INVESTIGATION OF RAPESEEDWINDROWING PROBLEMS IN

SASKATCHEWAN

INTRODUCTION

Although rapeseed has been grown inWestern Canada for many years, therecent increase in acreage has focusedmore attention on the problems. Rape isharvested with the same windrower-combine system as cereals, but the crop'scharacteristics are quite different. Relative to cereals, rapeseed is tall andbranchy, with thick, springy stems.Nevertheless, the windrowers used forharvesting are designed primarily forcereal crops.

The Canada Committee on Agricultural Engineering (CCAE) has receivedreports by researchers and extensionpeople of windrowing problems duringrapeseed harvesting. Although the CCAEadvised machinery manufacturers of theseproblems, the reports have been toogeneral to make specific recommendations, or to allow industry to considermaking appropriate machinery modifications.

To better define rapeseed harvestingproblems, the CCAE requested a moredetailed study. This paper reports thefindings of this study.

PROCEDURE

The information contained in this

report was gathered through observationsof rapeseed windrowing operations, anddiscussions with farmers regarding theirexperiences in cutting the crop. At thesame time, other observations on soiltype, topography, cultivars grown, andmodifications made to the windrower

allowed an insight into the effects ofother variables, and pointed up problemareas with particular machines.

Contribution No. 381, Engineering ResearchService, Research Branch, Agriculture Canada,Ottawa, K1A 0C6.

RECEIVED FOR PUBLICATION FEBRUARY

20, 1974

34

M. Feldman

Member CSAE

Engineering Research ServiceAgriculture Canada

Ottawa, Ontario

Figure 1. Bunchy rapeseed windrows, often caused by the windrower design, are a problem duringcombining.

Saskatchewan farmers were visited in

August 1972, in the Waldheim and Delisleareas, as well as in the vicinity of Melfort.In each area, cutting operations wereunderway, so that observations could bemade in the field. Observations and com

ments were recorded, and various fieldproblems and windrower characteristicswere photographed.

OBSERVATIONS

Although it was not possible to see allmakes of machines in a wide range ofconditions, a representative number ofwindrowers were observed. A total of 22

machines were seen, representing sevenmanufacturers. Five were pull-typemachines, and the remainder self-propelled. From these observations, andfrom the different experiences related bya number of farmers, conclusions couldbe drawn regarding general characteristicsinherent in rape windrowing operations.

Varieties and Conditions

In addition to differences between

machines, great differences in crop conditions exist as well. Crop differences aredue to different cultivars, managementpractices, and weather conditions. Cultivar influences growth characteristics;management practices, such as seedingdepth and use of pesticides, affect cropgrowth, uniformity of maturity, andpresence of weeds; weather conditionsaffect crop characteristics such as lodging.

Dimensions of some rapeseed windrows are shown in Table I.

During this study, favorable weatherconditions and the cultivars grown considerably reduced the severity of problems compared to the previous year,according to farmers' reports. In particular, the cultivar Oro had caused manyproblems due to its excessive vegetativegrowth. Span and Zephyr were the onlytwo cultivars observed in this study.Span, a turnip rape, is shorter whereas

CANADIAN AGRICULTURAL ENGINEERING, VOL. 17 NO. 1, JUNE 197S

TABLE DIMENSIONS OF SOME RAPESEED WINDROWS MADE BY 16-WINDROWERS

AND 18-FT

Crop Windrow

Cultivar

Height(ft)

Stubble

(inches)Width

(ft)Height

(ft)

SpanZephyrZephyrZephyrZephyr

3

4-5

3Vi-4

4-5

4

8

16-18

14-15

12-17

5

4

4Vi

5

6

2

3

3

3

3

TABLE II VERTICAL CLEARANCE, TABLE OPENING, AND TABLE DEPTH FOR SOMEWINDROWERS

Vertical Table

clearance t opening

(inches) (inches) Croplength*

Machine § a b c d e (inches) Comments

SP-18' 34V2 24 Plugging at table opening. Mounted roller added to problem.

SP-18' 27 47 3244 Crop flow on table hindered. Tabledepth too narrow.

SP-18' 38 47 28-34 Flow satisfactory. Crop short enough.Table opening adequate.

SP-18' 35 38 Farmer reported table opening too smallfor shoulder-high crop.

SP-18' 38 46 Farmer reported table opening as a problem.

SP-18' 32 38 47 32-44 Some crop flow problem. Cutting lessthan full width helped.

PT-16' 35 32 44 Farmer did not report any flow problem.SP-18' 31 33V2 Similar Much plugging. Not enough flow space.SP-16' Crop catching under frame.

or 18' 30-33 23 39 Similar Projecting cylinder caused bunching. Deflector rods aided flow.

SP-16' 34 34 31-36 Plugging at table, unless cut excessively high.

SP-16' 33 38 33 3446 Plugging, but less than expected due tosmooth flow path.

* Crop length calculated by taking the differencet Location of measurements are shown in Figure

projecting member.§ SP, self-propelled; PT, pull-type.

between crop height and stubble length.2. Dimension b is under lowest of any

Zephyr, an Argentine type, grows tallerand yields slightly more.

Although some farmers reported problems due to weeds, particularly wildbuckwheat, crops observed were generallyquite weed-free. In many fields, unevenmaturity was a problem. This meant thatthere might be random areas in the fieldwhere the crop was green, resulting indifferences of density and flow characteristics.

Windrowers

Windrowers generally encounteredproblems in dividing the crop, and in

allowing the cut crop to flow unimpededthrough the machine to produce a uniform windrow. Problems of this sort arenot peculiar to any specific machine, butdepend on certain physical factors. Problems observed with any one machine canbe considered to exist with others byextrapolation of the physical conditions.Certain other problems were morespecific to the particular machine, andmany of these resulted from insufficientcarrying or drive capacity to handle theextra weight of the rape crop comparedto cereal crops. Some swather dimensions, and a detailed account of theproblems existing for different machinesobserved are given in Tables II, HI, andIV.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 17 NO. 1, JUNE 1975

DISCUSSION

Crop Flow

The problem of crop flow through themachine resulted from the tall, bushy,heavy characteristics of the rape plant. Awindrower table deep enough to accommodate the cut height of the crop, as wellas a large swath opening and sufficientunderneath clearance to allow the crop topass unobstructed, were essential. Twoproblems result when -obstruction occurs.The flow may be hindered sufficiently tocause plugging and interruption of theoperation. Also, bunching or unevennessin the windrow causes plugging and poorthreshing during combining (Figure 1).

A table depth of 42 inches (107 cm)or less was found on many windrowers.This dimension was borderline to accom

modate stems cut from tall crops. Somecultivars may grow to 5 ft (1.5 m) ormore in height. Operators will cut as highas possible, but this is limited by thelocation of the lowest pod on the stems.Also, a taller stubble will reduce theclearance for the windrow underneath themain frame on a self-propelled windrower.

During observations of flow problemson some machines, measurements weremade of table openings and underneathclearances, as shown in Table II. Generally, greater clearance resulted in fewerplugging problems. However, the machinewith the largest clearance did not necessarily produce the most uniform windrowwith the least amount of plugging. Inconjunction with adequate clearance,absence of obstructions that would inhib

it flow was also essential. Use of windrowdeflector rods in the table opening, andtable openings wider than the spacebetween the inside canvas rollers aidedcrop flow. Table openings narrower thanthe canvas roller spacing and projectionsunder the body such as drive shafts,pulleys, table lift cylinder, or cotter pinshindered the flow. Design of a smoothflow path is important, since economics,physical size, and suitability for othercrops will compromise the physical spacethat can be provided.

Various means were used by farmersto minimize plugging problems. Manyconstructed makeshift shields aroundrotating components and projecting members in the area of the windrow. Acommon practise was to reduce width ofcut to produce a more manageable windrow size when cutting rapeseed, sincewindrower table widths were sizedprimarily for cereal crop requirements.Forward speed did not appear to have asignificant effect on plugging, although

35

TABLE III LIST OF WINDROWING PROBLEMS*

Code Name

Dv PI Divider plugs

Dv Ls Divider loss

Wr Wrapping

Sw Op Swath opening

CI Clearance

Sp Windrow spacing

Cy CylinderTa Table depthDvMd Divider modified

Cv Canvas

CvDr Canvas drive

Rd Radiator

ReDr Reel drive

Rl Roller

Description

In lodged, tangled, or weedy crops, plants drape on the divider,eventually causing plugging.In any crop, some plants are bent down by the divider, and aretoo low to be cut on the next round.

Plants wrap on exposed, rotating components, particularly thosenext to the windrow flow path. Severe wrapping will cause plugging.Size and design of swath opening in the header restricts flow ofthe windrow, causing bunchy windrows and plugging.Lack of clearance under machine, or projecting machine member, restricts flow of the windrow, causing bunchy windrows andplugging.Not enough clearance between windrow and standing crop forlarge tractor, with pull-type, center delivery swather (minimumimportance).Plants drape on reel lift cylinders.Table depth (i.e. canvas width) insufficient for tall crops.Divider successfully modified to reduce problem of plantsdraping on braces.Heavy, green patches in crop overload canvas, causing it to slip.Belt driving canvas roller slips under heavy load.Radiator screen for cooling air intake plugs with trash.Belt driving reel slips under heavy load.Plants wrap on roller under canvas. Problem solved when farmeradded deflector.

Machines experiencing these problems are identified in Table IV, using the code for correlation.

^ ^i=-^

~x

I i i i _ri_

^yS'Sl'^'' !•*-a-^J ":'v"

Front view

Table Opening

If/t*;si XM^

Figure 2. Location of critical windrower dimensions.

different farmers had different policies onrate of travel.

Dividing the Crop

Intertwined branches made the cropdifficult to divide. This problem wascompounded if any lodging of the cropoccurred. Although farmers have experimented with a wide variety of dividershapes, none were found to be completely satisfactory. In very tangled crops,a pointed divider may uproot some of theplants.

Most dividers were able to work satisfactorily by pushing the crop down andriding over it. In this case, some lossoccurred because the stems were bentdown, and were left uncut after thesucceeding pass with the windrower. Withself-propelled windrowers, cutting backand forth so that the bent stems alwaysleaned into the machine tended tominimize this loss. This was not possible

with pull-type machines, although onefarmer suggested that being able to adjustthe right-hand end of the table to cuthigher than the left-hand end might provide a solution.

The divider and table end needed to beof a smooth design so that the cropwould not catch on cross braces or reellift cylinders, and reel ends needed to berelatively close to the divider to keepstems clear. Closing in the reel batt ends,or adding flaps to the reel end may be ofsome assistance.

For very tangled or lodged conditions,where dividing the crop was a seriousproblem, a special attachment was usedby some farmers. Essentially, the attachment replaced the divider rod with arotating device similar to a circular saw,and was powered from a swather drive.The attachment was not observed inoperation since conditions in 1972 didnot require its use. However, three farm-

ers who owned such attachments reported that the device made operation inbadly lodged conditions feasible the previous year. On the other hand, safetywould be a major concern with this typeof design.

Windrow Size

Since windrow width measured 4 - 6 ft

(1.2-1.8 m; Table I) clearance betweenthe windrow and the swather tail wheel

was of some concern. Inadequate clearance may not cause plugging, exceptwhere projections from the axle catch onthe crop, but shattering losses wouldoccur if the wheel travelled on any pods.Also, for machines having two tail wheels,one wheel will travel over the swath on

any sharp corner. Since physical locationof the tail wheels is a compromise situation, and since no measurement of fieldloss due to the tail wheel was obtained,this problem must be considered of minorimportance at this time.

Other problemsdescribed in Table III.

Windrow Rollers

encountered are

Depending on conditions, many farmers were using windrow rollers. Most ofthese were units towed behind the wind

rower, but some were designed to bemounted on the windrower either at therear or immediately behind the table. Theroller is intended to compress the windrow somewhat and force it slightly downinto the stubble, in order to minimizelosses by wind. Roller height adjustment,and the opinion of their usefulness, variedconsiderably with cultivar and area.

Sufficient information regarding benefits of rolling the windrow, as well asdisadvantages such as shelling losses andcombining problems caused by forcingthe windrow into the stubble, would berequired to analyze the value of the rollerin the rapeseed harvesting system.Although farmers seem to be experiencedin setting roller height, more informationmay be needed to derive optimum adjustments.

Rollers towed behind the windrowerdid little to interfere with the machine orthe cutting operation. However, mountedrollers, particularly those behind thetable, added an additional hindrance tothe flow of the cut crop through thewindrower.

Combining

The combining operation was not included or observed in this study, butsome problems were mentioned by farm-

36CANADIAN AGRICULTURAL ENGINEERING, VOL. 17 NO. 1, JUNE 1975

TABLE IV WINDROWING PROBLEMS NOTED FOR EACH MACHINE

Windrow

Rape Problems §

Height Stubble Dv Dv Sw Dv Cv ReMachine roller1* Cultivar* (ft) (inches) PI Ls Wr Op CI Sp Cy Ta Md Cv Dr Rd Dr Rl

SP-18'or 20' None Span 3 8 pil o"SP-15' None SpanSP-20' PT Zephyr 4 11 0PT-20' F FPT-21' PT Span VhA 12-14 OSP- FSP-18' PT F FPT-16' None Zephyr 3 11-14 F 0PT-15' PT Zephyr 3V44 14 0SP-18' Mtd. Span 3 12 0 F 0SP-18' None Zephyr 4-5 16-18 F 0 0 0 0 0SP-18' F F FSP-18' None Zephyr 3V2-4 14-15 0SP-18' F F F F FSP-18' None Zephyr 4-5 F 0 0 FSP-16' None Zephyr 4 12-17 0 F 0 0PT-16' None F F F FSP-18' None Zephyr 4-5 14-17 0 O 0SP-16'or 18' None Zephyr 4-5 14-17 0 0 0SP-16' Mtd. Zephyr 4-5 14-17 0 0 0

f PT , pull-type attached to rear of windrower; Mtd., mounted on windrower frame.* Where crop isnot recorded, machine <^ Fnr Pvn1nnatir»n r»f nmWpmc onH i^an

was observed in operation.

F, problem reported by farmer;O, problemobserved duringvisit.

ers. Some investigation may be requiredof the pickup losses and operation. Somefarmers claimed that windrows pressedinto the stubble were difficult to liftwithout loss, and that vibration of thestubble ahead of the pickup caused shattering. Also, there are indications thatseparation and cleaning may not beoptimum, due to excessive material falling through the walkers and overloadingthe shoe.

CONCLUSIONS

Based on growth characteristics ofcurrent rapeseed cultivars, and the use of15- to 18-ft machines, the observationsindicate improvements that could bemade in windrower design, or features tolook for in choosing a windrower, asfollows:

1. The swath opening in the tableshould be in the range of 40-50 inches(102-127 cm), and vertical clearance forthe windrow approximately 30-40inches (76-102 cm). However, more important than the precise dimension is theprovision of a smooth, obstacle-free flowpath for the windrow to pass through themachine. Similar to any material flowdesign, the opening in the rear of thetable must be at least as wide as thespacing between the inside canvas rollers,and there should be no machine members

or sharp edges projecting into the flowareas.

2. All rotating machine componentsshould be adequately shielded or locatedso as to prevent contact with the cutcrop.

3. Although perfect dividing of the cropmay be impractical to achieve, thisoperation can be enhanced by eliminatingedges or transverse machine members,and maintaining close reel batt-to-dividerclearance to prevent plugging tendenciesat the divider. For difficult conditions,attachments such as the saw blade may berequired, but only with due considerationfor safety aspects. Proper resolution ofthis problem would require furtherresearch.

4. The load-carrying capacity of thetable canvas, the canvas drive and reeldrive should be adequate to handle thisrelatively heavy crop.

In addition, this study leads to suggestions for other research, and managementof other factors, particularly since plantfactors also are related to the problem:

1. Rapeseed cultivars that have lesstendency to lodge and tangle, and do notproduce excessive vegetative growth, butmaintain good yields, should be chosenand developed.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 17 NO. 1, JUNE 1975

2. The effect of factors such as seedingrate and fertilization on rapeseed growthand lodging tendencies, as well as yield,should be studied along with weed control so that growers can optimize returnsby reducing harvesting costs.

3. Factors that influence the uniformityof maturity within a field should beinvestigated.

4. The effect of crop, height and windrow roller use and adjustment on windand pickup loss should be studied,including the effect on pickup loss ofstubble agitation ahead of the pickup.

5. Investigation of methods of improving efficiency of combines when harvesting rape, particularly regardingproblems due to shoe over-loading, mayalso be needed.

SUMMARY

Observations of current rapeseed wind-rowing operations, along with farmers'reports of previous experience, confirmedthat special problems exist with windrowing of this crop. The problems were dueto the large physical differences betweenthe rape plants and cereal plants, whereasharvesting machines and procedures werethe same.

37

Since many of the problems depend made to improve handling of this crop, so ACKNOWLEDGMENTSon crop characteristics, opportunity long as these changes are not detrimentalexists to obtain some solutions through to operation in other crops. Most serious Appreciation is extended to thecultivar choices and crop management. problems were in dividing the crop and Canada Committee on Agricultural Engi-

achieving a uniformly laid windrow with- neering for encouraging this study, andGeneral recommendations can be out stoppages and without crop bunches for recommending publication of the

made regarding swather design improve- that seriously hinder the combining results. Also, the author is grateful to thements, since many of the problems are of operation. Narrow openings and projec- many farmers who took time to discussa general nature, and not peculiar to a tions that catch on the crop need to be these problems and demonstrate theirspecific manufacturers' machine. avoided. Rotating components should be operation, as well as to others who

shielded or removed from the vicinity of assisted in locating suitable areas andWindrower design changes can be the crop flow. farms for observation.

38 CANADIAN AGRICULTURAL ENGINEERING, VOL. 17 NO. 1, JUNE 1975