水稻对镉的吸收规律及大米的安全控制技术研究进展

重金属特别是重金属镉的污染对水稻的生产安全构成了威胁。总结了水稻对镉的吸收、分配和积累规律及近年来对大米的安全控制技术的研究进展,以期为大米的安全生产奠定基础。     

榆神府矿区农业用水安全性研究

榆神府矿区煤炭资源的大规模开发利用给区域内农业用水带来极大的安全隐患。利用2011-2014年矿区内农业用水的水质监测数据对农业用水安全进行研究。首先依据地表水功能划分的要求分析水质状况,其次评估水质是否满足绿色食品生产环境的要求。结果表明:榆神府矿区用于农业灌溉的地表水综合污染指数为0.292~0.478,部分符合Ⅲ类水质标准,窟野河上游多个断面水质较差,2013-2014年化学需氧量超标率达100%,为Ⅳ类水;矿区内大部分断面水质都符合绿色食品生产环境的要求,但是2014年部分断面的pH有少量超标。为防止农业用水污染,必须加强入境水质监测,增加水污染检测项目,并加强农业用水监测和相关研究。     

科学认识和防治耕地土壤重金属污染

农产品产地环境质量直接影响农产品质量。近年来,我国部分地区土壤重金属污染问题日益凸显,已成为影响农产品质量安全,并受到广泛关注和重视的突出的问题之一。本文在分析土壤重金属污染具有来源复杂、评价难度大和治理任务艰巨等特点的基础上,提出为科学防治耕地土壤重金属污染,必须本着科学认识、统筹规划、综合防治、分类指导、治用结合的原则,从加强普查监测、加强科技支撑、完善法律法规、培育环保产业、构建工作体系等方面入手,以切实加强和改进耕地土壤重金属污染防治工作。     

江西省可持续食物安全评价

选取了化肥用量等22个指标,采用层次分析法测算江西可持续食物安全度。结果表明,1978~2003年江西可持续食物安全度逐步提高,目前食物处于安全水平。江西食物生产因子、资源禀赋因子和气候因子安全水平较高,对食物安全较有保障;食物保障因子和社会经济因子安全水平偏低,是可持续食物安全的薄弱环节;可持续环境因子的安全水平正逐步加强,有利于提高可持续食物安全度。     

Measurement of erosion: Is it possible?

Reasons for erosion measurements are: (1) to determine the environmental impact of erosion and conservation practices, (2) scientific erosion research; (3) development and evaluation of erosion control technology; (4) development of erosion prediction technology and (5) allocation of conservation resources and development of conservation regulations, policies and programs. A handicap for the control of the insidious erosion process is the difficulty of determining its magnitude. Four causes are often mentioned in the literature: the large temporal and spatial variation of erosion, the paucity of accurate erosion measurements, the problem of extrapolating data from small plots to higher scales and the conversion of erosion into production and monetary units (impact). It is an illusion to think that the role of measurements can be taken over by the application of erosion prediction technology. Measurements are needed to develop, calibrate and validate that technology. Measurement techniques differ in accuracy, equipment and personnel cost. The most accurate (and often most expensive) techniques do not always serve the measurement purpose. This paper gives a critical overview of current measurements techniques for erosion at different spatial and temporal scales. Examples are presented of techniques for direct measurements as well as for indirect measurements, i.e. measurements of soil properties that serve as input for models. The paper is concluded with a critical evaluation.     

区域生态质量的模糊综合评价——以福建省2006年7-9月为例

采用模糊综合评价法,选取湿润指数、植被覆盖指数、水体密度指数、土地退化指数、灾害指数作为评价因子,采用专家打分法确定各评价因子权重,利用福建省2006年7-9月67个市(县)的地面气象观测资料和福建省各地土地利用数据,从气象角度对福建省的生态质量进行评价。结果表明:福建省各地生态质量等级均属良好,各地(市)综合评价值介于0.54～0.67,地区间差异较小,这与福建省自身独特的气候、地貌和生物生态环境特征相对应。     

Accuracy of methods for field assessment of rill and ephemeral gully erosion

To properly assess soil erosion in agricultural areas, it is necessary to determine precisely the volume of ephemeral gullies and rills in the field by using direct measurement procedures. However, little information is available on the accuracy of the different methods used. The main purpose of this paper is to provide information for a suitable assessment of rill and ephemeral gully erosion with such direct measurement methods. To achieve this objective: a) the measurement errors associated to three methods used for field assessment of channel cross sectional areas are explored; b) the influence of the number of cross sections used per unit channel length on the assessment accuracy, is analysed and; c) the effect of the channel size and shape on measurement errors is examined. The three methods considered to determine the cross sectional areas were: the micro-topographic profile meter (1); the detailed measurement of section characteristic lengths with a tape (2); and the measurement of cross section width and depth with a tape (3). Five reaches of different ephemeral gully types 14.0 or 30.0 m long and a set of six 20.4 to 29.4 m long rill reaches were selected. On each gully reach, the cross sectional areas were measured using the three above mentioned methods, with a separation (s) between cross sections of 1 m. For rills, the cross sectional areas were measured with methods 1 and 3, with s = 2 m. Then, the corresponding total erosion volumes were computed. The volume calculated with method 1 with s = 1 m for gullies and s = 2 m for rills was taken as the reference method. For each channel, and for each one of the possible combinations of s and measurement method (m), the relative measurement error and the absolute value of the relative measurement error (E_sm^r and |E_sm^r|), defined with respect to the reference one, was calculated. |E_sm^r| much higher than 10% were obtained very easily, even for small s values and for apparently quasi prismatic channels. Channel size and shape had a great influence on measurement errors. In fact, the selection of the more suitable method for a certain gully shape and size seemed to be much more important than s, at least when s < 10 m. Method 1 always provided the most precise measurements, and its results were the less dependent on s. However, s must be < 5 m to guarantee an error smaller than 10%. Method 2 is not recommended, because it is difficult, time consuming and can lead to large errors. Method 3 seems to be enough for small, wide and shallow gullies, and for small rills, but only if s is shorter than 5 m. Results obtained after the analysis of rill measurement errors were similar to those of gullies. The analysis of E_sm^r and |E_sm^r| when calculating channel volumes using a unique representative cross section highlighted the importance of correctly selecting the adequate cross section. Due to the high error values that this method can entail, it is not considered as advisable whenever accurate erosion measurements are pursued.     

海南岛土壤质量系统评价与区域特征探析

研究建立了海南岛热带地区土壤质量系统评价模型 ,并对该岛土壤质量进行综合评价 ,结果表明海南岛土壤养分有效性为主要限制因子 ,水分有效性和根系适宜性状较好 ,土壤综合质量中等偏上。与林地相比其他土地利用方式土壤质量均有所下降     

农业生态系统能值分析方法

阐述了能值分析理论基本概念和原理及其具体分析步骤 ,能值计算方法在农业生态系统的应用、农业生态系统能值分析指标体系内容及其对资源环境价值评价和量化的意义     

混凝土简支梁桥承载能力自动评估系统的开发

针对现有及新建桥梁需要快速准确地评估其承开车能力与技术状况这一急待解决的问题，开发了桥梁承载能力自动评估系统，并通过实例验证了此系统的准确性。