东北典型农区土地利用变化的生态效应研究——以公主岭市为例

在人为活动占优势的景观内,不同土地利用方式和强度产生的生态效应是不同的,并且可以直观地反映在生态系统的结构和组成上。因此,本文利用Landsat TM和MSS遥感数据,以具有相对完整的自然生态过程的小流域作为评价单元,借助GIS空间分析和地统计分析功能,从景观生态学角度提出了景观生态指数来反映LUCC变化所带来的生态效应。研究发现,公主岭市1975—1986年间由于土地利用/土地覆被变化造成的生态风险不断增加,随后逐渐减小,到2000年局部地区又有所回升,这种变化与该地区土地利用类型的变化,特别是耕地、林地和草地的变化趋势呈高度相关,说明该地区土地利用/土地覆被变化对生物多样性及生态安全具有重要影响。     

第二代杉木林养分动态研究

根据连续定位观测所取得的数据,对4个小集水区第二代10年生杉木人工林生态系统中的养分循环进行了研究.结果表明.集水区由降水输入的N、P、K、Ca、Mg等营养元素总计为59.285kg/hm2a,径流输出为38.938kg/hm2a,净积累量为20.347kg/hm2a.与该林分7年生时相比,净积累量提高了7.2%,说明集水区第二代杉木林生态恢复处于进展的变化过程.     

岔巴沟流域次暴雨产流无量纲模型

为了建立小流域次暴雨产流预报模型,在岔巴沟流域选取大小不同的4个小流域10 a水文资料,分析降雨、地貌等因素对流域产流的影响,选取主要因素最大30 min雨量、最大30 min雨强、流域沟道比降、流域面积和流域狭长度。用无量纲参数和逐步回归分析的方法估计模型参数,得到了岔巴沟流域次暴雨产流无量纲模型,用模型预报结果与实测结果对比,模型预报精度为70%。结果表明,所建立的模型具有参数少、结构简单、量纲和谐、物理意义明确的特点,可为流域产流模型进一步研究提供参考。     

新县小流域综合治理开发结硕果

新县小流域综合治理开发结硕果韦彦学（河南省水利厅水土保持处，郑州４５０００３）河南新县连续１０年大搞水土保持小流域综合治理开发，取得了显著的生态、经济和社会效益。１０年间，全县农民人均纯收入、人均存款均增长了９倍，９０％的贫困户摆脱了贫穷开始走向富裕...     

Phosphorus loss from agricultural catchments: pathways and implications for management

Abstract. The contribution non-point P sources make to the total P loading on water bodies in agricultural catchments has not been fully appreciated. Using data derived from plot scale experimental studies, and modelling approaches developed to simulate system behaviour under differing management scenarios, a fuller understanding of the processes controlling P export and transformations along non-point transport pathways can be achieved. One modelling approach which has been successfully applied to large UK catchments (50-350km² in area) is applied here to a small, 1.5 km² experimental catchment. The importance of scaling is discussed in the context of how such approaches can extrapolate the results from plot-scale experimental studies to full catchment scale. However, the scope of such models is limited, since they do not at present directly simulate the processes controlling P transport and transformation dynamics. As such, they can only simulate total P export on an annual basis, and are not capable of prediction over shorter time scales. The need for development of process-based models to help answer these questions, and for more comprehensive UK experimental studies is highlighted as a pre-requisite for the development of suitable and sustainable management strategies to reduce non-point P loading on water bodies in agricultural catchments.     

基于参数移植法的SWAT模型模拟嘉陵江无资料地区径流

该文选用嘉陵江中游9个中小流域,基于参数移植方法(距离相近法、属性相似法、综合相似法)探求分布式水文模型SWAT在嘉陵江中游无资料地区径流模拟的适用性。3个有资料试验流域模拟结果显示,参数移植法的模拟精度NS、R2平均值大于0.8,径流模拟精度较好,表明基于参数移植法的SWAT模型在研究区域具有一定的适用性,同时综合相似法(0.66NS0.93)的径流模拟结果优于距离相近法(0.65NS0.93)和属性相似法(0.65NS0.92),另研究表明参证流域个数对参数移植的结果有较大影响,多个参证流域参数移植效果消除单个参证流域参数移植结果的不确定性。     

Nutrient and bulk density characteristics of soil profiles in six land use systems along topo-sequences in inland valley watersheds of Ashanti region,Ghana

The bulk density and nutrient distribution in soil profiles as affected by various land use systems were studied. Mean bulk densities of the various soil profiles, 0-20, 20-40, and 4060 cm in the selected five land use systems along the upland / lowland topo-sequences were, 1.26, 1.73, and 1.44 Mg m^-3 for the primary forest (PF) plot in the upland area, 1.13, 1.51, and 1.50 Mg m^-3 for the cacao farm (CP) plot, 1.16, 1.63, and 1.26 Mg m^-3 for the mixed cropping (MC) plot, 1.39, 1.61, and 1.50 Mg m-a for the fallow (Fallow) plot, all three land use systems being in the upland / fringe areas, and 1.46, 1.72, and 1.60 Mg m^-3 for the lowland traditional rice farming (TR) plot, respectively. The very high bulk density of the second layer, especially in the PF plot, may be related to the hardening of the iron / quartz stone layer due to prolonged dry conditions, which may affect plant growth and hydrological cycles in the benchmark inland valley watersheds. The TC contents of the topsoil samples were 43, 32, 24, 26, 18, and 15 g kgm^-1 for the PF, CP, Fallow, MC, TR, and sawah (Sawah) plots, respectively. The C / N ratios of the topsoil samples were 10, 10, 9.8, 9.1, 8.8, and 8.8 for the CP, Fallow, MC, Sawah, TR, and PF plots, respectively, displaying a higher natural fertility, especially for the N supply in the PF plot in the upland area. The available phosphorus levels were low even for the topsoil samples, 1.8 to 3.4 mg kg^-1 for the upland soils while the lowland TR and Sawah plots recorded values of 4.4 and 4.9 mg kg^-1, respectively. The contents of exchangeable K, 0.1-0.4 cmole kg^-1, of the topsoil samples were in the range of those of normal inland valley soils in West Africa. In contrast to the content of available P, although the MC plot showed a depletion, the PF, Fallow, and CP plots showed a replenishment of available K through biological nutrient cycling. The levels of exchangeable Ca and Mg as well as eCEC, were also relatively high compared to those of mean inland valley soils in West Africa. The major component of eCEC was Ex. Ca. The levels of Ex. Ca in the topsoil samples were 11.1, 9.1, 7.8, 4.7, 5.1, and 3.9 cmol_c kg^-1 for the PF, CP, Fallow, MC, TR, and Sawah plots, respectively. The distinctive feature of Ex. Mg was its large distribution in the upper soil profiles in the CP plot, indicating that in the cacao farms, Ex. Mg was enriched, probably due to the high level of Mg in the leaf litter. The lowland soils, normally, should have been enriched in exchangeable bases such as Ca, K, and Mg, leading to a higher eCEC value and higher general fertility through the process of geological fertilization, Le., nutrient flows from upland to lowland areas, as in the case of lowland sawah in monsoon Asia. At the benchmark sites, however, the effects of the geological fertilization process were not evident. This is one of the most important characteristics of West African inland valley watersheds.     

云南五大流域生态环境类型区划分

云南省防护林工程区地处伊洛瓦底江、怒江、澜沧江、红河、珠江五大流域上、中游，为了揭示地域上的相似性与差异性，分析其林业生态建设条件的异同，进行了该五大河流流域生态类型区划分。区划指标选择“土壤侵蚀量”、“坡度级”等若干直接因子以及“输沙模数”等若干间接因子，区划方法为非严格系统聚类方法，对流域项目区划分为三个生态环境等级类型区。并进行了生态重要性等级划分。     

自动基流分割方法在黄土区流域的应用研究

基流是河川径流在枯水季节的主要径流来源.由于难以通过实测方法获得基流量数据,选择适合的基流分割技术对于基流研究至关重要.利用黄土区6个流域的多年径流量资料,选取PART法、滤波法及滑动最小值法等目前广泛使用的自动基流分割方法对区域内河流的基流量进行了分割,以检验自动基流分割方法在本地区的适用性,并应用选定的基流分割方法对黄土区流域的基流特点做了简单分析.研究结果表明,3种方法所获得的基流指数值有所差异,滤波法分割的基流过程与实际基流状况更为相符.因此,滤波法可作为黄土区流域基流的最优分割方法.应用滤波法得到的研究流域基流占总径流比重为37%～64%,而基流量在近50 a中呈现逐渐降低趋势.     

基于原型观测与DEM的强风化花岗岩小流域水文过程模拟

为了解华南花岗岩小流域特殊的产流机制,以土壤为砂壤土、基岩为强风化花岗岩的中山大学珠海校区滨海小流域作为研究对象,观测了2个分别代表森林、灌丛覆盖的5 m×10 m的径流试验场的产流过程和土壤含水率变化过程。观测结果表明超渗产流、优先流是试验场的重要产流方式,壤中流（尤其是在土壤-基岩界面上产生的壤中流）对试验场的总产流量也有较大贡献。在径流试验场原型观测基础上,建立了一个基于数字高程模型（DEM）的、包括地表径流、壤中流和基岩裂隙出流的三水源小流域水文模型。利用9次降雨径流过程对模型参数进行率定,利用4次降雨径流过程进行验证,模型的率定、验证均取得了良好的拟合效果。根据模型的模拟结果,在径流的起涨阶段地表产流贡献最大,而基岩裂隙出流对退水过程贡献明显。综合试验场原型观测结果与模型模拟结果得出结论：明显的壤中流和基岩裂隙出流是华南花岗岩小流域显著的产流特点。