A Guide to Managing Crop Residues Corn and …...crop residues takes time, and farmers new to crop...

Residue Management Choices

A Guide to

Managing Crop Residuesin

Corn and Soybeans

RESIDUE MANAGEMENT CHOICES

USDA Natural Resources Conservation Service andUniversity of Wisconsin - Extension

in cooperation with: Wisconsin Department of Natural Resources USDA Farm Service Agency

Wisconsin County Land Conservation Wisconsin Department of Agriculture,Departments and Committees Trade & Consumer Protection

Mulch-till:Uses chisel plows or disks to till the entire field.

AdvantagesAdapted to poorly-drained to well-drained soils,depending on implements and number of passes;good to excellent incorporation.

DisadvantagesModerate erosion control; moderate soilmoisture loss; medium labor and fuelrequirements depending on implements andnumber of passes.

Zone-till or strip-till:Uses coulters to till a 5" to 7" strip for plantingand/or injecting starter fertilizer in one operation.

AdvantagesExcellent erosion control; conserves soilmoisture; allows soil warming in the row; allowsin-row incorporation; low fuel and labor costs.

DisadvantagesMay increase dependence on herbicides; higherequipment costs.

No-till:Leaves the soil and crop residue undisturbedexcept for the crop row where the seed isplaced in the ground.

AdvantagesMaximum erosion control; conserves soilmoisture; lowest fuel and labor costs.

DisadvantagesNo incorporation; may increase dependence onherbicides; slows soil warming in spring; limiteduse on poorly drained soils, particularly withheavy residue (corn).

32

Residue Management Choices Residue Management Choices

housands of Wisconsin farmers have found that changing tillageand planting operations to increase crop residues on the soil

surface can pay off. Research shows that crop yields are generallyequal to or only slightly lower thanthose produced by systems thatleave little or no residue on thefield after planting. However, moreresidue means fewer trips acrossthe field, which translates to lowerfuel bills, less soil compaction, andless wear and tear on equipment.These lower costs offset any slightreduction in yield.

Leaving residue on the soil surfaceafter planting has benefits off thefarm, too. The residue prevents the“mud splash” during a rain stormthat starts erosion, and slows therunoff water from rainfall ormelting snow. Preventing erosionand slowing runoff water keepstopsoil on your fields, and keepssoil, nutrients and chemicals out of our streams and lakes.

Which tillage system is right for you?Three crop residue management systems are common in Wisconsin:T

Farming with crop residues is different than planting in clean-tilledground – not necessarily harder, just different. Learning to farm withcrop residues takes time, and farmers new to crop residue managementwill make some mistakes. But overall, farmers find working withincreased crop residues fairly easy.

If you’re just getting started with higher residue farming, thispublication will help steer you in the right direction. It describesdifferent residue management systems common in Wisconsin, andoffers practical tips on common issues that you’ll face when farmingwith increased residue.

Crop residues not onlyminimize soil erosion,but result in fewer tripsacross the field, lowerfuel bills and less wearand tear on equipment.

Is less tillage better for your farm?

Getting Started

Start smallWhen it comes to residuemanagement, all the adviceand volumes of informationare no substitute forexperience. The best way to get started with residuemanagement is to select afield that is typical of yourfarm and experiment on afew acres.

For mulch till that maysimply mean eliminatingone or two tillage passes.Refer to the tillage/planting tables on the followingpages for other options that fit with the equipmentyou have. Leasing or borrowing equipment mightbe another option for trying a system such as notill or strip till, where you might not have a no-tilldrill or the right finishing tool.

The residue left after a tillage pass depends on anumber of factors:

• Corn produces higher amounts of residuethan some other crops such as soybeans.Naturally, a good crop will leave moreresidue than a poor one.

• Tillage speed and depth affect residue levels.Slower speeds and shallower depth leavemore residue, as will changing from twistedshanks to straight points or sweeps.

• Harvesting equipment and methods can affect the amount and distribution of residue. Spreader attachments on acombine distribute residue evenly over thefield, while chopper attachmentsreduce residue levels by creatingsmaller residue pieces thatdecompose more easily.

Because these and other factors affect the residue left on your fields,it’s always best to measure residueafter each tillage pass to see whatyour equipment and management are leaving.

54


Start in fallThe goal of residue management is to leave a pro-tective layer of crop residue on the field afterplanting. But residue management really starts atharvest. Remember that natural weathering duringwinter reduces the amount of residue left on thefield in spring. Every tillage pass in fall and springburies some residue and further reduces the pro-tective cover on the field.

Corn stalk residue is relatively heavy and providesexcellent over-winter cover if left with limitedtillage in fall. (Many farmers chop stalks before fallchisel plowing. Chopping reduces plugging, butcan significantly reduce residue levels.) Fragilesoybean residues call for extra care. Small, finepieces of soybean residue blow away easily anddecompose rapidly. Experience shows that it’s bestnot to disturb soybean residues at all after harvest.

Spreading residue evenly across a field is almost as important as the amount of residue left. Use a

spreader on thecombine that distrib-utes residue evenly.Attachments areavailable that dis-tribute the fine chaffthat would other-wise fall in a narrowband and spread itacross the width ofthe combine.


Measuring residueThe residue left on your fields will depend on the weather, crop yields, how deep and fast youoperate equipment, and many other factors. So,the best way to know how much residue you’releaving is to measure the residue after planting.

A simple and accurate method for measuringresidue uses a tape measure or any line divided

1. Stretch the line Place it diagonally across the crop rows.

2. Walk and countAs you walk along the line, look down directlyfrom above and count the number of marks thathave residue beneath them. Walk the entirelength of the line.

3. Total the resultsThe total number of marks with residue underthem is the percent cover for the field. If yourline has only 50 marks, multiply the number bytwo.

into either 50 or 100 equal parts. For example,take a 100-foot cord and mark it every one foot.

Take three to five measurements in different parts of the field and take the average percentageto get a good estimate of residue cover for theentire field.

Corn ResidueCorn Residue


36%77%

RESIDUECOVER(low to high)

HARVEST

plant – doubledisk opener

25%55%HARVEST


field cultivate6-12" sweeps

tandem disk(fall)

25%62%HARVEST



V-rippersubsoiler

14%54%HARVEST


tandem disk(finishing)

V-rippersubsoiler

13%36%HARVEST


soil finisherdisk chiselstraight points

18%41%HARVEST

WINTER

WINTER

WINTER

WINTER

WINTER

WINTER



disk chiselstraight points

••• Fall Tillage

Harvest/Winter

After winter weathering 80-95 70-80

Machine or operation

Moldboard plow 0-10 0-5

Paraplow/paratill 80-90 75-85

V-ripper/subsoiler 70-90 60-70

Chisel plows with:Sweeps 70-85 50-60Straight points 60-80 40-60Twisted points 50-70 30-40

Coulter chisel plow with:Sweeps 60-80 40-50Straight points 50-70 30-40Twisted points 40-60 20-30

Disk chisel plows with:Sweeps 50-70 30-50Straight points 50-60 30-40Twisted points 30-50 20-30

Disks:Offset primary cutting 30-60 20-40Offset heavy plowing 25-50 10-25Tandem disk (primary cutting) 30-60 20-40Tandem disk (fall) 70-80 40-50Tandem disk finishing 40-70 25-40

Field cultivators as primary tillage:Duckfoot points 35-65 30-55Sweeps or shovels 6-12” 35-75 50-70Sweeps 12-20” 60-80 55-75

Field cultivators as secondary operation:Duckfoot points 60-70 35-50Sweeps or shovels 6-12” 70-80 60-75Sweeps 12-20” 80-90 65-80

Finishing tools:Soil finisher (disk, shank, leveler) 50-70 30-50Seedbed conditioner

(spring tooth and rolling basket) 70-90 50-70Culti-packer 60-80 50-70Harrow, spike tooth 70-90 60-80

Drills:Hoe openers 50-80 40-60Disk Openers 80-100 60-80No-till coulters 75-80 60-80

Planters:Double disk opener planters 85-95 75-85Runner planters 85-95 80-90Sweeps or double row cleaning disks 60-80 50-60Ridge-till planter 40-60 20-40No-till planters with:

Smooth coulter 85-95 75-90Ripple coulter 75-90 70-85Fluted coulter 65-85 55-802 or 3 fluted coulters 60-80 50-75

Anhydrous applicator 75-85 45-70

Estimated residue left after harvest, winter, anddifferent tillage/planting operations

% residue leftCorn/Small Grain Soybeans

low to high low to high

7


6


RESIDUE ESTIMATES

How much residue am I leaving?A great deal of research has been done on tillageand planting equipment and the amount of residuethey leave on the surface after a single pass. Thetable at right summarizes this research, and is thebasis for the tillage/planting estimates shown onthe following pages.

Each of the examples shows a common sequencefor tillage and planting, and also shows the averagelow and high residue to expect after harvesting,winter weathering, tillage and planting. For example,a common tillage sequence for corn is:

The following pages show estimated residues fortypical tillage/planting sequences. If you don’t find a sequence that exactly matches your tillageand planting operations, you can develop anestimate that does. Just look up the numbers foreach operation you use, along with the “winter”and “harvest” numbers, and multiply them out asshown in the example above.

While these tables give a fair estimate ofresidue left after a year’s typical tillage and planting operations, remember thatmeasuring residue in your fields is the mostaccurate method.

You needn’t do the multiplication for the optionsshown on the following pages – the results arealready calculated.

%

plant-doubledisk opener



WINTERHARVEST 10%36%

low residue expected:(using numbers from the table)

low: .75 x .80 x .50 x .40 x .85 = 10%

How we calculated residue levels

high residue expected:

high: .95 x .95 x .60 x .70 x .95 = 36%

Using the numbers in the table on the right, we estimated theaverage high and low for residue left after planting. For example,in this corn sequence:

V-rippersubsoiler

%





After harvest 75-95% 65-90%

%%

Corn ResidueCorn Residue

9


8



soil finisher

WINTERHARVEST

%


tandem disk(primary cutting)

WINTERHARVEST

%




WINTERHARVEST

%




WINTERHARVEST

%




WINTERHARVEST

%




WINTERHARVEST

26%

60%

15%

11%

6%

18%

10%

RESIDUE ESTIMATES RESIDUE ESTIMATES

••• No Fall Tillage

51%

41%

36%

41%

36%

%%

no till planterwith fluted coulters

WINTERHARVEST

%%

3-coulterplanter

WINTERHARVEST

%%

no-till planterwith fluted coulters

anhydrousapplicator

WINTERHARVEST


29%65%

36%72%

39%77%


Note: Drills leave residue similar to no-till planters.

21%

••• Fall Strip Till

Soybean ResidueSoybean Residue

%%




%%



WINTERHARVEST 7%24%

%%



anhydrousapplicator

WINTERHARVEST 4%17%

%%



anhydrousapplicator

WINTERHARVEST 9%32%

%%





%%




WINTERHARVEST 4%18%


soil finisher



anhydrousapplicator


••• No Fall Tillage

14%38%HARVEST

3-coulterplanter

V-rippersubsoiler

WINTER

3-coulterplanter

V-rippersubsoiler


no-till drill or planterwith fluted coulters


1110


RESIDUE ESTIMATES RESIDUE ESTIMATES



Note: This systemmay be useful onpoorly drained soils.

Note: Drills leave residue similar to no-till planters.


Consider your tillage equipmentThe points or shanks of a tillage implement largelydetermine how much residue remains after eachtillage pass. One pass with a shallow chisel withsweeps could leave as much as 85 percent corn

13


12

Manage manure.Manure applications to no-till fields are not recom-mended because excess phosphorus can be washedoff. Manure can also cause production problems byincreasing soil moisture and decreasing soil temper-ature. Consider using mulch till, which uses lightdisking to incorporate the manure into the top twoinches of soil. This reduces the manure runoffproblem while retaining residue for erosion control.

Prepare for weed control.

If weeds are a problem with the current systemthey will continue to be a problem. A full herbicideprogram the first few years can help manage weeds.Generally, increase use of pre- and post-emergenceherbicides that do not require incorporation. Rowcultivators are also available that work well in

high-residue systems.

Prepare for insect and disease control.The potential for insect problemsis slightly greater in reduced tillagesystems. Diseases favored by cool,moist conditions may be moretroublesome than those favored bydry, warm conditions in plowedfields. Field scouting and a pestmanagement plan are critical inreduced tillage systems. CountyExtension offices and Land Conser-vation Departments, NRCS fieldoffices and private consultants canhelp develop an effective manage-ment program for your situation.

Making the change to higher-residue farming

Higher-residue farming doesn’t mean changing overnight from the moldboard plow and cleantillage to no-till. You can make the change to higher residue gradually. From the moldboard,you might progress to a chisel plow with twisted shanks. To leave even more residue, you mightthen change to a chisel plow with sweeps, and eventually to strip-till or no-till.

If you’re already farming with crop residue, keep these tips in mind to maximize residue levels:

• Reduce the number of tillage passes. Two passes are usually the limit for leaving 30 percent residue.

• Drive slower, which will turn less soil and leave more residue.

• Use straight points or sweeps instead of twisted points.

• Align disk blades straighter to bury less residue.

• Set chisels and disks shallower.

• Spread residue from the combine evenly – don’t windrow residue.

SweepsSweeps with low crowns loosenthe soil but do very little turning.Chisel plows with sweepstypically leave 70 to 85 percentcorn residue with each pass.

Straight pointsStraight points, or spikes,bury less residue thantwisted points, typicallyleaving 60 to 80 percentcorn residue with each pass. A 2-inch wide pointleaves more residue thanwider points.

Twisted pointsTwisted points work likemini-moldboard plows,turning and throwing soil.Wider (4-inch) points burysignificantly more residuethan straight points or sweeps.Twisted points typically leave 50 to 70 percent cornresidue with each pass.

Getting to the point


Ready to Start?Farming with higher residue levelsmeans less time spent on the tractor, butmore time spent on management tasks. Here are some general tips for gettingstarted successfully.

Consider your nutrient andpest managementIncreased residue, cooler soils and highersoil moisture affect the availability ofnutrients. These factors also affect weedand insect populations. Careful nutrientand pest management strategies are criticalto working successfully with increased residues.

Prepare and test the soil.If the soil is compacted, subsoil before switchingto higher-residue farming. Adjust P and K levelsand soil pH based on six-to-eight-inch deep soilsamples. Broadcast and incorporate fertilizer andlime before starting to farm with increasedresidues. Surface pH may decrease in establishedhigh-residue fields and should be monitored overtime, especially in the top two inches of soil.

Manage fertilizer.Once increased residue levels are established,nitrogen fertilizer should be placed below theresidue to avoid losses through volatilization orrunoff. As a rule, the greater the residue, the more likely you are to see a response to bandedstarter fertilizer (see graph).

On fields where residuelevels are 50% or more,apply an additional30lbs/acre N for the firsttwo years. This will offsetthe N that may be immo-bilized in surface residuesand unavailable to crops,as well as the lower annualamount of N mineralizedfrom soil organic matter.

residue, while a deep disk chiseling with 4-inchtwisted points could leave as little as 30 percent.Below are some general relationships betweenpoints and residue.

100

125

150

175

147

167

159

167163

169 167164

springrow tillage

fallrow tillage

no-till chisel(mulch-till)

2X2 FERTILIZER PLACEMENT AT PLANTING

NO FERTILIZER AT PLANTING

Effects of in-row fertilizer(at planting) in different residuemanagement systems

Row fertilizer response in no-till and zone (strip) till systems demonstrates the value of this practice in corn.

Cor

n Yi

eld

(Bu.

/Acr

e)

Adapted from R.P. Wolkowski, Proceedings of the Wisconsin Fertilizer, Aglime and PesticideManagement Conference, 1997.


14


RESIDUEMANAGEMENTCHOICESA Guide to ManagingCrop Residues in Cornand Soybeans

UWEX: GWQ029DNR: WT-538-00I-03-00-20M-200-S

Publication of this documentmade possible through theEnvironmental Quality IncentivesProgram–Education AssistanceFunds and the US Department of Agriculture Natural ResourcesConservation Service in Wisconsin.

This publication is available from NRCS offices, county UW-Extension offices or from ExtensionPublications, 630 W. Mifflin St.,Madison, WI 53703. (608) 262-3346. ©2000 by the Board ofRegents of the University ofWisconsin System. Send inquiriesabout copyright permission to:Director, Cooperative ExtensionPublications, 201 Hiram SmithHall, 1545 Observatory Dr.,Madison, WI 53706.

University of Wisconsin-Extension isan EEO/Affirmative Action employerand provides equal opportunities inemployment and programming,including Title IX and ADA require-ments. The U.S. Department of Agriculture (USDA) prohibits discrim-ination in all of its programs and activities on the basis of race, color,national origin, religion, age, disability,political beliefs, sexual orientation, orfamily status. (Not all prohibited basesapply to all programs.) Persons withdisabilities who require alternativemeans for communication of informa-tion (Braille, large print, audiotape,etc.) should contact USDA’s TARGETCenter at 202-720-2600 (voice andTDD). To file a complaint of discrimi-nation, write USDA, Director, Officeof Civil Rights, Room 326-W, WhittenBuilding, 1400 Independence Avenue,SW, Washington, DC 20250-9410 orcall (202) 720-5964 (voice or TDD).USDA is an equal opportunityprovider and employer.

March, 200015

Editing and design by the Environmental Resources Center, University of Wisconsin–Madison.

Printed onRecycled Paper

ecause farming with crop residues is different than farming in clean-tilled ground, the key is

to develop a residue management system that fitsinto your total operation.

This booklet helps you get started by pointing outsome common tillage systems and answering somequestions you’ll have when getting started. But thisbooklet is only an introduction. Learning to farmwith crop residues takes time, and mistakes shouldbe expected.

That’s where neighbors experienced with reducedtillage, crop consultants and staff with your localNRCS office, USDA Service Center, county LandConservation Department, or county Extensionoffice can help with more specific information andassistance. Talk with them when you start todevelop a residue management plan for your farm.

Summing up . . .the benefits of farmingwith higher residue B

A Final Word

Farming with more residue will requirea change in management, especially atthe beginning. But in return, thechanges can bring about long-termbenefits, both on and off the farm.

Save time and moneyOn a 500-acre farm, annual timesavings can be as much as 225 hours,or almost four 60-hour weeks.

Fewer trips can save up to $5 per acreon machinery wear and maintenance,and 3.5 gallons of fuel per acre overconventional tillage.

Improve your soilDepending on the amount of residue,soil erosion can be reduced up to 90percent compared to intensively tilledfields. On a demonstration plot incentral Wisconsin, for example, a cornplot with 0 percent residue lost 8,623lbs. of soil after a rain storm, a plotwith 14 percent residue lost 239 lbs.,and a plot with 54 percent residue lostonly 20 lbs.

Field traffic required by intensivetillage compacts the soil over time. Lesstillage, particularly no-till, increasesaggregation of soil particles, whichallows water to infiltrate and allowsplants to establish strong root systems.

Crop residues reduce waterevaporation from the top few inches ofsoil, making more water available forplants in late summer. This isespecially important in dry summersand on sandy soils.

Help the environmentCrop residues slow runoff and allowwater to soak into the soil and rechargegroundwater. Reducing field runoff alsokeeps sediment and the chemicalsattached to soil particles out of streamsand lakes.

Crop residues can provide criticalshelter and food for wildlife such asgame birds and small animals.

Finally, crop residues contribute tocleaner air by reducing wind-blown soiland dust. Fewer trips across the fieldalso reduce fossil fuel emissions.

Technical guidance for this publicationprovided by:John W. Pingry, AgronomistUSDA Natural Resources Conservation ServiceRonald T. Schuler, Agricultural EngineerRichard P. Wolkowski, Soil ScientistUniversity of Wisconsin–ExtensionProject coordinated at the Environmental Resources CenterUniversity of Wisconsin–Extension

RESIDUE MANAGEMENT CHOICESA Guide to Managing Crop Residues

in Corn and SoybeansUSDA Natural Resources Conservation Service

andUniversity of Wisconsin - Extension

in cooperation with:

Wisconsin Department of Natural Resources

USDA Farm Service Agency

Wisconsin Department of Agriculture, Trade & Consumer Protection

Wisconsin County Land Conservation Departments and Committees

GWQ029I-03-00-20M-200-S

A Guide to Managing Crop Residues Corn and …...crop residues takes time, and farmers new to crop...

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