The arid areas in China are mainly located in North China and NorthwestChina. The North China is the main region for food production. There is 31. 19% of the totalfarmland and 26. 01% of the total population, but only...The arid areas in China are mainly located in North China and NorthwestChina. The North China is the main region for food production. There is 31. 19% of the totalfarmland and 26. 01% of the total population, but only 6. 14% of the available water resources ofChina. Groundwater is over pumped (6. 53 X 10~9m^3 every year) in the regions of Beijing, Tianjin,and Hebei Province, so water supply could not meet the water demand there. The distribution of waterin Northwest China is uneven, some inland rivers and lakes are dried up, and desertification hasexpanded since river water in the upper and middle reaches is diverted for irrigation. Up to 2050,population will be up to 1. 6 X 10~9 in China, and industry will be developed fast, therefore 50% ofthe water supply will be used by industry and resident, and water for agriculture will be decreasedyear by year. In the coming 50 years, water demand for agriculture will be increased by 5. 6 x10^9m^3 in the Huanghe (Yellow) River valley, and by 1. 7 x 10~9m^3 in the Northwest China. It willbe impossible for the Huanghe River to meet the water demand, because it always dried up in the coldhalf year since 1984. To avoid water shortage of agriculture in the arid regions, it is necessaryto divert water from the Changjiang (Yangtze) River in the south of China, and to use waterefficiently. It is the best way to use drip irrigation in agriculture, recycle water in industry andresident use, and control water pollution. Otherwise water shortage in the arid regions willrestrict the development of agriculture in China.展开更多
This research focused on the impact of mining on the permeability of key aquifuge (N2 laterite) that is widespread in the arid and semi-arid areas of northwestern China and is critical for preserving water resources...This research focused on the impact of mining on the permeability of key aquifuge (N2 laterite) that is widespread in the arid and semi-arid areas of northwestern China and is critical for preserving water resources. The impact of mining stress recovery on the permeability of cracked N2 laterite was assessed for parts of northwestern China that included the Jingle laterite and Baode laterite. The mineral compositions and swelling properties of the laterite at both locations were examined, and analytical results showed that the laterite contained abundant clay minerals. The Baode laterite exhibited higher expansibility than Jingle laterite. The triaxial creep permeability performance of laterite specimens with a prefabricated crack width of 1.0, 1.5, and 2.5 mm were tested. The results indicated that strain of cracked laterite all exhibited transient creep following each level of loading, and then unstable creep and stable creep. With the increase of loading, the transient creep deformation corresponding to each level of loading decreased, the unstable creep deformation produced by identical loading gradually and incrementally increased. The nonlinear power function equation was selected to fit creep grading curves which have high precision. The cracks within the laterite gradually closed with the stress recovery, and permeability gradually recovered. During the stress recovery, the narrower cracks exhibited a smaller change in permeability. However, for narrow cracks in mining soil, permeability recovered after mining stress when permeability was closer to initial permeability, and the Baode laterite showed greater recovery than that of the Jingle laterite.展开更多
Soil water is one of renewable water resources.Some properties of soil water concerning with its availability to plant are briefly described.An equation for estimating the amount of soil water resource is presented.Ba...Soil water is one of renewable water resources.Some properties of soil water concerning with its availability to plant are briefly described.An equation for estimating the amount of soil water resource is presented.Based on the evaporation demand of atmosphere,the evaluation coefficient for soil water resource is suggested.展开更多
Author of this paper introduced the formation and development, main viewpoints, and framework of the theory of soil and water ecology, as well as the role and value of realizing the sustainable utilization of soil and...Author of this paper introduced the formation and development, main viewpoints, and framework of the theory of soil and water ecology, as well as the role and value of realizing the sustainable utilization of soil and water ecological resources, the sustainable maintenance of ecological environment, and the sustainable development of economy and society. The paper argued that in the current era, it is imperative to maintain the integrity and continuity of soil and water ecology and culture, emphasize the planning and construction of soil and water ecological infrastructure, and ensure the service functions of urban ecosystem, so as to realize the sustainable utilization of soil and water ecological resources, and the sustainable maintenance of ecological environment, and the sustainable development of economy and society.展开更多
A field experiment was conducted in a well-puddled paddy field developed on the Tama River alluvial soil in the Farm of Tokyo University of Agriculture and Technology, Japan, to study the effect of intermittent irriga...A field experiment was conducted in a well-puddled paddy field developed on the Tama River alluvial soil in the Farm of Tokyo University of Agriculture and Technology, Japan, to study the effect of intermittent irrigation on water use efficiency of paddy rice. Four treatments were arranged with 2 replicates: continuous flooding irrigation treatments (CFI), and three intermittent irrigation treatments Ⅱ-0, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Water consumption was lower in treatment Ⅱ-0 than in treatment CFI because the percolation rate was reduced by the reduction in the hydraulic head of ponded water. Intermittent irrigation led to soil repeated shrinking and swelling in Ⅱ-1 and Ⅱ-2 plots and, therefore, soil cracks developed rapidly. Since they became the major routes of water percolation, the soil cracks increased water consumption in treatments Ⅱ-1 and Ⅱ-2. There were no significant differences in dry matter production and grain yields between treatment Ⅱ-0 and treatment CFI, but the dry matter production and grain yields in treatments Ⅱ-0 and CFI were significantly higher than those in treatments Ⅱ-1 and Ⅱ-2. Therefore, the water use efficiency in the treatments was in the order of Ⅱ-0 > CFI > Ⅱ- 2 > Ⅱ- 1.展开更多
The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixin...The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixing small watershed of the low mountain and hilly region of Jilin Province,Northeast China.This study aims to elucidate the effects of soil and water conservation practices on soil conditions after the short-term implementation of practices.Soil samples were collected from five soil and water conservation sites(ER,FP,FR,SS,and VR)and two controls(BL and CT)to investigate their properties.To evaluate the influence of soil and water conservation practices on soil quality,an integrated quantitative index,soil quality index(QI),was developed to compare the soil quality under the different soil and water conservation practices.The results show that not all soil and water conservation practices can improve the soil conditions and not all soil properties,especially soil organic carbon(SOC),can be recovered under soil and water conservation practice in short-term.Moreover,the QI in the five soil and water conservation practices and two controls was in the following order:ER>VR>BL>FR>CT>SS>FP.ER exhibited a higher soil quality value on a slope scale.In the low mountain and hilly region of Northeast China,ER is a better choice than the conversion of farmlands to planted grasslands and woodlands early in the soil and water conservation program.展开更多
Based on the analysis on the status quo of natural resources input in Brain production and on the policy of Brain subsidies, this paper puts forward a new idea - establishing grain subsidies through assessing the valu...Based on the analysis on the status quo of natural resources input in Brain production and on the policy of Brain subsidies, this paper puts forward a new idea - establishing grain subsidies through assessing the value of the natural resources in Brain production. The assessment of the natural resources in Brain production provides rationale and reference standard for the policy of Brain subsidies, which will promote the sustainable use of natural resources accordingly. This paper concludes: (1) it is necessary for the grain subsidies to assess the full value of natural resources, including economic value, ecological value and social value: (2) the government should give farmers direct subsidies or environment subsidies according to the economic and ecological value of natural resources in grain production, (3) the social value of natural resources can be realized by establishing the country social security system, taking the social value as the criterion for the payment for part of farmers' insurance.展开更多
In the Lower Cheliff Plain (northwestern of Algeria), the waters resources are limited; the adoption of a rational approach in the management of irrigation water in the irrigated perimeter poses an inequality in the...In the Lower Cheliff Plain (northwestern of Algeria), the waters resources are limited; the adoption of a rational approach in the management of irrigation water in the irrigated perimeter poses an inequality in the balance between supply and demand. The two surface water resources, Gargar and Merdjet Sidi Abed dams, do not satisfy the requirements of agriculture water. According to the National Office of the Irrigation and Drainage data, the quantity of allocated water is never distributed; the difference between allocated water and drop water can also exceed 20%, and then, another problem of management is that the water losses in the distribution can reach 20% again. The shortage irrigation water resource allocated has constrained the farmers to use groundwater. The chemical analysis of 56 simples to this water showed a significant chemical diversity in the compositions. There is a high salinity risk (C3 class) or very high risk (C4 class) of soil salinisation. A space chart distribution to the EC water probability to exceed 2.25 dS/m interpolated by the indicator kriging method showed that 78% of the groundwater surface presents a significant probability to exceed this limit. The average value of the SAR (sodium adsorption ratio) is lower than 10 that indicates a moderate risk of sodisation. This observation is in contradiction with the high values of the SAR measured in the soil solution. The approach of residual alkalinity (RSC) shows that a good number of drillings analyzed presents a positive sign RSC (RSC 〉 0). This water presents a real danger of sodisation. They have a low salinity, which, for a farmer, does not present any danger.展开更多
Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especiall...Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especially in the construction at the uninhabited area close to the sea where the procurement of fresh water is difficult. In this study, durability against chloride attack of seawater mixed concrete with different replacement ratio of BFS (blast furnace slag) and FA (fly ash) is discussed and the life time until the occurrence of corrosion crack is evaluated. The results show that: (1) Chloride penetration rate of seawater mixed specimens with BFS and FA is lower than that of freshwater mixed OPC (ordinary Portland cement) specimens; (2) Oxygen permeability of seawater mixed specimens with BFS and FA is almost the same or lower than that of freshwater mixed OPC specimens; (3) Total life time (corrosion incubation period and propagation period) of seawater mixed specimens with BFS and FA is almost the same or only slightly shorter than that of freshwater mixed OPC specimens. From the results, it was confirmed that the usage of seawater in concrete mixing is feasible in concrete with the appropriate BFS and FA replacement ratio.展开更多
Kuwait, one of the gulf council member countries, situated in the Northeastern part of the Arabian Peninsula, experiences hyper-arid desert environmental condition due to the geographical location. Kuwait faces many c...Kuwait, one of the gulf council member countries, situated in the Northeastern part of the Arabian Peninsula, experiences hyper-arid desert environmental condition due to the geographical location. Kuwait faces many challenges in the sustainable development of the agricultural sector due to the scarcity of arable land, water resources and high rate of land degradation. So it is essential to emphasis the efficient use of the available water and soil resources in a sustainable manner and also to rehabilitate the degraded land using proper rehabilitation techniques. This study concentrates on the water harvesting and organic mulching (e.g., using date palms) methods. The study area is an artificial playa (2,500 m2), formed through the dumping of the gravel quarries in December 2003. The application of the water harvesting and mulching technique in the study showed an improvement of soil physical properties. The average infiltration capacity has increased from 74 cm3/min to 112 cm3/min. The average difference in volume of infiltrated water was 33.5%. The bulk density and porosity of the control plot was 2 g/cm3 and 27%, respectively; while that of the treated soil was 1.5 g/cm3 and 44%, respectively. The moisture content of the treated soil was increased to 50%, more than control soil at depth 40-60 cm, and also there was a significant increase in organic matter. The temperature of the treated soil was 2 ℃ lower than the control soil at a depth of 60 cm. This study conserved the irrigation water through reducing the proportion of soil evaporation and thus creating an optimum condition for the plant growth.展开更多
The Upper Blue Nile Basin, the highest sources of the Nile River flow through this area, is still under severe land degradation, which aggravates water scarcity. The productivity of subsistence farming is below 50% of...The Upper Blue Nile Basin, the highest sources of the Nile River flow through this area, is still under severe land degradation, which aggravates water scarcity. The productivity of subsistence farming is below 50% of the potential of agriculture, mainly because of inappropriate rainwater management. At farm level, rainwater is exposed to poor partitioning described as flooding, land degradation, siltation and water scarcity for domestic, irrigation, hydropower and environmental uses in the basin. Hence, it is one of the root causes of food-insecurity in the region. To reverse this situation and achieve increased rainwater productivity knowledge of rainfall partitioning at grassroots level is significantly important. However, rainwater partitioning and partitioning points are not clearly known by farmers in the area. Besides, understanding water-routes helps to manage rainwater with integrated water resources management (IWRM) processes. The objective of this study was to identify the knowledge gap of farmers and experts on rainwater partitioning that help for increased water productivity. Intensive monitoring and interviews have been carried out for 81 farmers and 22 local experts in three pilot sites. The interviewed farmers and experts are clearly aware of the runoff partitioning, since it is easily observable. While, only 10% of the farmers and 25% of experts know about evaporation partitioning, which is the largest compared to other losses. The paper gives recommendations for better understanding of rainfall partitioning points and management of water-routes at grassroots level to increase rainwater productivity and enhance food security in the area with IWRM processes.展开更多
Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tiv...Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tive method for de-silication of diaspore. In this study the effect of different factors, including pulp tem- perature, density, pH value, depressant, and collector dosage, on direct flotation of diaspore were investigated by laboratory experiments. The optimum conditions were identified and the flotation perfor- mance was improved. The results show that under optimum conditions (a pulp temperature around 40℃, a pulp density from 30% to 33g, a pH value from 9.0 to 10.0, an air flow rate of 0.5 m3/(m2 rain), a dispersant level from 35 to 70 g/t, and a collector level around 1000 g/t) an AI/Si ratio of 6.97 is obtained starting from an initial Al/Si ratio of about 4.71. The recovery of A1203 under these conditions was 86.94%.展开更多
The production of hydro power from its natural water resources has come to mean more to Norway than to possibly any other country in world. The right to utilize the falling water in the rivers belonged to whoever owne...The production of hydro power from its natural water resources has come to mean more to Norway than to possibly any other country in world. The right to utilize the falling water in the rivers belonged to whoever owned the adjacent ground. The acquisition of water rights is not allowed without a license from the government. Any development is also dependent on a governmental licence. Important conditions such as return of the property to the government without any compensation after 60 years, compulsory delivery of power at production cost and license fees to the local municipalities have been important incentives for the public and political acceptance of hydro power development in Norway during a long period of economic development. Today, Norway is a rich and materially well developed country, and there is no longer any acceptance for further hydro power development. Some of the remaining potential will be utilized for small-scale local developments, but most of it will be incorporated in governmental conservation plans.展开更多
For the last two decades the world has undergone a population explosion which has been accompanied by a speeding up of urbanization and land use for industrial and agricultural products. These involve a vast increase ...For the last two decades the world has undergone a population explosion which has been accompanied by a speeding up of urbanization and land use for industrial and agricultural products. These involve a vast increase in the discharge of pollutants into very different receiving water bodies, and have had adverse effects on the various components of the environment. For a long time, human has concerned a little of the natural environment. It is obvious that this variation in surface temperature of the earth increases the level of sea due to snowmelt. So climate change is manifested by many phenomena: floods, droughts, fires, tornadoes, cyclones, earthquakes, volcanic eruptions, diseases etc.. The statement today is dramatic. Entire regions were devastated and many rivers and lakes have become polluted around the world. Pollution has it nature which is hard to be absorbed. Where did the different pollutants come from? What are the risks to the aquatic environment? To prevent and combat the general decline of these ecosystems, it is important to distinguish and determine the effects of different sources of pollution and any changes that may suffer the physical environment. The climate depends primarily on changes in earth orbit parameters, which affect the solar radiation received by the earth surface. Therefore, human participates strongly to these changes, for example, pollution is the main reason to argue the greenhouse effect, an increase of anthropogenic carbon dioxide (CO2) into the atmosphere, which promotes global warming to the planet. These modifications are already applied in order to ensure durable development in water resources by controlling discharges into streams to preserve water resources for future generations and to ensure reconciliation between man-climate and environment.展开更多
Urbanization is a process that is undergoing all over the world, which will speed up in the forthcoming years, especially in China as the boom of economy. On average, urbanization level is not only depended on the spe...Urbanization is a process that is undergoing all over the world, which will speed up in the forthcoming years, especially in China as the boom of economy. On average, urbanization level is not only depended on the speed, but theefficiency, particularly efficiency of using land resource which affects urbanization directly. This paper provided status quo of land resource utilization efficiency, indictors, methods and factors, and illustrated the reference of well land utilization, aiming at fostering urbanization in China.展开更多
There are some bad impacts from a critical land such as flood in rainy season and dryness in dry season. Long dryness could cause shortage of water for human consumption, industry and agriculture. Prevention has been ...There are some bad impacts from a critical land such as flood in rainy season and dryness in dry season. Long dryness could cause shortage of water for human consumption, industry and agriculture. Prevention has been made to avoid the both bad impacts by building hydraulic structures like reservoirs and ponds in order to reduce the peak flow during the rainy season and to store the water for use during the dry season. However, they gradually become full of sediment. This will make them work insufficiently and will cause high maintenance cost. Moreover, wells in agriculture field used as retention also suffer dryness to make crop failure. This study aims to develop a model of pond for conservation of land and water in non irrigated land. Community participation is crucial in order to solve the flood and dryness problems. The community, especially the farmers will participate actively in the implementation and maintenance of the model. There are benefits in using the pond model such as: (1) to control sediment transport to the rivers, reservoir or other hydraulic structures; (2) to reduce flood rate; (3) to increase ground water recharge; (4) to contain water for agriculture and (5) to control the fertility of land. The cost of making a unit of model (sedrainpond) of 1.5 m diameter and 1.5 meter depth is relatively cheap between $10 to $20 (US), and the maintenance is done by the farmers. When the pond model becomes functional, besides containing water in the rainy season, the water can be used to sustain water for agriculture in the dry season to avoid any crop failure. When the pond becomes dry, the farmers can harvest the suspended load sediment such as clay or silt to spread onto their land to keep its fertility.展开更多
Nowadays, mowing has an increasing role in the management of semi-natural and nature conservation areas. Semi-dry grasslands have been planted on cleared areas of forest in the Pannon Mountains, which would be reclaim...Nowadays, mowing has an increasing role in the management of semi-natural and nature conservation areas. Semi-dry grasslands have been planted on cleared areas of forest in the Pannon Mountains, which would be reclaimed by forest without use of the areas by humans. In our work we analysed cleared grasslands. The questions we tried to answer were which changes were caused by different land use, how favourable mowing can be for the purpose of grassland management and nature protection, do the composition of the plant species and the diversity vary within two years when conditions of precipitation are different. In four sampling areas, in 4 × 10 quadrats we registered the plant species and their cover values. We performed a site assessment in April, June and October, 2013-2014. We analysed the data by using cluster and ordination processes and we compared the sampling areas on the basis of the humidity preference and Shannon's index of diversity. According to the results, the composition of species and diversity on the analysed areas used for different purposes considerably deviate from each other. Further, we found a difference between two portions of the area whose had minor deviation in water management.展开更多
Plum is the major fruit species in the area of North Montenegro. Over a long period of growing in this region, autochthonous cultivars adapted, and have been achieving satisfactory results, despite poor growing condit...Plum is the major fruit species in the area of North Montenegro. Over a long period of growing in this region, autochthonous cultivars adapted, and have been achieving satisfactory results, despite poor growing conditions. A study conducted over a period of three years in a North Montenegro region included in situ identification of autochthonous plum cultivars. Observation and recording of their phenological and pomological traits were performed using International Board for Plant Genetic Resources (IBPGR) and International union for the Protection of New Varieties of plants (UPOV) methodologies. Eighteen cultivars derived from Prunusdomestica L. and two cultivars derived from P. insititia L. were identified. Flowering started between March 26th and April 12th and fruit ripening between 13th of July (Petrovaca) and 18th September (Trnovaca). Fruit weight ranged from 6.65 g ± 0.235 g to 53.88 g ± 0.654 g respectively and stone weight from 0.16 g ±0.003 g to 2.20 g ± 0.711 g. The cultivars were classified as being extremely small in terms of fruit size, except for cvs Crvenadurgulja (big fruit size). Rounded fruit shape and light green ground color were dominant. Skin color ranged from amber to black. Yellow green was a dominant flesh color and medium flesh firmness predominated. The fruits of the above cultivars could be processed, particularly into plum brandy, or they could be used fresh or dried. The selected plum cultivars can be used in breeding programmes, as rootstocks as well as in further disease related systematic studies under field and laboratory conditions.展开更多
The combined surface and groundwater allocation practice by wells and canals had contributed to the safety of groundwater environment and agriculture sustainable production. The typical area in the People's Victory C...The combined surface and groundwater allocation practice by wells and canals had contributed to the safety of groundwater environment and agriculture sustainable production. The typical area in the People's Victory Canal irrigation district was taken as a case, drawing together the irrigation district agriculture water consumption and precipitation from 1954 to 2014 in the People's Victory Canal irrigation district, ratios of surface to groundwater irrigation amount, dynamic of groundwater depth and hydrochemical characteristic of groundwater from 2008 to 2014 in the research area, the relationship between groundwater depth and ratio of surface to groundwater irrigation amount was analyzed, in order to ascertain the influence of precipitation on ratios of surface to groundwater irrigation amount and its effect on soil and groundwater environment. The results indicated that positive correlation between the ratios of surface to groundwater irrigation amount and annual precipitation was appeared, affected by climate change, average irrigation amount from surface in the recent 5 years was 2.90 x 108 cubic meters, accounted for 75.52% of total irrigation amount, on the other hand, decreasing tendency of precipitation was obvious, and groundwater depth dynamic in upstream of the branch canals was more dramatic than downstream because of surface water irrigation infiltration, under the unified condition of water use efficiency, ratio of surface to groundwater irrigation amount was negative correlation with area of the groundwater depth beyond 11 m, meanwhile, groundwater depth demonstrated negative correlation with the ratio of surface to groundwater irrigation amount, moreover, alkaline trend of groundwater hydrochemistry during the normal season in the research area was obvious because of phreatic evaporation and the agricultural irrigation from wells, along with irrigation from surface inflow of Yellow River, quality of groundwater hydrochemistry during the dry season was ameliorative greatly. Consequently, it was very important to the agriculture sustainable production that well-canal combined irrigation patterns alleviated extremely alkaline trend of the groundwater hydrochemistry and played a positive role of root layer soil salinity leaching.展开更多
文摘The arid areas in China are mainly located in North China and NorthwestChina. The North China is the main region for food production. There is 31. 19% of the totalfarmland and 26. 01% of the total population, but only 6. 14% of the available water resources ofChina. Groundwater is over pumped (6. 53 X 10~9m^3 every year) in the regions of Beijing, Tianjin,and Hebei Province, so water supply could not meet the water demand there. The distribution of waterin Northwest China is uneven, some inland rivers and lakes are dried up, and desertification hasexpanded since river water in the upper and middle reaches is diverted for irrigation. Up to 2050,population will be up to 1. 6 X 10~9 in China, and industry will be developed fast, therefore 50% ofthe water supply will be used by industry and resident, and water for agriculture will be decreasedyear by year. In the coming 50 years, water demand for agriculture will be increased by 5. 6 x10^9m^3 in the Huanghe (Yellow) River valley, and by 1. 7 x 10~9m^3 in the Northwest China. It willbe impossible for the Huanghe River to meet the water demand, because it always dried up in the coldhalf year since 1984. To avoid water shortage of agriculture in the arid regions, it is necessaryto divert water from the Changjiang (Yangtze) River in the south of China, and to use waterefficiently. It is the best way to use drip irrigation in agriculture, recycle water in industry andresident use, and control water pollution. Otherwise water shortage in the arid regions willrestrict the development of agriculture in China.
基金The study was jointly supported by the State Key Program of National Natural Science Foundation of China (Grant No. 41430643) and the National Key Basic Research Program of China (973 Program) (Grant No. 2015CB251601).
文摘This research focused on the impact of mining on the permeability of key aquifuge (N2 laterite) that is widespread in the arid and semi-arid areas of northwestern China and is critical for preserving water resources. The impact of mining stress recovery on the permeability of cracked N2 laterite was assessed for parts of northwestern China that included the Jingle laterite and Baode laterite. The mineral compositions and swelling properties of the laterite at both locations were examined, and analytical results showed that the laterite contained abundant clay minerals. The Baode laterite exhibited higher expansibility than Jingle laterite. The triaxial creep permeability performance of laterite specimens with a prefabricated crack width of 1.0, 1.5, and 2.5 mm were tested. The results indicated that strain of cracked laterite all exhibited transient creep following each level of loading, and then unstable creep and stable creep. With the increase of loading, the transient creep deformation corresponding to each level of loading decreased, the unstable creep deformation produced by identical loading gradually and incrementally increased. The nonlinear power function equation was selected to fit creep grading curves which have high precision. The cracks within the laterite gradually closed with the stress recovery, and permeability gradually recovered. During the stress recovery, the narrower cracks exhibited a smaller change in permeability. However, for narrow cracks in mining soil, permeability recovered after mining stress when permeability was closer to initial permeability, and the Baode laterite showed greater recovery than that of the Jingle laterite.
文摘Soil water is one of renewable water resources.Some properties of soil water concerning with its availability to plant are briefly described.An equation for estimating the amount of soil water resource is presented.Based on the evaporation demand of atmosphere,the evaluation coefficient for soil water resource is suggested.
文摘Author of this paper introduced the formation and development, main viewpoints, and framework of the theory of soil and water ecology, as well as the role and value of realizing the sustainable utilization of soil and water ecological resources, the sustainable maintenance of ecological environment, and the sustainable development of economy and society. The paper argued that in the current era, it is imperative to maintain the integrity and continuity of soil and water ecology and culture, emphasize the planning and construction of soil and water ecological infrastructure, and ensure the service functions of urban ecosystem, so as to realize the sustainable utilization of soil and water ecological resources, and the sustainable maintenance of ecological environment, and the sustainable development of economy and society.
基金Project (No. 49971043) supported partly by the National Natural Science Foundation of China.
文摘A field experiment was conducted in a well-puddled paddy field developed on the Tama River alluvial soil in the Farm of Tokyo University of Agriculture and Technology, Japan, to study the effect of intermittent irrigation on water use efficiency of paddy rice. Four treatments were arranged with 2 replicates: continuous flooding irrigation treatments (CFI), and three intermittent irrigation treatments Ⅱ-0, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Water consumption was lower in treatment Ⅱ-0 than in treatment CFI because the percolation rate was reduced by the reduction in the hydraulic head of ponded water. Intermittent irrigation led to soil repeated shrinking and swelling in Ⅱ-1 and Ⅱ-2 plots and, therefore, soil cracks developed rapidly. Since they became the major routes of water percolation, the soil cracks increased water consumption in treatments Ⅱ-1 and Ⅱ-2. There were no significant differences in dry matter production and grain yields between treatment Ⅱ-0 and treatment CFI, but the dry matter production and grain yields in treatments Ⅱ-0 and CFI were significantly higher than those in treatments Ⅱ-1 and Ⅱ-2. Therefore, the water use efficiency in the treatments was in the order of Ⅱ-0 > CFI > Ⅱ- 2 > Ⅱ- 1.
基金Under the auspices of Foundation of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau(No.10501-1210)National Natural Science Foundation of China(No.31101606)+1 种基金Basic Scientific Research Operating Expenses of Jilin University(No.200903377)National Key Projects in National Science&Technology Program during the 12th Five-Year Plan Period of China(No.2011BAD16B10-3,2012BAD04B02-3)
文摘The soil and water conservation practices of ecological restoration(ER),fish scale pit(FP),furrow and ridge tillage across the slope(FR),shrub strips(SS),and vegetation-covered ridge(VR)are characteristic of the Jixing small watershed of the low mountain and hilly region of Jilin Province,Northeast China.This study aims to elucidate the effects of soil and water conservation practices on soil conditions after the short-term implementation of practices.Soil samples were collected from five soil and water conservation sites(ER,FP,FR,SS,and VR)and two controls(BL and CT)to investigate their properties.To evaluate the influence of soil and water conservation practices on soil quality,an integrated quantitative index,soil quality index(QI),was developed to compare the soil quality under the different soil and water conservation practices.The results show that not all soil and water conservation practices can improve the soil conditions and not all soil properties,especially soil organic carbon(SOC),can be recovered under soil and water conservation practice in short-term.Moreover,the QI in the five soil and water conservation practices and two controls was in the following order:ER>VR>BL>FR>CT>SS>FP.ER exhibited a higher soil quality value on a slope scale.In the low mountain and hilly region of Northeast China,ER is a better choice than the conversion of farmlands to planted grasslands and woodlands early in the soil and water conservation program.
文摘Based on the analysis on the status quo of natural resources input in Brain production and on the policy of Brain subsidies, this paper puts forward a new idea - establishing grain subsidies through assessing the value of the natural resources in Brain production. The assessment of the natural resources in Brain production provides rationale and reference standard for the policy of Brain subsidies, which will promote the sustainable use of natural resources accordingly. This paper concludes: (1) it is necessary for the grain subsidies to assess the full value of natural resources, including economic value, ecological value and social value: (2) the government should give farmers direct subsidies or environment subsidies according to the economic and ecological value of natural resources in grain production, (3) the social value of natural resources can be realized by establishing the country social security system, taking the social value as the criterion for the payment for part of farmers' insurance.
文摘In the Lower Cheliff Plain (northwestern of Algeria), the waters resources are limited; the adoption of a rational approach in the management of irrigation water in the irrigated perimeter poses an inequality in the balance between supply and demand. The two surface water resources, Gargar and Merdjet Sidi Abed dams, do not satisfy the requirements of agriculture water. According to the National Office of the Irrigation and Drainage data, the quantity of allocated water is never distributed; the difference between allocated water and drop water can also exceed 20%, and then, another problem of management is that the water losses in the distribution can reach 20% again. The shortage irrigation water resource allocated has constrained the farmers to use groundwater. The chemical analysis of 56 simples to this water showed a significant chemical diversity in the compositions. There is a high salinity risk (C3 class) or very high risk (C4 class) of soil salinisation. A space chart distribution to the EC water probability to exceed 2.25 dS/m interpolated by the indicator kriging method showed that 78% of the groundwater surface presents a significant probability to exceed this limit. The average value of the SAR (sodium adsorption ratio) is lower than 10 that indicates a moderate risk of sodisation. This observation is in contradiction with the high values of the SAR measured in the soil solution. The approach of residual alkalinity (RSC) shows that a good number of drillings analyzed presents a positive sign RSC (RSC 〉 0). This water presents a real danger of sodisation. They have a low salinity, which, for a farmer, does not present any danger.
文摘Using seawater in concrete can be considered as one of the sustainable approaches in construction industry not only to save the freshwater resource but also to promote the use of abandoned seawater resource, especially in the construction at the uninhabited area close to the sea where the procurement of fresh water is difficult. In this study, durability against chloride attack of seawater mixed concrete with different replacement ratio of BFS (blast furnace slag) and FA (fly ash) is discussed and the life time until the occurrence of corrosion crack is evaluated. The results show that: (1) Chloride penetration rate of seawater mixed specimens with BFS and FA is lower than that of freshwater mixed OPC (ordinary Portland cement) specimens; (2) Oxygen permeability of seawater mixed specimens with BFS and FA is almost the same or lower than that of freshwater mixed OPC specimens; (3) Total life time (corrosion incubation period and propagation period) of seawater mixed specimens with BFS and FA is almost the same or only slightly shorter than that of freshwater mixed OPC specimens. From the results, it was confirmed that the usage of seawater in concrete mixing is feasible in concrete with the appropriate BFS and FA replacement ratio.
文摘Kuwait, one of the gulf council member countries, situated in the Northeastern part of the Arabian Peninsula, experiences hyper-arid desert environmental condition due to the geographical location. Kuwait faces many challenges in the sustainable development of the agricultural sector due to the scarcity of arable land, water resources and high rate of land degradation. So it is essential to emphasis the efficient use of the available water and soil resources in a sustainable manner and also to rehabilitate the degraded land using proper rehabilitation techniques. This study concentrates on the water harvesting and organic mulching (e.g., using date palms) methods. The study area is an artificial playa (2,500 m2), formed through the dumping of the gravel quarries in December 2003. The application of the water harvesting and mulching technique in the study showed an improvement of soil physical properties. The average infiltration capacity has increased from 74 cm3/min to 112 cm3/min. The average difference in volume of infiltrated water was 33.5%. The bulk density and porosity of the control plot was 2 g/cm3 and 27%, respectively; while that of the treated soil was 1.5 g/cm3 and 44%, respectively. The moisture content of the treated soil was increased to 50%, more than control soil at depth 40-60 cm, and also there was a significant increase in organic matter. The temperature of the treated soil was 2 ℃ lower than the control soil at a depth of 60 cm. This study conserved the irrigation water through reducing the proportion of soil evaporation and thus creating an optimum condition for the plant growth.
文摘The Upper Blue Nile Basin, the highest sources of the Nile River flow through this area, is still under severe land degradation, which aggravates water scarcity. The productivity of subsistence farming is below 50% of the potential of agriculture, mainly because of inappropriate rainwater management. At farm level, rainwater is exposed to poor partitioning described as flooding, land degradation, siltation and water scarcity for domestic, irrigation, hydropower and environmental uses in the basin. Hence, it is one of the root causes of food-insecurity in the region. To reverse this situation and achieve increased rainwater productivity knowledge of rainfall partitioning at grassroots level is significantly important. However, rainwater partitioning and partitioning points are not clearly known by farmers in the area. Besides, understanding water-routes helps to manage rainwater with integrated water resources management (IWRM) processes. The objective of this study was to identify the knowledge gap of farmers and experts on rainwater partitioning that help for increased water productivity. Intensive monitoring and interviews have been carried out for 81 farmers and 22 local experts in three pilot sites. The interviewed farmers and experts are clearly aware of the runoff partitioning, since it is easily observable. While, only 10% of the farmers and 25% of experts know about evaporation partitioning, which is the largest compared to other losses. The paper gives recommendations for better understanding of rainfall partitioning points and management of water-routes at grassroots level to increase rainwater productivity and enhance food security in the area with IWRM processes.
基金financial support from the National Key Technology R&D Program in the 11th Five Year Plan of China (No. 2008BAB31B02)the National Natural Science Foundation of China (No. 51174205)
文摘Most of the bauxite resources in China are kaolinite-diaspore bauxite of middle to low grade, with a fine dissemination, and are difficultly separated. Direct flotation de-silication has been shown to be an effec- tive method for de-silication of diaspore. In this study the effect of different factors, including pulp tem- perature, density, pH value, depressant, and collector dosage, on direct flotation of diaspore were investigated by laboratory experiments. The optimum conditions were identified and the flotation perfor- mance was improved. The results show that under optimum conditions (a pulp temperature around 40℃, a pulp density from 30% to 33g, a pH value from 9.0 to 10.0, an air flow rate of 0.5 m3/(m2 rain), a dispersant level from 35 to 70 g/t, and a collector level around 1000 g/t) an AI/Si ratio of 6.97 is obtained starting from an initial Al/Si ratio of about 4.71. The recovery of A1203 under these conditions was 86.94%.
文摘The production of hydro power from its natural water resources has come to mean more to Norway than to possibly any other country in world. The right to utilize the falling water in the rivers belonged to whoever owned the adjacent ground. The acquisition of water rights is not allowed without a license from the government. Any development is also dependent on a governmental licence. Important conditions such as return of the property to the government without any compensation after 60 years, compulsory delivery of power at production cost and license fees to the local municipalities have been important incentives for the public and political acceptance of hydro power development in Norway during a long period of economic development. Today, Norway is a rich and materially well developed country, and there is no longer any acceptance for further hydro power development. Some of the remaining potential will be utilized for small-scale local developments, but most of it will be incorporated in governmental conservation plans.
文摘For the last two decades the world has undergone a population explosion which has been accompanied by a speeding up of urbanization and land use for industrial and agricultural products. These involve a vast increase in the discharge of pollutants into very different receiving water bodies, and have had adverse effects on the various components of the environment. For a long time, human has concerned a little of the natural environment. It is obvious that this variation in surface temperature of the earth increases the level of sea due to snowmelt. So climate change is manifested by many phenomena: floods, droughts, fires, tornadoes, cyclones, earthquakes, volcanic eruptions, diseases etc.. The statement today is dramatic. Entire regions were devastated and many rivers and lakes have become polluted around the world. Pollution has it nature which is hard to be absorbed. Where did the different pollutants come from? What are the risks to the aquatic environment? To prevent and combat the general decline of these ecosystems, it is important to distinguish and determine the effects of different sources of pollution and any changes that may suffer the physical environment. The climate depends primarily on changes in earth orbit parameters, which affect the solar radiation received by the earth surface. Therefore, human participates strongly to these changes, for example, pollution is the main reason to argue the greenhouse effect, an increase of anthropogenic carbon dioxide (CO2) into the atmosphere, which promotes global warming to the planet. These modifications are already applied in order to ensure durable development in water resources by controlling discharges into streams to preserve water resources for future generations and to ensure reconciliation between man-climate and environment.
基金Supported the Major Research Plan of the National Natural Science Foundation of China(Grant No.91325302,91425303)
文摘Urbanization is a process that is undergoing all over the world, which will speed up in the forthcoming years, especially in China as the boom of economy. On average, urbanization level is not only depended on the speed, but theefficiency, particularly efficiency of using land resource which affects urbanization directly. This paper provided status quo of land resource utilization efficiency, indictors, methods and factors, and illustrated the reference of well land utilization, aiming at fostering urbanization in China.
文摘There are some bad impacts from a critical land such as flood in rainy season and dryness in dry season. Long dryness could cause shortage of water for human consumption, industry and agriculture. Prevention has been made to avoid the both bad impacts by building hydraulic structures like reservoirs and ponds in order to reduce the peak flow during the rainy season and to store the water for use during the dry season. However, they gradually become full of sediment. This will make them work insufficiently and will cause high maintenance cost. Moreover, wells in agriculture field used as retention also suffer dryness to make crop failure. This study aims to develop a model of pond for conservation of land and water in non irrigated land. Community participation is crucial in order to solve the flood and dryness problems. The community, especially the farmers will participate actively in the implementation and maintenance of the model. There are benefits in using the pond model such as: (1) to control sediment transport to the rivers, reservoir or other hydraulic structures; (2) to reduce flood rate; (3) to increase ground water recharge; (4) to contain water for agriculture and (5) to control the fertility of land. The cost of making a unit of model (sedrainpond) of 1.5 m diameter and 1.5 meter depth is relatively cheap between $10 to $20 (US), and the maintenance is done by the farmers. When the pond model becomes functional, besides containing water in the rainy season, the water can be used to sustain water for agriculture in the dry season to avoid any crop failure. When the pond becomes dry, the farmers can harvest the suspended load sediment such as clay or silt to spread onto their land to keep its fertility.
文摘Nowadays, mowing has an increasing role in the management of semi-natural and nature conservation areas. Semi-dry grasslands have been planted on cleared areas of forest in the Pannon Mountains, which would be reclaimed by forest without use of the areas by humans. In our work we analysed cleared grasslands. The questions we tried to answer were which changes were caused by different land use, how favourable mowing can be for the purpose of grassland management and nature protection, do the composition of the plant species and the diversity vary within two years when conditions of precipitation are different. In four sampling areas, in 4 × 10 quadrats we registered the plant species and their cover values. We performed a site assessment in April, June and October, 2013-2014. We analysed the data by using cluster and ordination processes and we compared the sampling areas on the basis of the humidity preference and Shannon's index of diversity. According to the results, the composition of species and diversity on the analysed areas used for different purposes considerably deviate from each other. Further, we found a difference between two portions of the area whose had minor deviation in water management.
文摘Plum is the major fruit species in the area of North Montenegro. Over a long period of growing in this region, autochthonous cultivars adapted, and have been achieving satisfactory results, despite poor growing conditions. A study conducted over a period of three years in a North Montenegro region included in situ identification of autochthonous plum cultivars. Observation and recording of their phenological and pomological traits were performed using International Board for Plant Genetic Resources (IBPGR) and International union for the Protection of New Varieties of plants (UPOV) methodologies. Eighteen cultivars derived from Prunusdomestica L. and two cultivars derived from P. insititia L. were identified. Flowering started between March 26th and April 12th and fruit ripening between 13th of July (Petrovaca) and 18th September (Trnovaca). Fruit weight ranged from 6.65 g ± 0.235 g to 53.88 g ± 0.654 g respectively and stone weight from 0.16 g ±0.003 g to 2.20 g ± 0.711 g. The cultivars were classified as being extremely small in terms of fruit size, except for cvs Crvenadurgulja (big fruit size). Rounded fruit shape and light green ground color were dominant. Skin color ranged from amber to black. Yellow green was a dominant flesh color and medium flesh firmness predominated. The fruits of the above cultivars could be processed, particularly into plum brandy, or they could be used fresh or dried. The selected plum cultivars can be used in breeding programmes, as rootstocks as well as in further disease related systematic studies under field and laboratory conditions.
文摘The combined surface and groundwater allocation practice by wells and canals had contributed to the safety of groundwater environment and agriculture sustainable production. The typical area in the People's Victory Canal irrigation district was taken as a case, drawing together the irrigation district agriculture water consumption and precipitation from 1954 to 2014 in the People's Victory Canal irrigation district, ratios of surface to groundwater irrigation amount, dynamic of groundwater depth and hydrochemical characteristic of groundwater from 2008 to 2014 in the research area, the relationship between groundwater depth and ratio of surface to groundwater irrigation amount was analyzed, in order to ascertain the influence of precipitation on ratios of surface to groundwater irrigation amount and its effect on soil and groundwater environment. The results indicated that positive correlation between the ratios of surface to groundwater irrigation amount and annual precipitation was appeared, affected by climate change, average irrigation amount from surface in the recent 5 years was 2.90 x 108 cubic meters, accounted for 75.52% of total irrigation amount, on the other hand, decreasing tendency of precipitation was obvious, and groundwater depth dynamic in upstream of the branch canals was more dramatic than downstream because of surface water irrigation infiltration, under the unified condition of water use efficiency, ratio of surface to groundwater irrigation amount was negative correlation with area of the groundwater depth beyond 11 m, meanwhile, groundwater depth demonstrated negative correlation with the ratio of surface to groundwater irrigation amount, moreover, alkaline trend of groundwater hydrochemistry during the normal season in the research area was obvious because of phreatic evaporation and the agricultural irrigation from wells, along with irrigation from surface inflow of Yellow River, quality of groundwater hydrochemistry during the dry season was ameliorative greatly. Consequently, it was very important to the agriculture sustainable production that well-canal combined irrigation patterns alleviated extremely alkaline trend of the groundwater hydrochemistry and played a positive role of root layer soil salinity leaching.