小流域范围土壤锰、铝形态分布及其相关性研究

分别在湖南的郴州和长沙选定两小流域(SZY和LKS),从小流域规模分析了酸雨频降区两小流域土壤的主要理化特性和土壤锰铝形态及其分布,并讨论了锰铝各形态和土壤有机质,土壤pH值之间的相关性。结果表明:在小流域SZY土壤中,各种形态的锰铝含量均高于小流域LKS土壤中对应形态的锰铝含量;在同一剖面,各种形态的锰铝含量有表土高于底土的趋势。在两小流域土壤中,除无定形锰(Mnox)外各种形态的锰铝均与土壤有机质呈正相关。铝的溶出与土壤有机质和土壤pH值有关。酸沉降能影响毒性元素铝形态的转化和淋溶。活性铝、锰形态可能富集在土壤表层或植物根际等富含有机质的区域,酸沉降或其它环境条件可能促进铝、锰形态在土壤表层或植物根际的转化和溶出,从而导致毒害。     

生物降解膜降解、保墒增温性能及对玉米生长发育进程的影响

通过3年试验,研究生物降解膜降解、增温保墒性能及全覆盖双垄沟播玉米苗期0~25 cm土壤温度动态和对玉米生长发育进程的影响,明确生物降解膜在生产中对普通农用地膜的可替代性。结果表明,生物降解地膜埋入土壤约30 d左右可以观测到降解效果,40 d以后开始快速降解,到80~90 d时降解可达到85%~95%,种植地膜玉米后,压入土壤或地膜上有土覆盖的部分同样有明显的降解效果,而垄上的地膜在玉米收后绝大部分仍与常规膜一样保持完好;生物降解膜保墒性能达普通农用地膜的90.4%~95.4%;作物生育前期0~25 cm土层08∶30、14∶30和20∶30平均温度比普通农用地膜低0.85℃,比露地高1.91℃;生物降解膜全覆盖双垄沟播玉米比裸地平作出苗提前5~9 d,成熟期提前11~12 d。生物降解地膜具有一定的增温、保墒作用,降低生产成本后,可在一定程度上替代不能降解的普通农用地膜。     

基于多流域同步率定的HBV模型参数移植方法研究

无资料地区洪水预报是水文学研究的难点之一.为提高无资料地区HBV模型参数移植的精度,以安徽屯溪流域为例,基于多目标优化函数实现多个流域HBV模型同步率定,获得同时适用于多个流域的模型参数,并对参数的移植效果进行验证.结果表明:基于单个流域率定的参数移植不确定性较高,移植效果不稳定;多流域同步率定的参数移植效果普遍较优,...     

Optimal farm management responses to emerging soil salinisation in a dryland catchment in eastern Australia

Secondary salinisation of soil and water resources is an acute management issue over large parts of Australia. This paper focusses on the situation in the Liverpool Plains, where secondary soil salinity is on the increase due to rising saline groundwater tables. The Liverpool Plains are famous for the vast alluvial floodplains where self-mulching black clays provide the production basis for an extensive dryland cropping industry. The farmers there are asking how best to manage their resources under the present hydrological conditions, and are concerned whether their businesses will remain viable in the future. A multi-period programming model is applied to a model farm situation. The objective function reflects the economic paradigm of farming. The model includes a simulation sub-routine which links land use, rainfall and lateral groundwater flow into a point water balance and estimates the salt-affected area. A feedback relationship applies between soil salinity and land productivity. The results of the model suggest that the prevailing cropping practices that rely on long fallowing for soil moisture retention are sub-optimal. Increased cropping frequency increases farm income and reduces on-farm recharge to groundwater. Diversification into lucerne is favourable for the same reasons. Unless trees have commercial value, tree planting is not a favoured option except on salt-affected land. The farm achieves complete on-farm recharge control. However, assuming that the groundwater table rises at a rate of 10 cm per year independent of on-farm recharge, salinisation continues despite these land management changes. The subsequent land productivity losses render the model farm financially unviable in the medium term. Sustaining the productivity of the Liverpool Plains is an issue of reducing recharge to the groundwater system by changing land-use practices throughout the entire catchment. © 1997 John Wiley & Sons, Ltd.     

论小集水区农业开发的可持续性问题

近年来,福建省出现个体工商户转向承包山地进行以果业为主的农业综合开发现象。这是福建省农业结构社会需求结构相协调的表现,针对如何引导个体户进行合理规划,有效投资,阐述了水土保持型集水区可持续发展的可行性并结合水土保持多在实践经验提出了治理的技术途径。     

宜川县油松人工林集水区水文状况分析

通过对人工油松（Pinus tabulaeformis）林集水区水文特征与产流特征的分析发现:人工油松林集水区产流有三种类型:坡面和沟道不发生径流;沟道产生径流;坡面和沟道均产生径流。     

森林水文研究概述

森林是一个复杂的生态系统, 森林水文是近年来研究的热点。如何正确看待森林对流域径流的调节作用, 评价森林水文效应, 是值得长期探讨的话题。文中主要探讨了森林对流域径流的调节作用, 以及如何利用流域水文模型模拟森林流域水文动态过程, 正确评价森林水文效应。     

Controlling dryland salinity by planting trees in the best hydrogeological setting

Revegetation by trees and shrubs is examined as the best long-term option for controlling dryland salinity. Since hydrogeological features in a catchment control and cause salinity, it is shown that management programs using trees should be developed on a hydrogeological basis through the use of hydrogeomorphic mapping. Catchment planning should ensure that trees suited to the area, and preferably of commercial value, are planted in the best hydrogeologically determined positions in sufficient numbers to reduce excess recharge generated following clearing. The programme should integrate other biological measures to increase water use, which includes improved crop and soil management and the introduction of salt-tolerant plants. Since trees will take several years to exert their full effect on recharge, engineering methods such as groundwater pumping, which lower water tables, and contour banks, which capture and redirect surface water, can best be used as short-term measures. Case studies from catchments in Western Australia are used to illustrate the application of control measures.     

Small dams need consideration in riverscape conservation assessments

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Behavior of glyphosate and aminomethylphosphonic acid (AMPA) in soils and water of reservoir Radeburg II catchment (Saxony/Germany)

The behavior of the herbicide glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) was investigated in soils and water in a well-defined catchment of the reservoir Radeburg II near Dresden (Saxony/Germany). The half-life of glyphosate in soil ranged from 11 to 17 days. Glyphosate and AMPA completely disappeared from soil after about 5 months following application of the products ”︁Roundup Ultra” and ”︁Touchdown”. The aquatic system in the test areas (surface water, soil solution, and groundwater) was not significantly affected by direct application of the compound. In general, there was a clear indication of strong sorption of the two substances by soil particles. Settlement areas were recognized as possible sources of glyphosate and AMPA intake in aquatic systems.