The wheat-fallow crop rotation was once the

foundation of High Plains agriculture and pheasant

populations. Today, researchers have found a new

way to increase both profitability and pheasant

production in this time-tested system.

New Life for Wheat-Fallow

By Randy Rodgers, KDWP wildlife biologist, Haysand Alan Schlegel, KSU agronomist, Tribune

photos by Randy Rodgers

Perhaps you remember thetimes when the wheat-stubblefields of the High Plains were

loaded with pheasants. That com-bination was no accident. Thosebirds were the by-product of acropping system that meshed beau-tifully with the pheasant’s annualneeds — the wheat-fallow rotation.

Designed for the semi-arid con-ditions of the High Plains, thewheat-fallow rotation producedonly one wheat crop every twoyears. The 14-month fallow peri-od between harvest of one crop ofwinter wheat and the planting ofanother permitted accumulationof moisture in the soil andreduced the risk of crop failure.Many farmers allowed weeds togrow in the stubble afterwheat harvest. While weedsand farming were perceivedby some as incompatible, thepracticality of letting weedsgrow after wheat harvest inwheat-fallow had beenproven in several High Plainsagronomic studies.

Pheasants were able to nestvery successfully in the abun-dant green wheat, but took par-ticular advantage of the 14-month fallow. The weedgrowth at the beginning of fal-low was a key to their abun-dance. Pheasant chicks dependalmost entirely upon insectsand other arthropods for food intheir first two-months of life, andthese broad-leaved weeds were theprimary source of those insects.

Not only did the weeds harborthis essential food source, theirstructure provided just the righthabitat for broods. At ground level,chicks were able to move aboutfreely to search for insects under aweedy canopy that branched abovetheir heads. That same overheadcanopy provided shelter from thehot summer sun, from dryingwinds, and from pelting storms.Equally important, the weeds con-cealed them from predators. Justimagine yourself walking througha cool, green forest and you’ll get a

fairly decent idea, on a differentscale, of what it’s like for chicksunder a canopy of broad-leavedweeds.

In winter, this combination ofbroad-leaved weeds and stubbleoffered food, shelter, and conceal-ment. The birds literally never hadto leave the field. It was all rightthere.

As the days lengthened, newgrowth of the next wheat crop innearby fields would draw pheas-ants away from the weedy stubble,typically just in time to avoidspring tillage. And so, the cyclewould start again. The needs oftheir entire life cycle had been pro-vided by the different phases of thewheat-fallow system.

The Decline

By the 1980s, economic pressuresand research-driven agriculturalintensification was rapidly chang-ing farming practices on the HighPlains. Agricultural researchersincreasingly considered wheat-fal-low’s 14-month idle period awaste. They had already foundways to insert more crops, eventhirsty crops like corn, into new

High Plains rotations.One crop in two yearswith wheat-fallowseemed inefficient com-pared to two crops inthree years, or eventhree in four, with thenew rotations. A 1987-91comparison of four vari-ations of the old wheat-fallow rotation to threemodifications of a newwheat-sorghum-fallowsystem concluded thatwheat-fallow could notcompete economicallywith the new systems.

2

100

80

60

40

20

0

RelativePheasant

Abundance

Winter

90-91 91-92 92-93 93-94 94-95

Effect of Post-harvestWeed Control on Pheasants

NoneSprayedTilled

Treatment

Weed growth in wheat stubble once provided excel-lent habitat for High Plains pheasants.

But a fundamental requirement ofthe new, more-intensive rotationswas thorough weed control. Thepractice of letting broad-leavedweeds grow after wheat harvest, aswas once common in wheat-fallow,was replaced with an herbicideapplication not long after the com-bines left. Instead of a green growinghabitat where insects were abundantand available, post-harvest wheatstubble became sterile and nearlylifeless in the new systems.

The subsequent reduction in thestubble’s quality for winter coverwas no less dramatic. Research con-ducted in the early 1990’s showedthat herbicide-treated wheat stub-ble harbored an average of only 16percent of the pheasants found intraditional weedy wheat stubble.The same was true for many small-er species of wildlife.

Advances in agricultural engi-neering and genetics also had aneffect. As combines became morepowerful and efficient, it becamepossible for harvesters to lowercombine headers in an attempt tocut even the shortest tillers in thewheat stand. Over the same peri-od, wheat breeders had createdand popularized strains of wheatthat were shorter and more resist-ant to lodging than earlier vari-eties. The net result of these

changes was shorter wheat stub-ble and poorer wildlife habitat.Studies showed that untreatedstubble 7-10 inches tall supportedan average of just 11 percent of

the winter pheasant use asoccurred in untreated stubble 15-18 inches tall.

In less than two decades, thiscombination of post-harvest her-bicide application and shorterheight caused wheat stubble habi-tats in western Kansas to losemost of their capacity to produceor sustain pheasant populations.

Other research indicated thateven the addition of ConservationReserve Program (CRP) grass-lands could not compensate forthis loss of weedy wheat stubble.CRP fields offered little in theway of food to pheasants andaveraged only 37 percent of thewinter pheasant use as was sup-ported by weedy wheat stubble.Prospects for High Plains pheas-ants seemed grim.

3

100

80

60

40

20

0

RelativePheasant

Abundance

Test Stubble Field

7-10"11-14"15-20"

90A 90B 92A 92B 94A

Effect of Wheat CuttingHeight on Pheasants

StubbleHeight

Southwest

Northwest

20

15

10

5

0

PheasantsPer 100Miles

Year65 70 75 80 85 90 95 00 05

Western KansasPheasant Population

Combined January, April, July, and October Rural Mail Carrier Survey RMCS

Wheat stubble cut short and sprayed with herbicide after harvest is nearlyuseless for wildlife

A New Approach

Progress in any field alwaysbuilds upon previous knowledge.And so it was that several agro-nomic principles gleaned from ear-lier High Plains research providedthe foundation for a new approachto the wheat-fallow rotation:

(1) Studies have shown there istypically little moisture left in thesoil after wheat harvest and, whilesome years are exceptions, it’s diffi-cult to store much soil moistureduring the summer after wheatharvest. Factor in the relativelyhigh amount of runoff from sum-mer thunderstorms and the evapo-ration caused by hot, windy condi-tions, and it’s easy to understandhow late summer soil moisturestorage is limited.

(2) Moisture from snow accountsfor less of our overall annual pre-cipitation than rain, but snow’svalue for crop production is pro-portionally greater than it mightappear. About 80 percent of themoisture we receive from snowactually penetrates deep enoughinto the soil that it can be effective-ly stored for availability to the nextcrop. That’s 3 to 4 times the “mois-ture storage efficiency” obtainedfrom an average August thunder-storm. Of course, storing soil mois-ture from snow requires that thesnow be held on the field. If highwinds blow the snow off a field,then little or no moisture will bestored.

(3) Overall, the greatest amountof soil moisture storage on the HighPlains occurs in the spring whenprecipitation is most frequent, andsoil and air temperatures remainrelatively cool. Frequent precipita-tion in spring means that the mois-ture from the latest rain will helpforce remaining moisture from pre-vious rains deeper into the soil.Cooler spring soil and air tempera-tures slow evaporation from thesoil, yielding a greater chance thatmoisture will accumulate.

(4) There is a positive relationship

between the amount of surfaceresidue (dead plant matter) and theefficiency with which moisture isstored in the soil. Plant residuescushion the impact of raindrops onthe soil, preventing the break up ofsoil particles that can seal the soilsurface. With plenty of residue, thesoil surface remains porous andcan take in moisture more rapidly.What’s more, residue also helpskeep wind from reaching the soilsurface, reducing evaporativemoisture losses. The bottom line onthe High Plains is simple; the moreresidue on the soil, the better thesoil moisture conservation.

(5) Taller and more upright plantresidues are more effective in fos-tering soil moisture storage. Thereare two main reasons for this.Anchored, upright residue cancatch and hold much more snow,particularly when wind accompa-nies the snowfall. During warmerperiods, upright residue is alsomuch more effective at reducingwind at ground level, and thattranslates into less evaporation.Pound for pound, anchored,upright residues are more effectivethan flattened residues at conserv-ing moisture: the taller the better.

(6) An extra inch of stored soilmoisture has been estimated toincrease High Plains wheat yieldsby four to six bushels per acre. With

that much grain yield in the bal-ance, it’s clear that farmers must tryto minimize moisture losses to thewind; whether that’s moisture lostto snow blowing off their fields ormoisture lost to evaporation duringthe growing season.

With those six principles in mind,a new approach to wheat-fallowwas developed. What if we letweeds grow after wheat harvest?Weed growth would sacrifice muchof any soil moisture left unused bythe wheat, plus some of that whichmight otherwise be stored in late-summer. But weed growth alsoprovides tall residue that, whenadded to the stubble, could catchmore snow and reduce evaporationbetter than either tilled or sprayedstubble alone. Could the late sum-mer moisture sacrifice from grow-ing weeds be outweighed by thesubsequent winter and springmoisture-conserving benefits ofthis added, taller residue? Howmight this affect future grainyields? Would the input savingsfrom not spraying or tilling stubblebetween wheat harvest and springbe enough to justify growingweeds?

To be sure, maximizing the mois-ture-conserving benefits of thistaller, weedy residue would requirethat it remain both anchored andessentially undisturbed during

4

From a pheasant’s perspective, the choice is obvious. Compared to sprayedwheat stubble (left), weedy stubble provides pheasants better concealment,a physical barrier to predators, more food, and far superior protection fromthe weather. The increased amount and height of residue provided bybroad-leaved weeds can also aid in moisture conservation.

spring, when the potential formoisture storage is greatest. To dothat, a spring herbicide treatmentwould be necessary.

The Research

To answer these questions,research was designed and con-ducted at the Kansas StateUniversity Southwest Research-Extension Center at Tribune. Thenew wheat-fallow system used nopost-harvest tillage or herbicideapplication, leaving the wheatstubble undisturbed until the fol-lowing spring. Once weed growthresumed in spring, a single contactherbicide application was used tocontrol that growth while main-taining the weedy residueanchored and upright throughearly summer. Any subsequentweed control operations (usuallythree) needed in summer were per-formed with subsurface tillageusing sweeps (undercutters). Thissummer subtillage also served asseedbed preparation for the nextcrop. The new wheat-fallow modi-fication was dubbed DelayedMinimum-Till or DMT.

Work began in 1995, and for sixcycles, the DMT system was com-

pared to two other more typicalwheat-fallow systems. In theConventional-Till system, weedswere controlled after wheat harvestand throughout the followingspring and summer with subsur-face tillage using sweeps. Thisinvolved two sweep operationsbetween wheat harvest and frost,plus five more passes the followingspring and summer. The No-Tillsystem required five herbicideapplications to control weedsthroughout the 14 month fallowperiod: two treatments betweenharvest and frost, plus three morethe following spring and summer.

Everything else was kept thesame for each of these three wheat-fallow systems. Each system wasrandomly assigned to four of the 12test plots, with buffers betweenthem. Having two sets of these 12-plot areas allowed harvest data tobe collected every year of the study.Each plot was fertilized, seeded,and harvested in the same way.And each received the same latewinter herbicide application to thegreen wheat for cool-season weedcontrol. Soil moisture was sampledusing a hydraulic probe shortlyafter harvest, in the fall, in spring,and again prior to wheat seeding.

The Results

Wheat yields in 1996, the firstharvest year, were surprising. TheDMT system proved to be the topyielder at 42 bushels per acre. Thatwas 6 bushels better than the 36bushel yield in the No-Till systemand double the 21 bushel yield ofthe Conventional-Till system. Interms of profitability, the DMT sys-tem returned $118 per acre com-pared to less than $8 for theConventional-Till system and $60for the No-Till system that year.

The last harvest year of theresearch, 2001, was a counterpointto 1996. That year, the DMT systemwas the poorest yielder and leastprofitable. The fallow period pre-ceding the 2001 harvest providedvirtually no significant winter orspring moisture. Predictably, theDMT system wasn’t able to com-pensate for the moisture lost topost-harvest weed growth, giventhere was no moisture to store, witha resulting net loss of just over $5per acre.

While these extremes wereinstructive, it’s the long-term aver-ages that count. The No-Till systemultimately yielded the best, averag-ing 53 bushels per acre over sixyears. The DMT system still fairedwell, with a 44 bushel average, andthe Conventional-Till system camein with an average of about 37bushels per acre. The No-Till sys-tem was the top yielder in 5 of the 6years of the study, with the DMTsystem best in 1996. Perhaps mostsignificantly, the Conventional-Tillsystem, with it’s post-harvesttillage, yielded the worst in 5 of the6 years.

The soil moisture data clearlyexplain these results. Because theNo-Till system controlled weedgrowth during all phases of the 14-month fallow and maintainederect, anchored residue, it had themost stored soil moisture throughthe first fall, in spring, and at plant-ing time. The Conventional-Tillsystem prevented moisture loss to

5

Agronomic research at the Kansas State University’s Southwest Research-Extension Center at Tribune compared Conventional-Till, No-Till, andDelayed Minimum-Till (DMT) variations of the wheat-fallow rotation for yieldand profitability. While the No-Till system produced the greatest grain yields,the DMT system was most profitable. The Conventional-Till system, with it’spost-harvest tillage, produced the poorest yields and almost no profit.

post-harvest weed growth, but wasnot very effective at storing mois-ture thereafter because the stubblewas repeatedly disturbed and nolonger anchored. As expected, theDMT system had the least availablesoil moisture by the first fallbecause weeds had been allowed togrow after harvest. But by spring,the extra upright residue providedby DMT had compensated for themoisture lost to weed growth. Atplanting time, the DMT system had1 inch more moisture stored in thesoil compared to the Conventional-Till system. That extra inch nicelyaccounted for the seven-bushelyield increase of DMT over theConventional-Till system.

If it’s just wheat-yield braggingrights you’re after, then read no fur-ther. But every farmer knows thatthe real bottom line is not yield; it’sprofit. And that’s where the DMTsystem stood out, thanks to the costcutting benefits of skipping post-harvest weed control. Troy Dumler,a Kansas State University agricul-ture economist based in GardenCity, handled the economic analy-sis. He calculated the average netreturn for the DMT system at $39per acre and DMT was the mostprofitable system in 4 of the 6 years.The No-Till system averaged a littleover $30 and was most profitable in2 years. Despite being the top yield-

er, the No-Till system’s profitabilitysuffered from high input costs. TheConventional-Till system came inwith an average net return of just$3 per acre and was least profitablein 5 of 6 years.

If there was only one concept tobe learned from this research, it’sthat post-harvest tillage of wheatstubble is a great way for HighPlains farmers to cut their ownfinancial throats. But anotherimportant lesson is that post-har-vest weed growth is not detrimen-tal to profit in the wheat-fallow sys-tem. The benefits gained by avoid-ing post-harvest expenses andgrowing additional residue willusually outweigh the loss of somepost-harvest moisture. And thatdoesn’t even take into account thewildlife benefits the DMT systemcan provide.

Favorablefor

Pheasants!

The DMTwheat-fallowsystem is

about as good for pheasant produc-tion and survival as any HighPlains cropping system could be.Provided the stubble is tall enough

(> 15 inches), the weed growth thatoccurs after wheat harvest can offerideal brood habitat. Little chicks areexceptionally vulnerable to weath-er extremes, insufficient food avail-ability, and predation. Weedy stub-ble offers a favorable microclimatethat’s more humid, cooler on hotdays, and warmer on cool days.Insect availability is high. Also, theoverhead canopy provided by theweedy stubble not only concealschicks, but also provides a structur-al barrier to predators. Simply stat-ed, chick survival is high in undis-turbed weedy stubble.

Over winter, the combination ofbroad-leaved weeds and tall wheatstubble provides excellent protec-tion from cold winter winds atground level, where pheasant live.Weedy stubble fields virtuallyalways offer adequate cover, evenin the worst of blizzards. Winddriven snow may drift shut theupwind side of a weedy stubblefield, but most of the field furtherdownwind will still furnish plentyof quality microhabitats that pheas-ants will find and exploit duringsevere conditions. Even if they’reable to spot a pheasant in thiscover, avian predators will find itdifficult to crash through the rigidstems of weeds such as kochia andsunflower. Weed seeds producedthe previous summer contribute a

10

8

6

4

2

0

SoilWater

inInches

Stage of Fallow

Post-harvest Fall Spring Pre-plant

Available Moisture1996-2001

No-tillConventional-TillDMT

Treatment

6

Even during stressful winter conditions,the weedy stubble provided by the DMTwheat-fallow system offers an abundanceof micro-habitats that pheasants can use.

vital source of food that supple-ments the waste grain left by thecombine. Being able to forage with-in this well protected habitat,instead of leaving to find food, fur-ther reduces a pheasant’s exposureto predation. Again, their survivalis enhanced.

Wheat-fallow, as it was tradition-ally practiced, had one very signifi-cant flaw when it came to pheasantproduction. Weed control in springis absolutely critical for soil mois-ture storage during fallow, and thatcontrol was typically accomplishedwith tillage. Particularly in yearswhen conditions slowed growth ofthe green wheat, hens place manynests in the previous year’s wheatstubble. Any nests present in stub-

ble are sure to be destroyed bydisking or other forms of surfacetillage. Some nests will survivesubsurface tillage with an under-cutter, provided no treaders areattached, but this alternative stillleaves much to be desired.

The DMT system virtually solvesthis problem by controlling weedswith an herbicide during spring.Inevitably some nests will becrushed by the spray rig’s tires, butthis loss amounts to roughly 5 per-cent. That’s nothing compared toover 50 percent loss with subtillageor 100 percent nest destructionwith a disk.

While DMT clearly offersgreat advantages to pheas-ants, the wildlife benefits arecertainly not limited to thisone species. Past studies onthe High Plains documentedat least 15 bird species nestingin weedy wheat stubble.Research in Kansas alsodetected more species andmuch greater winter wildlifeabundance in weedy wheatstubble than in stubble whereweeds had been controlledafter wheat harvest.

Other Considerations

Compared to Conventional-Till wheat-fallow, DMT offersseveral other agronomic ben-efits. The reduction in tillageand the added residue in theDMT system helps conserve organ-ic matter in the soil. Organic matteris critical not only in allowing thesoil to accumulate and hold mois-ture, but it also helps growingplants take up moisture.

Of course, the reduction in tillageand the added residue provided byDMT improves erosion controltremendously compared to theConventional-Till system. That’strue for both wind- and water-caused soil loss. The No-Till systemmay slightly outperform DMT inthis regard because the residue isnever tilled.

The taproots of broad-leavedweeds can provide other generallyoverlooked benefits. Taproots arecapable of penetrating hardpans, acompacted layer of soil created byrepeated tillage operations. Thesoil channels and improved soilstructure left by decomposed tap-roots not only allow better mois-ture penetration but also helpcrops tap into that moisture. Weedtaproots can also extract nutrientsfrom deep subsoils, releasing themclose to the soil surface whenweeds decompose.

Broadleaved weeds in DMT tendto suppress the germination andgrowth of volunteer wheat. That’s

important because volunteerwheat harbors the wheat curl mite,the carrier of the Wheat-Streak-Mosaic virus.

In contrast, post-harvest tillage orspraying operations create an idealsituation for volunteer wheat ger-mination; all that’s needed is onesignificant rain. In practice, post-harvest weed control almostinevitably necessitates a secondcontrol treatment to kill the volun-teer wheat released by the firsttreatment.

Some farmers have concernsthat weed seed will build up inthe DMT system and eventuallycut grain yields. This concern isn’tsupported by the evidence. A 27-year study done in the TexasPanhandle, showed that yields inwheat-fallow were unaffected byletting weeds go to seed. Efforts toreduce weed seed banks in the soilalmost inevitably lead to shifts inthe types of weeds that grow andvirtually never eliminate of alltypes of weed seed. Successfulelimination of one weed speciessimply opens the door for otherspecies. The weeds that resultfrom such shifts often cause moreproblems than the species theyreplaced.

7

At least 15 species of birds areknown to nest in wheat stubble.New weed growth after wheat har-vest helps shade and conceal thismourning dove nest.

Spraying or tilling stubble after harvestcreates ideal conditons for germination ofvolunteer wheat. Such conditions mayharbor the wheat curl mite, carrier of thewheat-streak moasic virus. Permittingbroad-leaved weeds to grow in stubbleafter harvest tends to limit germinationand growth of volunteer wheat.

Who Should Use DMT?

Farmers who currently usewheat-fallow are the best candi-dates for implementing DMT. TheDMT system offers an opportunityto substantially increase profitsover conventional wheat-fallowsystems with little or no investmentin new equipment, with reducedexpenses, and with a very lowchance of crop failure.

But DMT wheat-fallow isn’t foreverybody. Many High Plains pro-ducers have already made sub-stantial investments in expensiveno-till equipment and are commit-ted to more intensive croppingsystems with row crops. Givenfavorable moisture conditions,more intensive systems offer moreprofit potential than DMT.However, these intensive systemsalso require greater inputs andfinancial risk. That’s particularlyso if drought or excessive mid-summer heat significantly impactsrow-crop yields.

DMT’s greatest applicability is todrier areas of the High Plainswhere more intensive croppingsystems are less feasible. But evenin High Plains regions with some-what more precipitation, DMT

may have greaterpotential on lessproductive soilsthan row crops.

If long-termtemperature trendscontinue, the HighPlains may experi-ence increasing fre-quency and severi-ty of drought. Dr.John Heinrichs ofthe Fort Hays StateU n i v e r s i t yDepartment ofGeosciences inHays has analyzed1901-2000 tempera-ture and precipita-tion trends in thestate of Kansas. Hefound that, over the

last century, temperatures on theHigh Plains of western Kansashave increased an average of morethan 2 degrees Fahrenheit.Precipitation also increased insome areas, but warmer tempera-tures will increase evaporativemoisture losses, potentially creat-ing drier overall conditions. Thesetrends suggest that DMT wheat-

fallow could play an increasing rolein High Plains agriculture.

If producing wildlife, particularlypheasants, is important to a HighPlains landowner, then DMTwheat-fallow should be given seri-ous consideration. More landown-ers and producers are placinggreater emphasis on wildlife pro-duction on their High Plains crop-lands. These landowners treasurethe chance to offer their familiesand friends a great place to contin-ue the hunting tradition.

Implementing DMT wheat-fal-low is a great way to boost pheas-ant numbers on the High Plains.Not only will DMT produce farmore birds, but these fields are alsolikely to attract pheasants from sur-rounding lands. Integrating prac-tices like strip cropping and feder-ally-subsidized grass wind strips,grassed terraces, or other buffersinto a DMT system can create max-imum hunting potential and finan-cially solid models of soil andwater conservation. If you own ormanage cropland on the HighPlains and pheasants matter to you,take that first step and contact us.We’ll be glad to help.

8

LYON

ELK

GREENWOOD

CHAUTAUQUA

BOURBON

CRAWFORDNEOSHOWILSON

MONT- GOMERY

LABETTE CHEROKEE

MIAMI

WOODSON ALLEN

COFFEYANDERSON LINN

FRANKLIN

OSAGE

CHEYENNEDECATUR

SHERIDAN

GOVE

SHERMAN THOMAS

RAWLINSNORTON

GRAHAM

TREGO

ROOKS

ELLISWALLACE LOGAN

PHILLIPS SMITH

RUSSELL

OSBORNE

RUSH

OTTAWA

ELLSWORTH

LINCOLN

MITCHELL

CLOUD

JEWELL WASHINGTONREPUBLIC

CLAY

DICKINSON

SALINE GEARYWABAUNSEE

POTTAWATOMIE

NEMAHAMARSHALL

RILEY

JEF

FE

RS

ON

JACKSONATCHISON

DONIPHAN

BROWN

JOHNSONDOUGLAS

SHAWNEE

LEA

VEN

- W

OR

TH

MORRIS

WYANDOTTE

SCOTTWICHITA

HAMILTON

GREELEY

EDWARDS

KIOWA

NESSLANE

FINNEYKEARNY

MORTONMEADE

GRAY

SEWARD

HASKELLSTANTON

STEVENSCOMANCHE

CLARK

GRANT

PAWNEE

HODGEMAN

FORD

BARTON

PRATT

BARBER

STAFFORD

RICE

COWLEY

SEDGWICK

HARVEY

BUTLER

CHASEMcPHERSON

RENO

KINGMAN

HARPER

SUMNER

MARION

100-year Temperature Trend(degrees F per Century)

-0.9 to -0.5

-0.5 to 0.0

0.0 to 0.4

0.4 to 0.9

0.9 to 1.3

1.3 to 1.7

1.7 to 2.2

2.2 to 2.6

2.6 to 3.1

Temperature Trends1901-2000

0.90 - 0.95

0.95 - 1.00

0.75 - 0.90

0.90 - 0.95

0.95 - 1.00

Significance of Trend

Graphic courtesy of Dr. John Heinrichs, Fort Hays State University

High Plains farmer Bruce Rosenbach believes theDMT system will pay off on fuel savings alone

photo by Mark Herwig

9

Planting: Select wheat varieties adapted for yourarea with enough height potential to produce stub-ble at least 15 inches tall. Shorter varieties may notprovide enough residue or stubble height for subse-quent moisture conservation, wildlife habitat, orerosion control. Fertilize as needed.

From Planting through Spring: If control of cool-season broad-leaved weeds is needed, treat withnon-residual herbicides (e.g. 2,4-D and Banvel) inlate winter or early spring. Do not use herbicideswith residual activity because such herbicides (e.g.sulfonylureas) will prevent subsequent growth inthe stubble of broad-leaved weeds most preferredby wildlife. Residual activity herbicides are morelikely to shift weed species from relatively benignwarm-season species (e.g. sunflower) to more diffi-cult-to-control species, especially grasses.

Harvest: Set conventional combine headers no lowerthan two-thirds the height of the primary wheatheads. If at all possible, resulting stubble should be aminimum of 15 inches tall. Little grain is present inlow-level tillers and the quality is often poor. Settingthe combine header too low forces the machine toprocess excessive straw which decreases threshingefficiency. This can cause a net loss of grain. Cuttingwheat too short will also slow harvest, increase fuelconsumption, accelerate parts wear, and increase thechance of combine breakdown. Tell custom har-vesters to “keep the headers high!” This will alsobenefit them. Consider harvesting with a stripperheader, particularly if wheat is less than 24 inchestall. Harvest fields inside-out giving young wildlife abetter chance to escape machinery.

Taller stubble enhances moisture conservation bycatching more snow and reducing evaporative mois-ture loss. A doubling of wheat-stubble height from 8to 16 inches can increase pheasant use up to tenfoldif broad-leaved weeds are permitted to grow afterharvest. Taller stubble fosters more benign weeds,like annual sunflower. Shorter stubble tends toincrease grassy weeds and Russian thistle.

After Harvest: Do nothing. Unless an exceptionalamount of soil moisture remains after wheat harvest,post-harvest weed control reduces profitability in thewheat-fallow system. Post-harvest weed control

must be avoided if wildlife is important to theproducer. Weed control at this time reduceschick survival and will decrease pheasantnumbers in the stubble during fall and winterby an average of more than 80 percent.

Allowing broad-leaved weeds to grow afterharvest will remove some moisture. Butmoisture subsequently gained as a result ofthe extra residue and increased height typi-cally compensates for moisture lost to weedgrowth after harvest. Surface or subsurfacetillage of wheat stubble, after harvest or in thefall, will decrease overall moisture storage,reduce yields, and minimize profit. Post-har-vest herbicide application can increase yieldsbut is not cost-effective in wheat-fallow.

Use of a stripper header leaves stubble nearly as tall asunharvested wheat. If broad-leaved weeds are allowed togrow in stripped stubble, the resulting cover providestremendous pheasant habitat.

Combine header height makes a difference in sub-sequent moisture conservation and weed growth.Test cuttings revealed interesting results. Grassyweeds were more common in short-cut stubble,but sunflowers dominated the tall stubble at right.Tall stubble better reduces evaporation, leavingmore moisture for plant growth and better pheas-ant habitat.

DMT Wheat-Fallow: Step by Step

10

Early Fall: If bindweed control is needed, apply 2,4-D plus Tordon, Landmaster plus Tordon, or otherappropriate herbicides soon after the first frost.Bindweed moves nutrients to its roots in early fall,so herbicides applied at this time are effectivelytranslocated, resulting in optimum control. Early fallbindweed treatment will not significantly damagestubble habitat quality as desirable broad-leavedweeds have completed most growth by this time.Spot spray only affected bindweed areas to mini-mize habitat damage and reduce treatment costs.

Winter: Do nothing. Weedy stubble will effec-tively capture snow. Moisture in snow is muchmore efficiently stored in the soil profile thansummer rains. Weedy stubble provides excel-lent winter cover for pheasants and manyspecies of songbirds.

Spring: Spray the stubble/weed residue with anon-selective herbicide such as glyphosate(Roundup) after weeds have begun growth.This controls new weeds and maintainsanchored, erect residue on the field for maxi-mum moisture conservation when moisturestorage potential is greatest. Avoid springtillage because this loosens and reduces surfaceresidues at exactly the time when undisturbedstubble is most valuable for moisture conserva-tion. Spraying for spring weed control also min-imizes nest destruction that would otherwiseoccur if tillage was used. Keep thestubble/weed residue undisturbed at leastthrough June. A second non-selective herbicidetreatment to control the next flush of weeds will

optimize moisture conservationand extend the period of wildlifeuse through mid-summer.

Summer: Use subtillage, prefer-ably with an undercutter, asneeded for weed control aftermid-summer. Potential for fur-ther moisture storage declinesduring the summer months dueto hot, often windy conditions.When tilling, work the field“inside-out” to give youngwildlife their best chance toescape the operation. Tilling afield from the outside edgesinward tends to force broodstoward the middle, where chicksmay be lost through repeatedexposure to the tillage . Late sum-

mer surface tillage with a disk is acceptable, ifdesired, for seedbed preparation. Remember toselect taller varieties at planting time.

In the DMT wheat-fallow system, spraying for spring andearly summer weed control permits most nests to surviveand maintains anchored, upright residue when it’s mostneeded for fallow soil moisture storage.

Taller wheat stubble trapped much more snow than the short stubble onthese test plots.

photo by Mike Blair

11

75

60

45

30

15

0

Wheat Yields

(Bushels/Acre)

Year

1996 1997 1998 1999 2000 2001 Average

Effect of Weed ControlMethod on Wheat Yields

in Wheat-FallowConventionalNo-TillDMT

Method

140

120

100

80

60

40

20

0

CostPer Acrein Dollars

Year

1996 1997 1998 1999 2000 2001 Average

Input Cost by Weed ControlMethod in Wheat-Fallow

ConventionalNo-TillDMT

Method

120

100

80

60

40

20

0

-20

-40

Year

1996 1997 1998 1999 2000 2001 Average

ConventionalNo-TillDMT

Method

Effect of Weed Controlon Profit in Wheat-Fallow

ProfitPer Acrein Dollars

INPUTS VERSUS RETURNS: THE BIG PICTURE

In Wheat-FallowIF ALL YOU

CARE ABOUT IS

YIELD THEN NO-TILL WHEATFALLOW IS FOR YOU

IF WHAT MATTERS MOSTIS INCREASING YOUR

PROFIT THEN LET THE WEEDS

GROW AFTER WHEAT HARVEST AND

SPRAY IN SPRING

YOU FACTORIN THE COSTS OF

INPUTS NO-TILL WHEAT-FALLOW

IS THE MOST EXPENSIVE

BUT WHEN

SO

Inputs Returns

NT CT DMT Year NT CT DMT

Seed $4.00 $4.00 $4.00 $ / unit Yields Rate 50 50 50 0.08 / lb. (bu/ac) 1996 36 21 42 1997 46 30 36Fertilizer $28.56 $28.56 $28.56 $ / unit 1998 72 56 57 N - Rate 70 70 70 0.23 / lb. 1999 72 48 65 P - Rate 42 42 42 0.21 / lb. 2000 41 27 32 Applications 1 1 1 $3.64 / ac. 2001 52 37 30*

Herbicide $60.74 $6.75 $16.02 $ / unit Avg. 53.2 36.5 43.7 Landmaster 44 44 44 0.156 / oz. Atrazine 0.6 0.0 0.0 2.69 / lb. Fallow Appl. 5 0 1 Year NT CT DMT Banvel 2.0 2.0 2.0 0.72 / oz. Price 2,4-D 4.0 4.0 4.0 0.123 / oz. (Avg.) 1996 4.98 4.98 4.98 Ally 0.05 0.05 0.0 24.24 / oz. 1997 3.06 3.06 3.06 Gr. Wt. Appl. 1 1 1 1998 2.53 2.53 2.53 Total Appl. 6 1 2 $3.61 / ac. 1999 2.45 2.45 2.45 2000 2.45 2.45 2.45Tillage / Planting $5.83 $41.74 $21.22 2001 2.76 2.76 2.76 Sweep 0 7 3 $5.13 / ac. Drill 1 1 1 $5.83 / ac. Avg. 3.04 3.04 3.04 Non-harvest Costs $99.13 $81.05 $69.80 Year NT CT DMT GrossHarvest Returns 1996 179.28 104.58 209.16 Base 1 1 1 $13.20 / ac. 1997 140.76 91.80 110.16 Extra Charge 20 20 20 0.13 1998 182.16 141.68 144.21 Hauling 0.127 1999 176.40 117.60 159.25 2000 100.45 66.15 78.40 Year NT CT DMT 2001 143.52 102.12 82.80Harvest Costs 1996 19.85 16.00 21.39 Avg. 153.76 103.99 130.66 1997 22.42 18.31 19.85 1998 29.10 24.99 25.25 1999 29.10 22.94 27.31 Year NT CT DMT 2000 21.14 17.54 18.82 Net 2001 23.96 20.11 18.31 Returns 1996 60.30 7.53 117.97 1997 19.21 -7.56 20.51 Avg. 24.26 19.98 21.82 1998 53.93 35.63 49.17 1999 48.17 13.61 62.15 Year NT CT DMT 2000 -19.82 -32.44 -10.22Total Costs 2001 20.43 0.95 -5.31

1996 118.98 97.05 91.19 1997 121.55 99.36 89.65 Avg. $30.37 $2.95 $39.05 1998 128.23 106.05 95.05 1999 128.23 103.99 97.10 The Bottom Line 2000 120.27 98.59 88.62 2001 123.09 101.16 88.11 Avg. 123.39 101.03 91.62

Economic comparison of three wheat-fallow cropping systems tested at the KSU Southwest Research and Extension Center at Tribune, Kansas, 1996-2001. The No-Till (NT) system utilized herbicide weed control throughout the 14-month fallow period. Sweep tillage was used for weed control throughout the fallow period in the Conventional-Till (CT) system. The Delayed Minimum-Till (DMT) system used no post-harvest weed control, one herbicide treatment for initial weed control in spring, and sweep tillage for the remainder of the fallow period.

INPUTS VERSUS RETURNS:THE BOTTOM LINE

Equal opportunity to participate in and benefit from programsdescribed herein is available to all individuals without regard torace, color, national origin, sex, religion, age or handicap.Complaints of discrimination should be sent to Office of theSecretary, Kansas Department of Wildlife and Parks, 1020 S KansasAve. Suite 200,Topeka, KS 66612-1327 12/04