青海土壤资源评析

介绍了青海省土壤资源概况,根据气候、地貌、植被和土壤类型组合以及改良利用方向措施不同,将青海省土壤划分区域,并提出改良利用意见。     

中国中温带农区种养结合型农业科技园区模式研究

根据区域特点和农业科技园区发展要求,研究概述了我国中温带地区种养结合型农业科技园区模式的生成、特征、类型及实施,为区域农业科技园区发展提供了依据和借鉴。     

近百年中国北部南温带北界界限的动态变化

<正> 1.前言在研究气候冷暖变化时,气候学家所采用的指标主要有年平均气温、最冷(暖)月平均气温、气温距平、寒冷指数等;在研究农业气候的热量变化时,所采用指标集中在≥0℃或≥10℃积温上。本文则从农业气候的角度出发,采用农业气候带分界的热量指标,来研究近百年我国北部南温带北界界限的动态变化。采用农业气候带分界指标不仅可以反映出气候的冷暖变化,而且有一定的农业意义。     

Comparison of structural diversity of tree-crop associations in Peripheral and Buffer zones of Gachabari Sal forest area,Bangladesh

The structural diversity of different tree-crop associations were studied at Gachabari Sal forest area of Madhupur Garh on Buffer and Peripheral Zone during 2006. The total density, basal area of trees in the Buffer and Peripheral Zone were 155.5 trees·hm^-2, 795.4 trees·hm^-2 and 3.9 m^2·hm^-2, 5.8 m^2·hm^-2, respectively. No regeneration and natural trees were found in Peripheral Zone and the Zone is totally occupied by exotic species where the Buffer Zone comprised of both natural and exotic trees. The Peripheral Zone belonged to younger and smaller trees whereas the Buffer Zone belonged to mixture of smaller, taller, younger and mature trees simultaneously. For the practicing of different agroforestry systems both Zones have lost their original characters of Sal forest.     

构建珠江三角洲地区稳定森林生态安全体系的探讨

文章根据珠江三角洲地区森林生态安全体系建设现状的详细调查数据,深入分析存在的主要问题,提出了构建珠江三角洲地区稳定森林生态安全体系的基本思路及政策建议。     

基于VAR模型的森林生态系统适应性管理与经济发展动态关联分析———以黑龙江省大小兴安岭森林生态功能区为例

将衡量森林生态功能区森林生态系统适应性管理效果的指标分解为气候调节、生态保持、产品供给、休闲服务4项,通过主成分分析计算得到各个指标的重要性; 利用VAR模型分析黑龙江省大小兴安岭森林生态系统适应性管理与经济发展的相互影响; 根据脉冲响应函数分析得到森林生态系统适应性管理与经济发展之间的动态关联关系,据此给出若干提高森林生态系统服务水平和促进经济发展的对策和建议。     

中国亚热带森林小流域植物生长驱动下矿物风化评估

Plant growth contributes to mineral weathering, but this contribution remains poorly understood. Weathering rates in an aggrading forested watershed in subtropical China were studied by means of geochemical mass balance. Rainfall, dry deposition, and streamwater were monitored from March 2007 to February 2012. Samples of vegetative components, rainfall, dry deposition, streamwater, representative soils, and parent rock were collected and determined for mass balance calculation and clarifying plant-driven weathering mechanisms stoichiometrically. Ignoring biomass, weathering rates of Ca²⁺, Mg²⁺, Na⁺, and Si were 25.6, 10.7, 2.8, and 51.0 kg ha^-1 year^-1, respectively. Taking biomass into consideration, weathering rates of Ca²⁺, Mg²⁺, and Si and the sum of weathering rates of Ca²⁺, Mg²⁺, Na⁺, K⁺, and Si were 2.6, 1.8, 1.2, and 1.5-fold higher than those ignoring biomass, respectively. This is attributed to plant-driven weathering due to the nutrient (e.g., Ca²⁺, Mg²⁺, and K⁺) absorption by vegetation and substantial proton production during assimilation of these nutrients, with the former acting as a pump for removing weathering products and the latter being a source of weathering agents solubilizing mineral components. The same pattern of weathering, i.e., higher rates of weathering with than without including biomass in mass balance calculation, was reported in previous studies; however, the extent to which plants drive weathering rates varied with vegetation types and climatic zones. The documented biological weathering driven by plants is expected to play a critical role in regulating nutrient cycling and material flows within the Earth’s Critical Zone.     

辽河干流坝间耕地土壤重金属污染特征研究

通过对辽河干流坝间10个断面耕地土壤0~5 cm、5~15 cm、15~30 cm沉积层重金属铜、镉、锌、铅含量测定,评价了该区土壤重金属污染程度,并采用地质累积指数法评价单一重金属污染状况与潜在生态危害指数,综合评价重金属生态危害程度。研究结果表明,该区土壤铜、铅、锌与镉含量均值分别为32.42 mg?kg~(-1)、38.23 mg?kg~(-1)、47.35 mg?kg~(-1)和1.625 mg?kg~(-1);铅、锌含量均值在达牛渡口最大,分别为55.54 mg?kg~(-1)和80.51 mg?kg~(-1);铜、镉含量均值在通江口处最大,分别为50.24 mg?kg~(-1)和3.103 mg?kg~(-1)。除镉外,铅、铜、锌含量各断面不同深度浓度均低于全国土壤环境质量Ⅱ级标准,镉含量均值是全国土壤环境质量Ⅱ级标准的1.70倍,最大值为3.402 mg?kg~(-1);辽河大桥上游干流镉含量是下游镉含量的6.47倍。镉的地质累积指数值在坝间均显污染,其中,辽河大桥以上各断面显强污染。通江口至毓宝台特大桥重金属潜在生态风险指数值最强。各断面镉对多种金属潜在生态风险指数值的贡献达78.77%~98.23%,贡献率与潜在生态危害指数(RI)呈正相关。多种重金属潜在生态风险指数值变化趋势与镉地质积累指数分布趋势相同,最大值出现于通江口断面。     

2016年帕隆藏布流域群发性泥石流的活动特征及成因分析

帕隆藏布流域山高谷深、构造强烈、冰川广布,区域内冰川泥石流数量多、规模大、分布密、暴发频率高。2016年9月5日,流域内几条泥石流集中暴发,造成较为严重的财产损失,并阻碍了G318国道的正常通行。为研究本次群发性泥石流的成因,指导泥石流的监测预警工作,在实地调查的基础上,分析了泥石流的地形地貌条件、物源条件、水热条件。分析结果表明:本次暴发泥石流的沟谷具有良好的地形条件,流域高差大,沟道纵比降大,尤其沟谷上游因冰川作用而形成的冰蚀围谷利于水源、物源的聚集。泥石流以沟源处的松散冰碛物为主要物源。此外,北岸比通沟泥石流因沟岸崩滑物源丰富、沟道狭窄,形成多处堵点,产生堵溃放大效应。南岸赤担隆巴泥石流则沟道宽缓,崩滑物源较少。本次群发性泥石流的诱发因素主要为强降雨。泥石流暴发前两日出现强降雨,使得沟内松散物质含水量增加,趋近饱和,稳定性降低。泥石流暴发当日再次出现强降雨,直接激发了泥石流。经对暴发当日小时雨量分析,认为比通沟泥石流由凌晨2点的集中降雨启动,但由于沟道堵塞严重,龙头数小时后才到达沟口。赤担隆巴由当日11点的集中降雨启动,随后顺沟下泄,堆积于老扇之上,形成灾害。经分析,沟口观测的激发本次泥石流的小时雨量为3.3～3.6 mm,推测主要形成区激发泥石流的小时雨量为7.6～8.3 mm。     

河西走廊凉州绿色农业示范区耕地土壤养分及栽培模式影响分析

位于甘肃河西走廊的凉州区是2006年4月经中国绿色食品协会批准、在西北干旱内陆地区建立的首批五十个国家重点绿色农业示范区之一,本研究以绿色农业理念为基础,通过大范围调查取样、测试分析,对绿色农业示范区内耕地土壤肥力状况进行综合分析评价,并对比分析了栽培模式对土壤质量的影响,设施栽培土壤有机质低于大田土壤,而全氮、全磷、全钾、碱解氮、有效磷、速效钾均高于大田,全盐量远远高出大田4倍。