Small saplings in a new shelterbelt often need irrigation for the first years until their roots reach deep ground water. Drip irrigation is perfect for starting a shelterbelt or windbreak.
You can use overhead sprinklers but drip irrigation is far more efficient using only 60% of the water. Drip irrigation trickles down to the roots unlike overhead sprinkler water that soaks the surface of the ground and can cause runoff. Drip is not affected by strong winds that can blow sprinkler water away from the saplings.
In the following case study we will design the system to keep the initial costs low. The system will also be scaled small enough to fit the typical water pumping system found on a family farm.
Shelterbelt rows are often very long - from 400 feet to 1000 feet. Our shelterbelt is 800 feet long and has five parallel rows of trees and shrubs. The trees are spaced from 3 feet to 12 feet apart in the row depending on the species. Some rows need less water flow than other rows but every row needs a small volume of water pumped over a long distance.
So what size of tubing in the rows will be the most economical? The smallest tubing suitable is 1/2" in diameter such as our T21000 tubing. We could use 3/4" tubing like our T9500 to make the rows twice as long or even 1-1/2" tubing such as our T6600 for very long rows but larger tubing and longer rows will require more pumping capacity and larger diameter mainlines to supply water to the rows. We'll choose 1/2" tubing for its low cost, and ease of installation. It will also keep our water pumping requirements low.
Let's divide our 800 foot long shelterbelt rows into two 400 foot long zones similar to those in the illustration to the right. The main supply tubing from the pump will bisect each 400 foot zone so that each individual row in each zone is 200 feet, half the zone length. That way we can use 1/2" tubing and keep the cost of tubing in each row to a minimum.
The total flow rate for each zone will be in the 400 gallon per hour range, well within the capacity of many farm water pumps. If our farm has a larger pump, we may be able to operate more than one zone at a time.