粉煤灰土壤及所产蔬菜的有害元素含量变化和环境意义

利用南京第二热电厂湿排的粉煤灰,进行了改良蔬菜土壤的试验,并对试验用的粉煤灰、不同施灰量的土壤及所产蔬菜共３８ 个样品的有害元素和放射性元素含量进行了系统的测定。结果表明：这些元素在土壤中的含量与粉煤灰施用量无明显相关性;在本次试验范围内施用粉煤灰没有造成土壤的污染;其所产蔬菜的这些元素含量也均低于国家卫生标准限值,食用是安全的。     

太阳能动力用于沙漠戈壁蔬菜管道栽培——植株形态、结构及生理表现

针对沙漠戈壁土壤贫瘠、水分渗漏严重、地表温度高、蒸发强烈的植物生境特征,组装了一套太阳能沙漠戈壁蔬菜管道沙培技术设备,包括光伏发电系统、蔬菜管道沙培系统、自动控制系统。光伏电能驱动水泵,保障蔬菜沙培系统定时供液、回流。管道沙培的黄瓜、西红柿、西瓜与大田种植的相对照,进行了叶绿素荧光参数测定,植株个体特征测定,茎解剖结构对比研究。结果表明：管道沙培黄瓜、西红柿、西瓜光合系统Ⅱ的原初光合转化效率高;植株个体矮化、茎粗化;髓和维管束发达,皮层厚度增大。这表明,该设备适用沙漠戈壁蔬菜栽培,具有开发应用前景。     

北京市蔬菜和菜地土壤砷含量及其健康风险分析

通过对北京市蔬菜和菜地土壤砷含量状况进行大规模调查,研究了蔬菜和土壤砷含量及其健康风险,并筛选出抗砷污染能力强的蔬菜品种。根据蔬菜的消费量并兼顾品种多样性的原则,在北京市规模化蔬菜栽培基地 (采集蔬菜及土壤样品) 和蔬菜批发市场 (蔬菜样品) 共采集93种蔬菜400多份蔬菜样品和39个土壤样品系统地分析其砷含量。研究发现：北京市菜地土壤砷含量范围和平均含量分别为4.44~25.3和9.40 mg/kg,明显超过北京市土壤砷背景值;北京市蔬菜砷含量最高达0.479 mg/kg,平均含量为0.028 mg/kg,均未超过《食品中砷限量卫生标准》(GB4810-94) 的限量值,但其中有2个蔬菜样品 (萝卜和大蒜) 砷含量超过WHO/FAO制订的限量标准。北京市蔬菜砷含量在东偏北方向 (偏转11^o-30^o) 存在明显的"U"型趋势分布。裸露地蔬菜砷含量显著高于设施蔬菜。油菜、萝卜、小白菜、大葱、芥菜、黄瓜、大白菜和甘蓝抗砷污染能力较弱,而辣椒、云架豆、冬瓜、茄子、菠菜、西红柿、芹菜等抗砷污染能力则较强。北京市居民从蔬菜中摄入砷平均值为0.016 mg/(人·d),蔬菜砷对北京市部分人群存在一定的健康风险。     

海南冬种瓜菜气象灾害风险评估与区划

基于自然灾害风险理论,利用海南省18个站点气象资料、瓜菜生产和社会经济要素资料,通过灾情反演,构建苗期湿涝、冬季寒害和春季干旱致灾等级指标。综合致灾、孕灾、灾损、防灾能力,进行瓜菜气象灾害的综合风险分析与区划。结果表明:苗期湿涝危险性从西南至东北增加,春季干旱危险性东西高、中间低;西瓜寒害危险性从中部向两边减小,豇豆和丝瓜寒害危险性从南往北加重,辣椒寒害危险性从东南到西北增加;苗期湿涝孕灾环境敏感性从中部山区向沿海和平原地区增加,春季干旱和冬季寒害趋势相反;瓜菜灾损风险和防灾能力在区域上存在明显差异;西瓜、豇豆和辣椒气象灾害综合风险总体趋势一致,高风险区集中在海南东部地区;丝瓜气象灾害综合风险高值区在北部地区。     

Arsenic in the water–soil–plant system and the potential health risks in the coastal part of Chianan Plain,Southwestern Taiwan

The present study investigates the bioavailability, soil to plant transfer and health risks of arsenic (As) in the coastal part of Chianan Plain in southwestern Taiwan. Groundwater used for irrigation, surface soils from agricultural lands and locally grown foodstuffs were collected from eight locations and analyzed for As to assess the risks associated with consuming these items. The concentration of As in groundwater ranged from 13.8 to 881 μg/L, whereas surface soil showed total As content in the range of 7.92–12.7 mg/kg. The available As content in surface soil accounted for 0.06–6.71% of the total As content, and was significantly correlated with it (R² = 0.65, p < 0.05). Among the leachable fraction, the organic matter (3.23–54.8%) and exchangeable portions of oxides (6.03–38.4%) appear to be the major binding phases of As. The average As content in fourteen studied crops and vegetables varied from 10.3 to 151 μg/kg with maximum in mustard and minimum in radish. All the plants showed considerably higher As content (21.5 ± 3.64–262 ± 36.2 μg/kg) in their roots compared to the edible parts (9.15 ± 1.44–75.8 ± 22.9 μg/kg). The bioaccumulation factor (BAF) based on total As (ranging from 0.0009 to 0.144) and available As in soil (ranging from 0.039 to 0.571) indicate that mustard, rice, amaranth and spinach are the highest accumulators of As. Although the health risk index (HRI) of the studied crops and vegetables ranged from only 0.0068–0.454, with the maximum in rice, the combined HRI indicates an alarming value of 0.88. Therefore, the possible health risks due to long-term consumption of rice and other As-rich foodstuffs could be overcome by controlling the contamination pathways in the water–soil–plant system.     

TRENDS IN THE URBANIZATION PROCESS

Matthiessen, Christian Wichmann: Trends in the urbanization process. The Copenhagen case. Geografisk Tidsskrift 80: 98–101. Copenhagen, June 1980.

Within the framework of the international comparative research project (Cost of Urban Growth) new trends in urban development have recently been observed. The object of this article is to discuss the trends and give impirical evidence on Danish data.     

寿光市蔬菜品质与农业地质背景关系

根据寿光市蔬菜种植区种植特征,采用对部分茄果类蔬菜、水、土的样品抽样测试、数理统计、相关分析等方法,得出蔬菜的品质与农业地质背景存在一定的相关性,以及土壤有选择蔬菜品种性,蔬菜在品质上有选择农业地质条件性的结论。     

Agribusiness and farmers in Mexico: the importance of contractual relations

In recent decades contract farming as a mechanism that integrates and subordinates agricultural production to export oriented agribusiness has expanded in Third World countries. In Mexico contract farming dominates the production of horticultural crops for processing and export. It is also used for barley and to grow some varieties of wheat for Cargill . The contract farming labour agreement represents an institution that links local and global processes where agribusiness is the key actor that integrates local farmers to national and world markets. The purpose of this paper is to analyse the implications of contract farming for productive relations by examining its impact upon farmers and firms. The study found that despite the disadvantages of contract farming for growers, and the disproportional risks born by producers, they enter into contract farming labour agreements because they lack alternatives for financing, technical assistance and access to markets. The experience of contract farming in Mexico and several Third World countries shows that its growth is related to the implementation of neo-liberal policies that are accompanied by the withdrawal of state support and regulation of agricultural production. In this context, contract farming represents a livelihood strategy for many Mexican growers.     

寿光市蔬菜品质与农业地质背景关系

根据寿光市蔬菜种植区种植特征,采用对部分茄果类蔬菜、水、土的样品抽样测试、数理统计、相关分析等方法,得出蔬菜的品质与农业地质背景存在一定的相关性,以及土壤有选择蔬菜品种性,蔬菜在品质上有选择农业地质条件性的结论。     

10—11月海南省瓜菜苗期湿涝风险评估与区划

为了评估海南省冬种瓜菜苗期生长阶段容易遭受的湿涝灾害,基于1998—2011年海南省18个气象站气象资料、各市县西瓜、豇豆、辣椒、丝瓜4种冬种瓜菜产量及苗期湿涝灾情资料,以降水量、降水日数等因子建立主成分分析综合指标,通过灾情反演构建苗期湿涝致灾等级指标,结合孕灾、灾损和防灾能力进行瓜菜苗期湿涝灾害综合风险分析与区划。结果表明:瓜菜苗期湿涝危险性从西南至东北增加,轻度与重度湿涝风险概率分布趋势相反,苗期湿涝孕灾敏感性从中西部山区向沿海和平原地区增加,瓜菜苗期湿涝灾损风险和防灾能力分布存在差异,且不同瓜菜差异明显;4种瓜菜苗期湿涝综合风险总体分布趋势一致,从西南至东北地区风险等级加重,降水、地势、土地等因素综合导致东部和北部部分地区苗期湿涝的风险高。