Home | Business | Agriculture & Farming

The Use of Shelterbelts in Farming

By: Helen Disler

Read More About Agriculture & Farming

Strong winds can be a significant factor leading to low yields. For instance, grape cultivation in the wine-growing areas of Western Australia can be severely affected by dominant strong winds. Unless controlled, the winds can increase soil erosion, water evaporation from the soil, and water loss through transpiration by plants.

Farmers are able to achieve a measure of control on most factors related to wind-caused erosion. The basic approach is to reduce wind velocity close to the soil surface, and the most common methods employed for this purpose are mechanical techniques, cultural practice, and vegetative cover.

Wind control by mechanical methods may include setting up artificial fences (such as low-slung stone walls and woven mats of reeds, corn stalks, etc.) and allowing for bigger clods of earth during tilling to have rougher surfaces. Cultural techniques may involve strip cropping, crop rotations, surface mulching, and planting rows at right angles to the most prevalent wind direction.

Vegetative cover includes high-density crops, windbreaks and shelterbelts. Small groups of shrubs or trees meant to protect people and livestock are known as windbreaks. Shelterbelts are more extensive assemblies of shrubs or trees primarily intended to minimise wind erosion in fields.

Although the primary role of shelterbelts is to cut wind velocity, they have a subsidiary role in modifying the micro-climate in and around them and, therefore, in influencing growth of the crop.

Wind velocity reduction
The effective distance protected by shelterbelts is a function of the height. Both sides of a shelterbelt are benefited, but the leeward side enjoys more protection. A properly oriented shelterbelt can cut wind velocity up to half of speeds in open areas. Its effectiveness on the windward side extends as far as the equivalent of 2 times the shelterbelt height, and on the leeward side to a greater expanse of 15 to 20 times its height.

Dense shelterbelts lower velocity the most near their location; more open shelterbelts can provide protection over longer distances downwind. The benefits appear to be greatest in shelterbelts with about 50 per cent porosity. For vegetable crops, however, shelterbelts made of inert materials about 1.5-2 metres high may be better because less space is consumed and the barrier is transferable.

Shelterbelts consisting of 7 rows are very effective, but may occupy too much space. Whether the shelterbelt has three, five or seven rows, wind diversion is optimised when the tallest shrubs or trees are in the middle row, that is, the second, third, and fifth row, respectively, going leeward.

Effects on micro-climate
Shelterbelts help to reduce water losses through evaporation and transpiration because of the lower wind velocity. The downside is that they may compete with the growing crop for water, soil nutrients, and sunlight leading to interference with growth and possible reduced yields. These disadvantages are limited, though; yield losses are likely to occur only within the area of about 1 shelterbelt-height.

Installation of shelterbelts
The length of the shelterbelt is determined by the area that needs protection. The length should be at least 12 times the height to minimise turbulence around the sides. Maximum protection is obtained by positioning it perpendicular to the most dominant wind direction. The length of protected area goes down as wind velocity goes up; therefore, it may be necessary to plant several parallel rows in succession. Spaces between rows can between 15 and 20 times the shelterbelt height. The shelterbelt should target to reduce wind speed to at most 20 km/hr -- the speed at which soil particles become airborne.

Article Source: http://depositarticles.com/

For More Info: Helen M. Disler Farming Secrets www.farmingsecrets.com/ Email: info@farmingsecrets.com

Please Rate this Article

 

Not yet Rated

Click the XML Icon Above to Receive Agriculture & Farming Articles Via RSS!
Additional Articles From - Home | Business | Agriculture & Farming
Sign Up for a free account.
Our other websites
All about SEO
Beauty Tips Forum
Submit Articles
Member Login
Link Us
Submission Guidelines
Ezine Notifications
Article RSS Feeds
Sitemap
New Stuff
About Us
Developer
Good shopping portal
Link to Us
Contact Us
Privacy Policy
Terms of Service

counter easy hit

Powered by Article Dashboard