伦晚脐橙园区规划与土壤改良设计

伦晚脐橙属晚熟脐橙品种,因其汁多化渣、可食率高和品质上乘具有较高的社会经济价值。另外,与众多柑橘品种上市高峰错开(每年3月下旬上市),因而具有极高的推广种植意义。当前,关于伦晚脐橙的种植技术还不成熟,本文根据伦晚脐橙生长习性,总结伦晚脐橙种植园区规划方案与土壤改良设计方案,以期为更好的生产实践提供指导。

世界主要国家土壤调查工作回顾

自19世纪末100多年以来各国实施的土壤调查可分为四类,分别为土壤分类调查、农田土壤基础地力调查与评价、科学施肥与耕地保育所需农田化学性状采样调查和以土壤环境质量为主题的调查。土壤分类调查是近代各国最早开展,也是在全球最广泛实施的土壤调查,主要目的是弄清成土过程导致的土壤资源类别差异及其分布特征。由于自然条件下成土过程可达数万年,分类调查的主要产出--土壤图和各类土壤典型剖面理化性状表,具有很长的时效性,广泛用于各研究领域。各发达国家在20世纪完成全国性分类调查之后,未再进行新的、全国性的土壤分类调查。中国在全国第二次土壤普查中通过较高密度地面采样完成的大比例尺土壤图和与之匹配的10余万个典型剖面数据表,精度和指标丰富度超过许多发达国家分类调查成果,可供科学界和各行业长久使用。在人均耕地资源紧缺的中欧国家,为满足土地管理部门和农民对更方便、好懂的农田土壤质量指标的需求,20世纪中叶以来,通过高密度地面采样,进行了农田土壤基础地力调查与评价,为每个田块建立了具有官方认证性质的农田土壤百分价指标和基础地力底档。这一调查结果广泛用于土地与农田管理、税收、农业补贴、农田租赁、交易、借贷、保险等行业,成为各行业不可缺少的农田土壤质量百年基础数据。中国人均耕地面积较中欧国家更少,但至今农地管理中土壤质量信息短缺,难以实现耕地数量与质量的合并管理,需要探索与中国经济、社会制度和社会发展相适应的农田基础地力调查、评价方法与运行机制,为每个田块建立精准、可靠、科学、可长期使用的基础地力底档。对施肥推荐及耕地保育所需农田化学性状采样调查的总结显示,发达国家已将该类调查纳入科学施肥和耕地保育技术支撑体系。对于提高农民科学施肥技术水平,构建并保障技术支撑体系运行,比开展全国性农田土壤养分普查更为重要。多年来,中国土壤肥料领域从基础研究到农民田间应用的全链条中,应用技术与农技推广两个环节比较薄弱。中国至今尚未发布适合各地农民田间应用的分区、分类、量化科学施肥与耕地保育技术指标,也缺少能对农民进行针对性指导的智能化手段。在占中国作物总播种面积23.6%的蔬菜、水果、花卉等经济作物农田上,农民过量施肥情形严重,影响产量和农民经济效益,并导致农业面源污染。弥补技术支撑体系中的短板成为合理施肥和提升耕地质量的关键。20世纪末以来,为了解土壤和环境污染与变化,科学制定控制对策和检验控制效率,各国陆续启动了环境主题的土壤调查。随着3S和大数据技术发展,新的土壤调查普遍采用数字土壤制图方法替代传统人工制图。而准确界定调查目标,全面了解与调查目标相关的研究进展,了解可用的相关基础图件和辅助信息,在此基础上确定地面采样原则、采样密度、采样土层深度、需要采集的其他辅助信息,是未来科学实施各类土壤调查的关键,可收到事半功倍效果。

园林土壤工程方法研究与展望

园林土壤工程是集土壤学、风景园林学、材料学等多学科的交叉应用,是园林工程的重要组成,贯穿于园林工程的规划设计、预算编制、施工、监理、竣工验收,以及后期的养护管理,园林土壤工程的质量直接影响植物的景观效果和后期的养护管理成本。文章通过对国内外园林土壤工程理念和实践研究,阐述了园林土壤工程背景、概念及其在园林工程中的重要作用,提出了基于园林工程设计的土壤调查、土壤设计原则、程序,以及主要技术,以期为新时代城市园林绿化建设提供科学参考和技术支撑。

夏热冬暖地区冷却塔耦合土壤源热泵系统分析

结合具体的工程实例,介绍了夏热冬暖地区冷却塔耦合土壤源热泵空调系统的设计及特点,通过实验说明采用冷却塔耦合土壤源热泵系统不仅能很好地解决土壤热平衡问题,同时还能降低初投资,使其优越性得到充分发挥。

基于生态理念的风景园林设计

文章阐述了风景园林设计中的生态学理论与基本原则,提出了基于生态理念的风景园林设计策略,包括以原有生态为基础进行设计、合理选择与配置植物、加强土壤改良设计、使用可再生能源或清洁能源、改造废弃场地、更新设计手段。

Major factors controlling nitrous oxide emission and methane uptake from forest soil

Soil samples were taken from depth of 0-12 cm in virgin broad-leaved Korean pine mixed forest in Changbai Moun-tain in July 2000. The effects of temperature, soil water content, pH, NH4+ and NO3- on N2O emission and CH4 uptake of a for-est soil were studied in laboratory by the method of orthogonal design. It was observed under laboratory conditions in this study that there were significant correlations between N2O emission rate, CH4 oxidation rate, soil pH and temperature. Nevertheless, N2O emission rate also showed a significant positive correlation with CH4 oxidation rate. The results suggested that pH and temperature were important factors controlling N2O emission and CH4 oxidation under this experiment conditions.

船式拖拉机的开发与应用

有些地区因土壤稀软 ,拖拉机无法下田耕作。本文提出了船式拖拉机的设计理论 ,为其开发应用提出了可行性方案。

Impact of Seasalt Deposition on Acid Soils in Maritime Regions

The characteristics of seasalt deposition and its impact on acid soils in maritime regions are reviewed. It is pointed out that studies involving the impact of seasalt deposition on acid soils have been concentrated on short-term effects on soil and water acidification. A deep consideration of long-term effects on soil acidification in maritime regions is still needed.

Penetration grouting reinforcement of sandy gravel

To study the relationship between grouting effect and grouting factors, three factors （seven parameters） directionless pressure and small cycle grouting model experiment on sandy gravel was done, which was designed according to uniform design method. And regressing was applied to analysis of the test data. The two models test results indicate that when the diffusing radius of grout changes from 26 to 51 cm, the grouted sandy gravel compressing strength changes from 2.13 to 12.30 MPa; the relationship between diffusing radius（R） and water cement ratio（m）, permeability coefficient（k）, grouting pressure（p）, grouting time（t） is R=19.953m^0.121k^0.429p^0.412t^0.437; the relationship between compressing strength（P） and porosity（n）, water cement ratio, grouting pressure, grouting time is P =0.984n^0.517m6-1.488p^0.118t^0.031. So the porosity of sandy gravel, the permeability coefficient of sandy gravel, grouting pressure, grouting time, water cement ratio are main factors to influence the grouting effect. The grouting pressure is the main factor to influence grouting diffusing radius, and the water cement ratio is the main factor to influence grouted sandy gravel compressing strength.

Hydraulic conductivity of GCLs in MSW landfills

The state of the art of the study on the hydraulic conductivity of GCLs is presented in terms of the influence of the effective stress,chemical interactions,freeze-thaw cycles and temperature gradients.The changes of void ratio caused by changes of effective stress have a direct linear effect on the hydraulic conductivity,regardless of the cation concentration or the thickness of the adsorbed layer.The hydraulic conductivity is related to the relative abundance of monovalent and divalent cation(RMD),and RMD has a great effect on the hydraulic conductivity in weak solution.The long-term susceptibility of GCLs to increased hydraulic conductivity as a response to repeated freeze-thaw cycling is minimal,which has been proved after 150 freeze-thaw cycles.The potential of desiccation cracking increases with the increasing temperature gradient and is related to the initial subsoil water content,the applied overburden stress,etc.

Analytical expressions for determining the stability of cohesionless soil slope under generalized seismic conditions

In recent major earthquakes, the researchers have found the need for consideration of vertical seismic acceleration for the stability analysis of the man-made and natural slopes. However, in most past studies, the performance of slopes has been assessed by accounting only the horizontal seismic component of the ground motion, without giving due weightage to the effect of vertical component. In the present study, analytical expressions are derived to determine the factor of safety, yield seismic coefficient and consequently the seismic displacement of cohesionless soil slope under combined horizontal and vertical components of the ground motion. The derivation uses the Newmark's sliding block approach, in which the soil slope with a planar failure surface within the framework of conventional pseudo-static analysis is assumed to follow the Mohr-Coulomb failure criterion. The effects of vertical seismic coefficient on the stability of cohesionless slope have been studied through a set of graphical presentations for a specific range of soil parameters. It is observed that overlooking the effect of the vertical component of the ground motion on factor of safety and the displacement while designing the slope may be detrimental, resulting in the slope failure. The general expressions presented in this paper may be highly useful in the field of earthquake geotechnical engineering practice for designing the cohesionless soil slopes under combined horizontal and vertical seismic loads.

The Drainage Exchange of Stormwater Potential in Flat Area Problems

Groundwater as an alternative source still does not contribute to the water supply in area of Parit Raja because of the limitation of water availability in the ground. This lacking of groundwater could be caused by the circumstance that the top layer of soil is dominated by compacted clay around 2 meters in which its permeability is small, so the water is difficult to infiltrate the ground. The recharge well technique was designed based on the flat area problems, layer of real condition, flow water table and low infiltration rate. Resistivity soundings were made at existing wells to assess the subsurface layers. Beside that, the past records on floods event, sub surface and surface studies were collected around study area as a preliminary studies. It was presented that the study area promised good prospects to increase the capability of groundwater and contribute to the drainage system by reducing the volume of rainfall runoff using the recharge well technique.

The Role of Soil Investigation on Performance-based Design in Geotechnical Earthquake Engineering

The spatial variability of geotechnical earthquake engineering critical parameters obtained by laboratory and in situ tests in the same area is affected by different measurements. The paper provides a brief synthesis of ground motion and site effects analysis procedures within a Performance-Based Design framework. In particular it focuses about the influence on the evaluation of site effects in some active regions by different shear waves velocity measurements （Down Hole D-H and Seismic Dilatometer Marchetti Test SDMT）. Moreover the variation of shear modulus and damping ratio with strain level and depth from different laboratory dynamic or cyclic tests for soil characterisation （Resonant Column Test RCT） was evaluated. The available data enabled one to compare the shear waves velocity profile obtained by laboratory and in situ tests （Cone Penetration Tests CPT） with empirical correlations proposed in literature.

Soil Uncertainties on Performance of Geotechnical Works

Performance-Based Design （PBD） is a more rational approach, particularly in seismic environments. In this approach it is relevant the performance required to structures and to geotechnical works, as well as the geotechnical constitutive models used to predict the performance. The parameters of the constitutive models are related in turn to soil properties. So soil properties are a key point for Performance-Based Design. Questions arising are： （i） which are the more relevant soil properties to solve a specific PBD geotechnical problem？ （ii） which are the more relevant model parameters and how they can be evaluated and/or correlated to soil properties？ （iii） which is the role of the soil parameters uncertainty in Performance-Based Design？ An answer to these questions is given in this paper, outlining the potential offered by the new advanced in-situ and laboratory tests and discussing the performance required by some geotechnical works.

Improvement of Physical and Biological Quality of Soil in a Sugarcane Plantation through the Management of Organic Matter Input

Changes in soil quality of sugarcane plantation as a result of changes in land management can not be measured directly, but must be demonstrated by measuring the change in the properties of the ecosystem as an indicator. This research aimed to study the effect of the addition of various quality and quantity of organic matter on soil biology （earthworms） and physical quality （aggregate stability, macroporosity and infiltration rate）. There were i 5 treatment combinations tested. The first factor is the type of organic matter： （1） cattle manure （CM）, （2） filter cake （FC）, （3） sugarcane trash （ST）, （4） a mixture ofCM ＋ FC and （5） a mixture of CM ＋ ST. The second factor is the application dose of organic matter, which consists of three levels-5, l0 and 15 Mg/ha. The treatments were arranged in a factorial randomized block design with three replicates and one control treatment （without organic matter input）. The result of this research showed that the highest population density of earthworms was found in the treatment of ST （78 individuals/m2） and a mixture of CM ＋ ST （84 individuals/m2）. The type of organic matter with C/N ratio ranged from 15.5 to 34.7 and cellulose content in 33.3%-40.1% gave better growth of earthworm. The effect of increase in earthworm growth on soil physical improvement is more apparent in the treatment of mixture of low quality and high quality organic matter. The increase of earthworm density and biomass enhanced soil macroporosity （from r = 0.683 to r = 0.606） and infiltration rate （from r = 0.669 to r = 0.756）. The results of this study suggest a mixture of CM ＋ ST or ST alone as organic matters, which is recommended to improve soil physical and biological quality of sugarcane land, with the dose application ranged from 10 Mg/ha to 15 Mg/ha.

Comparison of Wheat Planting Methods and Residue Incorporation Under Saline-Sodic Soil

The present research was conducted to monitor the wheat productivity along with residue incorporation under saline-sodic soils by examining different planting methods at Zaidi Farm, Kakar Gill, Sheikhupura District, Punjab Province in 2007-2008. Randomized Complete Block Design （RCBD） with three replications was used having treatments： control （broadcast）, zero till wheat plantation, wheat plantation using happy seeder and wheat plantation on raised beds. It was observed that tillering was pretty higher （141 and 139 m2） under raised bed as well as happy seeder plantation as compared to zero tilled wheat and broadcast technique. A significant relation was detected among maximum straw and grain yield （4,898 and 1,752 kg-ha1） in raised bed followed by happy seeder planting method. The lowest grain yield was recorded in the broadcast method. Maximum net revenue earned by raised bed planting method （39,908 PKR） followed by happy seeder methodology （37,533 PKR）. The overall study suggests that raised bed and happy seeder wheat plantation are the superior planting methods.

Vibration Analysis of Frame Structure with Soil-Structure Interaction

A common design practice for dynamic loading assumes the frame fixed at their bases. In reality, the supporting soil medium allows movement to some extent due to its property to deform. This may decrease the overall stiffness of the structural system and may increase the natural period of the system. The effect of soil flexibility is suggested to be accounted through consideration of springs which have specified stiffness and soil half space. Results show that the dynamic response of frame structure to vibrations is due to applied dynamic load and is highly dependent on the soil type and the method of modeling soil structure interaction. The response of frame structure under dynamic load is higher in case of linear discrete independent spring as comparing with perfect bond cases. Except the response of frame in case of piles embedded in soft clay, half space are higher than frame with piles and linear elastic spring due to the interaction between the frequencies of applied load and frequencies of frame structure. Also, result showed that it is important to include the soil-structure interaction in the analysis of the system in order to correctly simulate the dynamic problem for controlling on the resonance phenomena.

A Review on Genetically Modified Plants Designed to Phytoremediate Polluted Soils： Biochemical Responses and International Regulation

In recent years,there has been an increasing interest in finding sustainable strategies for the efficient removal of contaminants from soils.The objective of this review is to examine the biochemical principles of specific genetic modifications in plants,their applications in the field for specific contaminants as phytotechnologies,and their international regulation.In addition,the review presents some biological aspects of rhizosphere-related phenomena,the interactions of organic and inorganic pollutants with plants,and the performance of the phytotechnologies across the continents.During the last few decades,at least eight genera of genetically modified plants(GMPs)have been tested and used for soil remediation with outstanding results.Arabidopsis,Nicotiana,and Oryza are the plant genera most widely studied.Specific plant genes such as metal transporters,chelators,metallothioneins,phytochelatins,and oxygenases have been transferred to plants to improve the elimination of contaminants in soil.We discuss some important aspects of gene manipulation and its application for removal of diverse contaminants.A key challenge faced by phytotechnologies is the final disposal of the generated biomass,from a safety aspect.We argue that the commercial success of phytotechnologies depends on the generation of valuable biomass on contaminated land and its use for bioenergy generation.The use of such technologies would promote a broader understanding of the importance of plants,especially GMPs,in the environment and their contribution to environmental sustainability.

Land consolidation engineering and modern agriculture: A case study from soil particles to agricultural systems

Land consolidation engineering is one of the very important ways to improve the quality of farmland and the level of agricultural productivity. Studies of land consolidation and crop cultivation still mainly focus on single land functional optimization or crop breeding and yields. However, whether the improved crop varieties were sown on healthy and fertile soils is still a question. This paper introduces new ideas and engineering measures for sandy land rehabilitation and modern agricultural development in the Mu Us Sandy Land, Shaanxi Province, Western China. The important roles of particles and aggregates in soil reconstruction were confirmed following three innovative microscopic theories, including micro-structure, micro-morphology and micro-mechanism. New soil was constructed based on the physical complementarity of sandy, clay and loess particles in the Yulin area, northern Shaanxi Province. Field experiments were carried out to study the appropriate mixture ratio of different soils and their suitability for different crops. The improved crop varieties were sown on healthy and fertile soils, which were chosen by coupling according to its soil ecological suitability and crop physiological adaptability. The fertility improvement practices in the new constructed soils with different crops integrated water and fertilizer management measures, which were also provided in the experiment. Overall, an integrated land optimization configuration with improved and optimized crop variety selection was suggested for engineering sandy land-oriented consolidation from the soil particles to the agricultural system.

Sampling Designs for Validating Digital Soil Maps: A Review

Sampling design(SD) plays a crucial role in providing reliable input for digital soil mapping(DSM) and increasing its efficiency.Sampling design, with a predetermined sample size and consideration of budget and spatial variability, is a selection procedure for identifying a set of sample locations spread over a geographical space or with a good feature space coverage. A good feature space coverage ensures accurate estimation of regression parameters, while spatial coverage contributes to effective spatial interpolation.First, we review several statistical and geometric SDs that mainly optimize the sampling pattern in a geographical space and illustrate the strengths and weaknesses of these SDs by considering spatial coverage, simplicity, accuracy, and efficiency. Furthermore, Latin hypercube sampling, which obtains a full representation of multivariate distribution in geographical space, is described in detail for its development, improvement, and application. In addition, we discuss the fuzzy k-means sampling, response surface sampling, and Kennard-Stone sampling, which optimize sampling patterns in a feature space. We then discuss some practical applications that are mainly addressed by the conditioned Latin hypercube sampling with the flexibility and feasibility of adding multiple optimization criteria. We also discuss different methods of validation, an important stage of DSM, and conclude that an independent dataset selected from the probability sampling is superior for its free model assumptions. For future work, we recommend: 1) exploring SDs with both good spatial coverage and feature space coverage; 2) uncovering the real impacts of an SD on the integral DSM procedure;and 3) testing the feasibility and contribution of SDs in three-dimensional(3 D) DSM with variability for multiple layers.