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5.2. Read the text. Text b. Get rid of irrigation problems.

By Eric Athorp

Our goal has been to enable growers to run their irrigation system in the most efficient manner possible. The process considers the crop, soil, and irrigation method as three separate but interdependent pieces of the same picture. We have performed irrigation reviews for many systems over the past decade and have encountered several common problems. Here they are, along with some solutions.

1. Pressure

Pressure is the key component in drip, microsprayer and sprinkler system. Undersized or worn pumps deliver inadequate pressure. Friction within the filter and the laterals can also hamper system performance. All of these situations lead to poor distribution uniformity, loss of yields and excess energy costs.

The first place to watch is the pressure out of the pump. Impeller wear is the most common pump problem, but bearing failures and motor wear are also possibilities. The solution is pump repair or replacement.

Filtration devices are another common location for pressure loss. Some pressure losses are to be expected here, but pressure losses greater than 5 pounds per square inch (psi) are considered excessive.

The third potential location for pressure problems is within the delivery system. For optimum uniformity, pressure should be within 2-3 psi.

2. Plugging

Plugging degrades emitter performance by reducing the flow through the emitter, which is often unnoticed until crops have been damaged. Plugging is random in its distribution, although the ends of the laterals are more likely to plug. Causes include hard water , improper filtration, or organic debris. Individual emitters can usually be cleaned using specialized cleaning tools or chemical methods. Regular system flushing and chemical treatment can reduce the risk of this problem occurring again.

3. Multiple Emitter Sizes

This occurs when the emitters are replaced but not matched to the original equipment. This can lead to wide variances in flow rates and the loss of uniformity for the system. Uneven flow rates can also be the result of excessive emitter wear. In this case, the emitter replacement is the only solution. Growers should keep a supply of the original emitters so that any bad emitters can be replaced with the same model.

4. Variable Set Times

Furrow and border strip irrigation often suffer from variable set time caused by uneven flow rates. Differing advance times affect uniformity because some areas are getting too much water while other areas are getting stressed. Areas with times that are too high are subject to leaching of nutrients below the root zone, causing water table problems, ground water quality problems, and wasted energy.

The solution of these problems include laser levelдing, alternative tillage practices such as deep tillage for compaction reduction, and changing management practices.

('"American Western Fruit Grower Journal, April 2003, p. 21)

5.3. Find in Text в English equivalents of the following words:

зустрітись із, понизити, вимивання, позбавитись від, керувати роботою системи, тиск, зношені насоси, недостатній тиск, заважати роботі системи, неоднорідність розподілу, амортизація робочого колеса насосу, пошкодження підшипника, надлишкові втрати, довільне розташування, жорстка вода, нерівномірні витрати, поживні речовини, рівень ґрунтових вод.

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