a tropical Rhodustalf. Alley cropping increased the mean aggregate diameter and water stability of soil aggregates. The mean aggregate diameter obtained from dry sieving increased from 1.3 mm of the control to 2.68 and 3.11 mm after three years in Pigeon pea and Gliricidia alley cropped plots, respectively. This is an indication of resistance to wind erosion in alley cropped plots. The wet aggregate stability which shows the resistance to erosion by water also increased in alley cropped plots. These increases were significant after three years of hedge row establishment. The increase in soil organic C in alley cropped plots contributed to the higher dry and wet aggregate stability, and decreased soil bulk density. The improvement was higher in plots alley cropped with Gliricidia than Pigeon pea. This study shows the importance of ally cropping in increasing aggregate stability of degraded sandy soils which in return reduce erosion by wind and water. 相似文献