In the world’s driest rainfed wheat region, Washington State University researchers have identified summer fallow management practices that can make all the difference for farmers, water and soil conservation, and air quality.
Wheat growers in the Horse Heaven Hills of south-central Washington farm with an average of 6-8 inches of rain a year. Wind erosion has caused blowing dust that exceeded federal air quality standards 20 times in the past 10 years.
“Some of these events caused complete brown outs, zero visibility, closed freeways,” said WSU research agronomist Bill Schillinger.
Science to anchor farmer incentives
He and WSU agricultural economist Doug Young compared three fallow management systems in the western part of the Horse Heaven Hills with six inches of annual rainfall and the same practices in the eastern part with eight inches of rain.
The study was published in the Soil Science Society of America journal in September: Schillinger, W. F. and D. L. Young. (2014). Best Management Practices for Summer Fallow in the World’s Driest Rainfed Wheat Region. Soil Science Society of America Journal. 78:1707-1715 doi: 10.2136/sssaj2014.04.0168.
The five-year study provides the U.S. Department of Agriculture’s Natural Resources Conservation Service with science-based information needed to develop incentives for wheat farmers to change from traditional-tillage fallow practices to undercutter-tillage or no-till fallow systems.
Timing to trap moisture
Farmers in the Horse Heaven Hills practice a winter wheat-summer fallow rotation where only one crop is grown every other year on a given piece of land.
Average yields can be as low as 18 bushels per acre – compared to upwards of 120 bushels per acre in the higher rainfall area of the Palouse in eastern Washington. Though the margins are tight, with careful management wheat farming in the Horse Heaven Hills can be profitable.
To get the highest yield, farmers need to plant winter wheat in late August or early September after a year of fallow. The fallow period allows enough moisture from winter and spring rains to accumulate in the soil for seeds to get established.
“In east-central Washington, if you can’t plant in late summer into deep seed-zone moisture in fallow, then you have to wait for fall rains in mid-October or later,” Schillinger said.
The longer it takes to get winter wheat seedlings established, the lower the potential for good yields.
To help ensure precious soil moisture remains in the seeding zone, farmers till the soil in the spring. Tillage breaks up the capillary action of the soil; this helps slow soil moisture evaporation in the seed zone during the hot, dry summer months.
But too much tillage can cause soil loss through wind erosion that feeds hazardous dust storms.
Undercutting in the east
Compared to traditional tillage, Schillinger and Young found that undercutter tillage was the best option for fallow in the slightly moister eastern region of the Horse Heaven Hills, where late-August planting is possible and spring tillage helps retain summer soil moisture.
With wide, narrow-pitched, V-shaped blades, the undercutter slices beneath the soil surface to interrupt capillary action in the seed zone without causing much disturbance of the soil surface.
Schillinger said scientists and farmers have conclusively shown that spring tillage with the undercutter effectively retains seed-zone moisture. It also retains significantly greater surface residue and surface soil clods – which are less likely to be disturbed by wind and become airborne – compared to traditional tillage implements such as a tandem disk or field cultivator.
No till in the west
In the western region of the Horse Heaven Hills, the best option for controlling wind erosion was to practice no-till fallow; that is, to avoid tillage altogether. Most of the time, rainfall in this area simply isn’t sufficient to establish an early stand of winter wheat with any fallow management system.
“There’s no reason to till the soil when you already know in the spring that it will be too dry to plant wheat in late August,” Schillinger said.
Economist Young found that, despite the modest grain yield potential, wheat farming in this environment can be profitable – with enough acreage and judicious use of inputs to manage costs. In fact, late-planted winter wheat on no-till fallow was just as profitable as traditional-tillage and undercutter-tillage fallow treatments at the western site.
Bill Schillinger, WSU Department of Crop and Soil Sciences, 509-235-1933, email@example.com
Bill Schillinger | EurekAlert!
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
Scientists reveal source of human heartbeat in 3-D
07.08.2017 | University of Manchester
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
17.08.2017 | Physics and Astronomy
17.08.2017 | Earth Sciences
17.08.2017 | Physics and Astronomy