基于景观安全格局的农村居民点用地布局优化

农村居民点用地布局优化不仅是农村土地整治的基础,也是新农村建设和实现美丽乡村的重要路径。该文以江苏省宜兴市为例,根据其经济发达、生态环境优越以及风景名胜众多的特点以及农村居民点用地特征,运用景观安全格局理论和最小累积阻力模型相结合的方法,分别从水土保持、生物多样性保护和风景名胜保护三方面构建单一景观安全格局,进而建立宜兴市农村居民点用地布局综合景观安全格局。通过与宜兴市农村居民点用地的叠加分析,针对不同景观安全水平的农村居民点提出不同的布局优化方向,将宜兴市农村居民点用地划分为优先整治型、限制扩展型、适度建设型、重点发展型4种类型,分析各类型现状特征并提出优化方案。研究结果强调农村居民点用地布局工作中生态环境和景观保护优先的思想,不仅为当地新农村建设提供理论支撑,而且为相关规划制定提供参考。     

基于点轴理论的农村居民点布局优化

为合理确定农村居民点整治范围和布局优化方向,揭示农村居民点布局的点-轴空间作用机制。该文系统分析了村镇增长极点(城镇、中心村和基层村)与发展轴(道路)对农村居民点规划布局的空间作用机制,引入空间引力修正模型,测算村镇之间的相互作用值,采用加权Voronoi图划分各增长极点空间作用范围,结合道路与地形对农村居民点的综合作用,构建面向点-轴空间作用的农村居民点布局优化体系。研究以大冶市大箕铺镇为例进行实证研究,通过点-轴空间综合作用分析与测算,将大箕铺镇农村居民点用地空间划分为城镇化型、内部改造型、迁村并点型(包括中心村建设、村中心建设)3种模式;通过不同优化模式的空间引导与整合,实现村镇层次农村居民点科学规划与合理布局。     

基于多因素综合评价的居民点整理时序确定

为了科学确定农村居民点整理时序,构建了"潜力大小-斑块复杂程度-区位条件优劣"多因素评价体系,从农村居民点斑块形状复杂程度以及所处区位条件的优劣两方面分析其整理的难易程度和必要性大小,并将农村居民点分为"一级必要整理斑块"、"二级必要整理斑块"和"三级必要整理斑块",最后结合整理潜力分级结果将玉门市农村居民点整理划分为近期整理、中期整理和远期整理。结果表明:玉门市农村居民点潜力较大涉及22行政村,面积960.31 hm2,主要分布在昌马盆地区和花海绿洲平原区以及赤金-清泉绿洲区的部分行政村,潜力一般涉及32行政村,面积2 053.72 hm2,主要分布在玉门镇老城区以及玉门绿洲地区大部分行政村,潜力不大涉及3个行政村,面积304.90 hm2,主要分布在玉门新市区城市规划范围内的部分行政村;玉门市一级必要整理农村居民点斑块面积1 291.08 hm2,二级必要整理农村居民点斑块面积1 712.2 hm2,三级必要整理农村居民点斑块面积315.64 hm2。通过叠加居民点整理潜力及整理优先度分级结果图层,得出玉门市近期需整理农村居民点426.05 hm2,中期需整理635.40 hm2,远期需整理2 257.48 hm2。该文研究结果可为农村居民点整理时序确定提供一个新思路,为玉门市农村居民点整理规划提供决策依据。     

凹凸棒土-稳定塘工艺提高严寒地区农村生活污水处理效果

针对严寒地区农村生活污水处理面临的低效率、高能耗、排水不达标的典型问题,首次提出凹凸棒土—稳定塘模式处理严寒地区农村生活污水。该研究创新的通过PLC（programmable logic controller）自控试验设计,考察在低温10℃条件下工艺的最优运行参数,经过平行对比试验研究凹凸棒土作为载体填料对低温生活污水处理效果的影响。结果表明,pH值在7.2～7.8之间,兼性塘水力停留时间为4d,好氧塘的水力停留时间与曝气时间分别为36、4 h时,工艺对化学需氧量（chemical oxygen demand,COD）、氨氮（ammonia nitrogen,ammonia-N）、总磷（total phosphorus,TP）的平均去除率分别为91.5%、87.7%、84.1%,平均出水质量浓度分别为35.6、4.5、1.0 mg/L,满足国家二级排放标准,而单一式稳定塘工艺的低温生活污水处理效果显著降低,COD、氨氮、TP的去平均去除率分别降低了3.6%、6.0%、4.7%。凹凸棒土—稳定塘工艺可以有效的去除严寒地区农村生活污水中有机物及氮磷污染物,对削减农村水污染、降低水环境负荷及改善农村生态环境具有重要作用,同时也为凹凸棒土的应用拓展了新的方向。     

基于灰色系统模型的阿拉尔垦区农业水资源供需平衡预测及分析

对新疆阿拉尔垦区农业水资源短缺情况进行分析,并运用灰色系统GM（1,1）方法,预测了其农业供需水状况及其余缺水程度。结果表明：当供水保证率P=50％时,2015年缺水为3．178亿m^3,占总水量的24．47％;而在供水保证率P=75％时,缺水则增加到3．614亿m^2,占总水量的28．79％,可见,缺水越来越严重。因此,在常规灌溉条件下,供水量不能满足农业用水的需求,且农业水资源的短缺将严重制约阿拉尔垦区经济的发展。水资源供需矛盾必须依靠垦区水资源的深度开发和节水等措施才能得以解决,以此来实现垦区农业水资源和经济的可持续发展。     

农村小型水利工程管理的发展现状及对策

水利是国民经济的基础产业,是新时期建设社会主义新农村的基础。随着农村经济体制改革的深入,农村小型水利工程建设与管理中存在的权责不明、投入不足、发展滞后、管理不善、效益衰减等问题越来越突出,已成为提高农业综合生产能力的主要制约因素。文章分析了我国现行农村小型水利工程管理普遍存在的问题,并提出了系列具有针对性的建设措施,探讨了农村小型水利在规划、建设、管理与改革等方而的些具体做法。     

Differential hydrological response of biological topsoil crusts along a rainfall gradient in a sandy arid area: Northern Negev desert,Israel

Drylands are regarded as highly sensitive to climatic change. The putative positive relationship between average annual rainfall and runoff, assumed for areas between 100 and 300 mm ignores the fact that climatic change in drylands is not limited to climatic factors alone, but is often accompanied by a parallel change in surface properties. Data on rainfall, runoff and soil moisture regime were collected at five monitoring sites in a sandy area, along a rainfall gradient from 86 to 160 mm. Despite the uniform sandy substratum the frequency and magnitude of runoff declined with increasing annual rainfall. Under wetter conditions a thick topsoil biological crust develops. This crust is able to absorb and retain large rain amounts, limiting the depth to which water can penetrate, and therefore water availability for the perennial vegetation. In the drier area, the thin crust can absorb only limited rain amounts, resulting in surface runoff and deeper water infiltration at run-on areas. Our findings demonstrate the important role played by different types of biological soil crusts along the rainfall gradient considered, and question the generally held belief that higher rainfall necessarily leads to deeper water infiltration in sandy arid areas; and higher water availability for the perennial vegetation.     

Association between the purchase price of Thoroughbred yearlings and their performance during the 2- and 3-year-old racing seasons

OBJECTIVES Describe the association between the purchase price of Thoroughbred yearlings sold in Australia and racing performance as 2- and 3-year-olds. METHODS Race performance data of 2773 Thoroughbred yearlings sold at auction during 2003 were collected. Associations between purchase price and the probability of starting, the number of race starts and the prize money earned were examined. RESULTS In total, 2206 (79.6%) horses started a race. The mean number of race starts was six and the mean prize money earned was A$24,420. A total of 1711 (61.5%) horses earned prize money, 402 (14.4%) earned more than their purchase price, 312 (11.2%) earned more than A$40,000, the estimated cost of training, and 142 (5.1%) earned A$40,000 more than their purchase price. There was a positive association between purchase price category and the probability of starting, number of starts, earning prize money and earning greater than A$40,000 (P < 0.001). Purchase price category was negatively associated with the probability of earning greater than the purchase price (P < 0.001). The proportion of horses earning greater than the purchase price plus $40,000 was significantly different (P = 0.03) among the five price categories. CONCLUSION Yearling purchase price was positively associated with all race performance outcomes measured and researchers examining the race performance of yearlings purchased at sales should consider including purchase price when modelling. The Thoroughbred yearling market in Australia behaves in a similar manner to the United States market; owners pay a premium to enter the sport of racing and an additional premium in the quest to own a champion.     

张宣葡萄产区土壤硒含量与葡萄品质关系研究

调查分析了张宣地区葡萄园产区土壤硒分布状况,并与葡萄品质进行了相关分析,结果表明:张宣葡萄产区表层土壤硒含量低于中国表层土壤硒含量,在怀涿葡萄产区总面积占67.74%的土壤属于缺硒土壤,24.73%产区土壤为少硒土壤,足硒土壤面积较少;宣化葡萄产区面积达81.82%产区土壤为足硒土壤;土壤硒含量与土壤有机质含量呈极显著正相关,与土壤pH呈极显著负相关,偏相关分析显示该产区土壤有机质与土壤硒含量的关系更密切;土壤硒含量与葡萄果实Vc有负相关关系,与果实中pH、单粒重呈正相关关系,分析表明土壤硒与酿酒葡萄品质关系密切;土层深度在土壤硒含量与葡萄品质的关系中影响不大。     

常州市农村能源消费影响因素实证分析

农村地区能源消费是能源和环境的可持续发展的重要组成部分,它受许多因素的影响。该文运用2000－2009年的统计数据,通过相关分析、主成分分析和灰色关联分析法对影响常州市农村能源消费的各个因素进行重要性评价,得出了人均纯收入是最主要的影响因素,并由此提出了提高当地农村能源消费水平,改善农村能源消费结构,引导农户合理利用能源的政策建议。