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1.
Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year (2003), the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.  相似文献   

2.
Water is the source of all the creatures on the earth and energy is the main factor driving the world. With the increasing population and global change, water and energy conservation have become worldwide focal issues, particularly in the water-stressed and energy-limited regions. Rainwater harvesting, based on the collection and storage of rainfall runoff, has been widely used for domestic use and agricultural production in arid and semiarid regions. It has advantages of simple operation, high adaption, low cost and less energy consumption. This study reviewed rainwater harvesting systems adopted in the Loess Plateau of China and analyzed water use efficiency (WUE) for various rainwater harvesting techniques. Supplemental irrigation using harvested rainwater could increase crop yield by more than 30%, and WUE ranged from 0.7 to 5.7 kg m-3 for spring wheat, corn and flax, and 30-40 kg m-3 for vegetables. Moreover, energy consumption for rainwater harvesting based on single family was compared with traditional water supply in the city of the Loess Plateau using the life cycle assessment (LCA) method. Results showed that energy consumption yielded per unit harvested rainwater was 25.96 MJ m-3 yr-1 which was much less than 62.25 MJ m-3 yr-1 for main water supply in Baoji City, Shanxi Province, meaning that rainwater harvesting saved energy by 139.8% as compared to the main water supply system. This study highlights the importance and potential of rainwater harvesting for water and energy conservation in the near future.  相似文献   

3.
Improving crop water productivity is necessary for ensuring food security. To quantify the water utilization in grain production from multiple perspectives, gross inflow water productivity (WPg), generalized agricultural water productivity (WPa), evapotranspiration water productivity (WPET) and irrigation water productivity (WPI) were examined in this study. This paper calculated and analyzed the temporal and spatial variation in these water productivity (WP)indices in the irrigated land of Heilongjiang Province.The results showed that almost all of the municipal WP indices increased from 2007 to 2015.The four indices showed large differences in scientific connotation and numerical performance, and their degrees of spatial variation were ranked as WPI>WPa>WPg>WPET.The spatial patterns of WP indices in different years were similar;the central and southern regions on the Songnen Plain and the eastern region had high WP values,while those of the northern region were low.Each WP index was used to evaluate the relationship between the input of water resources and the output of grain between different regions. Most cities had the potential to improve WP by reducing the input of irrigation water.Furthermore,the results provided recommendations to decision makers to plan for efficient use of water resources in different cities.  相似文献   

4.
对重庆青木关岩溶槽谷区内一条地下河的pH值、电导率、HCO3-、Ca2+、SO24-、Mg2+以及NO2-、NO3-等水化学指标进行了7个月至1年不等的监测,这些指标在空间和时间分布上具有不同特征.在空间上,电导率及HCO3-、Ca2+、Mg2+、NO3-浓度自地下河上游至下游逐步升高,比较地下河入口(D1)和出口(S2)处,电导率升高100μS/cm,HCO3-浓度升高1.5 mm0l/L,Ca2+浓度升高17 mg/L,Mg2+浓度升高5.1 mg/L,NO3-浓度相差6.4倍,而pH值和SO24-浓度则呈逐渐降低的趋势,D1和S2处的pH值相差0.16,SO24- 浓度相差26 mg/L.在时间分布上,pH、电导率、HCO3-、Ca2+、SO24-、Mg2+浓度季节变化明显,夏、秋季的值比冬、春季低.NO2-、NO3- 浓度变化在6、7月份有明显升高-回落的过程.对以上指标的影响因素分析显示:地质背景对水化学的控制、降雨的稀释效应、地下河的不同补给来源、岩溶作用的强弱程度以及农业活动的影响.
Abstract:
The hydrochemical indicators [pH, electrical conductivity (EC), HCO3- , Ca2+ , SO24- , Mg2+ ,NO2- and NO3-] of the underground water in a karst valley in Qingmuguan, Chongqing was monitored for 7-12 months, and the hydrochemical characters were found to be different in their temporal and spatial distribution. Some factors, such as EC, HCO3- , Ca2+ , Mg2+ and NO3- , increased from the upstream to the downstream, while pH and SO24 decreased. Compared with the data at D1 (the inlet), EC, HCO3-,Ca2+ and Mg2+ increased by 100μS/cm, 1.5 mmoll/L, 17 mg/L and 5.1 mg/L, respectively, at S2 (the outlet), and the concentration of NO3- at S2 was 6.4 times that at D1. In contrast, pH and SO24- concentration showed an opposite trend, being 0.16 and 26 mg/L lower at D1 than at S2. The underground water hydrochemistry differed in different seasons, pH, EC, HCO3- , Ca2+ and SO24- showed significant seasonal variations, being higher in winter and spring than in summer and fall. NO3- and NO2 showed a sharp in-crease followed by a decrease in June and July. It is concluded from an analysis of these monitoring data that the major influencing factors are geological background, precipitation dilution, different underground water recharge, karstification and agriculture activities.  相似文献   

5.
The aim of this study was to assess the crop water demand and deficit of spring highland barley and discuss suitable irrigation systems for different regions in Tibet, China. Long-term trends in reference crop evapotranspiration and crop water demand were analyzed in different regions, together with crop water demand and deficit of spring highland barley under different precipitation frequencies. Results showed that precipitation trends during growth stages did not benefit the growth of spring highland barley. The crop coefficient of spring highland barley in Tibet was 0.87 and crop water demand was 389.0 mm. In general, a water deficit was found in Tibet, because precipitation was lower than water consumption of spring highland barley. The most severe water deficit were in the jointing to heading stage and the heading to wax ripeness stage, which are the most important growth stages for spring highland barley; water deficit in these two stages would be harmful to the yield. Water deficit showed different characteristics in different regions. In conclusion, irrigation systems may be more successful if based on an analysis of water deficit within different growth stages and in different regions.  相似文献   

6.
The virus disease threatening wheat production in Hulunbeir District of Inner-Mongolia was identified as NCMV(Northern Cereal Mosaic Virus)or WRSV(Wheat Rosette Stunt Virus)by test of host range,transmission,virus particle and serology.The main vector for spreading the virus is planthopper,Laodelphax striatellus(Fallen),Which overwinters in the stubbles of wheat underground.The overwintered viruliferous nymphs emerged in late Pril is responsible for the early infection of the disease.Agropyron repens,an important perennial weed in cultivated regions,is also an important wild host of the virus and its vector.Severe loss is induced when wheat is infected before 3-leaf stage.The disease incidence could be predicted by a model with the population and viruliferous rate of overwintered vectors as independent variables.  相似文献   

7.
The growth of tobacco is sensitive to environment conditions. The tobacco production is strictly restricted by regional cultivated land. Based on the principal of hiberarchy analysis and fuzzy mathematics and the technique of geographic information system (GIS), the comprehensive evaluation of tobacco ecology suitability were studied according to the actual circumstances of the whole Henan tobacco planting regions, China. The evaluation index system of tobacco ecology suitability of Henan tobacco planting regions was established by choosing 17 evaluation indexes from 3 respects of climate, soil and landform with Delphi method. Furthermore, the membership function was set up according to the effects of each ecology factors on the growth and quality of tobacco suitability. And the analytical hierarchy process (AHP) was used to determine the weight of indexes by using quantitative analysis. Then the tobacco ecology suitability map of Henan tobacco plantation was drawn with GIS software mapGIS. It is found that the most areas of the western and southern parts of Henan Province, China, are the highly suitable regions, accounting for 22.52% of Henan tobacco planting areas. It is because that there are medium air temperature, sunshine and rainfall, medium soil pH value, and high contents of soil organic matter in the regions. Moreover, the topography is hill and massif, and the height above sea level is between 150-800 m there. Some areas of the southern and middle parts of Henan Province are the suitable ones, accounting for 34.99% of Henan tobacco planting areas. It is because that there are enough rainfall, medium air temperature, high contents of available N and available K in the soil in these regions. There are less suitable regions in the northern and eastern parts of the investigated regions because of drought, too high pH value and CI in the soil and irrigation water, accounting for 35.54% of the whole areas. It can be conducted rapidly and correctly by combining AHP and membership function for comprehensive evaluation of tobacco ecological suitability supported by GIS. There are above moderate ecological suitability for most part of tobacco planting fields in Henan Province. The distributions of tobacco ecological suitability calculated are identical with actual tobacco productivity completely.  相似文献   

8.
In order to evaluate the quality of water environment, the conception of entropy is applied in information science, and the entropy weight model is built to evaluate comprehensively water quality. The indexes weights of water quality are determined by value of entropy. This kind of method is applied on evaluating water quality in the new water to be built. The result shows that the water quality in it which supply water is between grade Ⅲ and Ⅳ, and the result is similar to that of gray related method.  相似文献   

9.
duniperus sabina Linnaeus, an evergreen shrub with prostrate life form, can effectively prevent sand moving and is an important tree species for reforestation in semiarid areas of China. It has laterally distributed adventitious roots and a deeply distributed main root system. To detect water movement between the main root system and adventitious roots, we adopted heat pulse sensors using the Heat Ratio Method, a high precision method for measuring low sap flow rates. Two sensors were implanted in each individual in the stem between the main root system and adventitious roots, and another two in lateral stems distal to all the roots. Positive sap flows during nighttime, even under saturated air moisture conditions, were detected only between the main root system and adventitious roots under drought conditions, and the rate of flow increased as drought progressed and decreased or disappeared after rain events. The results demonstrated the existence of water movement from the main root system to adventitious roots, and combined with the high contribution of nighttime sap flow to transpiration (11%-16%) the results indicate that it also involves the process of hydraulic lift, a water movement from moist subsoil to dry surface soils. Integrated water use strategy between the main root system and adventitious roots via the process of hydraulic lift of soil water maximizes water acquisition efficiency from both subsoil water and water from rain pulses on the soil surface; this increases survivability in the water-limited environment of semiarid areas.  相似文献   

10.
Water and energy are closely linked natural resources - the transportation, treatment, and distribution of water depends on low-cost energy; while power generation requires large volumes of water. Seawater desalination is a mature technology for increasing freshwater supply, but it is essentially a trade of energy for freshwater and is not a viable solution for regions where both water and energy are in short supply. This paper discusses the development and application of a renewable-energy-driven reverse osmosis (RO) system for water desalination and the treatment and reuse of aquaculture wastewater. The system consists of (1) a wind-driven pumping subsystem, (2) a pressure-driven RO membrane desalination subsystem, and (3) a solar-driven feedback control module. The results of the pilot experiments indicated that the system, operated under wind speeds of 3 m s-1 or higher, can be used for brackish water desalination by reducing the salinity of feedwater with total dissolved solids (TDS) of over 3 000 mg L-1 to product water or permeate with a TDS of 200 mg L-1 or less. Results of the pilot experiments also indicated that the system can remove up to 97% of the nitrogenous wastes from the fish pond effluent and can recover and reuse up to 56% of the freshwater supply for fish pond operation.  相似文献   

11.
饲料中有效能是供动物生长发育的基础.不同动物所用的有效能体系不同,目前大多数动物采用消化能、代谢能体系,但随着研究的发展与深入,发现最能反映饲料有效能的是净能体系.无论哪种体系,采用合理的测定技术准确测定饲料中的有效能值显得尤其重要,通过对饲料有效能值的准确测定可以实现动物所需能量的精确供给,减少养殖成本,使经济效益最大化.文章综述了几种有效能评价体系的测定技术.  相似文献   

12.
国家贫困生资助政策实施以来,对贫困生帮助很大,同时在实际运行中还存在着一些问题。本文提出贫困生认定工作仍需要进一步采取各种相关配套措施,以推动和保障贫困生资助工作更好地开展。  相似文献   

13.
《河北农业大学学报》创刊年代考   总被引:3,自引:0,他引:3  
清光绪二十八年(1902)河北农业大学前身—直隶农务学堂诞生,经几易其名,于1958年更名为河北农业大学至今。清光绪三十一年(1905)直隶高等农业学堂时期创办了《北直农话报》,清光绪三十四年(1908)更名为《直隶农务官报》,中华民国七年(1918)改出《农学月刊》,中华民国十七年(1928)易名为《河大农刊》,中华民国二十三年(1934)更名为《河北通俗农刊》,中华民国二十四年(1935)易名为《河北农林学刊》,1948年更名为《河北农学院研究专刊》,1959年更名为《河北农业大学学报》至今。《河北农业大学学报》前身诸刊都与现时的《河北农业大学学报》有着一脉相承的历史渊源,各刊之间联系紧密,连续性、继承性强。因此,《河北农业大学学报》的创刊时间应追溯至1905年创办的《北直农话报》。  相似文献   

14.
为探明客源市场生态旅游消费的潜在特征,采用问卷调查的形式,就长沙市居民对湖南金洞生态旅游开发的意向等问题进行抽样调查.结果显示,生态旅游符合人们“回归自然”的旅游新时尚,有着极大的开发空间,指出生态旅游的开发要注重环境保护和可持续发展.开发的产品要以休闲度假类的大众产品为主,开发生态旅游都市客源市场还要多种渠道并用,尤其是要注重媒体的宣传.  相似文献   

15.
板栗属壳斗科栗属(Castanea mollisima Blume),其种子属于顽拗型种子,不耐贮藏。基于近年来板栗贮藏保鲜技术研究成果,从合理采收、贮前处理、贮藏方法等方面进行论述。  相似文献   

16.
陈勇 《广西农学报》2007,22(1):30-31,56
动物疫病是畜牧业生产的大敌,要发展畜牧业生产就要防治动物疫病。但在疫苗接种时,经常出现正常反应外的其他不利于机体的反应,如废食、皮疹、休克、死亡等,正确处理或避开这些问题,对推行动物疫病的计划免疫,实施强制免疫,保护人畜安全具有十分重要的现实意义和作用。  相似文献   

17.
为了预测厚胶合板弹性模量,通过简化层合板理论,该文建立了胶合板弹性模量预测模型,并以单板条、经过涂胶热压处理的单板条和相同工艺条件下的单板层积材的弹性模量,采用4种不同铺层方式的19层桉树胶合板对模型进行了验证。结果表明:3种预测值与实测值的趋势一致,相关系数R2顺纹在0.86以上,横纹在0.88以上,但是精度不同。采用单板条弹性模量预测的胶合板弹性模量比实测值偏低;采用经过涂胶热压处理后的单板条弹性模量预测的胶合板弹性模量比实测值偏高;采用相同工艺条件下的单板层积材弹性模量预测的胶合板弹性模量与实测值偏差较小,顺纹平均误差为4.64%,横纹平均误差10.94%。因此,采用相同工艺条件下的单板层积材的弹性模量来预测胶合板的弹性模量是可行的。   相似文献   

18.
赵经华  张春姹 《安徽农业科学》2006,34(17):4480-4481
分析了入世4年来,我国水果出口在量上实现了突破,但并没有实现质变的主要原因,指出我国水果业存在的问题。论述了引进外资对发展我国水果业的意义,并提出了具体可行的对策与建议。  相似文献   

19.
采用L(934)正交设计试验,对山茱萸浸提液中山茱萸多糖的酶水解法提取工艺进行了优化研究,并对浸提液的中有效成分马钱苷含量进行了HPLC法分析。结果表明,山茱萸多糖浸提的最佳工艺为:液料比1∶5,浸提时间4 h,浸提温度80℃,果胶酶添加量0.55 g/L。用HPLC法测定出的山茱萸浸提液中马钱苷平均含量为0.512 ...  相似文献   

20.
甘肃省设施农业发展历史悠久,古代创造了麦草覆盖生产韭 黄及泥碗护苗等传统设施农业技术,至今仍然受到农民欢迎,在 甘肃省中部应用面积约5万多hm2。建国后,甘肃设施农业获得 了新生,大致经历了三个阶段;第一阶段为引进应用北京改良式 温室阶段,时间在20世纪50-60年代;第二个阶段为塑料拱棚 与地膜覆盖栽培阶段,时间在20世纪70-80年代:第三阶段为  相似文献   

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