古县依托人字闸高效治理小流域的经验与做法

人字闸结构简单、投资省、见效快,是一项山地丘陵区充分利用小泉小水进行小流域治理开发的切实有效措施。介绍了山西古县以人字闸截流灌溉工程为突破口,高效治理小流域的经验与做法。     

人字闸的形式及建设要点

临汾市人字闸有钢筋混凝土人字闸、平板拆卸式钢制人字闸、拱形薄板拆卸式钢制人字闸 3种形式。人字闸一般由基础、闸墩、翼墙、放水建筑物、人字架和挡水面板等部分组成。自 2 0世纪 90年代以来 ,临汾市已建成人字闸 2 5 0座 ,总库容 10 5万m3 ,为该市山区沿河农村经济发展起到了较大作用。介绍了人字闸的建设要点。     

人字闸工程的规划设计和施工

人字闸是为拦蓄丘陵山区小泉小水而兴建的一种建筑物，其设计施工简单易行，能有效实现山区利用小泉小水进行灌溉的目的。就人字闸的规划、设计、施工过程及有关问题作一浅述，为类似地区修建人字闸提供参考。     

得卡河小流域综合治理开发模式

通过对水利部样板小流域——得卡河小流域水土流失综合治理的调查，总结了该流域治理的指导思想、原则、治理内容和措施配置形式，并对治理模式效益进行了定性和半定量分析。结果表明，开发性治理和观光型治理是山地小流域治理的一条有效途径。     

小流域治理的哲学思考

小流域是生态子系统、经济子系统和社会子系统组成的复合巨系统，小流域治理是对这三个子系统的协调过程。从哲学的观点分析小流域特征及治理特性，不仅要研究其线性，内在性、规范性、平衡性、渐进性、稳定性、透明性、确定性、精确性和定性性，而且要研究小流域的组成、结构和功能及其发展变化过程；影响治理效益的因素等，从而理解小流域特征与治理特性的对立面，为进一步认识小流域各组成因素及其相互关系。掌握系统总体的运动发     

黄土高塬沟壑区小流域暴雨侵蚀特征分析

基于黄河水利委员会西峰水土保持科学试验站历史实测降雨、径流、泥沙数据，分析水土保持治理对A、B两种暴雨(A类型以降雨时间不超过24 h的短历时强降雨形式出现，B类型以降雨时间超过24 h的连阴雨形式出现，下同)条件下小流域侵蚀特征的影响，结果表明：(1)研究区2005—2021年共出现暴雨事件13次，其中A类型暴雨占暴雨总次数的61.5%,B类型暴雨占暴雨总次数的38.5%,出现大暴雨2次，无特大暴雨出现；(2)在A、B两种类型暴雨条件下，水土保持治理小流域产流时间均值比非治理小流域延后17.97%和17.26%,涨水过程所用时间多109.72%和21.36%,非治理小流域退水过程所用时间均值分别比治理小流域多84.25%和1.21%,洪水总量均值为治理小流域的3.06倍和3.39倍，径流深分别为治理小流域的2.75倍和3.06倍，洪峰流量分别为治理小流域的1.95倍和2.09倍；(3)在A类型暴雨条件下，治理小流域产沙量峰值出现时间较非治理小流域滞后15.09 min,但输沙率峰值出现时间较非治理小流域提前10.33 min,在B类型暴雨条件下，治理小流域产沙量峰值出现时间及输沙率峰...     

黄土高原生态农业建设与小流域治理

小流域治理开发历来都把治理作为开发的基础，按大流域进行总体设计，按小流域及其内部各种地形层层进行优化布设和建设。小流域治理开发与生态农业建设的目标相一致，并为生态农业建设找到了较为理想的模式。提高小流域治理开发水平，可促进黄土高原生态环境和生态农业建设的可持续发展。     

靠小流域治理开发奔小康途径初探

靠小流域治理开发奔小康途径初探曹丽玫（黄委会黄河上中游管理局，西安７１００４３）通过治理开发，建设小流域经济，从而加快山区农村奔小康的步伐，是社会主义市场经济的需要。不同类型区、不同面积、不同社经情况和不同自然环境的小流域，治理策略不同，主导产业与拳...     

小流域治理环境质量综合评价指标体系研究

分析、研究了小流域治理效益评价的常用指标，提出了小流域环境质量综合评价指标体系。指标体系由流域生态环境、农村环境和社会经济3类指标和17个子指标构成，从整体上反映小流域治理后环境质量的改善、生态资源储备价值的增值和区域可持续发展能力的变化，为小流域治理的规划、设计、环境质量评价和验收管理提供科学依据。     

把小流域综合开发治理推向社会主义市场经济新阶段

把小流域综合开发治理推向社会主义市场经济新阶段吕茂田（山西省忻州地区行署，忻州市０３４０００）在１９９２年山西省第四次小流域治理工作会议上，全国政协副主席钱正英同志高瞻远瞩，提出要把小流域治理引向商品经济大道。钱副主席的指示，为新形势下加快小流域开发...     

Physical Properties of the Soils of Sibay City of the Republic of Bashkortostan

Eurasian Soil Science - The results of the study of the properties of urban soils of the city of Sibay located in the mining region of the Republic of Bashkortostan are presented. A specific...     

Heterogeneity of Organic Matter of Aggregates of Protocalcic Chernozems

Eurasian Soil Science - Layers were step-by-step removed from macroaggregates (2–1 mm in diameter) of Protocalcic Chernozems via successive abrasion in a revolving rotator during 5, 10, 15,...     

食用仙人掌萎蔫气象条件分析

塑料大棚内种植的食用仙人掌在土壤墒情较好时也有萎蔫现象发生，通过试验观测和对仙人掌生理习性的分析，发现阴雨过后天气突然放晴温度急剧上升易使仙人掌发生萎蔫现象，并提出了田间管理的应对措施。     

姬松茸多糖提取工艺的优化

对姬松茸子实体多糖提取的工艺条件中的多糖提取温度、提取时间、浸提液pH值3因子的最优化组合问题进行了定量研究,建立了具有良好预测性能的姬松茸多糖提取条件的模型,并利用回归模型对工艺条件的最优化组合,对各单因子要素的多糖得率及其交互作用进行了探讨。试验表明,当浸提温度为100℃、浸提时间为3h、浸提液pH值为6.3时多糖得率处于较高水平     

青海省耕地资源开发利用分析及对策研究

分析论述了青海省耕地资源开发利用的现状、特点和问题。在此基础上,提出了对青海省耕地资源进行研究的框架体系和思路,同时基于GIS/RS技术设计了相关的技术路线。最后依据所做设计对青海省耕地资源开发利用做了初步分析,并进行了相关的对策研究分析。     

济南山丘区土壤侵蚀潜在危险度景观格局分析

土壤侵蚀潜在危险度景观格局的形成及其变化是自然的和人为的多种因素相互作用的结果 ,运用景观生态学原理 ,通过分析景观斑块的类型、数量、面积大小和空间组合状况 ,揭示出济南市山丘区的土壤侵蚀潜在危险度分布特征及空间变异规律     

Characterization of physical and chemical properties of Varzea soils of Goias State of Brazil

Abstract

Brazil has approximately 30 million hectares of lowland areas, known locally as “Varzea,”; distributed throughout the country. Soils in these areas have the potential to support agricultural production, but very little is known about their fertility. The current experiment was undertaken to characterize the chemical and physical properties of representative “Varzea”; soils collected at 0–20, 20–40, 40–60, and 60–80 cm depth intervals from 23 sites in Goias State of Brazil. Organic matter contents averaged 42 g/kg in the surface 20 cm of soil and should make a significant contribution to overall nutrient availability. Soil pH increased slightly with depth from a mean value of 5.2 in the surface 20 cm of soil to a mean value of 5.4 in the 60–80 cm depth interval. Several soils had exchangeable Al values ≥ 1.0 cmol Al/kg, but soil Al saturation was generally less than the 60% level frequently associated with Al toxicity. However, cereal and legume production could benefit from lime addition in many of these soils. Although base saturation was fairly low in some soils, exchangeable Ca and Mg levels were, in general, adequate throughout the profile. Extractable P levels were adequate in most surface soil samples. Extractable K levels in these soils were generally low, and the application of K fertilizers should be beneficial, especially in conjunction with lime addition. The high clay content “Varzea”; soils of the Brazilian lowlands have some drainage problems but generally exhibit favorable chemical properties for crop production when compared to soils of the well‐drained Cerrados.     

Estimation of potential nitrogen-fixing activity of agrophytocenoses soils of the subtropical zone of Russia

An estimation of potential nitrogen-fixing activity of various soil types under agrophytocenoses of tea, filbert, peach, and pawpaw which grow in the area of Greater Sochi is given. High indicators of nitrogen fixation activity in the soil in the course of vegetation were characteristic of agrocenoses of pawpaw, peach, and filbert. The lowest level of nitrogen fixation was noted in the soil of a tea plantation. A negative correlation dependence of potential nitrogen-fixing activity on the acidity of the soil solution was established. A study of the seasonal dynamics of the activity of nitrogen fixation of soils of agrocenoses of the subtropical zone of Russia made it possible to distinguish a less active winter and more active spring-summer-autumn periods.     

Kinetics of Popping of Popcorn

The rate of popping of popcorn was measured in oil and in air. Kinetic data for lifetimes of individual kernels from a large population were obtained in oil at six constant temperatures (180–250°C) and also in an air‐popper at 202°C. The data are characterized by an induction period, which is, significantly, followed by a first‐order decrease in the number of unpopped kernels versus time. The activation energy for the first order process is 166.7 kJ/mol between 180 and 210°C, and 53.8 kJ/mol between 210 and 250°C. These data are consistent with a model that assumes 1) that the rate of heat transfer into a kernel follows Newton's law of cooling; 2) that in a sample of kernels there exists a distribution of critical pressures; 3) that for an individual kernel, the probability of popping is directly proportional to the difference between the internal aqueous vapor pressure and the kernel's critical pressure; and 4) that the measured rate constant at any temperature is an average overall of the kernels in the sample with critical pressures equal to or less than the internal aqueous vapor pressure. Minimum popping temperatures predicted by the model are 181 ± 2°C (oil) and 187 ± 2°C (air), in good agreement with previously reported direct measurements.