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Conservation Planter, Drill and Air-TypeSeeder Selection GuidelineJ . E . Mo rr i son , J r . R . R . Al len , D . E . W i lk ins , G. M. Powel l , R . D . Gri sso , D . C . Er ba ch ,

M EM B ER M EM B ER M EM B ER M EM B ER AS S OC. M EM B ER M EM B ERASAE ASAE ASAE ASAE ASAE ASAEL. P . Hern d o n , D . L . M u r ray , G . E . F o rm an ek , D . L . P fo s t , M . M . Her ro n , D . J . B au m er t

MEMBER ASSOC. MEMBER ASSOC. MEM BER MEMBER ASSOC. MEMBER ASSOC. MEMBE RASAE ASAE ASAE ASAE ASAE ASAE

ABSTRACTTHIS guideline contains descriptions of machinesused for planting in conservation-tillage conditionsand of soil-engaging components for those machines.The functions of available components are discussedrelative to soil and crop residue conditions that may beencountered with conservation tillage. The guideline aidsin determining planting machine specifications byidentifying c omp onents th at will work best under specificanticipated conditions. The user can then match thosespecifications with available commercial machines ormodify existing machines by adding the desiredcomponents .

INTR ODUC TIONConservation-tillage planting conditions require theuse of special "conservation-seeders," such as specialrow-crop p lan ters , d r i l l s , o r a i r - type seeders .Conservation-seeders are machine which have beendesigned or modified to be different machines or to havedifferent machine components than those which havebeen designed for planting into residue-free tilledseedbeds. Farmers, as well as action-agency personnel,consultants, and other farm advisors need to be aware ofthe machine requirements for conservation-tillageplanting. Because many machines have been developedand marketed in specific regions, local advisors andfarmers are not necessarily familiar with the availabilityand performance capabilities of special machines andcomponent opt ions.

Article was submitted for publication in August, 1987; reviewed andapproved for publication by the Power and Machinery Div. of ASAE inMay, 1988.The authors are members of ASAE SW-225 Conservation Systemstechnical committee and the content has been prepared as a SW-225/1Subcommi t t ee pro jec t : J O H N E . MO RRISO N (Chai rman) ,Agricul tural Engineer , USDA-ARS, Temple, TX; RONALD R.ALLEN, Agricul tural Engineer , USDA-ARS, Bushland, TX; DALE E.WILKINS, Agricul tural Engineer , USDA-ARS, Pendleton, OR; G.MORGAN POWELL, Extens ion Engineer , Kansas State Univers i ty,Manhattan; ROBERT D. GRISSO, Assis tant Professor , Univers i ty ofNebraska, Lincoln; DONALD C. ERBACH, Agricul tural Engineer ,USDA-ARS, Ames, IA; LEE P. HERNDON, Engineer , USDA-SCS,Washington, DC; DAVID L. MURRAY, Project Engineer , Deutz-All is Corporat ion, Independence , MO; GARY E. FORMA NEK ,Engineer , USDA-SCS, Port land, OR; DONALD L. PFOST, Extens ionEngineer , Univers i ty of Missouri , Columbia; MAYNARD M.HERRON, Engineer , Hess ton Corporat ion, Hess ton, KS; andDANIEL J . BAUMERT, Engineer , USDA-SCS, W. Warwick Is land,RI.

The objectives of this guideline are: (a) to providebackground information, for public agencies, equipmentsuppliers, and farmers; and (b) to assist in the selectionof conservation-seeders to match specific needs. Theguideline includes a description of general types ofconservation seede rs, lists of mach ine com ponen t op tionsf o r s e v e n p l a n t i n g f u n c t i o n s , a n d l i m i t e drecommendations for the selection of component optionsfor specific conditions.General Types of Conservation Seeders

Conservation seeders include many variations of row-crop planters, drills, and air-type seeders. Thesemachines typically include separate components for soiland residue cutting, depth control, soil opening for seedplacement, and seed slot closure. Some machines alsohave components for row preparation, uncovered-seedfirming, and seed covering (Fig. 8). The majordistinctions among conservation seeders are given in thefollowing descriptions of six types of seeders.PlantersRow-Crop Planters: Row-crop planters are used toestablish widely spaced crop rows which allow wheeltraffic or cultivation between rows. Rows are usually atleast 60 cm (24 in.) apa rt. Seed is singulated and meteredfor each planter row unit. The soil-engaging componentsoperate independently between row units. Surfaceresidue accumulation and blockage between row units isuncommon because of the wide row spacings.Equipment options include coulter attachments, rowpreparation devices to permit ridge planting, in-rowsubsoil rippers, fertilizer and pesticide placementattachments, and ballast or springs to increasedownforce on row units. Most of these devices permit theplanter to also be used for planting residue-free tilledseedbeds. Major distinctions among row-crop plantersare designs for broadcast-tillage, strip-tillage, slot-planting, and for ridge-planting versus planting on non-ridged surfaces.Narrow-Row Planters: Narrow-row planters are usedwhen mechanical cultivation is not going to be used andwhen there is some advantage, such as higher yields, tojustify the investment in a more expensive machine.Rows are typically 19 to 50 cm (7.5 to 20 in.) apart (Fig.9) . Some planters are set up to have groups of narrow-row units separated by wider spacings for unplantedwheel traffic lanes. The width of individual seedmetering hopp ers and of side-mounted unit gauge wheelsoften limit the narrowness of the row spacings. Residue

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(front view)

1.1. Smooth coulter 1.2. Notched coulter 1.3. Coulter with depth bands

(front view)

1.4.a. Offset bubb le coulter 1.4.b . Offset rippled coulter 1.4.c. Offset fluted coulter

(front view)flRPRRflI x B E E d

1.5. Straw straightener 1.6. Powered blade or coulter 1.7. Strip rotary tiller

(oblique view]

1.8 Dual secondary residue discs

Fig. 1Component options for soil and residue cutting.

accumulation and blockage between row units can be aproblem with closely spaced row units which are notstaggered. Narrow row spacings can sometimes beachieved by the use of planters with remote seedmetering units or by use of frames and hitches thatcouple two or three row-crop planters in tandem fornarrow-row "sol id-seeding."

DrillsDisc Drills: Conservation disc drills (no-till) use singleor double discs for furrow openers and presswheels forsoil firming and depth gauging. Most manufacturersoffer coulters or staggered double-disc openers forcutting soil and residue. Ballast may be added to framesor row units to improve soil penetration.The following com men ts apply to other types of drills,as well as to disc drills: Seed cup block-offs andmoveable openers allow row spacing adjustments.Normally, drill meters do not singulate seed nor provideas uniform row-to-row seeding rate as planters,especially at low seeding rates. Depth control hastraditionally been less accurate, because there isinadequate space for some types of depth controlcomponents. Clearance for residue may be limiting whenseeding into high-residue conditions, but staggering ofadjacent row units increases clearances and residu e flow.Row spacing is sometimes wider than desired to allowadequate space for depth gauge wheels or for residueflow. Common uses of disc drills are for seeding small

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2 . 1 . Sweep row cleaner(top view)

2.2.a. Even discs row cleaner

(front view)

(top view)2.2.b. Staggered discs row cleaner

"1"2.3. Horizontal-disc row cleaner 2.4 . Wide fluted coulter loosener 2.5. Chisel ripper

N(front view)

K K (front view]

V2.6. Subsoil ripper 2.7. Packer roller 2.8. Basket roller

2.9. Rotary cultivator 2.10 . Spring tine cultivator 2.1 1. S-time cultivatorFig. 2Component options for row preparation.

grains, soybeans, peas, and other "solid-seeded" cropsand for interseeding grasses and legumes.Hoe Press Drills: Hoe-opener press drills are primarilyused in drier climates for seeding small grains where thedepth to moist soil may be 7.6 cm (3 in.) or more (Fig.10). The hoe opener can penetrate and place the seed inmoist soil, leaving a small furrow without having an

excessive amount of soil covering the seed. Much of thedrill weight is carried on rear presswheels that roll in theseeded furrows to improve soil firming for seed-soilcontact and furrow stability. The openers are spaced andstaggered for residue flow. Models with coultersmounted in front of the openers have improved seedingthrough crop residues but large amounts (5000 kg/ha302 APPLIED ENGINEERING in AGRICULTURE


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(top view) (top view) O3 . 1 . Double-disc opener; with shoe 3.2. Staggered double-discopener; without shoe 3.3 Runner opener

3.4. Stub-runner opener 3.5 Hoe opener 3.6. Single-disc opener

(oblique view)

3.7. Coulter opener 3.8. Chisel opener 3.9. Wide-sweep opener

(top view)

3.10. Triple-disc opener 3.11. Powered blade or coulter openerFig. 3Component options for soil opening for seed placement.

(4500 lb/acre) or more of wheat straw) may causeblockages. Moisture content and orientation of wheatstubble greatly affect the amount of straw that can betolerated.Air-Type SeedersAir Seeders: Air seeders consist of two machine unitswhich are hitched and pulled in tandem (Fig. 11). Thefirst machine has a central seed hopper with a meter thatdischarges seed into an air distribution and deliverysystem. The second machine is a tillage implement suchas a chisel plow, field cultivar, or stubble mulch plow.Individual seed tubes go from the air delivery system tosoil openers on the second machine. Soil openers may be

chisel points, chisel sweeps, or large, 1.5 to 1.8 m (60 to72 in.) wide V-blades with seed tubes. Presswheels areoptional in humid climates, but essential in non-humidclimates to insure seed-soil contact. W hen releasing seedbehind wide V-blades, seeding rates may need to beincreased because scattered seed which is not directlyunder press-wheel tracks may not germinate. Some airseeders are well adapted for operating through largeamounts of residues. The relatively large machines havehigh field capacities and can be easily folded fortransport. Air seeders are commonly used for plantingsmall grains but also may be used for soybeans.Variability in depth of seed placement has been aconcern because most air seeders lack individual depth

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(front view)(oblique view)

4 . 1 . Semi-pn eumatic wheel 4.2 . Solid wheelFig. 4Component options for firming uncovered seed.

control for each row.Air Drills: Air drills have a central seed hopper,integral seed metering, and an air distribution anddelivery system, similar to those used for air seeders. Thedifference between air drills and air seeders is that airdrills have hoe or double-disc furrow openers as used onother types of drills. Individua l row unit suspensions anddepth controlling presswheels follow soil surfacecontours and control seed depth better than air seeders.Air drills can have field capacities and residue tolerancessimilar to air seeders.FUNCTIONAL FACTORS TO CONSIDER

Equipment SelectionSelecting a brand and the specific components for aconservat ion seeder can be bewi lder ing . Somemanufacturers offer a very wide range of componentoptions. Other manufacturers offer add-on equipmentfor modification of owned m achin es. Advice for selectingcomponent opt ions may be avai lable from them a n u f a c t u r e r ' s r e p r e s e n t a t i v e , o t h e r p r o d u c e r s ,conservationists, extension specialists, or experienced

farm machinery dealers. Field demonstrations ofconservation seeders can be very helpful in evaluatingcomponents. Conservation tillage farmers and supplierswho work closely with them, have valuable experiencewhich should be sought to avoid trial and errorcomponent selection.Residue A ccumulationFor conservation tillage, surface residues m ust cover atleast 30% of the soil surface after planting. Plantingmachines must operate in residues which may be coarseor fine, tall or short, chopped or long, and soil-attachedor loose. Machine components should not be expected tooperate through large piles of residue deposited bycombine harvesters, although the ability to pass throughsuch piles without blockage is beneficial.Residues accumulate on planting machines in twoway s . R es i d u es h a i rp i n a ro u n d s o i l - en g ag i n gcomponents, such as hoe and chisel shanks, supportingstruts, and frame members. Hairpinning is usuallyprevented by effective residue cutting ahead of eachcomponent. Residues also accumulate between adjacentcomponents . Accumulat ions can be reduced bystaggering the components, using smooth-sided wheels,and eliminating protrusions and constrictions betweencomponents. Tillage operations and components ofplanting machines that detach residues can createproblems; residues anchored to the soil flow betweenplant ing machine components much bet ter than looseresidues.Component TrackingOn hillsides and curved rows, the seed slot opener m aynot follow in the coulter slit or the presswheel may nottrack over the seed slot. This is usually caused byrelatively large distances between successive seeder

(top view) (top view) EL(top view)

5.1. Single covering disc 5.2 . Dou ble covering discs 5.3 . Covering padd les

5.4. Covering knives 5.5. Covering chains 5.6. Spring covering tinesFig. 5Component options for seed covering.

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(front view) (front view) (front view)

6 . 1 . Wide presswheel

(front view)

6.2. Single-rib presswheel

(front view)

6.3. Double-rib presswheel

6.4.a. Narrow presswheel; V-shaped

(front views)

6.4.b. Narrow presswheel; rounded

(front view

6.5. Dual angled presswheels

p d

6.6. Split narrow presswheels 6.7. Dua l wide presswheelsFig. 6Component options for seed furrow closure and firming.

components. Strip tillage and closer-spaced componentshelp overcome this problem. The use of pivots betweenthe coulter, furrow opener, and presswheel improvestracking on curved rows. Pull-type planters track betterthan mounted planters on curved rows, but mountedplanters track better on hillsides.Rocks and Other ObstructionsRocks and other obstructions require reduced fieldspeeds for safe operation and to minimize machinedamage. Obstruct ions may be more fi rmly implanted innon-tilled soils than in soils loosened by primary tillage.Rolling coulters and disc openers will roll over mostobstructions with only momentary loss of depth control.In rocky soils, rigid shank-type openers should beequipped with trips, shear pins, or other protectiondevices.Equipment ModificationsMany producers have modified their equipment forconservation planting. Such innovations will continue tobe important for special conditions and tillage systems.If an existing conventional machine is to be convertedto a conservation planter, the frame, linkages, wheels,and bearings may require s trengthening to support the

addition of coulters and ballast for soil penetration. Donot use old wide-slot type furrow openers because theymay open a furrow which is too wide to close in firm nonfilled soil. Original equipment presswheels may need tobe replaced with presswheels that concentrate or directthe downforce to enhance furrow closure and seedfirming.A few short-line equipm ent ma nufa cturers offercomponents or whole row units which can be used toupda te older models. An updated machine may be nearlyas useful as a new model at a substantial cost savings.C OM P ONENT F UNC TIONS

The following descriptions partition the soil-engagingcomp onents of conservation seeders into seven functionalgroups (Fig. 8). Several alternative machine componentsare identified for each of those functions. A personselecting components for a conservation seeder to workin certain conditions should consider each functionalgroup. All components selected for a specific machinemust be compatible with one another, but a machine willnot necessarily require all seven component functions. Abrief discussion follows the listing of availablecomponents to assist in the selection process.Vol. 4(4):December, 1988 305


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(top view)

i TLJX 37.1. Rear press wheel

(top view)

7.2. Side gauge wheels; on double-discopener

< fl7.3. Skid plate; on double-disc opener

7.4. Front wheels and rear presswheels tandemed

(front view) (front view, sectioned )

7.5. Frame lifting/gauge wheels 7.6.a. Depth bands on front leading coulter 7.6.b. Depth bands on double-disc openerFig. 7Component options for planting depth control.

I. Soil and Residue CuttingComponents for soil and residue cutting (Fig. 1) are:1.1. Smooth coulter1.2. Notched coulter1.3. Coulter with depth bands1.4 Offset coultera. Bubble coulterb . Rippled coulterc. Fluted coulter1.5. Straw straightener1.6. Powered blade or coulter1.7. Strip rotary tiller1.8. Dua l secondary residue discsA rolling coulter is generally used for cutting soil andresidue although it may be omitted on machines that

have an opener designed to perform this task and to alsoopen the seed slot (such as a staggered double-disc, asingle disc, or coulter opener). A wide range of coulteroptions are available. Smooth coulters require lessdownforce than other types of coulters and can besharpened. Rippled coulters tend to be self sharpeningand will tolerate some sticky soils. Narrow fluted coultersand bubble coulters loosen some soil in the row; however,they do not work well in sticky soil conditions. Widefluted coulters provide strip tillage in friable soils, butthey throw too much soil out of the row at speeds above

6.4 km/h (4 mph). Additional problems with wide-flutedcoulters include the lack of a clean-cut path for thetrailing furrow opener, and the formation, in some soils,of a ragged row of clods which often gives non-uniformseed coverage. Coulters cut residue if the soil surface ishard, but they tend to push residue into soft, prepared,or loosened soil. Large diameter coulters cut residues

LikJ

* DEPTH CONTROL

Fig. 8Exa mple of a soil-engaging com ponent sequence on aconservation-tillage seeding machine. The depth control componentmay be located at any one or more of the locations indicated.

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Fig. 9Example of a narrow-row planter with two ranks of closely-spaced row units.

easier than small coulters, but require more downforcefor penetration. Downforce requirements range from 70to 180 kg (150 to 400 lb) per row unit for penetration inmany residue and soil conditions. A powered blade orcoulter may improve residue cutting and residue flowthrough the machine.II . Row PreparationComponents for row preparation (Fig. 2) are:2 .1 . Sweep row cleaner2.2. Vertical-discs row cleanera. Even discs row cleanerb . Staggered discs row cleaner2.3 . Horizontal-disc row cleaner2.4. W ide fluted coulter loosener2.5. Chisel ripper2.6. Subsoil ripper2.7. Packer roller

2 .8 . Basket roller2.9. Rotary cultivator2.10. Spring tine cultivator2.11 . S-tine cultivatorSome machines include a device for preparing the rowarea behind a soil and residue cutting component. Suchdevices include those used to clear residue for ridge andstrip-till, or to deeply loosen soil ahead of the seeding

Fig. 10Example of a hoe press drill with all of the machine weightcarried by the presswheels and hitch.

Fig. 11Example of an air cedar consisting of a forward machine withseed hopper and metering, and a tandemed second machine withpneumatic seed delivery tubes to the tillage tools.

unit. Row clearing devices remove dry surface soil, newlydeposited weed seed, and crop residues. This surfaceremoval brings the planter into contact with the moistunderlying soil. Row clearing is not recommended onsoils which crust, nor on soils which are unmanageablysticky when moist. Deep loosening at planting time isrecommended only on sandy soils with a compactedzone.III. Soil Opening for Seed PlacementComponents for soil opening for seed placement (Fig.3) are:3 .1 . Double-disc opener; with or without shoe3.2. Staggered double-disc opener; with or withoutshoe3.3. Runner opener3.4. Stub-runner opener3.5. Hoe opener3.6. Single-disc opener3.7. Coulter opener3.8. Chisel opener

3.9. Wide-sweep opener3.10. Triple-disc opener3.11. Powered blade or coulter openerMany row-crop planters and grain drills have eithertraditional or staggered double-disc openers to open seedfurrows. Other opener devices used include runners, stubrunners, hoes, and single discs. Additionally, somemachines precisely shape the seed groove with a "V-" or"U-" shaped shoe. Air seeders place the seed under orbehind tillage points or blades. Air drills have seedplacement methods commonly used on row-crop plantersor drills.If not preceded by soil and residue cuttingcomponents, most openers will either collect surfaceresidues or roll over and crimp them into the seedfurrow. Moist soil sticking to opener parts may catchresidues. Disc openers with scrapers are usually self-cleaning. Special rotating scrapers are available for discand coulter type openers in sticky soil conditions. Rigidrunner, hoe, and chisel openers may collect residues andwet soil if clay content is high.Narrow furrow openers throw less soil laterally so thatmore soil is available for seed covering. Shallow plantingand slower speeds also help reduce lateral soil removalfrom the row area.

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IV. Firming Uncovered Seed4 .1 . Semi-pneumatic wheel4.2. Solid wheelA seed firming wheel is sometimes used to press theseed into the bottom of the seed furrow. These devicesare semi-pneumatic rubber wheels ranging in size from2.5 x 15 to 2.5 x 25 cm (1 x 6 to 1 x 10 in.), or solid platewheels as narrow as 0.64 cm (0.25 in.). Downforce, inaddition to the weight of the wheel assembly, may besupplied by springs. Firming wheels improve seedemergence rates under dry soil conditions. They aresometimes used without rear presswheels if followed byseed covering devices. In sticky soil conditions, seedfirming wheels collect soil and can become unuseablebecause they pick up seed from the furrow.V. Seed CoveringComponents for seed covering (Fig. 5) are:5.1 . Single covering disc5.2. Double covering discs5.3. Covering paddles5.4. Covering knives5.5. Covering chaina. Loopb . Trailing

5.6. Spring covering tinesSeed covering components are used when seed-slotclosure components are ei ther not used or are ina dequa teto consistently cover the seed. Covering devices musthave loose soil available to place on top of the seed ormust loosen soil and move it over the seed. Soil may beavailable for seed covering with ridge and strip tillage b utis not available with narrow slot type no-tillage plantersand drills which disturb a minimum amount of soil.Residues may accumulate on covering devices.VI. Comp onents for Seed Furrow Closure and FirmingComponents for seed slot closure and firming (Fig. 6)are:

6.1 . Wide presswheel6.2. Single-rib presswheel6.3. Double-rib presswheel6.4. Narrow presswheela. V-shapedb. Rounded6.5. Dual angled presswheels6.6. Split presswheels6.7. Dual wide presswheelsMost seeders have presswheels to close and/orcom pact the seed slot. The ex ceptions are drills with dragchains and planters with only seed firming wheels andcovering discs. Presswheels are available in a wide varietyof sizes, shapes, and configurations. Most presswheelshave semi-pneumatic rubber coverings to prevent soilbuildup. Some manufacturers offer steel presswheels fordry soil or sod planting. The method of slot closure mustbe compatible with the amount of soil loosened bypreceding components. Dual angled wheels provideaggressive seed covering as well as soil firming. Somepresswheels, such as the single rib and the narrowV-shaped and rounded presswheels, are used to transmitpressure down to the buried seed to firm it in the soil.Double ribbed or dual wheels are used on some soils toavoid surface pressure directly over the seed which

reduces soil crusting. Presswheel driven planters musthave enough downforce on the rear presswheel to bothclose the seed slot an d to provide a non- slipping p lanterdrive. Slot closure and firming wheels may be eitherindividually mounted or arranged in gangs. Gangedwheels lack individual flotation over soil surfaceundulations and may not align with the seed rows.VH. Depth ControlComponents for depth control (Fig. 7) are:7.1 . Rear presswheel

7.2. Side gauge wheel7.3. Skid plate7.4. Front wheels and rear presswheels tandemed7.5. Frame lifting/gauge wheels7.6. Depth banda. Bands on front leading coulterb . Bands on disc openerUniform seeding-depth control is essential for u niformcrop emergence. Many row crop planters have depthgauge wheels on the sides of each seed slot opener. Frontwheels and rear presswheels are used to give a tandem-wheel depth averaging on some planter units. Because ofspace limitations, the rear presswheels are often used toprovide depth control on no-till drills. Openers for mostair seeders and some drills are attached semi-rigidly tothe tillage implement frame in which case depth iscontrolled by the lifting/gauge wheels. Seeding depth is afunction of applied downforce and soil strength formachines without positive depth controls. Seeding depthwith these machines varies depending on soil and residueconditions.Optional FunctionsF er t i l i ze r an d s o m e ch em i ca l i n co rp o ra t i o nattachments may require additional ballast for soilpenetration, and therefore planting machine framesmust be stronger. Such attachments may reduceclearance between plant ing machine components andthus reduce machine tolerance to heavy residues.Trailing incorporators, which mix a band of materialwith the surface soil, may be limited to rolling-types toavoid the raking of residues. Surface residues mayreduce the incorporation effectiveness of these devices.

MACHINE SELECTIONThis guideline can be used for selecting plantingmachines for conservation tillage by following five steps:1 . Determine the crop , res idue, so i l , andmanagement practices which are going to be used withthe machine.2. Follow the descriptions of each of the seven soil-

engaging planting machine functions, and selectpotentially useable components for each function.3. Develop a set of specifications by deleting fromfurther consideration all of the components which arenot functionally compatible with other selectedcomponents .4. Match the remaining list of potential componentspecifications to available planting machines andoptions.5. Discuss the specifications and machines with aknowledgeable specialist before making purchases.30 8 APPL IE D E NGINE E RING in AGRICUL T URE


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A hypothetical example of the machine selectionprocess would be:Step 1 Crop(s):Residue:

Soil:

Corn, soybeans, cottonHeavy (corn), shredded, notincorporatedMemphis clayey silt loam,crusting, no stones, gravel, orh a rd p anManagement: Crop rotation, no-tillage, stripcropping across slopes, curvedrowsStep 2 Soil and residue cutting com ponents:Smooth coulterNotched coulterCoulter w/depth bandsBubble coulterRippled coulterNarrow fluted coulterNoneRow preparat ion components:NoneSoil opening for seed placement components:Double-disc openerStaggered double-disc openerStub-runner opener

Powered blade or coulter openerFirming uncovered seed components:NoneSeed covering components:Double covering discsNoneSeed furrow closure and firmingcomponents:Double-rib presswheelDual angled presswheelsDepth control components:Rear presswheelSide gauge wheelFront wheels and rear presswheelstandemedDepth bands on front leading coulter

Step 3 Delete incompatible componentcombinat ions.Steps 4,5 Contact manufacturers and advisors toobtain information and assistance inmatching needs to available machines.For this example, there appear to be several workablecomb inations of com pone nts. It is likely tha t at least twoor three no-till planters currently on the market wouldplant successfully under the given conditions. In othersituations, it may be impossible to find a manufacturedmachine matching the list of components remainingafter Step 3. That problem may be resolved by makingmodifications with components from other sources tocomplete the machine.

DISCUSSIONComponents for planters, drills, and air-type seedersmay be selected from lists of available components toform the specifications for a specific conservation-tillageplant ing machine. In many cases, competi t ivecomponents will be identified as alternatives forperforming one of the seven functions. Final machine

selection or m odification needs to be don e with the helpof an experienced advisor.Future systems have been proposed to automate theplanting machine selection process. Computerized" Ex per t S ystem s" will have s tored lists of availablemachine component opt ions. Farm and croppingpractice conditions will be matched to the bestcomp onents for those cond itions. The o utpu t will be a setof machine specifications matched with availablemachines and components .Planting machine selection must consider year-to-yearand field-to-field variations in planting conditions.Although specific information on planter componentadjustmen ts is often unava ilable, careful mach ineselection can reduce the time and experience needed toget the planter adjusted and working properly.

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