Dike it to dam it

Furrow diking not only saves
water – as has been proven by more than a decade of field research – but also
slashes irrigation costs, says Russell Nuti of the USDA Agricultural Research
Service.

Nuti and team researcher
Clint Truman, both with the ARS National Peanut Research Laboratory, have been
exploring the use of furrow diking in southeast states where water runoff is a
problem. That team has looked at the effects of furrow diking on water needs
and yields.

Furrow diking is a tillage
system where soils are scooped into ridge-like barriers running alongside row
crops. The ridges hold irrigation and rainwater.

Diking During A Drought

In one study run by Nuti and
Truman, the researchers compared the effects of runoff and erosion in cotton
fields with and without furrow diking. They used a rain simulator, which
replicates rainfall amounts from past storms, and moisture meters that
automatically determine the soil's water needs.

They found that furrow
diking during a moderate drought saved farmers 1 inch of irrigation water per
acre, reduced runoff by 28%, and curbed soil erosion.

The next year, when drought
conditions were more severe, Nuti and Truman discovered that furrow diking
saved 5 inches of irrigation water per acre.

In a second study, the researchers
compared crop yields, water needs, and the effects of different irrigation
rates on tracts of furrow-diked cotton with traditionally tilled cotton. They
found that in one of three years, growers could reduce the irrigation rate by a
third and still achieve the same yield as a traditional cropping system. The
difference in yields in this drought year was sufficient to pay for the
practice of furrow diking for 12 years, according to Nuti.

Furrow diking has enjoyed a
long history of proving itself in field tests. A Texas A&M University
study, for example, projected that diking could increase yields in the High
Plains by as much as $87 million a year. The equipment needed for furrow diking
is relatively inexpensive and can be purchased from several manufacturers. It
is also simple enough for farmers to build with materials found in most farm
machinery shops. According to Texas A&M research, the equipment needed to
form dikes can pay for itself in just one season with the increased yields from
only 75 acres of cotton.

Furrow diking equipment was
designed and tested in the mid-1970s by Bill Lyle, an agricultural engineer at
the Texas A&M research center in Lubbock, Texas. Lyle also designed a
plow-out attachment that's placed in front of tractor tires to break down the
dikes prior to harvest to smooth the row for harvest equipment.

Texas research determined
that diking just during the growing season could boost grain sorghum yields by
5 to 9 bushels per acre and corn yields by 3 to 9 bushels an acre. Furthermore,
keeping furrow dikes in place year-round could boost yields 7 to 17 bushels per
acre for sorghum and 3½ to 12¾ bushels for corn.

The practice may be useful
in other areas of the High Plains to mitigate the effects of short-duration
moisture stress on crop yields.