The main line pipe is 6-inch Wade Rain aluminum pipe that will take a maximum safe pressure
of 180 psi. The reason we use 6-inch over 5- or 4-inch is less pressure loss over a long distance.
For instance, 6-inch pipe loses 0.4 lbs. pressure for every 100 feet of distance where 5-inch pipe
loses 1.4 lbs. for every hundred feet. The smaller the diameter of pipe, the more the turbulence as
water moves. At present, we have 3300 feet of pipe and we need another 1000 feet so that we
can irrigate all of our orchards. If we were to use smaller diameter pipe, we would need another
tractor and pump in line to boost the pressure. This would be necessary to maintain line pressure
to the reel. By using 6-inch pipe we can run the whole system from one tractor and one pump.
This size pipe costs a little more and is a little heavier and harder to handle, but I feel the
expense is justified.

Our orchards are planted at a spacing of 4.5 x 2 m (15 x 7 feet). Apple cultivars grown at
Birnham Orchards include Gala, Golden Delicious, McIntosh, Empire, Mutsu (Crispin), Spartan,
Delicious and Jonagold. Our oldest trees are 9 years old. M.26 and M.9 are the rootstocks of
choice. The gun cart goes between the rows nicely and, with some modifications, could be used
on even narrower rows with ease.

During the very dry 1998 growing season, we irrigated our young peaches only once in their
second leaf with 1 inch of water through the whole season and this seemed to be enough to keep
the trees growing. These trees were not cropped in 1998 but appear to have set up a good
percentage of fruit buds for the 1999 season.

In conclusion, irrigating has helped give us control of crop volume and fruit size as well as
achieving better fruit color. By eliminating moisture stress in the orchard, we can maintain the
carbohydrate production needed for crop production, tree growth and survival, especially with
peach. We are able to grow higher fruit quality and still come back next year with a good crop
because of return bloom coupled with good tree health.

Irrigation is not the whole answer to growing better fruit but plays a big part and is another tool
we can use to maximize returns from our orchards. In our situation, money spent on this
irrigation system has been well spent.