Efficient Irrigating 中文 Practices for a Water-Conscious World

In China, traditional irrigation practices like the qiao system, which uses gravity to distribute water, are still effective today. This ancient method can be adapted for modern use.

Water scarcity is a pressing issue in China, with some regions facing severe droughts. For example, the Yellow River Basin has experienced frequent droughts in recent years.

Using drip irrigation can reduce water waste by up to 50% compared to traditional sprinkler systems. This is especially important in water-conscious China, where every drop counts.

By implementing efficient irrigation practices, farmers in China can save water and increase crop yields.

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The global context of irrigation is quite fascinating. By 2021, the global land area equipped for irrigation reached 352 million hectares, a 22% increase from 2000.

Asia accounts for 70% of the world's irrigated land, with India and China having the largest equipped areas, at 76 million and 75 million hectares respectively.

Irrigation has enabled the production of more crops, especially commodity crops, in areas that couldn't support them otherwise.

The global context of irrigation is a fascinating topic. The scale of irrigation has increased dramatically over the 20th century, with 8 million hectares globally irrigated in 1800.

By 1990, 30% of the global food production came from irrigated land, a significant shift from earlier centuries. The majority of irrigation schemes are led by national governments, but private investors and other nations also play a role.

The global land area equipped for irrigation reached 352 million hectares by 2021, an increase of 22% from 2000. Asia accounts for the vast majority of this area, with 70% of the world's total.

India and China have the largest equipped areas for irrigation, with 76 million and 75 million hectares respectively. The United States has a significantly smaller equipped area, with 27 million hectares.

The world's population has more than doubled since the 1960s, reaching over seven billion people today.

This significant increase in population has led to a substantial rise in water consumption, with people now requiring a full volume of water compared to just a third in the past.

Broaden your view: Water Timer

With more people on the planet, the competition for water resources is much more intense, creating a critical constraint to farming in many parts of the world.

The growing demand for food, particularly from water-thirsty animal agriculture and intensive farming practices, exacerbates the issue, making it essential for farmers to increase productivity to meet the growing demands.

People are consuming more calories and meat today, which requires more water to produce their food, further contributing to the competition for water resources.

Water sources for irrigation can come from various places, including groundwater, surface water, and even non-conventional sources like treated wastewater.

Using treated or untreated wastewater for irrigation has its benefits, such as lower costs and a consistent supply of water. This can be especially attractive to farmers in developing countries where water is scarce.

In some cases, treated wastewater can even act as a fertilizer due to its nutrient content, like nitrogen, phosphorus, and potassium. However, using untreated municipal wastewater for irrigation can pose significant health hazards due to the presence of chemical and biological pollutants.

Farmers often have no alternative but to use polluted water to water their crops, especially when competing for water resources with industry and municipal users.

Water can come from various sources, including groundwater extracted from springs or wells, and surface water withdrawn from rivers, lakes, or reservoirs.

Groundwater is a reliable source of water, but its availability can be limited in some areas.

Surface water is a common source of irrigation water, often used in surface irrigation systems.

Non-conventional sources like treated wastewater, desalinated water, drainage water, or fog collection can also be used for irrigation.

Fog collection is a unique method of harvesting water, often used in arid or semi-arid regions.

Treated or untreated wastewater is being used for irrigation in agriculture, which can have both benefits and drawbacks. This practice can serve to fertilize plants if it contains nutrients like nitrogen, phosphorus, and potassium.

In developing countries, agriculture is increasingly using untreated municipal wastewater for irrigation, often in an unsafe manner. Cities provide lucrative markets for fresh produce, making them attractive to farmers.

There can be significant health hazards related to using untreated wastewater in agriculture, particularly in low-income countries where high levels of pathogens from excreta are common. Municipal wastewater can contain a mixture of chemical and biological pollutants.

The World Health Organization developed guidelines for safe use of wastewater in 2006, advocating a 'multiple-barrier' approach to wastewater use. This approach includes encouraging farmers to adopt various risk-reducing behaviors, such as ceasing irrigation a few days before harvesting to allow pathogens to die off in the sunlight.

Broaden your view: Automated Irrigation System Using Soil Moisture Sensor

Irrigation methods vary in how water is supplied to plants, with the goal of applying water uniformly to meet each plant's needs. This can be achieved through supplementary irrigation, where water is added to rainfall, or full irrigation, where crops rely solely on water supply.

Drip irrigation is a water-efficient method that delivers water at or near the root zone of plants, minimizing evaporation and runoff. It can be combined with plastic mulch to further reduce evaporation, and is often used with fertigation to deliver fertilizer.

Subirrigation involves artificially raising the water table to moisten the soil from below the plants' root zone, typically used in areas with high water tables or in commercial greenhouse production.

Consider reading: Irrigating Tomato Plants

Irrigation methods vary in how water is supplied to plants, aiming to apply water uniformly to meet each plant's needs.

Drip irrigation is a water-efficient method that delivers water at or near the root zone, one drop at a time, minimizing evaporation and runoff. It's often used in modern agriculture, combined with plastic mulch, and can be designed for uniformity or precise water delivery to individual plants.

Broaden your view: Irrigating Plants

Subirrigation involves artificially raising the water table to moisten the soil from below the plants' root zone, typically used in field crops with high water tables or in commercial greenhouse production. This method requires sophisticated equipment and management.

Irrigation by lateral move, also known as side roll or wheel line, involves a series of pipes with wheels and sprinklers that are rolled across the field to irrigate different strips. This system is less expensive to install than a center pivot but more labor-intensive to operate.

Sprinkler irrigation is a popular method that uses high-pressure sprinklers or guns to distribute water over a wide area. These can be mounted overhead on permanently installed risers or used on moving platforms connected to the water source by a hose.

Some sprinklers can rotate in a full or partial circle, and are driven by a ball drive, gear drive, or impact mechanism. Guns, on the other hand, operate at very high pressures and flows, making them suitable for industrial applications like dust suppression and logging.

Automatically moving wheeled systems known as traveling sprinklers can irrigate areas like small farms, sports fields, and cemeteries unattended. These systems use a length of polyethylene tubing wound on a steel drum, which is powered by the irrigation water or a small gas engine.

There are also hose-end sprinklers that attach to the end of a garden hose, allowing you to adjust the water flow, pattern, and range for efficient irrigation. These come in various designs and styles, including oscillating, impact, stationary, rotary, and traveling sprinklers.

Center pivot irrigation systems use several segments of pipe joined and supported by trusses, mounted on wheeled towers with sprinklers positioned along its length. These systems move in a circular pattern and are fed with water from the pivot point at the center of the arc.

For more insights, see: Irrigating Trees with Drip Systems

Efficiency is key when it comes to irrigation, and modern methods can supply the entire field uniformly with water, so each plant gets the right amount. This is crucial for maximizing crop yields.

Increased irrigation efficiency has a number of positive outcomes for the farmer, the community, and the wider environment. Improved efficiency means that the amount of crop produced per unit of water increases, which can lead to higher yields in the same area of land.

Water use efficiency can be determined by the formula: Field Water Efficiency (%) = (Water Transpired by Crop ÷ Water Applied to Field) x 100. This formula helps farmers understand how much water is being used effectively.

Low application efficiency can result in excess water being lost through seepage or runoff, which can have negative impacts on the surrounding environment. Improving the efficiency of irrigation can be achieved by improving system design or optimizing irrigation management.

Explore further: Circular Crop Irrigation

Efficiency is key in irrigation, and modern methods are designed to supply the entire field uniformly with water, giving each plant just the right amount it needs. This is achieved through efficient irrigation systems that reduce waste and excess water.

Water use efficiency in the field can be determined by the formula: Field Water Efficiency (%) = (Water Transpired by Crop ÷ Water Applied to Field) x 100. This calculation helps farmers measure how effectively their irrigation systems are working.

Increasing irrigation efficiency has a number of positive outcomes, including higher crop yields and reduced water costs. Farmers who apply less water to their fields can achieve the same or even higher yields, making their agricultural production more sustainable.

Low application efficiency means that too much water is being applied to the field, resulting in waste and potential harm to the environment. In some areas, farmers are even charged for irrigation water, making excess application a costly mistake.

Improving irrigation efficiency can be achieved through two main methods: improving system design and optimizing irrigation management. By upgrading to more efficient systems or making small changes to their current setup, farmers can significantly reduce water waste and costs.

Reducing water use on one field can also allow farmers to irrigate a larger area of land, increasing their overall agricultural production. This is a win-win for farmers and the environment, as it promotes sustainable agriculture and reduces the strain on natural resources.

Recommended read: Crop Steering Irrigation Schedule

Environmental impacts can be severe when irrigation projects divert too much water, leading to a more extreme regional climate. This has happened in some areas where surface water sources were drained, causing water shortages and altering local ecosystems.

Overdrafting of underground aquifers is a significant problem, especially in areas like the North China Plain and the Great Plains of the US, where groundwater is being pumped out faster than it can recharge. This can lead to permanent loss of aquifer capacity and decreased water quality.

Pumping too much groundwater can also cause ground subsidence, a phenomenon where the ground surface sinks due to the loss of water pressure. This can have serious consequences for agriculture and urban planning.

Salinization of irrigation water is another issue, as it can damage crops and contaminate drinking water. This happens when too much water is pumped from underground aquifers, causing the water to become salty and unusable.

Irrigation canals and ponds can become breeding grounds for pests and pathogens, leading to regional outbreaks of diseases like malaria and schistosomiasis. This is a serious concern in areas where irrigation projects have created large bodies of still water.

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Irrigating 中文 involves both technical and social aspects. Competition for surface water rights is a significant social challenge that arises from the need for water in agriculture.

This competition can lead to disputes over territory defense, making it essential to find ways to manage water resources sustainably.

Assisting smallholders in managing irrigation technology can help alleviate some of these issues. By providing collective management and support for changes in technology, smallholders can work together to ensure a stable water supply.

Here are some key considerations for technical and social aspects of irrigating 中文:

Micro-irrigation is a system where water is distributed under low pressure through a piped network, in a pre-determined pattern, and applied as a small discharge to each plant or adjacent to it.

This method is also known as localized irrigation, low volume irrigation, or trickle irrigation.

Micro-spray and micro-sprinklers are types of micro-irrigation systems that belong to this category.

Traditional drip irrigation uses individual emitters, and subsurface drip irrigation (SDI) is another type of micro-irrigation system.

Curious to learn more? Check out: Micro Sprinkler Irrigation

Irrigation schemes involve solving numerous engineering and economic problems while minimizing negative environmental consequences. Ground subsidence is a major concern, as seen in New Orleans, Louisiana.

Underirrigation or irrigation giving only just enough water for the plant can lead to poor soil salinity control, resulting in increased soil salinity with consequent buildup of toxic salts on soil surface in areas with high evaporation.

Overirrigation wastes water, chemicals, and may lead to water pollution due to poor distribution uniformity or management.

Deep drainage from over-irrigation may result in rising water tables, leading to problems of irrigation salinity in some instances. For example, in Australia, over-abstraction of fresh water for intensive irrigation activities has caused 33% of the land area to be at risk of salination.

Drainage front instability, also known as viscous fingering, occurs when an unstable drainage front results in a pattern of fingers and viscous entrapped saturated zones.

Irrigation with saline or high-sodium water may damage soil structure owing to the formation of alkaline soil.

Clogging of filters is a common problem, often caused by algae, which can also clog drip installations and nozzles. Chlorination, algaecide, UV, and ultrasonic methods can be used for algae control in irrigation systems.

Accurately measuring irrigation performance is complicated due to changes over time and space, using measures such as productivity, efficiency, equity, and adequacy.

The social aspects of a system are just as important as the technical ones. Competition for surface water rights and territory defense are significant social concerns.

When it comes to managing irrigation technology, smallholders can benefit from collective management. This approach can help them sustainably manage changes in technology.

In fact, collective management can lead to more efficient use of resources and better decision-making. It's an approach that has been shown to work in various contexts.

Here are some ways that smallholders can assist each other in managing irrigation technology:

By working together, smallholders can create a more sustainable and equitable irrigation system.

China has a long history of hydraulic engineering, with the oldest known hydraulic engineers dating back to the 6th century BCE, working on large irrigation projects.

The Dujiangyan Irrigation System in Sichuan, built in 256 BCE, still supplies water to this day, making it one of the oldest and most enduring irrigation systems in the world.

The Chinese also used chain pumps, powered by manual foot-pedal, hydraulic waterwheels, or rotating mechanical wheels pulled by oxen, to lift water from a lower elevation to a higher one by the 2nd century CE.

The Hohokam culture in North America also relied heavily on irrigation canals to water their crops, and their irrigation systems supported the largest population in the Southwest by CE 1300.

Here's a comparison of crop water needs in different regions:

These examples demonstrate the importance of irrigation in different regions and cultures, and how it has been used to support agriculture and human settlements for thousands of years.

Let's take a look at some regional examples of irrigation systems from around the world.

In Australia, irrigation is a crucial aspect of agriculture, with many farms relying on it to grow crops.

The oldest known hydraulic engineers of China were Sunshu Ao and Ximen Bao, who worked on large irrigation projects in the 6th and 5th centuries BCE respectively.

China's Dujiangyan Irrigation System, built in 256 BCE, is still in use today, supplying water to a vast area of farmland.

Bolivia has a long history of irrigation, with evidence of ancient systems dating back to the 16th century.

Brazil, on the other hand, has a more modern approach to irrigation, with many systems relying on pumps and pipes.

India is home to some of the world's most impressive irrigation systems, including the ancient ones built by the Indus Valley Civilization.

Iran's irrigation systems date back to the ancient Persian Empire, with many systems still in use today.

Mexico's irrigation systems are a testament to the ingenuity of its ancient civilizations, with the Aztecs and Mayans building complex systems to support their agriculture.

Here is a list of some of the countries we've discussed so far:

The earliest agricultural irrigation canal system in the United States was discovered in Marana, Arizona, and dates back to between 1200 BCE and 800 BCE.

The Hohokam culture was the only one in North America known to rely on irrigation canals to water their crops.

Their irrigation systems supported the largest population in the Southwest by CE 1300.

The Hohokam built extensive irrigation networks along the lower Salt and middle Gila Rivers between the 7th and 14th centuries.

These irrigation systems rivaled the complexity of those used in the ancient Near East, Egypt, and China.

The Hohokam cultivated cotton, tobacco, maize, beans, and squash varieties.

They also harvested wild plants and used dry-farming systems to grow agave for food and fiber.

Their reliance on canal irrigation allowed the aggregation of rural populations into stable urban centers.

Recommended read: Solar Garden Irrigation Systems

Irrigation plays a vital role in increasing crop yields and food production. The total fertile land equipped with irrigation infrastructure worldwide was 2,788,000 km in 2000.

In Asia, a significant portion of the fertile land is found in Northern and Eastern India and Pakistan along the Ganges and Indus rivers. This region accounts for a substantial part of the world's irrigation area.

The irrigation of 20% of farming land accounts for the production of 40% of food production. This highlights the importance of irrigation in global food production.

Sugarcane is one of the crops with the highest water needs, requiring 1500-2500 mm of water throughout its growing period. This is significantly higher than many other crops.

Bananas need a substantial amount of water, too, with a range of 1200-2200 mm. They thrive in warm and humid climates.

Citrus crops, on the other hand, require relatively less water, with a range of 900-1200 mm. This makes them a good option for areas with limited water resources.

Potatoes need around 500-700 mm of water, making them a relatively water-efficient crop.

Tomatoes need between 400-800 mm of water, which is a moderate range compared to other crops.

Here's a comparison of the water needs of different crops:

Barley, oats, and wheat all have similar water needs, ranging from 450-650 mm. Cabbage, onions, and peas also have relatively low water needs, all below 550 mm.

The extent of irrigated land is quite impressive, covering a significant portion of the world's fertile land. In 2000, the total fertile land was 2,788,000 km, with 68% of it located in Asia.

Most of the world's irrigated land is concentrated in a few regions, such as Northern and Eastern India and Pakistan, China's Hai He, Huang He, and Yangtze basins, and the Nile river in Egypt and Sudan. These areas have high irrigation density.

By 2012, the area of irrigated land had increased to 3,242,917 km, which is roughly the size of India. This expansion has significantly boosted global food production.

Interestingly, the irrigation of just 20% of farming land accounts for 40% of food production. This highlights the importance of irrigation in supporting global food security.