Flooding has been the traditional means of irrigation since
the early days of the Fort when fields were first cleared and
irrigation ditches installed to deliver water from the La Plata
River. In 1982, a three mile underground pipeline was installed
to irrigate 300 acres. The underground irrigation line is on
a 2% grade which provides more than enough pressure from gravity
to operate one pivot, six siderolls and a traveling gun sprinkler
system. Eighty acres of gamble oak brush range was cleared for
the gravity sprinkler system. One hundred fifty acres of meadow
are still irrigated by flooding.
Irrigated small grain variety trials have yielded in excess
of 100 bushels per acre of winter wheat, 80 bushels for spring
wheat, 110 bushels for spring barley and 150 bushels for oats.
These yields were obtained on years when growing conditions were
above average. With the short growing season, corn varieties
have been limited to silage varieties which yield approximately
20 ton per acre in better growing seasons.
The 450 irrigated acres is used primarily for producing feed
for the cows and calves wintered at Hesperus. Alfalfa yields
from new hybrid varieties have yielded in excess of five tons
per acre. Varieties with high yield potential are Thor, Pike,
Magnum, and Husky.
Irrigated Pasture
Fifty acres sprinkle irrigated with a sideroll system were
seeded to Regar brome grass (25 acres) and Regar and Cisor mild
vetch (25 acres) in 1985. Limited grazing was allowed in 1986
and in 1987 both pastures were stocked for maximum beef production
using light yearling steers at the rate of 2.1 steers per acre
for a four month grazing season. A contemporary group of steers
were also grazed on native range and rotated within pasture type
as were the steers on irrigated pasture. Average daily gain and
pounds of beef produced per acre by pasture type were: Regar,
2.54 and 562; Regar and mild vetch, 2.55 and 605; native 2.62
and 41. Research Center steers gained 2.86 pounds per day compared
to 2.36 for purchased steers. Implanting improved summer gains
27 pounds and implanting plus 1.5 pounds of corn per day improved
gains 59 pounds. These pastures will continue to be evaluated
for several years.
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