BABY CARROT PRODUCTION SYSTEM ON ORGANIC SOILS

J. A. Millette1, R. Bernier1, and G. B. Hergert2

1Research Station, Research Branch, Agriculture Canada, Saint-Jean, Quebec J3B 6Z8, and Engineering andStatisticalResearch Institute, Agriculture Canada, Research Branch, Ottawa, Ontario KIA 0C6. Contribution nos.

659' and 6812

Received 18 July 1980

Millette, J. A., R. Bernier, and G. B. Hergert.Agric. Eng. 22: 175-178.

1980. Baby carrot production system on organic soils. Can.

Two experiments were used to devise a baby carrot production system on organic soils. In the first experiment, twocarrot varieties Minicor and Little Finger, and four seeding methods — wide and narrow beds, broadcast and rowseeding — were used. All the methods resulted in the same plant density at harvest even though two of the methods had25% less seed sown. Both total and marketable yields followed the plant density results. After field testing of the specialcarrot harvester losses averaged 9.1 t/ha. With a harvester speed of 0.265 m/sec and a 1,8-m wheel track, 0.171 ha areharvested every hour. In the second experiment the low seed density of 555 seeds/m2 significantly reduced yields. Thehighest seed density offered no yield gain. The optimum seed density seemed to be 1110 seeds/m2. The best cultivarswere AMCA, Minicor and Amsterdam Bak.

INTRODUCTION

There is an increasing demand for theproduction of carrot varieties (Daucuscarota) known as baby carrots whose sizeand shape are within defined limits. Rootdiameter and root length cannot exceed19 mm and 115 mm, respectively. Thesebaby carrots are now available on themarket in cello packs from Canadiansources or mostly imported as a canned orfrozen product.

Profitable yields of roots no larger than19 mm in diameter and 115 mm in lengthare difficult to obtain using row-orientedequipment. With this in mind, a projectwas initiated to investigate carrot varieties, plant densities, seeding andharvesting equipment that could be usedon organic soil. Baby carrot production inorganic soil is not yet wide-spreadbecause of these machinery problems.The equipment that is bought off-the-shelf must be modified or new conceptsmust be used to adapt available machinery to production systems on organic soil.

The investigation started in 1973,when Hergert (1973) suggested thatdifferent types of harvesters, such as theTawco radish combine or a digger chaintype of harvester with an appropriatetopping technique, should be investigated. He also recommended that studiesshould be done on plant densities foroptimum yields.

A year later, seeding trials were startedusing an experimental forage seeder witha double-row shoe spaced 5 cm apart withfront and back packing wheels (Hergertand Bernier 1974). The marketable yieldfrom this method and using higherdensities was acceptable, so furtherdevelopment of seeding techniques weresuggested to increase yield but still

maintain an acceptable percentage ofmarketable roots.

Later, Hergert (1975) concluded afterfurther investigation that a bed-typeharvester is no doubt the answer for

harvesting baby carrots, but additionalinformation is required. Under DREAM(Development, Research, Evaluation ofAgricultural Mechanization, a contractprogram of Research Branch, AgricultureCanada) contract 5-0035, a SAM (SpecialAgraische Machines, Broerdijkib,Oostwoud (N.-H.) Box 2, Holland) rootcrop harvester and a Martin (Etablisse-ments Martin, 45 Batilly-en-Gatinais,4350 Beane la Rolande, France) defoliator were imported from Europe,evaluated and modified (Groleau, deGuise and Associates 1976). For effectiveaction, the defoliator must operate oncarrots grown on a level surface so thatthe foliage beaters are able to remove topsevenly across the bed width. Likewise,with the harvester, the growth surfacemust be levelled to minimize the amount

of soil entering the harvester, and thewidth of seeding must be less than 1 m tomatch the harvester. It was also observed

that a more dense bed would be an

advantage to the bed-harvester to optimize the carrot-soil ratio, thus increasing the carrot tonnage output anddecreasing the amount of soil eliminationrequired.

MATERIALS AND METHODS

Experiment 1: Evaluation of theSeeding and Harvesting Equipment

In this experiment, baby carrot cultivars Little Finger and Minicor were usedbecause they had been evaluated and hadbeen shown to be suitable for organicsoils (Bernier 1976). The carrots were

CANADIAN AGRICULTURAL ENGINEERING, VOL. 22, NO. 2, DECEMBER 1980

sown on a well-decomposed organic soilat Agriculture Canada ExperimentalFarm, Ste-Clothilde, Quebec, on 22June, and harvested 26 Aug. 1976.

Two different bed-formers and two

different seeders were used in this

experiment composed of four treatments,replicated three times. Bed-former no. 1was designed and built by Engineeringand Statistical Research Institute (ESRI),Agriculture Canada, Ottawa, is 1 m wide(Fig. la) and is described elsewhere(Hergert 1976). Bed former no. 2 is anadaption of the Marvin Landplane set upto form two mini beds or dual beds in a

1-m width (Fig. lb). (Brand name doesnot imply advertisement or preference,but only describes the equipment used.)

Both seeders were built by ESRI for theproject. One is described by Hergert(1976) and consists of a drum having 29V-shaped rims to produce a ribbedseedbed, where seed is placed and thencovered to a shallow depth by flatteningthe grooves. The second seeder used eightPlanet Jr. furrow openers and coverers,each followed by a press wheel. Bothseeders are capable of producing a flatseedbed on prepared soil and both wereequipped with batch-type seed dispenserscommonly used for research purposes(Hergert 1976).

The harvesting equipment was asrecommended by Hergert (1975) andmentioned in the introduction, and alloperations pertaining to equipment werecarried out in a method simulatinggrowers' conditions to obtain resultssimilar to those expected in commercialfield situations.

The seeding rate as suggested by B. D.Frappel, Department of Agriculture,P.O. Box 303, Devonport, Tasmania,

175

700 cm

Ty-7T7-rr7-7-7-r7

U- 700 cm —M

\ Z7^- T7-7-T

V18 m

Figure la. Bed shape produced by the ESRI bed-former No. I.

k-700 cm m

/;;////

>|35cmU

1-8 m

Figure lb. Bed shape produced by the modified Marvin Landplane bed-former No. 2.

7310(pers. commun.) was 1000 seeds/m2for the treatment using the ESRIbed-former and 750 seeds/m2 for the dualbed-former.

Treatments

1. ESRI bed-former, 1 m wide on 1.8-m

centers, seeded with the drum seeder,29 rows.

2. ESRI bed-former, 1 m wide on 1.8-mcenters, seeded with the eight-rowbed-seeder.

3. Dual bed-former, two beds 0.35 mwide within 1-m width, 1.8-m centers,

seeded with the drum seeder, 11 rows

per bed.4. Dual bed-former, 1 m wide on 1.8-m

centers, seeded with eight-row bedseeder but three rows per bed (tworows blocked).

All plots were 30 m long on 1.8-mcenter.

Before seeding, 725 kg/ha of 5-15-30fertilizer was applied. Weed control wasdone by pre- and post-emergence application of linuron at 1 kg a.i./ha.

Baby carrots were harvested 65 daysafter seeding. Plant populations andyields were obtained by hand-harvesting,counting, weighing and screening all ofthe carrots in 1-m lengths for each plot.For the mechanical harvest, the carrottops were removed with the Martindefoliator and the carrots were harvested

with the SAM harvester over a length of20 m.

Experiment 2: Evaluation of PlantDensities

In the second experiment, four babycarrot cultivars: AMCA, Little Finger,

Minicor, and Amsterdam Bak; and fourdensities: 555, 833, 1110 and 1388seeds/m2 were used to determine the bestcultivar and optimum plant population forbaby carrot production in organic soil. Allplots were 10 m long and seeded on beds1 m wide, formed by the ESRI bed-former and seeded with the ESRI drum

seeder. Each treatment was replicatedfour times. The carrots were seeded at the

same location as experiment 1 but twocrops were seeded, 25 May and 21 June,and harvested 65 days later in both cases.Fertilizer and weed control were the same

as for experiment 1.

RESULTS AND DISCUSSION

Experiment 1No significant difference in carrot

population per square metre could befound for all seed methods and the two

cultivars, even though treatments 3 and 4using the dual bed-former had 25% lessseed sown. Similar results were obtained

for total and marketable yields whichaveraged 31.2 and 18.4 t/ha, respectively. It can be concluded from theseresults that a 1-m, solid-seeded bed doesnot produce more than smaller bands eventhough there is more vacant space. Yieldreduction in solid beds could be attributed

to such effects as poor germination,crowding, too much competition, insufficient light, desiccation of foliage andinsufficient air circulation.

Machine-harvested yields were considerably less than the hand-harvestedyields, but still there were no significantdifferences among treatments. However,there was a varietal difference, with

Minicor giving a significantly greatertotal yield of 24.4 t/ha compared to 19.8t/ha for Little Finger. As for marketableyields, there was no significant difference, with both cultivars averaging 12.2t/ha. Since the cultivar Minicor produceslarger carrots, the marketable-sized carrots became the same for the two

varieties.

Field losses of total carrots using theSAM harvester were calculated bysubtracting from the total yield harvestedby hand the total yield from the harvester.There were no varietal differences or

treatment differences. The losses aver

aged 9.1 t/ha for both varieties and thefour treatments. On a percentage basis,the losses for the cultivar Little Fingerwere higher due to the smaller carrotswhich were lost through the finger rollersof the harvester.

Carrot breakage and damage werecaused, in part, by the Martin defoliator.For an effective defoliation, the carrottops must be on level ground. The bedsinitially had level tops but as the seasonprogressed, edge erosion caused the bedsto drop away at the sides. The defoliatorleft a considerable amount of tops oncarrots on the outside rows. Lowering theflails to correct this caused considerable

carrot damage and breakage at the centreof the bed. The beds did not offer the

advantage that was anticipated.In general, the SAM harvester per

formed quite well. An initial problem oflack of soil elimination capacity wassolved by rebuilding the lifting belt. Thesoil elimination system works best in drysoil. Wet organic soil tended to formlumps which would be carried through tothe collection box. In this case, however,careful operation of the harvester withconstant depth control and uniform slowground speed reduced the amount oflumps.

The field operating rate of theequipment was calculated. The Martindefoliator operated at an average speed of0.6 m/sec or 0.385 ha/h when calculatedfor beds 1.8 m wide. The harvester

operated at an average speed of 0.265m/sec fora field rate of 0.171 ha/h. Withan average total yield of 19.8 tonnes/ha(cv. Little Finger), the rate of through-putwas calculated at 3.4 tonnes/h.

Experiment 2In this experiment, two crops were

sown. Both total and marketable yieldswere about the same except for LittleFinger which produced more in thesecond crop.

The first seeding, although done under

176 CANADIAN AGRICULTURAL ENGINEERING, VOL. 22, NO. 2, DECEMBER 1980

TABLE] TOTAL AND MARKETABLE YIELDS (t/ha) OF THE FOUR SEED DENSITIESFOR THE TWO CROPS

Yields

1st crop 2nd crop

Seed densities Total Marketable Total Marketable

555

833

1110

1388

24.3 a

26.6 aft

29.5 ft

28.4 ft

11.6a

15.0 ft

16.9 ft

16.7 ft

24.3 a

26.7 ft

28.6 ft

27.0 ft

13.2c

16.1 be

19.2a

18.4 aft

a-c Within each column, yields followed by different letters are significantly different at the 5% level.

dry and windy conditions, resulted insignificant differences within cultivarsand seed densities. The 1110- and

1388-seed densities produced significantly greater total yields than the555-seed density (Table I). The marketable yield was only significantly less in the555-seed density. In the second crop,total yields were significantly less in thelowest seed density (Table I). Furthermore, the 1110- and 1388-seed densitiesresulted in significantly greater marketable yields than the lowest seed density(Table I).

In the first crop, both total andmarketable yields were significantly lessfor Little Finger (Table II). However, inthe second crop, marketable yielddifferences among cultivars was notsignificant (Table II).

Carrot population for all carrot cultivars at harvest showed that a seed

density increase of 833 to 1110 seeds/m2resulted in a significantly greater numberof carrots. However, the greater seeddensity of 1388 seeds/m2 did notsignificantly increase the population atharvest time.

For both crops, it was noticed that thehighest seed density offered no yieldgain. This is contrary to early informationwhere the highest yields were obtainedfrom greater seed densities in mineral soil(Bussel 1973). An optimum seed densityfor baby carrots in organic soils would beclose to 1000 seeds/m2 similar to thatused in experiment 1.

CONCLUSIONS

Experiment 1Baby carrot population and total and

marketable yields were unaffected by thedifferent treatments. There was an

indication that the dual bed system wasmore efficient since less seed was used,but yields were equal to the solid-bedplanting.

Experiment 2For plant densities, the lowest density

used significantly reduced yields. A seeddensity above 1110 seeds/m2 did notprovide any increase in population ofmarketable yields.

Land PreparationSeeding on beds did not increase yields

and still hindered operation of the Martindefoliator although some improvementover use on unleveled land was noted

toward the center of the beds. It is

recommended that a levelling device beused prior to seeding.

Carrot Cultivars

Experiment 1did not show any varietaldifferences in operation of field equipment. Heavier field losses of Little

Finger, on a percentage basis, using theSAM harvester were noted, but this canbe attributed to smaller size at harvest. In

experiment 2, the cultivar Little Fingerrated poorly in both tests and the bestcultivars were AMCA, Minicor andAmsterdam Bak.

TABLE n. TOTAL AND MARKETABLE YIELDS (t/ha) OF THE FOUR BABY CARROTVARIETIES FOR THE TWO CROPS

Yields

I st crop 2nd crop

Cultivars Total Marketable Total Marketable

AMCA

Little FingerMinicor

Amsterdam Bak

27.5 ft

20.9 c

30.8 a

29.6 aft

17.6a

10.6 ft

15.7a

16.2 a

28.2 a

24.9 ft

27.3 a

27.0 a

17.1 a

16.3 a

17.4a

16.1 a

Within eachcolumn, yields followed by different letters are significantly different at the 5% level.

CANADIAN AGRICULTURAL ENGINEERING, VOL. 22, NO. 2, DECEMBER 1980

Seeding TechniquesAll plots in both experiments were

seeded on 1.8-m centers to suit the wheel

tracks ofexisting tractors. Commercially,the beds could be planted on 1.5-mcenters, thus increasing the planted areaand yield by 20%. Operations would notbe affected.

The seeding method experiment (exp.1) revealed that there was some advantageto leaving a fallow band at the center ofeach 1-m-wide bed. This reduced the

amount of seed required by 25%, yetmaintained yields equal to yields of bedsthat were solid planted. From theseresults, we can predict that the eight-rowbed-seeder would possibly produce amore efficient seed-yield ratio than theeight-row unit. There is reason to believethat wider-spaced rows or bands performbetter than solid-planted beds.

Bed forming was used to improve theoperation of the defoliator but because ofedge erosion, it gave problems withuniform topping removal. A raised bed isnot required for operation of theharvester. The formed beds tended to

round at the edges and in some cases, seedfrom the bed was washed into the wheel

tracks. It is thus recommended that anymethod producing a flat level seed bed,such as levelling boards or rollers, beused.

Soil and Crop ManagementWeed and insect control was done by

established methods for conventional

carrots with good results.The major problem after seeding was to

ensure uniform germination. As babycarrots can be seeded anytime from Aprilto July, moisture conditions can varygreatly. Irrigation should be available toinsure optimum moisture conditionsthrough germination and emergenceperiods.

Harvesting OperationsBaby carrots must be grown on level

beds at a width to match the narrowest

machine in the system. In this case, theregulating factor was the 1-mwidth of theharvester. Both the defoliator and the

harvester must have a level bed on whichto operate the defoliator to maintain aneven topping height and the harvester tomaintain a minimum digging depth, tokeep the soil flow at a minimum.

Carrots lost through the harvester canbe controlled by selection of varieties andby carefully controlling such factors asspeed, depth of cut and harvesting date.The operation of the harvester would beimproved greatly with the use of a

177

hydrostatic drive tractor as the power REFERENCES HERGERT, G. B. 1973. Harvesting babysource. BUSSEL, W. T. 1973. Effects of plant carrots. Report 7302-5, Eng. Res. Serv.,

Power requirements of the harvester density and timeof harveston yield of small Ottawa, Ont. Kl A 0C6.and defoliator were low, a 35 hp tractor finger carrots. N.Z. J. Exp. Agric. 1 (1): HERGERT, G. B. 1975. Baby carrotbeing sufficient in both cases. Some 69"72- production equipment. Report 7511-517,tractor brands are unuseable due to lack of BERNIER,R. 1976. Project report (internal), Eng. Res. Serv., Ottawa, Ont. K1A0C6.slow sneed pears Agric' Can- Res' Sta" Saint-Jean> Que- HERGERT, G. B. 1976. Bed planting systemsiow speea gears. GROLEAU, De. Guise and Associates. 1976. for baby carrots. Report 7511-599, Eng.

Developpement et evaluation de machines Res. Serv., Ottawa, Ont. K1A 0C6.agricoles: recolteuse S.A.M. pour mini- HERGERT, G. B. and R. BERNIER. 1974.carotte et effeuilleuse Martin DREAM Mechanization of baby carrot production.contract 5-0035. Groleau, de Guise et Report 7302-7, Eng. Res. Serv., Ottawa,Assoc, Longueuil, Que. Ont. K1A 0C6.

178 CANADIAN AGRICULTURAL ENGINEERING, VOL. 22, NO. 2. DECEMBER 1980