共查询到20条相似文献,搜索用时 109 毫秒
1.
干旱是一个长期存在的世界性难题。我国是一个干旱半干旱面积很大的国家,干旱严重地制约着农业的可持续发展。而雨水资源的利用是解决或缓解干旱的重要途径。围绕雨水资源的利用,人们做了许多创造性的理论探索和技术研究,研究出许多雨水资源利用的方式,归纳起来主要有3个方面;就地拦蓄利用,覆盖抑制蒸发利用和雨水富集叠加利用。针对这3个方面,对国内外雨水资源利用现状进行了总结,提出了雨水资源利用存在的问题。 相似文献
2.
区域雨水资源化潜力的定量评价对于雨水资源开发利用的宏观决策、规划设计具有十分重要的意义。该文以黄土高原地区为例,系统分析了影响区域雨水资源化潜力的各个因子,确定定量评价区域雨水资源化潜力的各项指标,并运用GIS技术,集成多种来源、多种比例尺和多种类型的数据,建立区域雨水资源化潜力定量评价模型。评价模型对于黄土高原地区雨水资源可持续利用及生态与环境保护具有重要作用。 相似文献
3.
水资源危机已成为全球性的问题,如何高效利用有限的水资源,特别是雨水资源,提高雨水资源的利用率,已被世界各国所关注。在详细阐述雨水集蓄利用的发展历史、概念和理论的基础上;对国内外雨水资源的集蓄技术和高效利用技术及其应用研究进行了系统分析和总结;同时,提出了目前雨水集蓄利用研究发展趋势。 相似文献
4.
在分析黄土高原水土保持工作难度的基础上,进一步研究区域水土保持的科学内涵,以及水土保持与雨水资源化的关系。认为:黄土高原水土保持的关键与核心在于如何实现雨水资源化;降雨径流调控与利用不仅可实现雨水资源化,而且可以同步解决制约该区发展的干旱缺水与水土流失并存2大难题。在此基础上,提出了黄土高原水土保持亟待研究的科学问题与技术问题,并初步构建了黄土高原水土保持与雨水资源化的技术体系框架。 相似文献
5.
60年代,我国曾掀起过旱井集蓄利用雨水的热潮,时隔30余年的今天,这一热潮再度兴起,其原因何在?本文从利用雨水资源的必要性、现实可能性、实践效果等三个方面进行了分析论证,结果表明:我国现阶段开发利用雨水资源前景十分广阔。 相似文献
6.
辽宁省西北部地区多年降雨量与蒸发量频率分析结果表明,春季抗旱保苗是这一地区发展旱地农业的技术关键。该区湿润系数的经验频率以夏季最高,秋季为85.71%。由于这一地区水资源短缺,发展灌溉困难,这不仅使春季保墒成为必需,也使跨季节调控土壤墒情成为可能。采取的夏深松-蓄集雨水,秋整地-施肥与覆膜保墒,翌年春季适时播种措施,改革栽培与耕作方式,春季保苗效果十分明显,减少了土壤水分的无效蒸发,有效地利用雨水资源,为该区作物高产和农业高效奠定了基础。 相似文献
7.
针对黄土高原地区水资源严重短缺的态势和生态环境建设的需要,基于可持续发展理念,以小流域作为研究单元,以雨水资源作为研究对象,提出小流域雨水资源化潜力的概念,分析不同层次的小流域雨水资源化潜力,探讨雨水资源可持续性与可持续利用的关系,建立了小流域雨水资源不同利用类型的判别模式,为黄土高原雨水资源的持续高效利用和流域生态环境健康发展提供理论依据。 相似文献
8.
雨水是一种宝贵的淡水资源,对其加以利用能够缓解城市水资源短缺的形势,雨水资源化利用正逐渐成为生态校园建设的重要内容.在对天津市某大学校园雨水径流水质进行监测的基础上,设计了雨水资源化技术方案,以保证景观湖、绿地及道路浇洒用水为核心,以自然净化、生态处理和循环净化为关键技术,多种途径收集利用雨水.同时还着重介绍了下凹式绿地、花坛式渗滤净化技术、景观湖净化系统等雨水生态化利用技术的特点及机理.分析与计算表明,该校园的雨水资源化利用方案具有明显的经济、社会和环境效益,能够为其它校园乃至天津市的雨水利用设计提供借鉴. 相似文献
9.
城市雨水资源利用是缓解城市水危机的重要途径。介绍了国外城市雨水资源利用的经验,分析了我国雨水资源利用的现状及其存在的问题,从化城市洪涝为城市水资源、改善城市水循环与生态平衡、减少城市面源污染、调节城市水资源时间分布4个方面分析了城市雨水资源利用对城市水安全的作用;提出了从挖掘城市湿地建设潜力、建立生态小区屋顶雨水回收处理系统、推广透水路面和凹式绿地、完善城市雨水资源利用立法和市场机制4个途径实现城市雨水资源利用的建议,为城市雨水资源利用决策与设计提供了参考。 相似文献
10.
我国城市利用雨水资源处于弱势态,这势必影响到城市经济的要持续发展。针对目前城市雨水资源利用存在的问题,结合新加坡、德国等雨水资源利用的经验,初步提出我国城市雨水资源利用的对策。 相似文献
11.
Intensive glyphosate use has contributed to the evolution and occurrence of glyphosate-resistant weeds that threaten production of many crops. Sustained use of this highly valued herbicide requires rotation and/or substitution of herbicides with different modes of action. Cotton growers have shown considerable interest in the protoporphyrinogen oxidase inhibitor, fomesafen. Following registration for cotton in 2008, use has increased rapidly. Environmental fate data in major use areas are needed to appropriately evaluate risks. Field-based rainfall simulation was used to evaluate fomesafen runoff potential with and without irrigation incorporation in a conventional tillage system (CT) and when conservation tillage (CsT) was practiced with and without cover crop residue rolling. Without irrigation incorporation, relatively high runoff, about 5% of applied, was measured from the CT system, indicating that this compound may present a runoff risk. Runoff was reduced by >50% when the herbicide was irrigation incorporated after application or when used with a CsT system. Data indicate that these practices should be implemented whenever possible to reduce fomesafen runoff risk. Results also raised concerns about leaching and potential groundwater contamination and crop injury due to rapid washoff from cover crop residues in CsT systems. Further work is needed to address these concerns. 相似文献
12.
Agricultural production systems are complex involving variability in climate, soil, crop, tillage management and interactions between these components. The traditional experimental approach has played an important role in studying crop production systems, but isolation of these factors in experimental studies is difficult and time consuming. Computer simulation models are useful in exploring these interactions and provide a valuable tool to test and further our understanding of the behavior of soil–crop systems without repeating experimentation.Productivity erosion and runoff functions to evaluate conservation techniques (PERFECT) is one of the soil–crop models that integrate the dynamics of soil, tillage and crop processes at a daily resolution. This study had two major objectives. The first was to calibrate the use of the PERFECT soil–crop simulation model to simulate soil and crop responses to changes of traffic and tillage management. The second was to explore the interactions between traffic, tillage, soil and crop, and provide insight to the long-term effects of improved soil management and crop rotation options. This contribution covers only the first objective, and the second will be covered in a subsequent contribution.Data were obtained from field experiments on a vertisol in Southeast Queensland, Australia which had controlled traffic and tillage treatments for the previous 5 years. Input data for the simulation model included daily weather, runoff, plant available water capacity, and soil hydraulic properties, cropping systems, and traffic and tillage management. After model calibration, predicted and measured total runoffs for the 5-year period were similar. Values of root mean square error (RMSE) for daily runoff ranged from 5.7 to 9.2 mm, which were similar to those reported in literature. The model explained 75–95% of variations of daily, monthly and annual runoff, 70–84% of the variation in total available soil water, and 85% of the variation in yield. The results showed that the PERFECT daily soil–crop simulation model could be used to generate meaningful predictions of the interactions between crop, soil and water under different tillage and traffic systems.Ranking of management systems in order of decreasing merit for runoff, available soil water and crop yield was (1) controlled traffic zero tillage, (2) controlled traffic stubble mulch, (3) wheeled zero tillage, and (4) wheeled stubble mulch. 相似文献
13.
Increase in alfalfa (Medicago sativa L.) production for energy (gasification of stems) and protein supplement (from leaves) has been proposed for the upper Midwestern United States, an area where corn ( Zea mays L.) in rotation with soybean ( Glycine max L.) is the predominant crop sequence. This study was undertaken to assess the impact on runoff and water quality, especially for the loss of oxygen demanding material with snowmelt. Four field size watersheds were instrumented at Morris, Minnesota, USA on a rolling prairie landscape. Snowmelt runoff from each watershed was measured with two flumes with overlapping ranges arranged in series. An automatic water sampler collected runoff samples for chemical analysis. Oxygen demand was used as a surrogate for reduced carbon. Water samples were analyzed for total solids, biochemical oxygen demand (BOD), and chemical oxygen demand (COD). Based on the results of snowmelt events of 1997, 1998, and 1999, the alfalfa fields yielded more runoff than corn-soybean fields. The loss of total solids was more consistent from alfalfa fields. Total solids losses interacted with crop and year. Compared to alfalfa fields losses were less following soybeans and greater following corn. On average losses were similar between alfalfa and corn-soybean fields. Runoff from alfalfa fields contained about four times more BOD than corn-soybean fields. Although not statistically significant due to only two replications, there was a similar trend for COD. This study shows that although losses of total solids in snowmelt from alfalfa fields was similar to corn-soybean fields, there can be increased losses of oxygen demanding materials. 相似文献
14.
In Tigray (Northern Ethiopia), soil moisture has been identified as the most limiting factor in agricultural production; on the other hand, loss of rain water through runoff as well as the induced soil loss has been determined as a critical problem in the region in the last two to three decades. To alleviate the above paradox, the government has mobilized communities and resources for the construction of physical soil and water conservation structures (stone bunds, terraces) in almost all land uses. However, yield improvement was mainly concentrated within the vicinity of the structures and runoff continued to overtop the structures, as no measures for in situ soil conservation were taken. The terwah system, consisting of traditional ploughing followed by making every 1.5–2 m contour furrows, and permanent raised beds with contour furrows at 60–70 cm interval treatments, were considered and evaluated as practices that could increase the efficiency of in situ water utilization and soil conservation. An experiment was started in Gum Selasa, which is one of the drought prone areas in Tigray, whereby runoff volume and sediment load were measured after every rain event. Permanent raised beds with contour furrows at 60–70 cm interval significantly ( P < 0.05) reduced runoff volume, runoff coefficient and soil loss as compared to traditional ploughing: 255, 381 and 653 m 3 ha −1 runoff was recorded from permanent bed, terwah and traditional ploughing, respectively during the whole cropping season. The above runoff induced 4.7 t ha −1 soil loss from permanent bed, 7.6 t ha −1 from terwah and 19.5 t ha −1 from traditional ploughing. Overall, contour furrows and permanent raised beds can be part of the ongoing intensification process which includes physical soil and water conservation, slope reforestation, irrigation development and agro forestry in crop lands. Moreover, the use of permanent raised beds if combined with crop mulching and crop diversification is an important component for the development of sustainable conservation agriculture practices in the region. 相似文献
15.
Abstract. Hierarchical crop growth models can contribute significantly to land quality research because the yield gap between the estimated optimum and the actual crop production has been identified as a major land quality indicator. This study describes a three-level, hierarchical crop production model, simulating radiation-thermal, water-limited and natural production potentials of annual crops. Input requirements have been kept low to ensure its applicability to developing regions, which often have access only to limited data. The simplicity of this model also has disadvantages: inconsistencies have been reported when applying this model in semiarid regions, which are characterized by very irregular rainfall patterns. Revision of the water balance, which simulates the availability of water, was required. The modified model was validated using the experimental yields of maize and sunflower in Guquka, a semiarid region of South Africa. Yields were estimated very well, possible improvements to crop production were identified and implications for land-use planning highlighted. Yield gap analysis revealed that radiation, sunshine and temperature are favourable for crop production, but the heavy dependence on rainfall makes the region very vulnerable to drought, with devastating impact on yields. The generally low chemical soil fertility further reduces crop performance. 相似文献
16.
Efficient mechanisation is a major factor underlying the high productivity and low cost of most Australian crop production systems. Efficiency has generally been associated with greater work rates, achieved by using equipment of greater power and weight. This trend has continued until very recently, despite a reduction in tillage for weed control. Scientists have warned of erosion and soil structural degradation caused by tillage and traffic, but tillage, rather than field traffic was seen as the major problem, and reduction of tillage as the solution. Reduced tillage has provided major benefits, but adoption has occurred slowly and sustained zero tillage is still rare, except in controlled traffic farming systems. The first part of this paper presents research evidence of the direct cost, practical impact and long-term effects of wheel traffic on cropped soil. Direct cost is associated with the energy requirements of disturbing wheeled soil. Practical impact occurs as a result of the lost opportunities and additional operations associated with wheel ruts. Long-term productivity and environmental impact occur because wheel traffic reduces plant available water and increases runoff and erosion. In controlled traffic all equipment wheels are restricted to compacted permanent traffic lanes, so that soil in the crop beds and traffic lanes can be managed respectively for optimum cropping and optimum trafficability. Controlled traffic farming recognizes the symbiosis between controlled traffic and zero tillage in providing opportunities for more productive and sustainable farming of soil uncompromised by wheel effects. The beneficial effects of controlled traffic have been demonstrated in widely different soils and mechanisation systems (e.g. Australia and China), and it has been vigorously advocated in both the USA and Europe, but large-scale adoption has been rare. The second part of this paper discusses cropping system response to controlled traffic farming, and the program which led to large-scale adoption in Australia. This happened first in extensive grain production, but adoption has since occurred in many Australian farming systems, supported by the availability of high-precision field guidance systems and a greater range of compatible equipment. Controlled traffic farming reduces soil degradation and the energy requirements of cropping. It is also more productive, and its practicality and economic viability have been clearly demonstrated in enthusiastic farmer adoption, and the formation of an Australian Controlled Traffic Farming Association. 相似文献
17.
为有效地根治 2 5°以下缓坡耕地的水土流失又不影响当地的粮食生产 ,对旱稻的水土保持作用进行了试验研究。研究结果表明 ,旱稻生长较快 ,根系发达 ,郁闭期长且正处在一年中的雨季 ,能够保护地面免受雨滴击溅 ,具有截留雨水、提高土壤蓄水能力、改变径流性质等作用 ,是很好的水土保持作物。浙江、四川、贵州、重庆、云南、湖北等省 (市 )都有一定数量的坡耕地 ,一般都不具备灌溉条件 ,不能种植水稻 ,而这一带人喜食米饭 ,旱稻栽培技术又较为简单 ,因此有较为广阔的推广应用前景。 相似文献
18.
杂草作为农田生态系统中的负效应组分,长期困扰农业生产活动。作物干扰,即作物对邻近杂草生长和繁殖的抑制作用,是基本的非化学除草方法之一。作物干扰可通过育种和栽培途径来增强,作物干扰能力的增强将伴随着一定的产量代价,但在某些条件下干扰能力强的作物品种有一定的产量优势。 相似文献
19.
Arkansas Discovery Farms (ADFs) are private farms that collaborate with on-farm research, verification, and demonstration of farming's impact on the environment. We have nine ADFs representing livestock (broiler poultry and pasture grazed beef and sheep) and row crop agriculture (corn, cotton, rice, soybean, and wheat), where we collect water use and water quality data as a function of conservation management, using autosamplers equipped with edge-of-field H-flumes or weir flow structures, which measure and collect surface runoff. On the poultry farms, we are monitoring nutrient and sediment runoff originating immediately near poultry houses due to concerns with spillage of litter during bird removal and house clean out, as well as dust from tunnel ventilation. On a nearby farm we are assessing the impact of rotational grazing on water quality, soil organic matter, and soil health metrics. On the row crop farms we are assessing the impacts of conservation tillage and cover crops on soybean–corn rotations and cotton on nutrient and sediment runoff and the benefits of water harvesting and reuse of water conservation and quality. The information in this paper while preliminary, demonstrates how a state-wide on-farm demonstration program operates. Elevated nutrient and sediment runoff from around poultry production areas are decreased three-fold by directing runoff into ponds or through grassed waterways. While conservation tillage and cover crops do decrease nutrient and sediment runoff, no significant difference between conventional and conservation operations is yet to be realized. Importantly, ADF empowers farmers to proactively address environmental concerns. This paper discusses the development, guidance, principals, and goals of ADF and contrasts this with other farm monitoring projects, where the sources of nutrient impairment are the subject of ongoing litigation. Monitoring in divisive and transparent situations presents unique challenges with data ownership and release of findings, which can hinder productive outcomes of such monitoring. 相似文献
20.
集流梯田工程是水平梯田和自然坡地沿山坡相间布置的一种水土保持工程措施,较水平梯田更能提高土壤含水率,改善土壤理化性状,针对这一特点,在黄前流域进行集流梯田与水平梯田、坡耕地对比试验,研究与分析结果表明集流梯田具有显著的保持水土和提高作物产量的效果。本试验研究为有效治理水土流失和增加农民收入提供科学依据。 相似文献
|