Emerald Robinson: Hi, I'm Emerald Robinson, and in this What is video, we'll take a look at the agricultural technique known as irrigation.
Irrigation is any means used by humans to bring water to the land. It can be as simple as using a garden hose to water a flowerbed, or as complex as a system of pipes and canals designed to bring moisture to a desert.
Irrigation is used wherever rainfall is either inconsistent, or does not provide enough natural water to grow crops. It's estimated that about half of the world's land is irrigated.
Humans have been using irrigation for thousands of years. The ancient Egyptians used the Nile's annual flooding to water their farmland, while the Persians were one of the first civilizations known to use a series of wells and tunnels to move naturally occurring groundwater to specific plots of soil.
There are many modern types of irrigation, but the three most common are:- Flood or furrow irrigation, when water is pumped or otherwise carried to fields and allowed to flow over the ground.
- Drip irrigation, when water is sent to crops through pipes that have holes in them. This method uses about 25% less water than flood irrigation, since less is lost to evaporation.
- Spray Irrigation, in which water is pumped through pipes at high pressure through a nozzle. Because it requires electricity, and wastes a significant amount of water, spray irrigation is becoming less popular.
Although irrigation is necessary, it also causes problems. Irrigation uses a lot of water; about 39% of the water in the U.
S. goes towards irrigating crops, and is a major expense for farmers. The excess water or runoff from irrigation contributes to pollution by carrying dissolved salt and pesticide residues into the local water supply.
Fortunately, computers are becoming more frequently used to sense where water is needed. This technology eliminates waste, lowers cost, and prevents damage to the environment.