Science and Technology is expected to improve the efficiency of agricultural irrigation under the condition of water shortage in the future
Water is limited but key important resource. On the most drainage basins in the world, water is essential for the industry, city and residents’ life. Meanwhile, water also plays a very important role in the natural system. But from the view of the world, most of water resource is used in the agricultural production—-In the water resources of human allocated from nature, 66% are used in agricultural production. In the water shortage area of western US it is not rare to see that the total irrigation water accounted for 75-90% of the total diversion water.
From the view of history, many water diversion projects are funded by the government in US. Besides, the water rights mechanism also give priority to ensure to supply agricultural water, this causes low price of water in agriculture, farmers have no incentive to improve the efficiency of irrigation water. Therefore, the amount of water allocated to agricultural irrigation water is 2-3 times to food production actual needs. On average, half of the deployment of irrigation water go into the groundwater or back to the surface runoff rather than being used for irrigation.
From the view of the world, 40% of the world’s food supply are from farmland irrigation；Irrigation area accounts for 18% of the total agricultural land area in US, but the benefit of this 18% accounts for half of the total food output. As the world’s population grows, the demand for food will also increase. It is difficult to meet the increasing demand by expanding the acreage, people should increase yields and improve the efficiency of agricultural water.
In addition, with the increase of population, the demand of water will also increase in non-agricultural department. It is expected, the period from 2000 to 2050, the world demand for water will increase by 55%. And most of the increased demand will come from the manufacturing, power generation, the city and domestic water. Therefore, in the future of more water shortage days, control of irrigation water consumption has become a necessity. To achieve this goal, human need to depend heavily on new technology.
‘Use water’ or ‘ Lose water’
There is water loss in the process of irrigation, for instance, in the process of transferring the water in reservoir or channel, leakage will happen. When the water is in the fields, part of water will leak into groundwater directly, which can’t be absorbed by the crop roots, other part of water will run directly from the field. The loss in the farmland is known as the “field” loss, the leakage in reservoir and channels is known as the “system” loss.
In the past 50 years, in order to reduce the losses in the field, people have developed several techniques such as laser technology, center shaft, etc sprinkler irrigation and drip irrigation technology. These technologies are not cheap, and the main use is to reduce the input in other aspects, such as labor costs. Also, the technology may not to realize improvement of overall water use efficiency, because they cannot solve the relevant problems of water storage, water transfer, water distribution.
Precise measuring water demand and the available amount of water
At present, the development of monitoring technology and information technology get people see the horizon of reducing the field loss and system loss at the same time.
Now, for example, people can achieve precise and comprehensive, real-time control for the whole irrigation area through the data acquisition and monitoring control system (SCADA). The SCADA system is able to automatically measure the reservoir water, the flow of channel and the water transferred to the farmland, you can also easily realize the remote control of the reservoir water, channel transfer and distribution.
At present, there are few farmers using remote sensing technology to reduce loss, improve the efficiency of irrigation water. But with the falling prices of the new technology and more simple access to its information, the situation will change.
For example, people can estimate the using of irrigation water anywhere in field all over the world by satellite images now. This technique is developed by Utah state university of Utah water research laboratory, and currently has been used in the state of seville irrigation area. Through the website, farmers can see the water conclusion and soil moisture conclusion of crops in this quarter, so that they can have a better plan for the future water and irrigation time. While irrigation channels and reservoirs managers can understand the conditions to local total water usage, and better predict the future demand for the entire irrigation.
Another nascent but very exciting technology is to use small uavs to collect scientific images, to provide information for the whole irrigation district management. Unmanned aerial vehicle can also help improve the efficiency of fertilizing, weeding, prevention and control of pest, harvesting. If the technology price of the unmanned aerial vehicle can come down, it will be able to help people to irrigate precisely, avoiding waste according to the requirements of different plots.
Water management in the future
Along with the increasing demand of water, various industries have more and more water demands. The difficulty of the water management is also getting bigger and bigger, especially in arid and semiarid areas and rapid population growth in the region. Due to the low water use efficiency of irrigated agriculture, water value created in agriculture is lower than other industries, reducing the agricultural water is a natural thing. Water managers and decision makers must understand how to coordinate balance and understand how different water distribution scheme will produce different economic, environmental and social impact.
Under the condition of climate change, the uncertainty of water supply is increasing in the future, water management institutions should have more flexibility, in order to effectively cope with the change of water demand and water supply. And remote sensing technology and information technology will be a powerful tool to solve the water problem in agriculture.