中亚热带人工经济林土壤有机碳含量及分布

人工经济林在中国南方种植面积大,并有不断增加的趋势.人工经济林生态系统受人为周期性经营活动影响比较大,是重要的流动性碳库.因此,选择福建省建瓯市万木林自然保护区内本地条件基本一致的毛竹(Phyllostachys heterocycla)、柑橘(Citrus reticulata Blanco)和锥栗(Castanea henryi)作为研究对象,探讨其土壤有机碳含量及其垂直分布特征,结果表明:3种林地土壤剖面有机碳含量的变化范围分别为毛竹林5.91～19.18 g.kg-1、柑橘5.70～13.31g.kg-1、锥栗3.84～10.78 g.kg-1,3种林地土壤有机碳含量随着深度的增加呈现递减趋势;3种林地0～20 cm、20～40 cm层土壤有机碳含量与40～60 cm、60～80 cm、80～100 cm各层均存在显著性差异(P<0.05);3种林地间土壤有机碳储量均存在显著性差异(P<0.05);使用对数方程对3种林地土壤有机碳含量随土壤深度的变化进行拟合均达到显著水平(P<0.05);土壤有机碳含量与土壤全N、C/N比之间存在一定的相关性,特别是3种林地土壤有机碳含量均与土壤全N含量的相关性最好(...     

New technologies and systems for high quality citrus fruit production,labor-saving and orchard construction in mountain areas of Japan

Novel technologies have been necessary for improving fruit quality and productivity of citrus,labor-saving and orchard conservation on steep slope lands since aging of growers and decrease in the number of successors is remarkable in mountain areas of southwestern Japan. The purpose of this paper is to introduce new technologies for improving citrus production that have been developed in recent years. A new fruit quality control system using drip irrigation and liquid fertilization technique combined with year-round plastic mulching was developed, and it enables high quality and stable citrus fruit production. Water and/or nutrient solution is automatically supplied through drip tubes that are laid under the mulching sheets to give adequate water stress, so as to improve sugar and acid content of fruit. A new transportation system for steep sloping citrus orchards, which is a combination of the monorail system and contour narrow paths, was suggested. A small walking cultivator was developed to explain the procedure of narrow path excavation. After introducing the narrow path, working hours for fertilizer and chemicalherbicide application were reduced. Disasterpr evention mapping of citrus orchards on slope landswas developed based on computer-aided seepage estimation and topographic data. The mapping can show zones of both ascending flow and descendingflow of underground water during heavy rains incitrus orchards. The mapping is considered to be effective for the management of orchards andprevention of erosion on slope lands.     

苍梧县砂糖桔种植气候区划

为了给苍梧县砂糖桔生产提供趋利避害和优化布局的科学决策依据.对苍梧县砂糖桔生产的气象条件进行分析,找出影响低温冷害的4个气候关键因子,采用国家基础地理信息中心提供的1：5万广西基础地理背景数据,通过归一化方法和加权综合评价法分析,利用地理信息系统（GIS）绘制出苍梧县砂糖桔低温冷害风险区划专题图.区划图明确分出苍梧县低温冷害的低风险区、次低风险区、中等风险区、次高风险区和高风险区.在此基础上,针对各风险区域进行了分析与评述,提出了防御低温冷害的相应对策.     

Biosorption of Cadmium(II) Ions by Citrus Peels in a Packed Bed Column: Effect of Process Parameters and Comparison of Different Breakthrough Curve Models

The efficiency of low cost citrus peels as biosorbents for removal of cadmium ions from aqueous solution was investigated in a fixed bed column, a process that could be applied to treat industrial wastewaters similar to commonly used ion exchange columns. Effluent concentration versus time profiles (i.e., breakthrough curves) were experimentally determined in a laboratory‐scale packed bed column for varying operational parameters such as flow rate (2, 9, and 15.5 mL/min), influent cadmium concentration (5, 10, and 15 mg/L), and bed height (24, 48, and 72 cm) at pH 5.5. Column operation was most efficient for empty bed contact times of at least 10 min, which were apparently necessary for mass transfer. While the sorption capacity was largely unaffected by operational variables, the Thomas (Th) rate constant increased with the flow rate, and slightly decreased with increasing column length. Three widely used semi‐mechanistic models (Th, Bohart–Adams, and Yoon–Nelson) were shown to be equivalent and the generalized model was compared with a two‐parameter empirical model (dose‐response). The latter was found to be able to better simulate the breakthrough curve in the region of breakthrough and saturation.     

Recharge estimates for various land uses in the Guarani Aquifer System outcrop area

ABSTRACT

The Guarani Aquifer System (GAS) is a subsurface reservoir that contains the largest volume of fresh groundwater in South America. Despite the relevance of the GAS, a lack of attention has been paid to land use effects on its recharge. We present the most detailed long-term (2004–2011) results of land-use effects on recharge in an outcrop area of the GAS. Water table fluctuations (WTFs) were measured at 11 monitoring wells, which are distributed between different land uses (i.e. eucalyptus, sugarcane, citrus and grassland). Recharge was estimated using a point-scale method (WTF) for each monitored well. The annual recharge estimates for different land uses are eucalyptus forest (135 mm year^-1), sugarcane (248 mm year^-1), citrus areas (296 mm year^-1) and grassland (401 mm year^-1). The results indicate that the evapotranspiration seems to be a key parameter in the assessment of recharge in the study area.     

湘西北2008年初持续冰雪灾害及对椪柑影响分析

2008年初湘西北出现了自1956年有气象记录以来低温持续时间最长、冰冻范围最大、强度最强的一次低温雨雪冰冻天气过程,罕见的特大冰冻灾害给当地支柱产业之一的椪柑生产带来严重影响.本文从天气学和农业气象学角度出发,对低温雨雪造成的椪柑冻害及椪柑成果的贮藏、销售影响进行了详细评估,旨在为湘西北椪柑生产恢复与制定防灾减灾措施提出科学依据.     

福建建瓯万木林柑橘与锥栗凋落物数量、组成及动态

2010年1-12月,对福建省建瓯市万木林保护区内的柑橘（CitrusreticulataBlanco）和锥栗（Castaneahenryi）凋落物的组成及动态进行观测研究,结果表明：柑橘和锥栗的年凋落物量分别为2315．47±149．02kg·hm^-2·a^-1和2414．62±211．05kg·hm^-2·a^-...     

福建建瓯万木林柑橘与锥栗凋落物数量、组成及动态

2010年1-12月,对福建省建瓯市万木林保护区内的柑橘（CitrusreticulataBlanco）和锥栗（Castaneahenryi）凋落物的组成及动态进行观测研究,结果表明：柑橘和锥栗的年凋落物量分别为2315．47±149．02kg·hm^-2·a^-1和2414．62±211．05kg·hm^-2·a^-1,凋落物均以落叶为主,分别占到年总凋落物量的57．6％和50．7％,落花和落果在凋落物中所占比例较大;经方差分析检验,柑橘和锥栗的落枝、落花和杂物差异显著（P〈0．05）,其他组分差异不显著;柑橘与锥栗凋落物量季节变化曲线均呈双峰型,柑橘凋落物量在3月和7月出现2次较大峰值,而锥栗凋落物量峰值则出现在6月和11月．     

中亚热带人工经济林土壤有机碳含量及分布

人工经济林在中国南方种植面积大,并有不断增加的趋势.人工经济林生态系统受人为周期性经营活动影响比较大,是重要的流动性碳库.因此,选择福建省建瓯市万木林自然保护区内本地条件基本一致的毛竹（Phyllostachys heterocycla）、柑橘（Citrus reticulata Blanco）和锥栗（Castanea...     

湘西北2008年初持续冰雪灾害 及对椪柑影响分析

2008年初湘西北出现了自1956年有气象记录以来低温持续时间最长、冰冻范围最大、强度最强的一次低温雨雪冰冻天气过程,罕见的特大冰冻灾害给当地支柱产业之一的椪柑生产带来严重影响。本文从天气学和农业气象学角度出发,对低温雨雪造成的椪柑冻害及椪柑成果的贮藏、销售影响进行了详细评估,旨在为湘西北椪柑生产恢复与制定防灾减灾措施提出科学依据。