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1.
农牧交错带不同土地利用方式对土壤质量的影响   总被引:1,自引:0,他引:1  
在我国北方农牧交错带,研究了不同土地利用方式对土壤质量的影响.结果表明,天然草地和过牧草地土壤全氮、总有机碳和全磷含量整体高于耕地和林间草地,退耕地种草后土壤全氮、总有机碳含量增加,全磷含量无显著变化.耕地和过牧草地土壤速效磷含量高于其他土地利用方式.天然草地、过牧草地和耕地土壤pH值显著高于林间草地和人工草地,而土壤电导率均为过牧草地显著高于天然草地,天然草地显著高于林间草地、人工草地和耕地.林间草地和过牧草地土壤容重显著高于天然草地和耕地,而天然草地土壤含水量显著高于其它土地利用方式,林间草地土壤舍水量最低.
Abstract:
The effect of land use conversion on soil qualities was studied in the agro-pastoral transitional zone in North China.The results showed that the contents of total nitrogen,total organic carbon and total Dhosphorus in soil of natural steppes and over-grazed steppes were higher than those of cultivated land and grassland openings.Land use conversion from cultivated land to perennial artificial grassland increased soil total nitrogen and total organic carbon but had no marked influence on total phosphorus.Available phosphorus in soils of cultivated land and over-grazed steppes was higher than that of other land uses.Compared with grassland openings and artificial grassland,nature steppe and over-grazed steppe had higher pH values and soil EC,while the cuhivated land had higher pH value and lower soil EC.Soil bulk density of grassland openings and over-grazed steppes was higher than that of nature steppes and cultivated land,while water content was the highest in natural steppes and the lowest in grassland openings.  相似文献   

2.
利用2003和2008年两期SPOT5卫星影像,对香港地区土地利用/覆盖变化情况进行监测,探讨和分析了香港地区土地利用类型变化、土地利用程度变化的特征和规律.结果表明5a间香港土地利用变化最大的特点是土地利用总面积略有增加,各土地利用类型中,农用地急剧减少,灌丛和草地显著增加;区域的土地利用效率较高,土地利用程度变化微小,目前已处于缓慢发展期.
Abstract:
Supported by RS and GIS technology and using the SPOT5 remote sensing images of 2003 and2008,the authorsr monitored and analyzed the change in land use/land cover in Hong Kong in this period.The results showed that the land area increased by 220 ha from 2003 to 2008 through reclamation and that of all land use types,cultivation land decreased sharply,but serubland and grassland,most of which were transformed from forest land,increased markedly,which was the most remarkable characteristic change of land use/land cover in the 5 years in Hong Kong.Land use extent index showed but little change(1.75),or the land used for urban development and construction changed very little,and the intensive utilization of land remained high.It is concluded that the land use in Hong Kong has come into a period of slow development.  相似文献   

3.
运用等高线数字化生成的数字高程模型(DEM),从中提取出研究区的高程和坡度数据,通过与土地利用现状数据的叠加分析得到在不同高程和坡度下的土地利用分布情况,并对土地利用类型与地形因子进行相关分析.研究结果表明:灌溉水田主要集中在高程300~400 m的区域,旱地则主要分布在高程300~600 m区域,并随海拔的升高而减少;灌溉水田、桑园、农村居民点均随着坡度的增加而减少,旱地、有林地、荒草地的分布则存在随着坡度增加而增加的趋势;灌溉水田、园地、农村居民点三个土地利用类型在不同坡度、不同高程的面积比例变化趋势具有高度相似性,在丘陵和低山地貌类型区域,坡度因子对耕地利用变化的影响程度最大.
Abstract:
Elevation and slope data were extracted from DEM (digital elevation model) generated by digital contour, and information about land use distribution was obtained through overlay analysis of present land use data and elevation and slope data. Then correlation analysis was made between land-use types and terrain factors. The results showed that irrigated paddy fields were mainly distributed on the elevation of 300-400 m and non-irrigated farmland was mainly distributed on the elevation of 300-600 m, decreasing with increasing elevation; irrigated paddy fields, mulberry gardens and rural residential areas decreased with increasing slope while the distribution of non-irrigated farmland, forest land and wild grassland showed an opposite trend; the tendency of change in the proportion of area with different slopes and elevations was highly similar among irrigated paddy fields, mulberry gardens and rural residential areas; and the factor of slope had the greatest influence on the change in land use in regions with geomorphic terrain features of hills and low mountains.  相似文献   

4.
The purpose of the investigation was to assess the opportunity to use spring waters as indicator for the load state of rural landscape ecosystems. In the periods from 2000-2003 and 2011-2012, the physical and chemical water quality of 55 freshwater springs in the German federal state of the Saarland was investigated in monthly intervals. The catchment areas of the springs represented the prevailing geological formations in the Saarland as well as the main land use types such as forest, grassland and arable land. The results show a clear correlation between the nitrate content and the share of arable land in the closer catchment area of the springs. The problem of acidification and related processes occurs mainly at the sites with acid parent rock material and accordingly substrates deficient in lime. Very low pH-values between 4 and 5 are observed and the aluminum concentration levels are consistently increased. Especially at sites with low calcium content in the geological substrate, a progressive destruction of the clay minerals can be assumed. In the extremely acidic spring waters, which showed the highest aluminum contamination during the measurement 10 years ago, the aluminum-values decreased slightly. This indicates that the clay minerals in these locations are already completely destroyed. Thus, it can be concluded that the investigation of spring waters provides information on the geo-ecological conditions in catchment areas. By means of the multi-temporal approach, changes of land use or other influences by human activities can be detected.  相似文献   

5.
Grassland, as one of the largest ecosystems on the earth, supports various goods and services to humanity.Historically, humans have increased agricultural output primarily by cropland expansion and agricultural intensification.The cropland area was primarily gained at the expense of grassland and forests.Apart from grassland conversion, increasing consumption of calorie- and meat-intensive diets drives the intensification of livestock systems, which is shifting steadily from grazing to feeding with crops.To cope with the environmental degradation due to agriculture, various forms of ‘green payment' were implemented to promote the adoption of sustainable farming practices over the last two decades in the European Union.The aim of this study is to monitor the recent transitions(1992–2010) between grassland and cropland during two Common Agricultural Policy(CAP) reforms at the French mainland scale.We proposed an innovative approach to link grassland conversion to agricultural commodities and farming systems practices.We first assessed the grassland-to-cropland conversion and further investigated the crop sequence patterns that were observed to be dominant after the conversion through mining land-cover survey data Teruti and Teruti-Lucas.We found the trends of the transitions between grassland and cropland over the two time intervals: The loss of grassland(1992–2003) and restoration or re-expansion of grassland(2006–2010) in mainland France.Our finding on the crop sequence patterns after the grassland conversion reveals two notable evolutions of agricultural production systems.These evolutions were related to the increase in the proportion of cropland in the total agricultural land use.One evolution was most likely influenced by the demand for fodder: The conversion from grazing livestock to feeding livestock.Another evolution was the conversion from livestock production to field crop production.Our results indicate that the intensification of livestock farming systems continued over the last two decades in France.We conclude that, the approach developed in this study can be considered as a generic method for monitoring the transitions between grassland and cropland and further identifying the crop sequence patterns after the grassland conversion from time-series land cover data.  相似文献   

6.
This research classified vegetation types and evaluated net primary productivity (NPP) of southern China's grasslands based on the improved comprehensive and sequential classification system (CSCS), and proposed 5 thermal grades and 6 humidity grades. Four classes of grasslands vegetation were recognized by improved CSCS, namely, tundra grassland class, typical grassland class, mixed grassland class and alpine grassland class. At the type level, 14 types of vegetations (9 grasslands and 5 forests) were classified. The NPP had a trend to decrease from east to west and south to north, and the annual mean NPP was estimated to be 656.3 g C m-2 yr-1. The NPP value of alpine grassland class was relatively high, generally more than 1200 g C m2 yr-1. The NPP value of mixed grassland class was in a range from 1 000 to 1200 g C m-2 yr-1. Tundra grassland class was located in southeastern Tibet with high elevation, and its NPP value was the lowest (〈600 g C m'2yrl). The typical grassland class distributed in most of the area, and its NPP value was generally from 600 to 1000 g C m-2 yr-1. The total NPP value in the study area was 68.46 Tg C. The NPP value of typical grassland class was the highest (48.44 Tg C), and mixed grassland class was the second (16.54 Tg C), followed by alpine grassland class (3.22 Tg C), with tundra grassland class being the lowest (0.25 Tg C). For all the grasslands types, the total NPP of forest meadow was the highest (34.81 Tg C), followed by sparse forest brush (16.54 Tg C), and montane meadow was the lowest (0.01 Tg C).  相似文献   

7.
利用~(137)Cs示踪技术,研究了戴家沟小流域不同土地利用类型和地貌部位的侵蚀特征.结果表明:不同土地利用方式下土壤~(137)Cs的面积活度大小依次表现为马尾松林,经济林,农耕地,灌木林;不同地貌部位的土壤~(137)Cs的面积活度大小依次表现为坡脚,坡中,坡顶;排除分布不均的土地利用类型(农耕地、裸岩地),各地貌部位土壤侵蚀模数大小依次为:坡中,坡顶,坡脚.流域内平均侵蚀模数为:897.37 t/(km~2·a),裸岩地侵蚀模数达9 240 t/(km~2·a),农耕地侵蚀模数达1 056.43 t/(km~2·a),在小流域土壤侵蚀防治中裸岩地、农耕地仍是治理的关键.
Abstract:
The ~(137)Cs tracer technology was used to study the soil erosion features for different land usage types and landform positions in Daijiagou small catchment of Chongqing. The results showed that ~(137)Cs activity per unit area for different land use types was in the order of masson pine forest> economic forest>farmland> shrub land and in the order of foot slope > middle slope position > slope crest for different landform positions; and soil erosion modulus size appeared in the order of middle slope position> slope crest > foot slope. The average erosion modulus within the catchment was 897.37 t/(km~2·a), the erosion modulus of uncovered rock land was as high as 9 240 t/(km~2·a), while that of farmland was 1 056.43 t/(km~2·a). Therefore, the control of soil erosion on uncovered rock land and farmland should be the key link in the prevention and control of soil erosion of the small catchment.  相似文献   

8.
In order to understand land use/land cover changes (LUCC) and the eco-environment response to LUCC in farming- pastoral zone of the northern China during the recent twenty years, Baotou prefecture was selected as a case study area for investigation and quantitative evaluation. Technologies of remote sensing (RS), global positioning system (GPS), geographic information system (GIS), and other statistical methods were employed to implement. Results showed that: (1) During the recent twenty years, the areas of forest lands, grasslands and water were reduced, whereas the areas of other types were enlarged. Parts of forest lands, grasslands, and waters had become farmlands, and about 31.5% of the changed grasslands transferred into unused lands. The newly increased farmlands mainly came from grasslands and unused lands. And the newly increased construction lands mainly came from grasslands and farmlands. (2) Regional eco- environmental quality decreased by 12.6%, for which the land degradation (especially the meadow degeneration) and the developing of the cultivated land were mainly responsible, and their contributions to the regional eco-environment changes were 51.84 and 23.63% respectively. (3) The tendency of LUCC and the eco-environment response to LUCC displayed spatial heterogeneity. It can be concluded that the present agricultural production mode was not sustainable in farming-pastoral zone of northern China. Land degradation, especially meadow degradation induced by over-trampling and overgrazing, and developing of cultivated land were mainly responsible for regional eco-environment deterioration. Changing the cultivated land to forest or grass, however, can relieve deterioration of local eco-environment to some extents. And in the farming-pastoral zone in the northern China, evaluating regional eco-environment responses to LUCC was very necessary due to its fragile eco-environments.  相似文献   

9.
Fractal method is a new method to estimate soil structure. It has been shown to be a useful tool in studies related to physical properties of soil as well as erosion and other hydrological processes. Fractal dimension was used to study the soil structure in soil at different stages of vegetative succession on the Ziwuling Mountains. The land use and vegetation types included cultivated land, abandoned land, grassland, two types of shrub land, and three types of forests. The grassland, shrub land, and forested areas represented a continuum in vegetative succession that had occurred naturally, as the land was abandoned in 1862. Disturbed and undisturbed soil samples were collected from ten vegetation types from depths of 0-10, 10-20, and 20-30 cm on the Ziwuling Mountains, at a site with an elevation of about 1 500 m. Particle size distribution was determined by the pipette method and aggregate size distribution was determined by wet sieving. The results were used to calculate the particle and aggregate fractal dimension. The results showed that particle and aggregate fractal dimensions varied between vegetation types. There was a positive correlation between the particle fractal dimension and the weight of particles with diameter 〈 0.001 mm, but no relationship between particle fractal dimension and the other particle size classes. Particle fractal dimension was lower in vegetated soils compared to cropland and there was no consistent relationship between fractal dimension and vegetation type. Aggregate fractal dimension was positively correlated with the weight of 〉 0.25 mm aggregates. Aggregate fractal dimension was lower in vegetated soils compared with cropland. In contrast to particle fractal dimension, aggregate fractal dimension described changes in soil structure associated with vegetative succession. The results of this study indicate that aggregate fractal dimension is more effective in describing soil structure and function compared with particle fractal dimension.  相似文献   

10.
以闽江流域为研究区域,采用Costanza等人对全球生态系统服务价值的测算方法,结合遥感技术,提江流域各个县市的水域、林地、草地、耕地和其他用地的专题信息,实现闽江流域生态服务功能价值以及流域态公益林生态服务价值的估算.研究结果表明: 1986-2003年,闽江流域生态服务功能的价值发生很大变化,了人为干扰对生态系统的影响. 2003年闽江流域生态服务功能价值较1986年增加3.147×10~(18)元,林地贡献最生态公益林生态服务功能价值的增长量为4.137×10~(18)元,占总增长量的37.093%.闽江流域生态服务功能价长率可划分为较低、一般、较高、高四个等级,对增长率处于10%以下的15个县市,应更加注意在经济发展时,加强对植被资源的保护.闽江流域生态公益林各生态服务功能价值增长趋于均衡化. 1986年生态公益林服务功能的价值为3.570×1018元, 2003年为4.737×10~(18)元,净增1.167×10~(18)元,年均增加6.867×10~(16)元.市生态公益林生态服务功能增长率除沙县和三明为负外,其他县市均为正,福州和长乐更是保持100%以上的率,这受益于政府相关保护和鼓励政策.
Abstract:
The values of the ecosystem service functions of Minjiang Watershed and the non-commercial ec-ological forests there are estimated with the method proposed by Contanza in combination with RS technol-ogy, based on the relevant information of waters, forest land, grassland, cultivated land and the other types of land of the counties within the watershed. Great changes in the value of the ecosystem service functions in Minjiang Watershed appear to have occurred from 1986 to 2003, which indicates the influence of human interruption on the ecosystem. Compared with the figures in 1986, the value has increased by 3.147×10~(18)yuan (RMB) in 2003 mainly due to the forest land. The value of the ecological forests has in-creased by 4.137×1018yuan (RMB), accounting for 37.093% of the total increase rate. The value of the ecological service functions of Minjiang Watershed is classified into 4 grades: lower grade, general grade,higher grade and highest grade. It is very important for the 15 counties whose rates of increase are below 10% to strengthen the protection to vegetation resources in developing their local economy. The increase of the value of the ecosystem functions of the ecological forests in Minjiang Watershed is becoming stable.This value in 1986 is 3.570×10~(18)yuan (RMB), while it is 4.737×10~(18)yuan (RMB) in 2003, which is 1.167×10~(18)more than the former and has an annual increased value of 6.867×10~(16)yuan (RMB). With the exception of Shaxian and Sanming all the other counties in the study area show a positive increase. The counties of Fuzhou and Changle have consistently maintained an increase rate greater than 100%, which is profited by the policies of protection and encouragement taken by the governments.  相似文献   

11.
针对兽医服务的职能,结合兽医服务在食品安全中的作用,对兽医从传统到现在的职能转变作一综述。  相似文献   

12.
津南区土壤耕层养分动态的研究   总被引:4,自引:0,他引:4  
根据本区的实际情况,通过连续多年对耕层土壤的有机质、全氮、碱解氮、全盐、速效磷、速效钾、PH值等7项理化指标的监测分析表明,我区耕层土壤有机质含量在园田区增长较明显,粮田区为持续下降趋势,以平均每年1%的幅度下降;土壤速效磷含量保持原等级;土壤速效钾含量在原等级内呈下降趋势;土壤全盐含量下降,PH值上升。按土壤养分分级标准划分,我区近80%的耕地土壤肥力为3—4级水平。  相似文献   

13.
不同时期防除冬小麦田禾本科杂草的研究   总被引:2,自引:0,他引:2  
周德美  孙怀山  汪云好 《安徽农业科学》2006,34(16):4038-4038,4122
用骠马和异丙隆进行不同时期防除冬小麦田禾本科杂草的示范试验,结果表明,用骠马6.9%EW1.5L/hm2于禾本科杂草3~4叶期防除效果较好。  相似文献   

14.
刘社平 《安徽农业科学》2011,39(10):5810-5811,5813
[目的]验证不同除草剂的除草效果,为直播冬油菜田的杂草防除提供借鉴。[方法]使用不同剂量25%胺苯磺隆可湿性粉剂和10.8%高效氟吡甲禾灵乳油在直播冬油菜田间进行单用和混用除草试验。[结果]25%胺苯磺隆可湿性粉剂在冬油菜4~5叶期使用可以有效防除田间的阔叶杂草;25%胺苯磺隆可湿性粉剂18.0~22.5 g/hm2+400 ml/hm2的10.8%高效氟吡甲禾灵乳油可以有效防除油菜田间的阔叶和禾本科杂草,总防效达90%以上,且可以比人工除草节省成本1 100元/hm2。[结论]25%胺苯磺隆与10.8%高效氟吡甲禾灵乳油混用可以更好地防除冬油菜田间杂草。  相似文献   

15.
大棚黄瓜于1月上旬播种,应用嫁接方法,苗龄50天左右,2月下旬定植,采用三层覆盖配合炉火临时加温及综合栽培技术,6月底拉秧。在同一棚内6月20日左右育番茄苗,苗龄25天左右,7月中旬定植,适当遮阴、防雨,挂防虫网及应用综合防治病虫害技术,取得高产高效益,在我街已形成比较成熟的配套栽培模式和规范化管理技术。  相似文献   

16.
荔枝胚性愈伤组织及其体胚发生过程中染色体数目的变化   总被引:10,自引:0,他引:10  
荔枝胚性愈伤组织及其体胚发生过程中,各离体培养物染色体数目均出现广泛的变异.除正常的荔枝体细胞染色体数目2n=2x=30外,还出现大量染色体数目异常的细胞.植物生长调节剂、培养时间、外植体种类及基因型等对染色体数目变异有一定的影响.愈伤组织染色体数目变异虽然在一定程度上影响荔枝体胚的再生植株频率,但胚性愈伤组织仍能分化形成大量的胚状体.  相似文献   

17.
本文分析了《红楼梦》的两个英译本在人名的翻译过程中所采用的技巧。笔者认为,文化内容的最大限度传达是判断采用何种译法的重要标准,因而汉语字、号的对等英译,人名的音译、意译、拉丁语译都是不同情境下可采用的不同技巧。  相似文献   

18.
我国贫困人口大多聚集在交通不便的内陆农村山区,少数民族聚集区,移民库区及高原荒漠区,而消除少数民族贫困,加强民族团结历来是我国政府的重点工作,作为主流扶贫模式的开发式扶贫自20世纪90年代中期在少数民族地区推行以来,取得了巨大成绩。但随着扶贫工作的进一步推进,开发式扶贫也不断暴露出自身的缺陷和不足。以湘西州少数民族推行开发式扶贫工作为例,对少数民族地区开发式扶贫工作提出一些问题。  相似文献   

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