This is the VOA SpecialEnglish AGRICULTURE REPORT.
Irrigation is the watering of land by other than natural methods.Irrigation projects provide water for crops in areas that have longperiods of little or no rainfall.
The United Nations Food andAgriculture Organization reports that only seventeen percent of allcropland is irrigated. However, irrigated land provides fortypercent of the world’s food. Irrigation is said to increaseproduction of most crops by one-hundred to four-hundred percent.
However, F-A-O officials say about ten percent of all irrigatedland has been damaged by salt. This is most severe in extremely dryareas. As much as twenty-five percent of the land is affected inthese areas.
F-A-O officials say this has become a threat to food security. Inthe past, the U-N agency said that increasing the use of irrigationcould be the answer to feeding the world’s people. Now, it warnsthat rising salt levels in the soil threaten much existing irrigatedland.
Salinization is the build-up of salt in the soil. F-A-O officialssay salinization reduces productivity and can seriously damage thesoil. It warns that salinization is reducing the world’s irrigatedland by one to two percent each year.
All soil contains some salt. As water wears away rocks and soil,small amounts of mineral salts are carried into rivers and otherwaterways. If a field has too little water, the mineral salts arenot washed away. They remain in the soil.
However, the worst danger to the soil is from too much water.When the ground is too wet, water levels rise. The water evaporates.However, salt remains underground, around plant roots. Thisinterferes with the ability of the roots to take in needed water.
The F-A-O says there are several ways to prevent or reducesalinization. One is for farmers to use just a little more waterthan the crops need. The extra water can carry salt away from theroots of the plants. Farmers can also build underground pipes or digdeep holes near crops. This can help remove extra water.
Finally, farmers can flood their fields. This can sometimes treatbadly salinized land that can on longer be used for agriculture.Adding a lot of water can be costly. But F-A-O officials say it maybe a wise economic decision, depending on the value of the land andcrops.
This VOA Special English AGRICULTURE REPORT was written by GeorgeGrow.