Different Irrigation Methods and Their Comparisons Based on the Parametric Evaluation Method in Khosouyeh Dam Subbasin,Iran

Today, the world's population is rising dramatically, and in line with this increase in the population of food and agricultural products, there must be an increasing in the number of problems associated with this process of agricultural land. Then it is necessary to use the maximum potential of this lands that product maximum yield without any damage. To reach this objective, land suitability evaluation is the most important way that can reach human to this objective. The main objective of this research was to compare different irrigation methods based on a parametric evaluation system in an area of 221402 ha in the Khosouyeh Subbasin of the Fars province, in the south of Iran. After preparing land unit map, 37 points were selected for sampling. Soil properties were evaluated and analyzed. Suitability maps for drop and gravity irrigation were generated using GIS technique. The results revealed land suitability of 98.42% of the case study was classified as permanently not suitable (N₂) and 1.52% currently not suitable (N₁) for gravity irrigation. On the other hand, land suitability of 77.73% of the case study was classified as permanently not suitability (N₂), 6.05% currently not suitable (N₁), 12.43% marginally suitable (S₃) and 3.79% moderately suitable (S₂) for drop irrigation. The limiting factors for both kinds of drop and gravity irrigation are soil depth and slope of land.     

Analysis of groundwater quality for irrigation purposes in shallow aquifers: A case study from West Aceh,Indonesia

The aim of this study is to evaluate the groundwater quality in shallow aquifers from West Aceh, Sumatra, for irrigation uses. Groundwater samples have been collected from 32 stations for pH, electrical conductivity (EC), sodium adsorption ratio (SAR), total dissolved solids (TDS), sodium percentage (per cent Na) and residual sodium carbonate (RSC) analysis. Evaluation of water quality for irrigation using the United States Salinity Laboratory classifications suggests that the majority of the groundwater samples are good for irrigation. The crop tolerance of irrigation water salinity, as based on EC value, showed that paddy (rice), soybeans and sweet tomatoes are suitable for agricultural cultivation, but that corn and field beans are not suitable. Results indicate that, if used for agricultural irrigation, the groundwater quality ranges from excellent to good, except for a few locations (e.g. Meureubo sub‐district) which indicate signs of deterioration.     

GIS based ecotourism potential assessment in Munessa Shashemene Concession Forest and its surrounding area,Ethiopia

This study aims to understand GIS based ecotourism potential of Munessa Shashemene Concession Forest and its surrounding area in Ethiopia. Landsat images from 2009/2010 and 2013 were used to drive baseline data including land cover, land use, stream and road. Elevation based agro-ecology and slope map were derived from SRTM DEM. Rapid wild animals survey, identifying the location of known historical, cultural and unique features were carried out in the filed with the help of key-informants. A suitability model was designed in GIS environment to assess the suitability of an area for tourism considering suitability factors such as land cover types, wild animal zone, unique features, topography and distance to a road. The result showed areas which are highly suitable, moderately suitable, marginally suitable, or unsuitable for tourism. The old giant, Podocarpus (Podocarpus falcatus) trees that serve as habitat of the endangered and endemic mountain nyala (Tragelaphus buxtoni), were identified as very high suitable areas for tourists. The highly suitable areas include forest area along the lake which is seasonally visited by mountain nyala and areas of plantation forest that are found adjacent to natural forest. These areas follow remnants of the natural forest and found along boundary between the mid-highland and the highland agro-ecologies. The agricultural land use types consisting of maize/haricot-bean and wheat/barley were evaluated as marginally suitable, nevertheless these could be considered as potential for agri-tourism. The study revealed that the concession area is found to be a suitable area with its huge potential for ecotourism development.     

GEO-Environmental Suitability Evaluation of Land for Urban Construction Based on A Back-Propagation Neural Network and GIS: A Case Study of Hangzhou

Evaluating the geo-environmental suitability of land for urban construction is an important step in the analysis of urban land use potential. Using geo-environmental factors and the land use status of Hangzhou, China, a back-propagation (BP) neural network model for the evaluation of the geo-environmental suitability of land for urban construction was established with a geographic information system (GIS) and techniques of grid, geospatial, and BP neural network analysis. Four factor groups, comprising nine separate subfactors of geo-environmental features, were selected for the model: geomorphic type, slope, site soil type, stratum steadiness, Holocene saturated soft soil depth, groundwater abundance, groundwater salinization, geologic hazard type, and geologic hazard degree. With the support of the model, the geo-environmental suitability of Hangzhou land for urban construction was divided into four suitability zones: zone I, suitable for super high-rise and high-rise buildings; zone II, suitable for multi-story buildings; zone III, suitable for low-rise buildings; and zone IV, not suitable for buildings. The results showed that a BP neural network can capture the complex non-linear relationships between the evaluation factors and the suitability level, and these results will support scientific decision-making for urban-construction land planning, management, and rational land use in Hangzhou.     

Land resources assessment for sugar-cane cultivation in Papua New Guinea

The nature of climatological, hydrological, geomorphological and soils information required for the locational planning of a sugar-cane estate is considered in the light of optimum needs for crop cultivation. In the Markham-Ramu Valley unstable river channels, swamps, alkaline groundwaters, climatological factors and shallow, stony soils all impose constraints on site location. The most significant factors, such as flood prevention, drainage works and supplementary irrigation needs, are those which impose an economic penalty in terms of high capital cost. These factors, along with climatological and pedological information, are used to develop a land suitability classification for sugar-cane cultivation. Careful land resource investigations help define potential problems and have enabled one site to be given preference over two others as the most suitable location for the development of Papua New Guinea's sugar industry.     

Groundwater Depletion and Agricultural Land Use Change in the High Plains: A Case Study from Wichita County,Kansas*

Shifts in resource availability and resulting land use changes are important research themes for coupled human and natural systems and human dimensions of global environmental change. This study examines the relationship between groundwater depletion and agricultural land use change within a single county in the High Plains, where agro-economic systems and populations are dependent on access to reliable groundwater supplies. Results indicate a significant relationship between high proportionate decreases in groundwater and land being removed from irrigation. This case study strengthens the links among local, regional, and global environmental change, and contributes to a greater understanding of the High Plains in the context of regional sustainability and vulnerability concerns.     

基于生态适宜性评价的西南丘陵区土地整治工程布局研究

如何科学合理地识别土地整治工程的生态适宜性,是评判当前土地整治工程是否实现“有利生产,方便生活,兼顾生态”目标的重要依据,更是土地整治理论与规划亟待解决的重要命题。选取川东平行岭谷区的垫江县为研究区,立足146个土地整治项目,借助生态位思想进行土地整治工程生态适宜性评价,计算土地生态整治工程布局潜力指数,对土地整治工程生态化布局进行定向。结果表明：① 土地整治工程生态适宜性指标影响显示出显著异质性,其中耕地连片度、坡度、灌溉保证率是开展土地整治工程生态适宜性评价的首选因素。② 土地整治项目中单项工程的生态适宜性水平差异较大,其中土地平整和灌排系统的生态适宜性低于临界水平,田间道路和生态景观工程的生态适宜性高于临界水平。③ 土地整治项目整体工程的生态适宜性程度差异显著,各项目土地整治工程生态适宜性均值为0.72,处于生态适性的临界水平。适宜等涉及土地整治面积7434 hm²,占9%。临界适宜等涉及土地整治面积54530 hm²,占67%。不适宜等涉及土地整治面积18845 hm²,占24%。④ 研究区土地整治工程生态适宜性布局整体呈多样化格局,Ⅰ等潜力区主要位于研究区中西部,布局方向为发展多功能农业,应注意如何保证其经济价值实现的同时不损害其生态价值。Ⅱ等潜力区分布范围较广,布局方向为发展大宗粮油产业,应思考在保证其粮食生产的同时尽量避免对农田生态系统的破坏。Ⅲ等潜力区主要位于鹤大台地区,布局方向为发展生态立体农业,应强调如何在保证生态环境不受破坏的前提下发展具有山区特色的生态农业。     

Groundwater vulnerability and risk mapping for the Basaltic aquifer of the Azraq basin of Jordan using GIS, Remote sensing and DRASTIC

Water consumption in Jordan already exceeds renewable freshwater resources by more than 20% and, after the year 2005, freshwater resources are likely to be fully utilised. Over 50% of supply derives from groundwater and this paper focuses on a small part of the northern Badia region of Jordan that is underlain by the Azraq groundwater basin where it has been estimated that annual abstraction stands at over 100% of the projected safe yield. While water supply is a crucial issue, there is also evidence to suggest that the quality of groundwater supplies is also under threat as a result of salinisation and an increase in the use of agrochemicals. Focusing on this area, this paper attempts to produce groundwater vulnerability and risk maps. These maps are designed to show areas of greatest potential for groundwater contamination on the basis of hydro-geological conditions and human impacts. All of the major geological and hydro-geological factors that affect and control groundwater movement into, through, and out of the study area were incorporated into the DRASTIC model. Parameters included; depth to groundwater, recharge, aquifer media, soil media, topography, and impact of the vadose zone. The hydraulic conductivity of the aquifer was not included in calculating the final DRASTIC index for potential contamination due to a lack of sufficient quantitative data. A Geographical Information System (GIS) was used to create a groundwater vulnerability map by overlaying the available hydro-geological data. The resulting vulnerability map was then integrated with a land use map as an additional parameter in the DRASTIC model to assess the potential risk of groundwater to pollution in the study area. The final DRASTIC model was tested using hydrochemical data from the aquifer. Around 84% of the study area was classified as being at moderate risk while the re mainder was classified as low risk. While the analysis of groundwater chemistry was not conclusive, it was encouraging to find that no well with high nitrate levels was found in the areas classified as being of low risk suggesting that the DRASTIC model for this area provided a conservative estimate of low risk areas. It is recognised that the approach adopted to produce the DRASTIC index was limited by the availability of data. However, in areas with limited secondary data, this index provides important objective information that could be used to inform local decision making.     

土壤流失方程在山区耕地可持续利用适宜性评价与土地利用规划中的应用

应用已建立的土壤流失方程进行了滇东北山区基于可持续利用的耕地适宜性评价,以土壤抗蚀年限为主要指标,将山区耕地适宜性和可持续性程度分为高度适宜（高度持续）、中度适宜（中度持续）、低度适宜（低度持续）、有条件适宜（有条件持续）、不适宜（不可持续）５个等级。研究结果表明,土壤流失方程在山区耕地适宜性与可持续性评价以及土地利用规划工作中具有较大的应用价值。     

Groundwater vulnerability mapping: A GIS and fuzzy rule based integrated tool

Contamination of groundwater has become a major concern in recent years. Since testing of water quality of all domestic and irrigation wells within large watersheds is not economically feasible, one frequently used monitoring strategy is to develop contamination potential maps of groundwater, and then prioritize those wells located in the potentially highly contaminated areas for testing of contaminants. However, generation of contamination potential maps based on groundwater sensitivity and vulnerability is not an easy task due inherent uncertainty. Therefore, the overall goal of this research is to improve the methodology for the generation of contamination potential maps by using detailed landuse/pesticide and soil structure information in conjunction with selected parameters from the DRASTIC model. The specific objectives of this study are (i) to incorporate GIS, GPS, remote sensing and the fuzzy rule-based model to generate groundwater sensitivity maps, and (ii) compare the results of our new methodologies with the modified DRASTIC Index (DI) and field water quality data. In this study, three different models were developed (viz. DI_fuzz, VI_fuzz and VI_{fuzz_ped}) and were compared to the DI. Once the preliminary fuzzy logic-based (DI_fuzz) was generated using selected parameters from DI, the methodology was further refined through VI_fuzz and VI_{fuzz_ped} models that incorporated landuse/pesticide application and soil structure information, respectively. This study was conducted in Woodruff County of the Mississippi Delta region of Arkansas. Water quality data for 55 wells were used to evaluate the contamination potential maps. The sensitivity map generated by VI_{fuzz_ped} with soil structure showed significantly better coincidence results when compared with the field data.     

卫宁平原包气带水分运移特征研究

降雨、灌溉入渗和潜水蒸发在卫宁平原地下水循环中有重要的作用。为了准确评价卫宁平原地下水垂向入渗补给量和蒸发量，通过设立中卫、中宁两个包气带原位试验点，观测期为2013年6月~2013年11月和2014年4月~2014年10月，获取了两个试验点不同埋深处的土壤水负压、温度、岩性及水分运移参数，并采用定位通量法计算试验点的地表蒸散发、入渗量和潜水面蒸发、入渗量。结果显示：在包气带岩性相同、灌溉期相同（7~10月）、总灌溉量相近条件下，作物的灌溉模式决定了灌溉对潜水的补给强度：玉米少次大量（150 mm·次^-1）灌溉对潜水的补给量为373.65 mm，远远大于茄子多次小量（50 mm·次^-1）的灌溉模式下的152.3 mm；而在包气带岩性相同、种植作物相同、灌溉模式不变的前提下，同时期潜水面净补给强度相近：中宁试验点2013年7~10月份潜水面净通量为32.88 mm，2014年同期为57.42 mm。在降雨情况或灌溉量较小（50 mm）的情况下，植被的生长会阻碍水分在包气带中的下渗；在灌溉量较大（100 mm和150 mm）的情况下，植被的生长会促进包气带水分的下渗。     

基于熵权-TOPSIS法的柴达木盆地地下水富水性评价

柴达木盆地作为一个典型干旱内陆盆地,其蕴藏的地下水是重要的自然资源。建立影响盆地地下水富水性的特征数据库,采用熵权法和TOPSIS结合的4种模型,对柴达木盆地地下水空间富水性分别进行定量评价。评价结果表明,造成柴达木盆地地下水空间富水性差异的主要原因是植被覆盖度(35.35%)、蒸发损失(26.92%)和入渗补给(18.90%)。盆地西北地区为弱富水性,中部地区为较弱富水性,南部和东部富水性较强。4种模型中E TOPSIS 2模型取得了较为合理的评价结果。最后,将评价得分和140个单井涌水量进行了拟合,建立了基于E TOPSIS 2得分的盆地单井涌水量预测模型。研究结果可对柴达木盆地地下水资源的开发和保护提供一定借鉴意义。     

青藏高原土地资源人类活动适宜性评价方法及实证应用

针对中国现有土地资源人类活动适宜性评价方法存在的问题,搭建了适用于青藏高原的评价流程框架,建立了基于栅格单元的建设用地和耕地适宜性定量评价模型,提出了空气密度、气温、坡地适建、坡耕地土壤抗蚀等关键参数的普适性算法,并以藏东南米林县为例进行了实证研究。结果表明：① 米林县建设用地和耕地适宜性可划分为适宜、较适宜、一般适宜、欠适宜、不适宜5个等级类型,30 m精度建设用地各适宜性等级面积占土地面积比例依次为1.26%、2.92%、2.12%、2.77%和90.93%;50 m、100 m各等级面积较30 m误差±0.34%,250 m误差 ±1.11%,500 m、1000 m误差较大。30 m精度耕地各适宜性等级面积占土地面积比例依次为0.72%、3.07%、2.62%、1.35%和92.25%;50 m、100 m、250 m与30 m误差±0.52%,500 m、1000 m误差较大;② 米林县现状城镇村及工矿用地主要分布在建设用地较适宜、适宜和一般适宜等级类型,30 m精度三者合计占比达95.96%,50 m、100 m占比分别为95.96%和94.74%。现状耕地和种植园用地主要分布在较适宜、一般适宜和适宜等级类型,3种栅格精度下三者合计占比大于96%;③ 业已建立的评价方法、定量模型及参数算法是可行的和适用的,青藏高原建设用地和耕地适宜性评价的适宜栅格精度为100 m,最大不超过250 m;④ 建立了可应用于青藏高原的土地资源建设用地和耕地适宜性等级类型与地形高程及坡度对应谱系。     

基于GRNN模型与邻域计算的低丘缓坡综合开发适宜性评价——以乌蒙山集中连片特殊困难片区为例

土地资源是最重要的自然资源,低丘缓坡开发能够为土地资源紧张地区产业发展提供重要的资源保障,而土地开发适宜性评价则是开展低丘缓坡综合开发利用的基础性工作,其核心在于综合评定低丘缓坡未利用地开发的适宜类型及其程度。以乌蒙山集中连片特殊困难片区为例,本研究在明确界定低丘缓坡范围的基础上,构建了低丘缓坡耕地、建设用地开发适宜性评价指标体系并基于GRNN模型划分土地开发适宜性等级;重点关注集中连片土地开发的规模化效益,采用邻域算法对研究区低丘缓坡综合开发适宜性进行评价。研究结果表明,乌蒙山片区低丘缓坡土地开发潜力巨大,耕地、建设用地开发单宜区面积分别为31.37 万hm²和3.84万hm²,其中多宜区面积达1.79 万hm²;而考虑同现有用地类型及土地开发类型的空间邻接关系,基于规模效益原则综合权衡,多宜区中0.84 万hm²更适宜开发为耕地,0.69 万hm²更适宜用于建设用地开发,0.26 万hm²因空间孤立而不作为土地开发区;综合开发适宜性评价确定耕地、建设用地开发区面积分别为27.68 万hm²和2.21 万hm²。研究结果对于乌蒙山片区低丘缓坡综合开发具有重要的实践指导意义。     

基于“三类”空间的后备可利用土地资源评价研究——以山西省介休市为例

针对当前国土空间规划“双评价”中存在的后备适宜建设用地与后备适宜耕地在城镇、农业空间分布上的重叠性问题,论文在对2类用地进行概念内涵辨析的基础上,尝试构建后备可利用土地资源集成评价方法,探讨不同类型后备可利用土地资源用途的地域导向,并选取山西省介休市作为案例区进行实证应用研究。结果表明：介休市后备适宜建设用地面积较大(45.3 km ²),但集中连片趋势不明显。人均后备适宜建设用地面积为0.16亩/人。区域后备适宜耕地面积74.1 km ²,人均后备适宜耕地面积为0.26亩/人。研究区域2类用地具有相似的空间分布格局,即绵山镇、连福镇等地区后备可利用土地资源潜力较大,而城区及周围地区的潜力较小。针对2类用地的重叠性和差异性,介休市城区、各乡镇中心及北部地区的后备可利用土地资源未来可转化建设用地,即未来应被划归城镇空间。连福、绵山、义棠、张兰等乡镇南部地区未来可转化为新增耕地,即应被划归农业空间。     

河北南部地区资源、环境、发展初析

河北南部地区山前平原区农业气候条件适于夏玉米的生长 ,黑龙港地区适于棉花的生长。本区水资源匮乏 ,地下水超采严重。浅层地下水超采模数为 8.0 1× 1 0 4 m3/( km2 ·a) ,深层地下水为 2 .5 8× 1 0 4 m3/( km2·a)。全区水资源利用的综合边际效益以廊坊市最高 ( 2 6.68元 /t) ,保定市最低 ( 1 4.85元 /t) ,两者之比为 1 .80。区内地下水降落漏斗与地面沉降等环境地质灾害频繁 ,1 998年浅层地下水漏斗区面积为 0 .5 4× 1 0 4 km2 ,深层地下水为 1 .5 9× 1 0 4 km2。地下水、粮食和蔬菜受到农药残留、过量化肥的污染。本区 2 0 1 0水平年外流域调水将占可供水量的 2 3.9% ,但缺水率仍达 36.2 %。若全区通过发展工程节水 (提高综合节水率 3.2 % )、实施适水种植 (冬小麦播种面积下调 7% ) ,利用水分胁迫处理 (减少一次灌溉 )等节水措施 ,则比 1 999年节水 1 7.2 %。     

华北地下水超采区冬小麦退耕的生态补偿问题探讨

压减冬小麦种植面积是有效减少华北平原地下水用量最为有效的方法。近期,国家和地方政府均出台了土地休耕政策,拟在华北地下水超采区退耕冬小麦,实现“一季休耕、一季雨养”。然而,华北平原已经出现农户主动退耕冬小麦的现象。在此背景下,明确冬小麦退耕的瞄准目标、制订合理适度的补偿标准是土地休耕政策有效实施所面对的核心问题。本文利用农户问卷数据,构建多层次logit模型分析农户种植制度决策的影响因素,并计算冬小麦退耕的机会成本,旨在确定华北平原地下水超采区土地休耕政策的瞄准目标,并为农户补偿标准的制订提供建议。结果表明：① 地块层次的土地质量和灌溉条件是解释农户种植制度差异的关键因素,近70%的四等耕地和90%以上的旱地已退出冬小麦耕作,土地休耕政策应瞄准一、二、三等土地质量的水浇地;② 相似耕作条件的地块种植春、夏玉米的净收益大致相同,土地休耕的机会成本等于种植冬小麦的净收益;③ 仅考虑冬小麦对地下水资源的影响,土地休耕政策初期以地下水回升和地下水环境恢复为主要目标时,建议以350元/亩作为补偿标准参考值,后期目标转为维持地下水资源采补平衡时,可调整至280元/亩左右。     

Spatial variability of selected soil properties in relation to land use and slope position in Gelana sub-watershed,Northern highlands of Ethiopia

Land degradation resulting from land-use changes and soil erosion has been a serious environmental problem in Ethiopia. This study addressed the effects of land use and slope position on soil physical and chemical properties in the Gelana sub-watershed, Northern highlands of Ethiopia. A total of 63 soil samples were collected and analyzed using a two-way ANOVA. Results showed that clay, soil pH, soil organic matter, total nitrogen, cation exchange capacity, and exchangeable base contents of the cultivated land were significantly (p < 0.001) lower than those of the forest land, while soil bulk density, available phosphorous, and percentage base saturation were higher for cultivated land than forest land. In general, soil fertility declines as land use changes from forest to grazing and cultivated lands. Sand, clay, bulk density, soil pH, organic matter, total nitrogen, carbon:nitrogen ratio, available phosphorous, cation exchange capacity, exchangeable cations, and percentage base saturation showed significant variation due to slope position differences. Therefore, the study reinforces the need for integrated watershed management for sustainable agricultural production in the study area.     

Drought, groundwater management and land use planning: the case of central Oahu, Hawaii

A recent decision to allow higher levels of urban development in central Oahu, Hawaii, has heightened the concern about possible loss of agricultural land and further drops in aquifer levels. This paper examines such potential impacts and offers a procedure for incorporating them into land use planning. First, a water-balance simulation model computes the change in groundwater recharge under changes in land use and irrigation technology. The resulting changes, together with estimated water demands for the agricultural, commercial and residential sectors, are then included in a multiobjective programming model that identifies optimal patterns of land use conversion under different objective trade-offs. Objectives treated are the minimization of agricultural land loss and of water demand, and the maximumization of recharge over withdrawal. The second objective pertains to water management during drought, while the third refers to sustainable groundwater management. Results show that, depending on the relative importance given each of these two objectives, land moving out of sugar cane will differ significantly in amount and by type of irrigation presently used. The relative importance of these objectives thus needs to be determined if water is to play a coherent and guiding role in land use planning.     

海南岛土地生态适宜性评价

以海南岛为例,在区域层面上选择高度、地形坡度、土地覆被等影响工业用地的关键因子,构建工业用地的生态适宜程度评价模型,并在G IS技术支持下进行工业用地生态经济适宜性评价,为将来区域工业开发区及重点工业项目布局提供依据。结果表明:海南工业用地生态适宜性呈现出由中部山地向四周逐渐增强,限制利用区占25%,不适宜利用区占28%,基本适宜区占41%,优先利用区占5%。其中优先利用区主要分布在西部和北部沿海地带,海口、儋州和东方及其连线一带应成为海南省未来工业用地布局的重点区域。