农业土壤的

The transformation from natural soil to agricultural soil results inevitably from the development of human life and production.

土地肥力是土地的客观属性；土地肥力包括了许多要素；具有肥力的土地是农业基本生产资料；土地自然肥力是自然历史过程的产物；土地经济肥力是人工肥力和自然肥力的统一体；科学技术在土地肥力发展中起着十分重要的作用；自然土壤向农业土壤的转化和发展，是人类生活和生产发展的必然产物。

However, the mechanisms of zinc and Cd interactions are not clear yet, most of the studies were limited to phenomena description and there are very few reports on physiochemical studies.

随着人类活动的加强、工业的发展，Cd对环境的污染日趋严重，尤其是对与人类食物息息相关的农业土壤的污染更为严重，直接威胁着人类的健康和安全。

This dissertation has six chapters, and the structure is in the following: The first chapter is about the background of agriculture. This chapter analyzes the influence which nature makes to agriculture, and indicates Mediterranean climate and natural situation are favor of the growth and distribution of agriculture. And with the effect of Etruscans and the opinion of physiocracy, Romans inevitably attach importance to agriculture.

本文共分六章，基本框架大致如次：第一章农业发展条件：本章重在分析自然地理对农业生产的影响，指出罗马所拥有的地中海气候及地形复杂、土壤肥沃等自然条件，有利于各种农作物的生长和分布；同时受伊达拉里亚人的影响以及传统上罗马人重农轻商的农业思想束缚，农业生产不可避免地受到人们的重视。

In this paper, as a case of Karamay, we have studied on space-time changement of soil quality in oasis of arid area. We measured quality for different land use types and years in same type by combinativing field sampling for Karamay in Xinjiang and analysis in laboratory, which is directed by former theory of soil quality. Then we did integrated evaluation of soil quality for different land use types, and had drew some conclusions as followed: In four land use types, the soil bulk density of layers(0～15cm) for farmland and tree land is bigger than the other land use types.The organic matter of every layer in manpower Tamarix Bulrush land is bigger; organic matter of Tamarix Bulrush land release efficiency nitrogen which result ration of C/N is higher; total nitrogen of all layers in farmland variety great as being effected by mass use of nitrogen in agriculture; deadwood and defoliation of tree、shrub and bulrush pooled in 5cm layer to result that quick nitrogen is the biggest among all layers. The total salt of nature shrub tree land for every layer being bigger than farmland explain that nature shrub thee land strongly stand salt and farmland for basification in this area; that the nutrient of face layer is bigger than the ground layer may be explained by that vegetation gather nutrient to be stored in deadwood and defoliation.

本文对以克拉玛依为例，对干旱区绿洲土壤质量的时间空间变化进行研究，在有关土壤质量的研究理论指导下，通过田间调查取样和室内分析相结合的方法，对新疆克拉玛依市农业开发区的不同土地利用方式及同一土地利用方式下不同利用年限土样土壤理化性质进行测定，从而对新垦绿洲不同土地利用类型土壤质量进行综合评价，结果如下：四种土地利用方式中，农地、乔木林地表层(0-15cm)土壤容重较大；各土层人工柽柳芦苇地的土壤有机质含量均较大；柽柳芦苇地的有机质在矿化过程中所释放出有效氮，导致柽柳芦苇地的C/N比例较高；受到农业耕作使用大量氮肥的影响，农地各土层全氮含量变异较明显；乔木、灌木及芦苇的枯枝落叶主要集中在5cm范围之内，导致几种土地利用方式类型下该层土壤速效氮最大；天然灌木林地的土壤总盐在各层均较大，其次是农地，说明天然灌木林地的高耐盐能力，以及该区农业生产用地的土壤盐碱化程度较重。

The soil erodibilities are compared and appraised for the majority of the soil types in Ningxia. The method published by D. W. Fryrear et al is adopted to calculate erodible fractions for the soils in Ningxia. The erodibilities of main soil types are compared and analyzed. Spatial distribution of soil erodibilities in the region can be perceived on the Map of Ningxia Soil Erodibility. The map is based on the digitized map of soil types of the all region by means of the geographical information system of Region Manager. Evaluation results show that erodible soils occupy a large portion of the total area of the region.(3) The third task is evaluation of effects of human activities for farming on soil erodibility. Tillage and cultivation can alter soil properties. The paper, based on the discussion on the characteristics of farmland suffering wind erosion in the region, analyzes the contents and intensities of farming disturbing surface soil. Emphasis is paid on the effect of farming on erodibilities of each type of soil.

W Fryrear等人的计算土壤可蚀部分含量的方程，此方程的自变量包括土壤有机质、碳酸钙、沙粒含量、沙粘比，计算了宁夏主要土壤类型表层的可蚀含量，进而比较它们的可蚀性，并以宁夏土壤分布图为底图用地理信息系统建立了宁夏土壤风蚀数据库，完成了宁夏土壤可蚀性图，评价结果显示宁夏地区主要的土壤类型较容易遭受风蚀；（3）农业经营对土壤风蚀的影响及其评价，在分析宁夏农业土壤遭受风蚀特征的基础上，首先讨论了农业活动对土壤理化性质的干扰，评价主要耕作栽培措施对土壤风蚀的影响，选取粗糙度、表面结皮、可蚀颗粒含量、留茬和有效时间为指标，用打分方法作了评价。

Scientific classification of soils is the basis of utilization and exploitation of soil resources. However, Soil Taxology, characterized by quantification, standardization and internationalization, is not popularized by far. So it is necessary to study its relationship with soil genesic classification and its application for agriculture and environment.

土壤的科学分类是土壤资源开发和利用的基础，土壤的系统分类以定量化、标准化和国际化为特点，但其大众化水平有待进一步提高，尚需加强与土壤发生分类的参比研究，并深化其在农业生产应用、土壤环境评价等方面的实践意义。

By analyzing soil quality of 4 kinds of land use types in Kalamay agriculture development area according to principal component analysis, we draw the conclusions: nature shrub tree land is affected little by mankind, a great deal of organic matter return to soil every year, and root system can improve soil physical quality, can absorb salt from soil, so the soil quality of nature shrub tree land is the best; the soil quality of farmland is better than the soil quality of manpower Tamarix Bulrush land, which may be reasoned that man make for soil quality by irrigation to exclude salt and fertilizing organic muck in the earlier oasis digging up period. Soil physical qualities of tree land get harden and worsen for flooding irrigation, furthermore climate in Kalamay is dry and rainless , the other irrigation is very long time after the former one, so soil get harden severity and result soil physical quality get worse and worse.

利用主成分分析法分析新疆克拉玛依农业开发区四种土地利用方式下的土壤质量，得出：天然灌木林地，受人为影响较小，每年有大量有机物质返还土壤，且天然灌木的根系可以很好的改良土壤的物理性质，同时所选天然灌木林灌木多是耐盐碱并且本身又具有吸收积累来自土壤的盐分，土壤质量最好；农田受到的人为影响最大，但农田综合得分却好于人工柽柳芦苇地综合得分，这可能是由于在开垦初期的绿洲农田，受到了人们灌水压盐及增施各种有机无机肥料等有利于土壤质量提高的措施所致；乔木林地，由于人们用大水漫灌的方式灌溉，致使林地土壤变得板结，土壤物理性质下降，加上克拉玛依地区气候干燥少雨，一次灌溉后较长时间后才有下一次灌溉，致使土壤理化性质恶化，土壤质量不高。

These deposits help build agricultural soil in the bahamas and supply nutrient for plants in uppper canopies of rain forest in brazil.

在巴哈马这些沉淀物帮助了农业土壤的组成，以及提供养分给在巴西雨林上游的植物。

Aimed at the increasing eco-environmental problems, including water shortage, water pollution, soil salinization, water loss and soil erosion, loss of function of the channel and river, biocenose degradation, etc, which severely infected the sustainable development for irrigation area, the main works in this paper are summarized as followed: constituting the measures of water resources shortages for developing agricultural water-saving technologies and adjusting agricultural structures; constructing the water polluting control and purification system of Mushroom lake: source control and decrement-sewage collection and treatment - channel ecological interception - wetland treatment -reservoir purification; putting forward the systematic projects for soil salinization and water loss and soil erosion of the integrated application of water conservancy agriculture and forestry.; constructing the ecological impervious channel model in west bank, from all of which theoretical bases and technical support for the eco-environmental rehabilitant in Manasi irrigation area were offered. All of these works were based on data collection, technical analysis, on-the-spot investigation, experimental research and technical development about Manasi irrigation area, etc.

通过对玛纳斯河灌区进行资料查阅收集、理论分析、现场勘察、试验研究和技术开发等途径，针对玛纳斯河灌区存在的水资源短缺、水体污染、土壤盐渍化、水土流失、沟渠河道功能缺失、生物群落退化等日益突出的严重影响灌区可持续发展的生态环境问题，制定了发展农业节水技术、调整农业结构的灌区水资源短缺的措施，构建了&源头控制减量-污水收集处理-引水调控-渠道生态截留-湿地生态处理-库区生态净化&的蘑菇湖水污染控制与净化系统；提出水利、农业、林业综合应用的灌区土壤盐渍化、水土流失问题的综合治理方案；构建了西岸大渠生态防渗型渠系模式，为玛纳斯河灌区生态环境修复建设提供了理论基础和技术支持。

This paper deals with the advantages of agricultural production in Jiujiang from atmosphere, water resources, soil and water areas. Jiujiang has high level and high intensity of agricultural production, great advantages of economic crops and sea fishery, the framework of agricultural distribution has already formed. Cotton, forestry, and fishery have level advantage and product advantage in Jiangxi province.

本文从气候、水资源、土壤、水域，探讨了九江发展农业生产的有利条件；探讨了九江具有农业生产水平和集约化程度较高，经济作物和水产养殖优势明显，农业专业化生产布局框架初步形成的农业发展特点，以及棉、麻、林业和渔业具有的规模和产值比较优势。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。