Cultivation techniques of new water-saving techniques (I)
Analysis of water-saving irrigation technology
Agricultural water consumption accounts for 70%~80% of China's total water consumption. Because the measures of agricultural water-saving irrigation are not fully implemented, water resources are wasted, so the full implementation of water-saving irrigation in irrigation areas is a key way to solve the water shortage problem in China. This paper analyzes the engineering technology of water-saving irrigation, and expounds the effect of implementing water-saving irrigation.
Keywords water-saving irrigation technology
China Library Classification Number: TU99 1 Document Identification Number: A
I. Introduction
From the point of view of water use, improving the utilization rate of water should be considered in combination with the operation of irrigation water. Irrigation is to meet crop demand by supplementing water to farmland, and create good environmental conditions for crop growth to obtain higher yield. The operation of irrigation water can be roughly divided into three links, and each link has the problem of improving water utilization rate. The first step is to transport water from the water source to the field through channels or pipelines to improve the efficiency of water delivery. The corresponding technology is called water transmission and distribution engineering technology. The second link is that irrigation water is irrigated in various ways in the field, and the corresponding technologies are called sprinkler irrigation, micro-irrigation and surface irrigation to improve irrigation efficiency. The third link is the utilization of field water by crops to improve water production efficiency. Therefore, the connotation of agricultural water saving includes rational development, utilization and allocation of water resources, water saving in water transmission and distribution system, water saving in field irrigation process, water saving in crop growth water conversion process, water saving in water management, agricultural water saving and technical measures to increase production, etc. Its purpose is to greatly improve the utilization rate of water, and blaze a trail of water-saving irrigation with China characteristics.
Second, water-saving irrigation engineering technology
1, canal seepage control technology
These are all technical measures taken to reduce the water permeability of channels or establish waterproof protective layers. According to the materials used, it can be divided into soil compaction, concrete pavement, masonry lining, concrete lining, plastic film seepage prevention and asphalt pavement seepage prevention.
The research work of canal seepage control in China has been focused on the development of seepage control materials with good performance, low cost, easy construction and easy grasp by the masses, and at the same time, the new section and lining form of seepage control channels have been studied and popularized. For example, in recent years, Baojixia Irrigation District in Shaanxi Province has launched a series of projects in the transformation process of the three major irrigation districts. u？ T-shaped canal lining machinery has played an important role in the construction. The main means of water conveyance for agricultural irrigation, which accounts for 80% of China's total water consumption, is channels, while the leakage loss of traditional soil channels accounts for about 50% ~ 60% of the total water diversion, and the annual water loss in China alone is about 1.7? 10 1 1m3。 At present, the anti-seepage length of canals in China only accounts for the required 1/3 ~ 1/4. Therefore, vigorously developing canal seepage control technology is an important way of water-saving irrigation.
2. Low pressure pipeline irrigation technology
Abbreviation? Pipeline irrigation? It is an irrigation method that uses low-pressure pipes instead of canals to deliver water. ? Pipeline irrigation? Because of the advantages of less one-time investment, simple equipment, water saving, labor saving, land saving, time saving, obvious benefit of increasing production, and easy for farmers to master, it has received great attention and has developed to 30? 106hm2. Guanzhong and northern Shaanxi of Shaanxi Province are widely used in large-scale pumped-well irrigation areas. Pipeline irrigation? Technology. Practice has proved it? Pipeline irrigation? It is one of the important ways to develop water-saving irrigation in northern China.
3. Sprinkling irrigation technology
This is an irrigation method that uses special equipment to spray pressurized water into the air to form fine water droplets and evenly fall into the field. According to the equipment composition, it can be divided into two categories: unit sprinkler system and pipeline sprinkler system. Since 1970s, China has developed sprinkler irrigation technology. After more than 20 years' efforts, the sprinkler irrigation area has grown to 8? 105 hm ~ 2, and achieved remarkable water saving and yield increasing benefits. This technology is more suitable for development in hilly areas, arid and water-deficient areas and cash crop irrigation areas.
4. Micro-irrigation technology
This is an irrigation method that uses special equipment to transport water and nutrients needed for crop growth to the surface layer or soil layer near the root layer of crops. According to the types of emitters, they can be divided into drip irrigation, micro-sprinkler irrigation and spring irrigation. Micro-irrigation technology was adopted in China from 1974 to 2? 104 hm2, which is suitable for hilly areas and areas with very poor water resources. At the same time, because it can integrate irrigation, fertilization and pesticide application, it is especially suitable for irrigation of cash crops. In theoretical research, a set of design parameters and calculation methods suitable for China's national conditions are summarized. In terms of equipment development and production, micro-irrigation belt, orifice emitter, compensation emitter, refractive rotary micro-sprinkler, pulse drip irrigation equipment, filter, air inlet and exhaust valve, pressure regulator, fertilizer applicator and so on have been developed.
5, improve the surface irrigation technology.
This is a technical improvement mainly around the shortcomings of traditional surface irrigation technology, such as poor irrigation uniformity and large irrigation quota. Including improving the specifications of furrows (such as changing long furrows into short furrows, changing wide furrows into narrow furrows, short furrow irrigation and drip irrigation, etc.). For example, in Luo Hui Canal and Baojixia Irrigation District, Shaanxi Province, after the long border was changed to short border, the wide border was changed to narrow border, and the irrigation amount was changed to small border and shallow irrigation, and advanced surface irrigation techniques (such as surge irrigation, furrow irrigation, film irrigation and thin cable irrigation) were adopted, the irrigation amount during the crop growth period was reduced by 20% ~ 30%. More than 98% of the irrigation area in China is surface irrigation, so it is of great significance to improve this technology, improve irrigation uniformity and save irrigation water. At present, the most valuable improved surface irrigation technologies in China are surge irrigation and film irrigation. Surge irrigation is a new technology introduced by the United States in the late 1970s, which is suitable for dry farming irrigation. Since 1980s, China has also carried out research in this field, and made a thorough and systematic study on the water-saving mechanism of surge irrigation, the formation of soil dense layer, infiltration characteristics and the movement law of surface water flow. At present, it is necessary to further study the problem of surge irrigation in muddy water theoretically and develop surge irrigation equipment suitable for China's national conditions, which is the key to expand the application of surge irrigation technology. Irrigation on film is a new technology, which was originally created by China. On the basis of plastic film cultivation, the water flow on the film side is changed to upward flow, water is transported by plastic film, and crops are irrigated through film holes and film side seepage. This technology has achieved a high effect of increasing production and saving water in Xinjiang, but it needs further research in theory.
6. Infiltration irrigation technology
This is an irrigation method that irrigation water is introduced into the field through underground pipeline system, and the irrigation water moistens the root soil through holes in the pipe wall. There are two main types in China, one is pipeline type and the other is rat-way type. At present, the main problems of infiltration irrigation are: the soil wetting is not uniform enough; It is easy to cause topsoil to return to salt; Underground pipelines are not easy to repair and maintain; Large investment and high construction requirements are the main reasons that affect the promotion at present; Theoretical research is still insufficient, and key technical problems need to be improved and perfected.
7, rainwater collection and utilization technology
This is a technology to collect surface runoff generated by heavy rainfall in arid and semi-arid hilly areas and supply it to crops when it is most needed. At the end of 1980s, our country carried out research on rainwater collection and utilization technology, such as thin cement treatment technology of confluence surface, pit and kiln construction layout technology, collection efficiency, and determination of the ratio of confluence surface to planting area, and achieved a number of meaningful results. However, there is a lack of systematic theoretical research on the guidance, collection, storage and efficient utilization of rainwater, and there is no overall planning of confluence and supporting irrigation technology and crop cultivation technology suitable for different regions. In recent years, pit irrigation agriculture developed in eastern Gansu, mountainous areas of White in Shaanxi and southern Ningxia has adopted typical rainwater collection and utilization technology, which has been welcomed as a poverty alleviation project in some areas.
Third, the effect of implementing water-saving irrigation
1, the utilization rate of irrigation water is obviously improved.
The national average irrigation water utilization rate increased from about 30% in 1970s to 47.5% in 2007, and the average irrigation water consumption per unit area decreased from 7 950 m3/hm2 to 6 435 m3/ hm2. The effective irrigation area increased from 48.87 million hm2 in the late 1970s to 57.782 million hm2 in 2007, but the total irrigation water consumption did not increase. For example, during the period from 1996 to 10 in 2006, the whole country invested 2 126 billion yuan to help 363 dangerous projects and projects in irrigation areas. Stuck in the neck? The project and the canal section with serious leakage were reformed, and the irrigation area was restored, improved and increased by 6.667 million hm2. According to the analysis and calculation, compared with before and after the implementation of the project, the water utilization coefficient of canal system increased from 0.49 to 0.54, and the irrigation water utilization rate increased from 42. 1% to 47.8%. The average irrigation water consumption per mu decreased from 529m3 to 469m3, and the new water saving was 654.38+025 billion m3.
2. Water productivity and comprehensive agricultural production capacity have been significantly improved.
According to the calculation and analysis of 363 large-scale irrigation areas that have been implemented with water-saving reconstruction, the average yield of grain crops has increased by 450 kg/ hm2, and the grain production capacity has increased by11500 million kg. It has realized the double benefits of increasing grain production capacity 1 kg and saving water 1. 1 m3 for every national input 1.84 yuan.
3. Accelerate the transformation from traditional agriculture to modern agriculture.
The development of water-saving irrigation has accelerated the transformation of China agriculture from traditional to modern. Good irrigation and drainage infrastructure, advanced agricultural technology and excellent varieties have changed many water-saving irrigation project areas from the decentralized management form of one household in the past to the management form of farmers' cooperative organizations and large-scale contracting, which has promoted regional planting, large-scale management and industrial production of agriculture and effectively promoted agricultural production and farmers' income.
conclusion
Water shortage and water saving will be a theme that China will have to face in the future. It is not only related to food security and ecological security, but also related to national security. It will be the development direction of water-saving irrigation in China in the future to continue to increase investment in water-saving irrigation engineering technology, vigorously develop various water-saving technologies such as canal seepage prevention technology, low-pressure pipeline irrigation technology, sprinkler irrigation technology, drip irrigation technology and rainwater collection and utilization technology, and strengthen water management in various irrigation areas.
refer to
[1] Building Macro. Problems and countermeasures in the construction of water-saving irrigation in our province [J]. Sichuan Water Conservancy, 2003,24 (2):10-12.
[2] Jiang Changyun. Water-saving agriculture in China: present situation and development approach [J]. Agricultural economic problems, 200 1,10 (10):19-23.
Cultivation Techniques of New Water-saving Techniques (Ⅱ)
Building a water-saving society
Abstract: Water is the source of life, the key to production and the foundation of ecology. In view of the severe situation of water resources in China, the government of China has put forward new requirements for building a water-saving society in the new period. Based on the present situation and existing problems of building a water-saving society in China, this paper puts forward the idea that building a water-saving society should start from three aspects: throttling, pollution control and open source, and introduces some new measures such as water price adjustment, water-saving publicity, seawater utilization and rainwater utilization.
Keywords: water-saving society; Save water; Water price; Seawater utilization; Rainwater utilization
China is a country with serious shortage of water resources and frequent floods and droughts. The per capita water resources are only 2,200 cubic meters, accounting for only 1/4 of the world average. In addition, the spatial and temporal distribution of water resources in China is extremely uneven, and the contradiction between supply and demand of water resources is prominent. The serious pollution of water resources has aggravated the shortage of water resources. Especially since the 1980s, with the rapid growth of population and the rapid development of economy and society, China's water consumption has increased sharply, and a large number of urban, domestic and industrial sewage have been discharged, which has led to the decrease of available water resources and seriously threatened people's normal production and life. At the same time, the extensive use of water resources in China has caused a lot of water loss in production and life, with low water use efficiency and great water saving potential. Therefore, building a water-saving society has become an urgent requirement for China's economic and social development.
1 Present situation and existing problems of water-saving society construction in China
Under the guidance of national policies, the construction of water-saving society in China has made some progress, the people's awareness of water saving has been gradually enhanced, the sewage discharge of industrial enterprises has been gradually standardized, the implementation and implementation of agricultural water-saving irrigation, the use of some advanced water-saving appliances and the rise of a large number of sewage treatment enterprises have provided powerful catalysts for the construction of water-saving society. However, there are also many problems in the process of building a water-saving society in China.
1. 1 nonstandard water right management
Because the division of responsibilities is not clear, once there is a problem, all departments shirk each other, and things are delayed again and again, and they cannot be effectively solved. In some cities, water management is seriously overlapping, sometimes there is a vacuum between urban construction and water conservancy departments, and sometimes it even brings resistance to law enforcement.
1.2 awareness of water resources protection needs to be strengthened.
In order to develop local economy, a few areas destroy existing water bodies at the expense of the environment. The national water-saving education only exists on paper and cannot be effectively implemented. Individual units over-exploit groundwater without a license. Some enterprises have moved to remote areas in order to escape government management, and sewage is discharged randomly in the local area, which has caused devastating damage to local water bodies and water environment.
1.3 The popularization of water-saving appliances is blocked and the development ability is weak.
Although a large number of advanced water-saving tools are facing the market under the call of national policies, only a few enterprises are willing to buy them because of the high cost. In addition, the quality of both agricultural irrigation sprinklers and urban shower sprinklers is not up to standard, the technical standards are not uniform, and they participate in market competition at low prices, which seriously affects the development process of water-saving technology industrialization.
2 throttling, pollution control, open source three effects simultaneously
2. 1 throttling
Implement new agricultural irrigation methods
Popularize water-saving irrigation throughout the country, develop advanced irrigation methods such as sprinkler irrigation, drip irrigation and micro-irrigation to improve water utilization. Compared with traditional agricultural flood irrigation, sprinkler irrigation saves water by 50% and micro irrigation saves water by 60%? 70%。 At the same time, adjust the planting structure of crops, plan the rational distribution of planted crops, and carry out centralized irrigation to avoid a large amount of water resources waste caused by spatial irrigation and uneven irrigation among crops.
In view of the reconstruction of existing soil canals in rural areas of China, the leakage loss of traditional soil canals is relatively large, accounting for about 50% of water delivery? 70%。 This problem can be solved by using canal seepage control technology. Considering the existing economic conditions in rural areas, using plastic film or concrete channels to deliver water can greatly reduce leakage and improve the efficiency of water delivery to more than 70%. At present, only about 20% of the channels in China have been treated with seepage control.
2. 1.2 industrial water saving
According to the survey, more than 70% of urban industrial water will be converted into sewage. In recent years, some countries rich in water resources have also vigorously advocated water conservation, mainly because they cannot afford the high burden of sewage treatment. China's water consumption per 10,000 yuan of industrial output value is 5- 10 times that of developed countries. It is necessary to adjust the industrial structure and layout, and vigorously develop and popularize water-saving appliances and water-saving industrial production technologies. According to the analysis and guidance, the unit investment of water supply facilities in 20 10 is about 8 yuan per cubic meter, sewage treatment is about per cubic meter 10 yuan, and the industrial water-saving cost is only about 3 yuan per cubic meter. Therefore, increasing water-saving investment is not only the need of sustainable development, but also has obvious economic benefits.
2. 1.3 water price adjustment
China's water price policy is extremely unreasonable, and groundwater overexploitation in some cities is very serious, but enterprises in these cities can still exploit groundwater for free, which makes it difficult for waterworks using groundwater and surface water to operate. The progressive water price and peak-valley water price popular abroad can be adopted, and the quarterly and standard methods can also be adopted to control water use. All kinds of situations show that water price is the main economic lever for water resources management and building a water-saving society. Under the unified leadership of the relevant state departments, China must formulate corresponding water price policies at this stage.
2. 1.4 water-saving management and publicity
Building a water-saving society requires extensive public participation, which requires relevant departments to improve water management systems such as water division coordination and water price hearings. Implement democratic supervision and widely mobilize the enthusiasm of water users to participate in water resources management. While mobilizing everyone's enthusiasm, relevant departments should also organize professionals to conduct business training for personnel in water and water transfer departments, improve the public's water-saving skills, and encourage the public to innovate new water-saving methods and technologies. Relevant departments should coordinate the promotion and application at the first time.
The government, schools, factories and other units should adopt various effective means such as radio, television and newspapers to carry out water-saving publicity and education, cultivate people's awareness of water conservation, and make people realize the crisis of water shortage and the importance of water conservation.
2.2 Pollution control
In 2009, China's total sewage discharge reached 53.68 billion tons, including 24.02 billion tons of industrial wastewater, accounting for 44.7% of the total discharge. The top four industries of wastewater discharge are papermaking, chemical industry, electric power and textile. The total discharge of water pollutants remains high, which leads to serious water pollution.
2.2. 1 Establish and improve laws and regulations on water environmental protection.
Relevant departments should strictly enforce the law, giving priority to prevention, supplemented by treatment, which is an effective way to prevent and control water pollution in China and the simplest, most effective and most economical way to build water environment.
2.2.2 Strengthen the protection of drinking water intake.
The relevant government departments should delimit the water source area, set up billboards in the area and strengthen the greening of the water intake. Organize regular personnel inspections to fundamentally eliminate pollution and achieve the goal of treating both the symptoms and the root causes. At the same time, it is necessary to improve the sinking system in rural areas and rationally plan the layout of village wells, which not only ensures that every household can drink safe drinking water, but also achieves the purpose of saving water resources and preventing water pollution.
2.3 open source
2.3. 1 seawater utilization
The amount of water in Shanghai accounts for 97% of the total water resources in the world, which is inexhaustible. Under the existing economic and technological conditions, it is not realistic to supply large-scale seawater desalination, but we can degrade seawater, that is, reduce its treatment standard for human production and life.
Seawater flushing, seawater industrial cooling, seawater car washing and so on can all be used through simple seawater purification. 5%-8% of domestic water in cities across the country is used for flushing toilets. Flushing toilets with seawater can reduce the overuse of groundwater resources by human beings. With the rise of service industry, many industries begin to use groundwater on a large scale, and car washing is one of them. At present, about 80% of car washing water in China is mined from groundwater, which leads to a large amount of uncontrolled waste of water resources because of its low cost. There is little water for car washing, which wastes a lot of water resources.
2.3.2 rainwater utilization
Rainwater is a natural water resource, and if it can be used well, it can greatly alleviate the current water crisis. Building rainwater collection projects and vigorously developing water cellars, plain reservoirs, ponds and rainwater interception projects are some reasonable measures to utilize rainwater resources. Taking the city as an example, the top of the building is designed as a concave funnel, and a drainage pipeline is connected in the concave shape, and a simple filter is arranged in the pipeline. Rainwater flows into the water storage tank through the pipeline, stays still in the water tank, and its particles sink or float to the surface of the water tank. After being filtered again by the filter in the middle of the pool, the effluent is pumped to the user's place to become washing water, washing water and courtyard greening water.
refer to
[1] Xu Degan, Mei. Water resources and urban sustainable development. Proceedings of the 2005 Annual Meeting of China Hydraulic Society, 2005: 42-48.
[2] Xue Ying et al. Discussion on urban water saving technology and management. Water-saving irrigation [J]2003(3)
[3] Wang Shucheng. Key points of building a water-saving society. China Water Conservancy, 2003( 1 1)
[4] Zhang Jing, Wang Bende, Zhou Huicheng. On the construction of water-saving society. Proceedings of the 2005 Annual Meeting of China Hydraulic Society, 2005: 32-36.
Brief introduction of the author
Liu (1993-), male, Han nationality, from Hebi, Henan Province, graduated from Zhengzhou University with a bachelor's degree of 20 1 1.
Meng Xiang (1992-), male, Han nationality, from Wuwei, Gansu Province, graduated from Zhengzhou Institute of Hydrology and Water Resources Engineering with grade 20 1 1.
Pan Chen (1993-), male, Han nationality, from Huanggang, Hubei Province, graduated from Zhengzhou University with a bachelor's degree of 20 1 1.
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