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INDUSTRIAL.CROPSAND PRODUCTS

N INTERN TION L JOURN LELSEVIER Industrial Crops and Products 3 (1995) 281-284

Mechanical harvesting and cleaning of Calendula oflcinal i s andD imorphot heca pluv i al i sH.G. Breemhaar *, A. Bouman

Insti tut e f Agri cult ural nd Environmental ngineeri ng I M AG -DLO ), ?O. Box 43, 6700 AA Wageningen, he Netherl andsReceived 7 March 1994; accepted 26 January 1995

AbstractFrom 1990 to 1994 the research institutes of the Agricultural Research Department in the Netherlands (DLO-NL)

investigated potential new arable oilseed crops for industrial application as part of the National Oilseeds Programme(NOP). The Institute of Agricultural and Environmental Engineering (IMAG-DLO) studied the mechanical har-vesting and cleaning of Crambe abyssinica, Di motphot heca pluvi ali s, Calendula ofi cinali s and Euphorbia lagascae.This paper describes the research conducted on the crops Calendula oficinalis and Dimorphotheca pluvialis, usingthree harvesting methods: combining (New Holland 8070), combining after chemical desiccation and combiningafter windrowing. Gross yield, moisture content of harvested seeds and foliage, seed losses and impurities of theseeds were measured. It was found that both crops could best be harvested with a combine harvester after chemicaldesiccation. Timely harvest seemed to be important to avoid weather damage and excessive seed shedding. Calendulaseeds were cleaned using an air-screen cleaner, Dimotphotheca seeds using an air-screen cleaner, a brushing machineand an indented cylinder separator.Keyw ords: Oilseed crops; Calendula oficinalis; Dimotphotheca pluvialis; Harvesting; Combining; Combine harvester;Chemical desiccation; Windrowing; Seed cleaning

1 Introduction

The launching of the National Oilseeds Pro-gramme (NOP) in the Netherlands in 1990marked an intensification of the research on po-tential new arable oilseed crops for industrial ap-plications. In this programme, research institutesstudied the entire chain of crop production, fromplant breeding to the utilization and marketingof the oils. This paper presents the results of re-search conducted on methods for mechanical har-vesting and seed cleaning of Calendula oficinalis

and Dimorphothecapluvialis carried out from 1990to 1993 (Breemhaar and Bouman, 1993, 1994).The crops were cultivated with conventional farmequipment normally used for cereals or pulses, toimprove the efficiency of existing farm machineryand to avoid the need for any additional invest-ment in equipment.

Indeterminate growth of Calendula producesan undesirably long maturation period. Each Cal-endula flower produces three different seed forms;vermiculate seeds, cymbiform seeds and rostrateseeds. The oil content of the seed is 14-20 .The major fatty acid of the oil is calendula acid,

*Corresponding author. accounting for 5561 of the oil fraction. The0926 - 6 690/ 9 5/ 0 9 . 5 01995 Elsevier Science B.V. All rights reserved.SSDI 0926-6690(95)00012-7

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282 H.G. Breemhaaq A. Bouman ndustrial Crops and Products 3 1995) 281-284

potential applications of this type of oil are paintand varnish additives (van Soest and de Bie, 1991;Derksen et al., 1993; Mulder, 1994).

Dimorphotheca not only showed indeterminategrowth; seed dehiscence was a great problem too.Harvested Dimorphotheca s a mixture of two seedforms (rods and wings) and impurities. The oilcontent of the seed is 18-25 . The major fattyacid of the oil is dimorphecolic acid, accountingfor 60-65 of the oil fraction. The oil is a suitableadditive for paint, varnish, lubricants, syntheticmaterials and cosmetics (van Soest and de Bie,1991; Derksen et al., 1993; Mulder, 1994).2. Materials and methods

Calendula and Dimorphotheca were grown onplots of about 0.5 ha on clay soils. Seeds weresown by a pneumatic seed driller (Vicon) at a rateof 6 kg/ha for Calendula (mixture of seed types)and 8 kg/ha for Dimorphotheca (rods). The inter-row distance was 25 cm. Emergence was about12 days after sowing. No weedicides were applied,instead, weeds were controlled mechanically withrear-mounted tractor inter-row cultivation imple-ments until the crop closed and thereafter werecontrolled manually. During flowering, both cropswere sprayed against aphids (Pirimor) and botrytis(Ronilan) .

In the first year of research, four harvest-ing methods were screened: combining; combin-ing after chemical desiccation; combining afterwindrowing; and stripping with a stripper header.It soon became clear that stripping was a veryunsuitable technique because of very high seedlosses. Therefore, in 1992 and 1993 more detailedtrials were conducted on the combine harvestertechniques.

Culendulu was windrowed with a self-propelledwindrower. The windrows lay on 20 cm highstubble, which allowed more air movement andhence promoted drying. The combine harvesterwas equipped with a normal cutter-bar table. Itwas not absolutely necessary to mount a drapertype pick-up on the combine. Calendula and Di -morphotheca were desiccated by spraying with Re-glone (diquat) at 3 l/ha. These pre-harvest treat-ments were carried out when the foliage of both

crops was still fully green and when about 50 ofCalendula seeds and 25 of Dimorphotheca seedswere mature. At that time Calendula showed noseed dehiscence but Dimorphotheca had alreadystarted shedding seed.After a field had been harvested the gross yieldwas determined. Samples were taken to determinethe moisture content of the seeds and the percent-age of impurities. Foliage samples were also taken,to determine the moisture content.

To ascertain seed losses caused by combining(mechanical seed losses), a cloth was placed un-derneath the combine harvester, to collect theseeds from the sieves and straw walkers.

The yield and loss samples were dried to 12moisture. Calendulu seeds were cleaned on anair-screen cleaner and Dimorphotheca seeds werecleaned using an air-screen cleaner, an indentedcylinder separator and a brushing machine.3. Results3 1 Calendula Table 1)

Harvesting Culendula with a combine harvesterwas not very satisfactory. The 81 moisture con-tent of the foliage was too high for direct heading,consequently the grain conveyors of the machinebecame clogged. The moisture content and per-centage of impurities of the harvested seeds werehigh (respectively 67 and 38 ). The results ob-tained after windrowing were much better, butwindrowing caused heavy seed losses.

The best results were obtained when the cropwas desiccated and harvested with a combine har-vester after 7-10 days. The seed dehiscence waslow and the foliage was dry enough to harvestwith a combine harvester. If the interval be-tween the pre-harvest treatments and harvest wastoo long, for example because of rainy weather,the windrowed and desiccated plants started toregrow, and subsequently moisture content in-creased. The seeds were cleaned several timeson an air-screen cleaner. The number of repeti-tions depended on the purity required. The totalcontent of impurities of the harvested product af-ter desiccation was about 37 . Total removal ofimpurities was not necessary because the oil of

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lhble 1H.G. Breemhaar; A . Bouman / ndustt ial Crops and Products 3 1995) 281-284 283

Results of mechanical harvesting and cleaning of Calendula officinalis in 1993Combining Combining after Combining after

windrowing desiccationGross weight (kg/ha) 8148 2281 2617Moisture content ( ) seeds a 67 24 28foliage 81 48 47Impurities b ( ) 38 40 37Net w eight b (kg/ha) 2273 1204 1385Mech. seed losses b (kg/ha) 175 7 10a Uncleaned.b At 12 moisture content.

Calendula is obtained by extraction of the seeds(Mulder et al., 1993). Impurities consisted of pul-verised plant material, sand and dust particles.After air-screening twice, 3 1 of the original sam-ple had been removed as impurities, the remainingfraction of impurities was about 6 .3.2. Di morphot heca Table 2)

Combining and combining after windrowing didnot seem to be successful methods for Dimor-photheca either. The moisture content of the fo-liage was too high for direct heading. The windrowwas too compact and therefore did not dry quicklyenough. No further attention was given to thesemethods, because combining was almost impossi-ble.

The only remaining harvesting method suitablefor Dimorphotheca was combining after chemicaldesiccation. The period between desiccation and

Table 2Results of mechanical harvesting and cleaning of Dimor-photheca pluvial is in 1993

Combining Combining afterdesiccationGross weight (kg/ha) 3037 2111Moisture content ( )seeds a 54 12foliage 79 15Impurities b ( ) 76 79Net w eight b (kg/ha) 423 443Mech. seed losses b (kg/ha) 27 11a Uncleaned.b At 12 moisture content.

combining was about 4-7 days. Seed dehiscenceoccurred at an earlier stage and more severely inDimorphotheca than in Calendula, especially whenthe crop was desiccated. Seeds were cleaned usingan air-screen cleaner, a brushing machine and anindented cylinder separator. The total percentageof impurities in the harvested seeds after desicca-tion was about 80 . About 78 of the originalsample was removed as impurities; the fraction ofimpurities remaining in the rod fraction was about2 of the original sample. After separation onthe indented cylinder the wing fraction was com-pletely cleaned. Total removal of impurities wasnot necessary because the oil of Dimorphothecais obtained by extraction of the seeds (Mulder etal., 1993). Most of the impurities consisted of pul-verised plant material, flower heads, sand and dustparticles.4. Conclusions

For satisfactory harvesting results it seemedto be very important that crops were kept freefrom weeds and that harvest was started timely.The best harvesting results were obtained whenCalendula and Dimorphotheca were chemicallydesiccated, at an early stage of maturing, be-fore combining. Seed dehiscence, especially inDimorphotheca, was severe when harvest had tobe delayed (e.g. because of bad weather). Com-bining after windrowing was a good alternative forharvesting Calendula, but the yield was lower com-pared to combining after desiccation, because oflarger mechanical seed losses. Regrowth of mownor desiccated Calendula plants caused moisture

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284 H .G. Breemhaar ; . Bouman ndustr i alCrops nd Products 1995) 281-284content to increase. The seeds of both crops couldbe cleaned satisfactorily with simple techniques.ReferencesBreemhaar, H.G. and Bouman, A., 1993. Onderzoek naar

mechanische oogst en schoning van nieuwe oliehoudendegewassen van 1990 t/m 1992. Institute of Agricultural andEnvironmental Engineering (IMAG-DLO), Wageningen,Nota P93-13,50 pp.

Breemhaar, H.G. and Bouman, A., 1994. Mechanische oogsten schoning van nieuwe oliehoudende gewassen. Instituteof Agricultural and Environmental Engineering (IMAG-DLO), Wageningen, Rapport 94-8,37 pp.

Derksen, J.T.P., Muuse, B.G., Cuperus, PP. and van Gelder,

W.M.J. 1993. New seed oils for oleochemical industry:evaluation and enzyme-bioreactor mediated processing.Ind. Crops Prod., 1: 133-139.

Mulder, E, 1994. Conclusie en aanbevelingen NationaalOlieprogramma (1990-1994). Centre for Plant Breedingand Reproduction Research (CPRO-DLO), Wageningen,17 PP.Mulder, E, de Bie, HP and Limburg, H., 1993. Verslag Na-tionaal Olieprogramma 1992. Centre for Plant Breedingand Reproduction Research (CPRO-DLO), Wageningen,pp. 65-76.

van Soest, L.J.M. and de Bie, HP., 1991. Potentitle gewassenvoor de industrie. Gids voor de demonstratietuin 1991.Centre for Plant Breeding and Reproduction Research(CPRO-DLO), Wageningen, pp. 18-20.