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Title: Groundnuts in Rhodesia
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
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Permanent Link: http://ufdc.ufl.edu/UF00074983/00001
 Material Information
Title: Groundnuts in Rhodesia
Physical Description: 1 v. (various pagings) : ill. ; 30 cm.
Language: English
Creator: Collett, W. E
Publisher: Department of Conservation and Extension
Place of Publication: Salisbury
Publication Date: 1973
 Subjects
Subject: Peanuts -- Zimbabwe   ( lcsh )
Peanut industry -- Zimbabwe   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: by W.E. Collett.
General Note: Cover title.
 Record Information
Bibliographic ID: UF00074983
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 002356283
oclc - 39446868
notis - ALW0704

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Full Text





GROUNDNUTS


R in


RHODESIA


by AUW

W E. Collett* I.F.A.S. -
Agronomist (Oilseeds)








Published by the
Department of Conservation and Extension,
P.O. Box 8117, Causeway,
Salisbury, Rhodesia.
1973








Assistance received from staff of the
Department of Research and Specialist Services
and J. E Robertshaw (Publications Officer-CONEX)
is gratefully acknowledged.


* Now with Windmill Rhodesia Ltd., P.O. Box 2208, Salisbury.


UNVifILCH OF F"0`A L:Z:r.nRIS


'7tUr. -*


oft







GROUNDNUTS-


Section 1

Section 2

Section 3

Section 4

Section 5

Section 6

Section 7

Section 8

Section 9

Section 10

Section 11

Section 12

Section 13

Section 14

Section 15

Section 16


CONTENTS

Plant development

Environment

Cultivars

Soils

Planting

Fertilization

Weeds

Irrigation

Diseases

Pests

Harvesting

Post-harvest operations

Marketing

Controlled prices

Bibliography

Appendix
























SECTION 1


PLANT DEVELOPMENT


1.1 History





SECTION 1


PLANT DEVELOPMENT


1.1 History
Various claims have been made regarding the origin of the groundnut, Arachis hypogaea, but the
most widely accepted theory is that it originated in South America. Peru is closely associated with the
history of groundnuts and early records tell of the plant being found along the Maranon River. Indians
and Spaniards ate the nuts as early as 1550.'Excavators of ancient graves discovered utensils filled with
a groundnut cultivar still grown in Peru today.
By the time Columbus discovered America, the groundnut had become an important food crop
from Mexico down through most of South America.
Groundnuts were taken from South .America by Portuguese and Spanish ships to Africa and the
East Indies. Incredible as it may seem, in view of the origin of the crop so nearby, groundnuts were
introduced into North America by slave traders from Africa.
Groundnuts have been grown in Rhodesia for a considerable number of years and have long
been an important constituent of the African peoples' diet. Even today African production accounts
for more than 90 per cent. of the total groundnut intake at depots of the Grain Marketing Board.
Despite several groundnut drives, yields have remained low, and only limited interest has been
shown in the crop by a few successful producers in European areas.
Recent developments in the production of groundnuts under irrigation have shown that exception-
ally high yields can be obtained and accordingly, interest is increasing considerably.











































Groundnuts
September, 1973 1























SECTION 2


ENVIRONMENT
2.1 Climatic and rotational limitations




SECTION 2


ENVIRONMENT

2.1 Climatic and rotational limitations
Figure 1 shows the suitability of different parts of the country to presently recommended cultivars
under conditions of dryland production. In areas suited to both Valencia R1 and Natal Common,
preference should be given to the former, purely from a marketing point of view, since it is easier to
market a large quantity of a single cultivar than small quantities of several.
Figure 1: Areas suitable for recommended groundnut cultivars
under dryland conditions









Salsbury

Gatooma


Que Que Umtali



; oi \*Fort Victoria
SNATABulawayo


VALENCIA R1




Figure I..

In areas up to 1 500 metres above sea level, the cultivars Makulu Red and Apollo will produce
maximum yields under irrigation. Good yields have been achieved in the lowveld with Natal Common;
although its potential is not as high as the long-season cultivars, its shorter season-length could make
it suitable in certain rotations. Similarly, Valencia R1 could be considered for middle-and highveld
conditions.
Groundnuts must be grown in a wide rotation to help prevent the build up of diseases such as
Cercospora leaf spot. Under dryland conditions, they must not be cropped more often than once in four
years on the same area of Land. Under irrigation, where lands are producing two crops a year, it is
thought -that groundnuts can be grown on the same land, every second year, provided the crop is
regularly sprayed with fungicide and the lands are kept free of volunteer plants and crop residues
between each planting.
In the middle-and highveld areas, the harvesting of winter wheat and planting of long-season
groundnut cultivars will clash, and it will only be possible to plant the groundnut crop after a winter
fallow. This means that long-season crops like maize and cotton could be included in a rotation such
as maize or cotton, fallow, groundnuts, wheat.:











Groundnuts
September, 1973 1























SECTION 3

VARIETIES
Revised by
G. L. Hildebrand,
Groundnut Breeder,
Department of Research and Specialist Services








SECTION 3


VARIETIES
3.1 Variety descriptions
Groundnut varieties are divided into two groups according to
the time taken to reach maturity.

TABLE 1
VARIETIES

Maturity group Variety GMB class Growth habit Maturity (days)
Short-season Valencia RI Red-skinned Bunch 100-150
Valencia R2 Red-skinned Bunch 100-150
Natal Common Pale-skinned Bunch 110-160
Jacana Pale-skinned Bunch 110-160
Long-season Makulu Red Red-skinned Spreading bunch 150-200
Apollo Pale-skinned Spreading bunch 150-200
Egret Pale-skinned Spreading bunch 150-200

Valencia RI
A short-season bunch-type variety which matures in 100 to 150
days depending upon temperature. It is suited to dryland production
under medium to high rainfall conditions, particularly on sandy soils
and in cool localities. High yields can be expected from early planted
crops grown under irrigation in the middle- and highveld areas of
Rhodesia. Kernels are red-skinned and non-dormant when mature.

Valencia R2
This variety is very similar to Valencia R1 and is adapted to
conditions outlined for Valencia R1. It is higher yielding than
Valencia R1 and kernel quality is superior. It is also more tolerant
of foliar diseases.

Natal Common
A short-season bunch-type variety which matures in 110 to 160
days depending upon temperature. It is suited to dryland production
under medium to low rainfall conditions, particularly on light sandy
soils. High yields can be expected from early planted crops grown
under irrigation in the middle- and lowveld areas of Rhodesia. Kernels
are pale-skinned and non-dormant when mature.

Jacana
This variety is similar to, and adapted to the conditions outlined
for Natal Common. Jacana is slightly higher yielding than Natal
Common and kernel size and quality are superior.

Makulu Red
A long-season spreading bunch-type variety which matures in
150 to 200 days depending upon temperature. It is particularly suited
to production under irrigation where it can be planted very early
and irrigated fully to maturity. Kernels are red-skinned and dormant
when mature.

Groundnuts,
October. 1976.








Apollo
This variety is very similar in type and performance to Makulu
Red except that the kernels are pale-skinned and are not prone to
purple discoloration.

Egret
This variety is very similar to Apollo. It is higher yielding than
Apollo and has larger kernels, which are pale-skinned and dormant
when mature.

3.2 Seed dressing and inoculant
Plant populations may be drastically reduced if a seed dressing
is not used. Seed dressings must be non-mercurial. Mercurial seed
dressings affect nodulation and are believed to cause a build-up of
crown rot. Thiram and Captan are recommended non-mercurial seed
dressings.
Research has shown that inoculation can increase yield by up
to 160 kg of kernels per hectare. Seed must be inoculated just prior
to planting and kept in the shade until planted. Inoculant is prepared
by Grasslands Research Station and is sold by the Farmers' Co-op.,
Salisbury.
For a more detailed account of varieties released by the Depart-
ment of Research and Specialist Services, see the following:
1. A description of crop varieties released by the Department of
Research and Specialist Services. Supplement to the Rhodesia
Agricultural Journal 72 (4) July-August, 1975.
2. Department of Research and Specialist Services (1974). Release
of Valencia R2 groundnut. Rhodesia Agricultural Journal 71 (5)
September-October, 1974.
3. Hildebrand, G. L. (1975). Crop variety release notice Jacana
groundnut. Rhodesia Agricultural Journal 72 (6) November-
December, 1975.
4. Hildebrand, G. L. (1975). Crop variety release notice Egret
groundnut. Rhodesia Agricultural Journal 72 (6) November-
December 1975.















Groundnuts,
2 October, 1976.
























SECTION 4


SOILS AND LAND PREPARATION
4.1 Soil suitability
4.2 Land preparation




SECTION 4


SOILS AND LAND PREPARATION

4.1 Soil suitability
Best results will be achieved on deep well-drained soils in good condition; production should not
be attempted on soils of low fertility or on soils known to be worked out. Good yields have been
achieved on sandy soils and on red clay loams.
Lifting is a problem in the heavier soils because some pods break away from the plants and remain
in the ground, and excessive quantities of soil often stick to the lifted pods. Built-up beds-the tram-
line system-together with an irrigation prior to lifting, will help reduce the number of pods left in the
soil and will reduce the quantity of soil adhering to the pods that have been lifted.

4.2 Land preparation
For maximum germination, lands must be well-ploughed and the soil in good tilth. The crop
must be planted in rows so spaced as to allow for easy tractor access for cultivation, spraying and
lifting.
FIGURE I.-Planting on the flat.
.750 mm 350 mm
(---------- } -----

_______ *, _. Ground level .



The spacing shown in Figure I, incorporating planting on the flat and in rows spaced in groups of
four, is suited for dryland production where difficulty in lifting is not expected. It is also suited for
production under overhead sprinkler irrigation.

FIGURE II.-Raised beds.
750 mm 350 mm




S Ground level.


For dryland production, where soil conditions are expected to be hard and dry when the crop matures,
consideration must be given to the lifting of the crop. In such cases some form of raised bed (Figure II)
or ridge (Figure III) must be adopted to enable lifting machinery to penetrate 100 to 150 mm below
the soil surface.

FIGURE III.-Raised ridges.
150 to 200 mm 1,8 metres 150 to 200 mm



G-rou- level-------- ---


The ridges on which the crop is to be planted must have flat tops, and planting will have to be by hand.
Two rows are planted approximately 150 to 200 mm apart on each ridge as shown in Figure III.

FIGURE IV.-Border strips.
750 mm 350 mm

--------- Ground level.





For flood irrigation, beds must be formed with small ridges to control the flow of water down each bed
(Figure IV). The ridges must be sufficiently large to control the flow of water, even if compacted by
tractors running over them.

Groundnuts
May, 1975 1
























SECTION 5


PLANTING
5.1 Planting date
5.2 Spacing and depth of planting
5.3 Population and seed requirements
5.4 Planting methods





SECTION 5


PLANTING

5.1 Planting date
If maximum yields are to be realized crops must be planted early, depending upon cultivar and
temperature; a delay in planting will cause a marked drop in yield. Optimum planting dates are set
out in Table II.
TABLE 11
Cultivars and planting dates

Type of production Cultivar type Altitude metres above sea level Planting date
Dryland Earlies below 900 14-30 Nov.
900-1500 10-20 Nov.
above 1 500 1-14 Nov.
Lates All altitudes 'As early as possible
Irrigated Earlies below 900 14-30 Nov.
900-1 200 10-20 Nov.
1 200-1 500 1-14 Nov.
above 1 500 15-30 Oct.
Lates below 900 8-23 Oct.
900-1200 1-15 Oct.
1 200-1 500 23 Sept.-7 Oct.
above 1 500 15-30 Sept.


These dates are suggested as being optimal but, in practice, will depend upon the other crops being
grown and upon the rainfall pattern.
Early planting for maximum yield is dependent upon good management at reaping time. Both
early and late cultivars must be lifted when they reach maturity to prevent sprouting and loss of quality.
A farmer growing the crop for the first time should plant slightly on the late side to acquaint himself
with the lifting and harvesting problems encountered after the main rains have ceased. Farmers who
have a knowledge of the crop and sufficient machinery and labour, should be able to lift six to eight
hectares per day, thereby preventing yield and quality losses.

5.2 Plant spacing and depth of planting
An average row spacing of 450 mm has been shown to give maximum yields. Row width must be
adapted to allow for easy access by machinery for cultivation, spraying, and lifting. Suitable systems
are discussed under Section'4.2, Land preparation.
Seed must be placed 100 to 150 mm apart in the row for late cultivars, and 50 to 75 mm apart for
early cultivars. Ideally, seed should be planted 50 to 80 mm below the soil surface, depending on soil
type. Shallow planting will result in patchy germination where the soil is allowed to dry out, while deep
planting will delay germination.

5.3 Plant population and seed requirements
Early maturing cultivars must be planted to give a plant population of 250 000 to 300 000 plants
per hectare. Half this number-125 000 to 150 000 plants per hectare-is sufficient for late-maturing
cultivars.
Approximately 120 kilograms seed per hectare should be sufficient for both cultivars.

5.4 Planting methods
Groundnuts may be planted either by machine or by hand.
Planters fitted with plates inclined at an angle cause less seed breakage than do those which have
horizontal plates. Planting speed can affect plant populations considerably; optimum results will be
achieved at speeds below 5 km/h. Planter plates should rotate as slowly as possible; greater plant
populations may be attained by drilling additional holes in the plates, rather than by increasing the
speed at which the plates rotate. Holes in the plates must be large enough to take the biggest seed in the
sample. Graded seed will reduce seed breakages and, therefore, ensure a higher plant population.
Ground inspections should be made behind the planter to ensure that depth of planting and the seeding
rate remain adequate.

Groundnuts
September, 1973 1





Hand planting has proved successful on many farms where the planting furrows are opened and
closed mechanically. The number of labourers required to place the seed will vary from five to 17
per hectare per day. Seed should be dribbled by hand at the rate of four to five seeds per 300 mm
of row for the early cultivars, and two to three for the late cultivars. An irrigation before planting
will help the planting furrows hold their shape and thereby ensure an even depth of planting.' Either
too much or too little soil may be placed on top of the seed when it is covered by badza, and the
result will be irregular emergence.
Under early planted irrigated conditions the area planted each day must be limited to enable
irrigation to keep pace with planting. Pre-irrigation will enable faster planting because only a small
topping-up irrigation will be required after planting.

























































Groundnuts
2 September, 1973






















SECTION 6

FERTILIZATION
Revised by
R. J. Fenner,
Department of Research and Specialist Services








SECTION 6


FERTILIZATION

6.1 Fertilizer requirements
Groundnuts have the remarkable ability to adapt themselves to
almost any soil type. Although they grow best on the well-drained
medium-textured soils, high yields are nevertheless attainable on the
sandier and heavier-textured soils.
This crop should preferably be grown in rotation with other
crops which have been well fertilized because evidence suggests that
groundnuts respond better when fertilizer is applied to the previous
crop. Nevertheless the nitrogen, phosphorus and potassium require-
ments of a particular land are most reliably assessed by soil analysis,
and farmers are strongly recommended to have samples from their
lands analysed regularly. Failing this, a rough assessment of the
probable requirements can be made from what is known of the past
history and fertilizer treatment of the land.
Accordingly, Table 6.1 gives the average requirements of nitrogen,
phosphorus and potassium for soils that are likely to have a "good",
"medium" or "poor" status in respect of the major nutrients. This is
followed by short notes to enable farmers to decide in which of the
three categories their soils are likely to fall. It is assumed that all crop
residues are to be returned throughout the rotation.

TABLE 6.1
THE AVERAGE NUTRIENT REQUIREMENTS OF GROUNDNUTS

Nutrient status of the soil
Fertilizer Good Medium Poor
nutrient
Kilograms per hectare of fertilizer nutrient required
N . Nil Nil 20-30
PsO1 . Nil 20-40 40-60
K,O Nil 20-40 40-60

Note.-Where high yields are attainable, with early planted irrigated crops, for example, the
rates given above should be increased by 50%.

Nirogen status of the soil
Good: Following a good leguminous green-crop turned-in at the
correct time and stage of maturity; and lands that have
regularly received heavy dressings of compost or manure.
Medium: Early-ploughed virgin or reverted lands and grass leys;
and cultivated lands. The higher rates should be used on
lands where cash crops are grown continuously and crop
residues are returned.
Poor: Late-ploughed virgin or reverted lands and grass leys.
Phosphorus status of the soil
Good: Cultivated lands on which a large quantity of fertilizer
phosphorus has been applied in the past by means of
regular, uninterrupted annual dressings.
Medium: Cultivated lands on which a moderate amount of
fertilizer phosphorus has been applied in the past.

Groundnuts,
October, 1976. 1







Poor: Virgin or reverted lands on which little or no fertilizer
phosphorus has been applied in the past.

Potassium status of the soil
Good: Most newly opened lands of normal fertility; and lands
that have received regular applications of fertilizer potassium
and the return of crop residues.
Medium: Lands of normal fertility that have been cultivated for
some time without regular applications of fertilizer potassium
or return of crop residues.
Poor: Lands where soil analysis has shown the potassium status
to be low.

Calcium status of the soil
Groundnuts have a high calcium requirement, particularly during
pod development. Low availability at this time will result in a
decreased shelling percentage and a high incidence of "pops" or
empty pods. Gypsum should be applied at the rate of 200 to 300 kg/ha
to ensure an adequate available calcium status.

6.2 Method and time of application
The whole of the nitrogen, phosphorus and potassium require-
.ments in the form of straights or compound fertilizers should be
applied at or before planting. These should be broadcast and disced
in as deeply as possible after ploughing.
Under dryland conditions the gypsum should be applied along
the top of the rows at early flowering. On early planted irrigated
crops two dressings of gypsum, each of 200 to 300 kg/ha, should be
given eight and 12 weeks respectively after germination.

6.3 Lime requirements
For maximum yields the calcium-chloride pH value of the soil
must be above 5,3. It is, therefore, essential to correct the pH of the
land by adequate applications of lime where necessary, but this should
only be done on the basis of a soil analysis.
The lime may be applied at any suitable stage in the rotation and
it may be applied immediately before planting. When applied immedi-
ately before planting, however, it must be broadcast and disced in
deeply, preferably after ploughing.
The available magnesium status of the lighter-textured soils
tends to be low, in some cases even where the pH is satisfactory.
Furthermore, in these soils under continuous cultivation, the mag-
nesium status falls rapidly to values approaching deficiency. Where
lime is required, the magnesium status can be maintained by the
use of a liming material containing an appreciable amount of mag-
nesium. Where lime is not required, an application of 200 to 300
kg/ha of ground dolomite should prove satisfactory, but again this
should only be done if soil analysis indicates that it is required.





Groundnuts,
2 October, 1976.



















SECTION 7







SECTION 7


WEEDS


7.1 Weed Control
Weed control is most important if high yields are to be achieved.
The following points are stressed for each crop.

Groundnuts
This crop is normally planted in closely spaced rows and weeds
must therefore be largely controlled by the use of herbicides. The
herbicides recommended break down completely within three or
four months and will not affect following winter crops.

Herbicides will not, however, provide complete weed control and
a certain amount of hand and machine cultivation will be necessary.
On suitable layouts and particularly on sandy soils, a rotary hoe or
a rotary tined cultivator (millipede) will remove shallow rooted weeds
resistant to the herbicide applied. This cultivation must be done two
to four days after an irrigation while the weeds are very small. Rotary
hoe cultivation may continue until flowering or until the crop is
150 mm high. Hand cultivation is also possible until flowering but
beyond this stage weeds must be handpulled to prevent damage to
the pegs.

Soya-beans
Since soya-beans are grown as a short-season crop, normally
planted after the start of the rains, it is often possible to destroy a
crop of weeds before planting. After germination the crop can be
cultivated effectively with a millipede, provided weather conditions
are suitable. This operation is also of value a day or two prior to
germination to break any soil crust and to assist germination while
removing small weeds. A millipede can be used until the crop is
150 mm high.
The ease of weed control in the soya-bean crop is affected by
the row spacing used. Whilst herbicides used correctly can give
extremely good results, some mechanical cultivation in the later
stages is usually necessary. The majority of growers would be well
advised therefore to use a row spacing similar to that of their maize
crop and so permit the same cultivators to be used. Closer row
spacings appear to give little increase in yield.
Herbicides used are similar to those used for the groundnut
crop and should leave no residues in a following winter crop.




Groundnuts,
October, 1976. 1







7.1 Herbicides available


Common name I Sold as Method of use


Trifluralin


Nitralin







On ridged crops th
ridging.
Naptalam + DNBP






Terbutryne

Linuron

Prometryne
Fluorodifen
Alachlor

Metolachlor
Paraquat


Trif
Trifluralin


Planavin WDL 4
Planavin 75% WP


Incorporate immediately
50 to 100 mm deep prior
to planting.
Incorporate within 24
hours 30 mm deep into
soil. Alternatively, apply
immediately after plant-
ing and incorporate with
12 to 25 mm of irrigation.
Do not irrigate sandy soils
heavily until the crop has
germinated.


e above herbicides must be incorporated after


Ancrack
Dyanap






Igran 50 WP
Igran 500 FW
Linuron
Afalon
Gesagard 500 FW
Preforan
Alachlor
Lasoclor
Dual
Gramoxone


Apply at ground cracking
stage groundnutss) or
crook stage (soya-beans)
or earlier if weeds are
seen. Crop damage will
occur if applied later than
the above stages of ger-
mination.



Apply prior to crop and
weed emergence.




Post-emergence. Will kill
all plant growth which it
contacts.


Note. Prometryne must not be used on soya-beans.

7.2 Weed problems
Grasses
Shamva grass Rottboellia exaltata
This grass occurs only on the heavier soils. Good herbicidal
control can be achieved by the use of trifluralin and nitralin,
both of which require soil incorporation.
Rapoko grass Eleusine indica, and Urochloa spp etc.
These occur on all soil types and are controlled by trifluralin,
nitralin, alachlor and metolachlor.
Groundnuts,
2 October, 1976.







Broad-leaf weeds
Pigweed Amaranthus spp
Easily controlled by naptalam + DNBP, terbutryne, linuron,
prometryne, and fluorodifen. May be controlled by triflura-
lin, nitralin, alachlor, and metolachlor.
Apple of Peru, Nicandra physalodes
Control with alachlor, metolachlor, naptalum + DNPB,
fluorodifen, terbutryne, prometryne and linuron.
Mexican clover, Richardia brasiliensis
A serious problem on some lighter soil areas, particularly
in a wet season. Trifluralin, nitralin, alachlor and meto-
lachlor may give some control. Mixtures or combinations
of these herbicides with naptalam + DNBP are probably
the most effective.
Starbur, Acanthospermum hispidum and Wild Hibiscus, Hibiscus
spp
Naptalam + DNBP is the most effective herbicide.
Blackjack, Bidens pilosa, Mexican marigold, Tagetes minute,
Gallant Soldier, Galinsoga parviflora
The most effective herbicides are naptalam + DNBP, ter-
butryne, prometryne and linuron. Alachlor and metolachlor
will give some control.
Wandering Jew, Commelina benghalensis
This weed can be particularly troublesome in wet seasons.
None of the herbicides recommended for soya-beans or
groundnuts is reliably effective although metolachlor is
showing promise. Where Wandering Jew is a major weed,
spacings suitable for mechanical cultivation must be selected.
Nutgrass, Cyperus esculentus
Satisfactory control can be achieved by using alachlor or
metolachlor at the full rate recommended for the particular
soil type. However, the soil must be disced immediately
prior to planting, followed by herbicide application immedi-
ately after planting. Rainfall or irrigation within one or
two days of application is also essential.

Late weeds prior to harvest
Groundnuts. Hand pulling only.
Soya-bean. A desiccant herbicide, paraquat, can be used just
prior to crop harvest to kill off all green top growth, most of which
will dry off prior to combining. However, thick weed stalks as some-
times experienced with Pigweed Amaranthus spp. and Apple of Peru
Nicandra physalodes may not dry out in time and this would neces-
sitate hand pulling.
After a final light cultivation, consideration can be given to a
"lay-by" application of herbicides such as linuron or terbutryne to
prevent re-infestation by late weeds. Discuss with supplier.
Note. Prometryne must not be used on soya-beans.
Groundnuts,
October, 1976. 3






TABLE 7.4

RECOMMENDED HERBICIDE RATES FOR GROUNDNUTS AND SOYA-BEANS


Application rate per hectare

Weed problem Herbicide Stage of application Sandy clay Remarks
Light Sandy loam Red clay
sand loam (clay 20% +) loam

Grasses only Trifuralin Pre-plant soil incorporated 1,1 litres 1,3 litres 1,3-1,6 litres 1,6 litres

Planavin DWL 4 Pre-plant soil incorporated, or 1,1 litre 1,3 litre 1,3-1,6 litre 1,6 litre Incresse rates to 2,2 litres or
Planavin 75% WP Pre-emergence with irrigation 0,7 kg 0,8 kg 0,8-1,0 kg 1,0 kg 1,3 kg if Shamva grass
present

Alachsolor Pre-emergence 3,5 litres 3,5 litres 3,5-4,2 litres 4,2 litres Also for nutgrass-see 7.3

Dual Pre-emergence 2,0 litres 2,0 litres 2,0-2,5 litres 2,5 litres Also for nutgrass-see 7.3

Gleaf d broad Trifuralinr } Pre-plant soil incorporated 1,1 litre 1,0 litre 1,0-1,6 litres 1,0-1,6 litres
or
Planavin WDL 4 Pre-plant soil incorporated, or 1,1 litre 1,0 litre 1,0-1,6 litres 1,0-1,6 litres
or
Planavin 75% WP Pre-emergence with irrigation 0,7 kg 0,7 kg 0,7-1 kg 0,7-1,0 kg
or
Alachlor Pre-emergence 3,5 litres 2,0 litres 2,0.2,5 litres 2,5 litres
or
Dual Pre-emergence 2,0 litres 1,5 litres 1,5-1,75 litres 1,75 litres
FOLLOWED BY OR MIXED WITH (consult supplier for details)

Dycrac Cracking or crook stage NR 9,0 litres 11,0 litres 11,0 litres Alachlor, Lasocloror Dual
on soya-beans

Igran 50 WP e-emergence NR NR 2,2 kg 2,2 kg Over-application can result in
Igran 500 WP Pe- rence NR N2,2 litres 2,2 litres serious crop damage
or
Preforan Pre-emergence NR 6,0 litres 8,0 litres 8,0 litres
or
Linuron Pre-emergence NR NR 2,2 kg 2,2 kg
or
Gesagard 500 SW Pre-emergence NR NR 2,2 litres 2,2 litres Note.-For groundnuts only.
Over-application can result in
serious crop damage.


R 0



-4J












0 00
-I?
aa
0a


TABLE 7.4-continued


Application rate per hectare
Weed problem Herbicide Stage of application Sandy Remarks
Light Sandy clay loam Red clay
sand loam (clay 20% +) loam
Minor grass but major Ancrack 1 Cracking or crook stage NR NR 11,0-14,0 litres 14,0 litres
broad-leaf weeds Dyanap J
or
use mixtures above which
include Alachlor,
Lasoclor or Dual

NR = Not recommended.
Tank mixes of Alachlor, Lasoclor and Dual can be made with Ancrack, Dyanap, Igran, Preforan, Gesagard 500 SW, Afalon and Linuron. Tank mixes of Planavin can be
made with Igran, Preforan, Gesagard 500 SW, Afalon and Linuron, provided irrigation is applied within 24 hours. Mix as recommended by supplier.
Read the label before use.























SECTION 8


IRRIGATION
8.1 Irrigation





SECTION 8


IRRIGATION
8.1 Irrigation
Groundnut irrigation is covered under a section in the Irrigation Handbook. The main points
to be borne in mind are:
Soil moisture must be brought to field capacity to a depth of 900 to 1 200 mm, either before or
just after planting. On sandy soils this will require approximately 75 mm of water and, on heavy
soils, about 125 mm. Furrows opened for hand planting retain their shape better where lands are
pre-irrigated, thereby permitting an even depth of planting. There is evidence that groundnuts respond
well to stress after planting; irrigation equipment can thus be used for other crops during this period.
The timing of the initial irrigation will depend on soil type and the herbicide treatment adopted.
It is advisable to pre-irrigate sandy soils to prevent fertilizer leaching. Where naptalam+DNBP is
to be applied, irrigate one or two days after planting so that the herbicide can be applied at the ground-
cracking stage. It is important not to irrigate at the cracking stage as this has been observed to retard
emergence.
Irrigation applications from the time of flowering to lifting must be related to readings from a
Class A Evaporation pan. It is very important for the crop to be fully irrigated throughout the growing
period up to the lifting stage. Once pegging commences, sandy soils should be irrigated at intervals
of approximately eight days; intervals on heavy soils should be approximately 16 days. Calcium
uptake by pods in sandy soils can be adversely affected if the top 50 to 100 mm of soil is allowed to
dry out.
Crops that are irrigated by overhead systems should be planted on the flat, or on raised beds
if this will assist at lifting; rows should run across the slope to reduce runoff.
Water management on flood-irrigated crops appears to be easiest where the crop is planted in beds
between well-constructed border strips. Border strips must be large enough to force water along the
bed, and permit tractor access even during wet spells. Germination on flood schemes may be assisted
by the use of water-planting techniques, e.g. rigid plastic piping, thereby overcoming the problem of
wash in the beds.




































Groundnuts
September, 1973 1























SECTION 9

DISEASES
Contributed by
A. Rothwell,
Dr. D. Cole,
Department of Research and Specialist Services







SECTION 9


DISEASES
Increased production and the introduction of irrigation into the
cropping programme have significantly altered the disease pattern
in recent years. At present the most serious groundnut diseases in
Rhodesia include the following.

9.1 Grey Mould-Botrytis cinerea
Large dark stem lesions, covered with grey spring fungal growth,
ultimately leading to the death of growth above the infection. Top
growth appears normal during the early stages of attack. Growers
should therefore examine stems beneath this top canopy from January
onwards for first signs of attack. Botrytis will not develop until plants
have completely covered the ground and so established a micro-
climate favourable for infection.

9.2 Leaf Blotch-Didymosphaeria arachidicola
syn. Phoma arachidicola
Ascochyta adzamethica
Despite the many recent changes of name for this pathogen, it
is the one originally called Ascochyta sp. in Rhodesia. Diffuse olive
brown lesions with wide pale margins develop on the upper
leaf surface. These eventually darken in colour and penetrate through
the leaf. With age, tissue tears and leaves drop. Symptoms, which
may appear from November onwards, are most severe during the
January/February period and result in severe defoliation.

9.3 Leaf Spots-Cercospora arachidicola and C. personata
Both pathogens cause similar leaf spotting on the upper surface.
The spots are dark brown with a yellowish halo and up to 50 mm in
diameter. The diseases can be distinguished by examining the lower
leaf surface where C. personata causes a definite black spot. Spore
initials are visible to the naked eye. The C. arachidicola lesions on
the underside of the leaf are brown in colour.
In the main groundnut areas on the highveld, C. personata
appears only late in the growing season, if at all, whereas in the
lowveld C. personata is the predominant cercospora species. Both
pathogens cause extensive defoliation.

9.4 Pod Rot-Rhizoctonia solani
In most instances these rots are associated with some other factor
restricting optimum crop development, e.g. drought conditions, insect
damage (Hilda), soil pH and so on. Various pathogens can then
invade the pods and cause discoloration and, very often, attack the
seed.
Control maintain optimum growing conditions.

9.5 Root and Crown Rot-Sclerotium rolfsii
This pathogen attacks a wide range of hosts, but under local
conditions has not severely damaged any particular one, including

Groundnuts,
October, 1976. 1








groundnuts. Damage is largely restricted to individual or small groups
of plants which show growth of thick white fungal strands over roots
and crowns adjacent to the soil surface. Associated are tan coloured
sclerotia (small bodies about the size of a cabbage seed). Top growth
withers.
Control maintain good growing conditions
plough deep to bury sclerotia.

9.6 Sclerotinia Wilt-Sclerotinia sclerotiorum
Another pathogen which attacks many different hosts. Infection
of stems causes foliage to wilt. Large black sclerotia, associated with
white mycelial growth, are produced in the diseased stem.
Control plough deep
rotate crops with non-susceptible hosts.

9.7 Rust-Puccinia arachidis
A recent introduction to Rhodesia. Undersides of leaves show
small orange to dark brown pustules. Infection occurs early in the
season in lowveld crops and can cause severe defoliation. In highveld
plantings, infection comes in so late that the disease has not been
of any consequence so far.


Control specific rust control has not so far
necessary in highveld crops.


been found


9.8 Rosette-Virus
Chlorosis, stunting and some deformity of young leaves. Very
often such an area will be surrounded by a fringe of normal, dark
green leaves which developed before infection occurred. Only serious
when plant stands are poor.
Control establish stands of high density
destroy overwintering plants.




















Groundnuts,
2 October. 1976.









TABLE 9.1
DISEASE CONTROL-GROUNDNUTS

Disease Fungicide Rate kg/ha Application
LEAF SPOT Mancozeb 80% WP 1,5
(Cercospora arachidicola Benomyl 50% WP 0,5
and Cercospora personata) Carbendazim 50% WP 0,5
Copper oxychloride 85 % WP 3,0 Start spraying 8-10 weeks after
emergence and apply 6-7 sprays
LEAF BLOTCH Chlorthalonil 77% 1,0-1,5 at intervals of 10 days.
(Didymosphaera arachidicola) Mancozeb + Benomyl 1,0+0,25
and Leaf Spot Maneb 80% + Carbendazim 2,0+0,25
Fentin hydroxide 50% 0,5-0,75
RUST Chlorthalonil + Benodanil 50% WP 1,0+0,25 Apply at first signs of rust and
(Puccinia arachidis) Chlorthalonil 1,0-1,5 continue at intervals of 10 days
until 4-5 weeks before lifting.
GREY MOULD Benomyl 0,25 Use either Benomyl or Carben-
(Botrytis cinerea) Carbendazim 0,25 dazim for the first 3-4 sprays in
a spraying schedule that does
not include these.
ROOT AND CROWN ROT Benomyl 0,25 If the land has a history of these
and WILT Carbendazim 0,25 fungi, include these fungicides
(Sclerotium Rolfsii in the schedule throughout the
Sclerotinia Sclerotiorum) season. The rates could be
doubled if necessary.


TABLE 9.2
FUNGICIDES

Common name Trade name Distributor
Bonodanil .. Calirus 50% WP . .. .Agricura Rhodesia
Windmill Rhodesia
Benomyl .. Agricura Special Fungicide 50% WP Agricura Rhodesia
Carbendazim Bavistin 50% WP . .. Windmill Rhodesia
Derosol 20% dispersion Hoechst Rhodesia Company
Chlorthalonil Daconil 2787 77 % . .. Agricura Rhodesia
Shell Rhodesia
Copper oxychloride Vitigran cone. 85% WP Hoechst Rhodesia Company
Cupravit 85% . .. .Bayer Agro-Chem
Copper oxychloride 85% . Windmill Rhodesia
Central African Machinery and
Spares
Rushton and Bywater
Agricura Rhodesia
Sprayquip
Rhodesia Fertilizer Corporation
Fentin hydroxide Du-Ter 50% WP .. Windmill Rhodesia
Mancozeb Dithane M45 80% WP Rhodesia Fertilizer Corporation
Shell Rhodesia
Agricura Rhodesia
Rushton and Bywater
Windmill Rhodesia
Maneb . MEB 80% WP . .. Sprayquip
Maneb 80% WP . Agricura Rhodesia


Groundnuts,
October. 1976.
























SECTION 10


PESTS
10.1 General
10.2 Termites
10.3 Cutworms
10.4 Aphids
10.5 Hilda patruelis
10.6 Semi-looper caterpillars
10.7 Looper caterpillars
10.8 Heliothis armigera American bollworm
10.9 Leaf hoppers
10.10 Weevil grubs





SECTION 10


PESTS

10.1 General
The following is a summary of the more important groundnut pests, together with their control
measures. Insect control is very important where maximum yields are expected. The,correct selection
of insecticides is most necessary, since several crops have been rejected in world markets owing to
excessive residues of pesticides.
The following are extracted from RAJ Bulletin No. 2427 "Groundnut Pests", by G. H. Broad,
and "Semi-looper caterpillars in Northern Rhodesia" by K. J. Wilson.

10.2 Termites
The importance of termite damage was not'fully appreciated until investigations into the cause of
mouldy kernels showed that substantial pod damage could be attributed to these insects. Plants may
be attacked at any stage of growth by Macrotermes spp. which construct the familiar large mounds
in the veld. Young plants may be surrounded by the coarse-grained earthworks of the termites, severed-
and killed. Damage to mature pods may be considerable, especially if the plants are under stress from
drought conditions. Small fungus growing termites, e.g. Microtermes spp. are also responsible for
damage to mature pods, and indeed, are on the whole more important than Macrotermes spp.
Termites can be controlled by the fumigation of nest sites after boring into the roof of the mound
or through air shafts; fumigants that may be used are:
10.2.1 Ethylene dibromide, 0,3 litres per mound. Place wads of cotton wool below the bored holes
or in the air shafts to absorb the liquid fumigant; or
10.2.2 Methyl bromide, 1 canister (454 grams) per mound. Applied by jiffy applicator with the tube
led into the mound. After fumigation has been completed, treated nests should be excavated
and refilled to prevent reinfestation of the site.

10.3 Cutworms, Agrotis spp.
Cutworms are the caterpillars of night-flying moths. The grey, greasy caterpillars are often found
lying curled in the soil near the damaged plants which are generally eaten off just below ground level.
Cutworms may be very important locally, but attack by them is rather unpredictable. The moths
will lay eggs on or near a wide range of crops, at any time of the year. Lands on which a green-manure
crop such as sunnhemp or dhal has been grown, and irrigated and/or manured, will attract moths to
lay eggs before the crop is planted. If cutworms are present when crops are at an early stage of growth
the young shoots will be eaten, but the qrop may recover. Should cutworms be present five to six
weeks after planting, they will cause considerable damage by consuming young pegs and by penetrating
the more developed pods, but only while they are still succulent. Mature pods are not attacked by
cutworms. There may be no sign of damage above ground, so examination of developing pods during
the susceptible period is recommended.
10.3.1 Where cutworms are expected, they may be controlled by preplant baiting with:
(a) 120 g trichlorfon 50 per cent. WP
20 kg mealie meal/25 litres water
500 g sugar or 1 kg molasses
20 litres of water; or
(b) 125 g endosulfan 50 per cent. WP (not on lands used for tobacco)
20 kg mealie meal
20 litres water.
Mix dry and then add water to obtain a crumbly texture. Apply in late afternoon. These quantities
are sufficient to treat one hectare.
10.3.2 Where cutworms become a problem after emergence, spray with either
(a) 2,2 to 4,4 kg DDT 75 per cent. WP in 500 litres water per hectare, applied only once
soon after emergence; or
(b) 215 ml monocrotophos 40 per cent. EC in 100 litres water, applied at the rate of 450-500
litres per hectare.
DDT should not be used if tobacco is to be grown on the same land.

10.4 Aphids, Aphis craccivora Koch
This is a common black aphid which is often found infesting beans and other legumes.It is impor-
tant as the vector of the virus disease known as rosette of groundnuts. The symptoms of the disease in
its severest form consist of stunting of growth and chlorosis of the leaves. Attack at a later stage of growth
produces only the occasional chlorotic leaf. The disease may cause substantial reduction of yield,
particularly in a poor stand of groundnuts. The risk of rosette disease may be minimized by establishing
a good stand; diseased plants should be removed to prevent the spread of the disease within the crop.

SGroundnuts
September, 1973





10.4.1 Aphids can be controlled by sprays of:
200 ml demeton-s-methyl 50 per cent. EC per hectare in a convenient volume of water, i.e. 200
litres or more/ha; or
800 to 1 000 ml dimethoate 40 per cent. EC per hectare in a convenient volume of water; or
2 litres endosulfan 35 per cent. EC per hectare in a convenient volume of water, i.e. 200 litres
.or more/ha; or
350 to 500 ml thiometon 25 per cent. EC per hectare, in not less than 220 litres/ha; or
200 g parathion 25 per cent. WP in 100 litres water.

10.5 Hilda patruelis Stal
Close examination of a wilting groundnut plant may reveal large numbers of ants around the
base of the stem. If this plant is pulled out of the ground, small hopping insects may be found in the
disturbed soil. Adults are about 5 mm in length. Batches of small elongated white eggs will'also be
found, fixed firmly and flat against the under-ground parts of the stem and pods, often within chambers
excavated by the associated ants. One generation is completed in about six weeks in summer. Breeding
continues slowly through the winter on alternate hosts or overwintering volunteer plants.
Hilda patruelis would seem to be important only when encouraged by ants which probably
protect them from predators and, in return, feed on the honeydew secretions of the hopper. The
presence of these hoppers feeding on the sap of the plant, and ants which expose the roots to desiccation
through their workings, results in the wilting of the plant. .
Hilda patruelis can be controlled by spot-spraying infected plants, and plants within a radius
o res around them, with
200 ml demeton-s-m r cent.- EC per hectare; or
155 ml monocrotophos 40 per cent. litres water applied at the rate of 80 to 400
litres per hectare; or
200 g parathion 25 per cent. WP in 100 litres water. (Will control an n a atruelis). The
crop should be inspected 10 days after treatment and resprayed if hoppers are ou

10.6 Semi-looper caterpillars, Plusia spp.
These caterpillars are smooth, usually bright green in colour with longitudinal stripes of dark
green and white down the length of the body. Where large numbers of these caterpillars feed together
on the same crop, they become very dark green in colour and have been confused with army-worm
caterpillars. However, semi-looper caterpillars are easily distinguished by their mode of progression.
When these caterpillars move, they draw the posterior part of the abdomen up to the thoracic region
of the body-thereby producing the characteristic loop in the middle of the body-whereas army-worm
caterpillars move in a normal crawling manner, like most caterpillars.
Iocontrol semi-loopers spray with either
600 to 1 to hos 40 per cent. EC per hectare in a convenient volume water; or
300 ml endosulfan 35 per cent. ECa convenient volume water with 5 per cent.
molasses (by volume); or
1 kg carbaryl 85 per cent. WP per hectare in a convenient volume water wi
molasses (by volume).

10.7 Looper caterpillars, Achaea finita Guen
These are yellowish green caterpillars which may be recognized by the presence of a thin red line
running along each side of the body above the legs. Their maximum length is approximately 60 mm.
The caterpillars move in a looping manner by bringing the back legs towards the head before moving
the front legs forward. They are common on soyabeans, castor beans, peas, beans and potatoes as well
as groundnuts. Adult moths are closely related to fruit-piercing moths which are pests of ripe fruit.
10.7.1 To control loopers, spray with carbaryl without molasses.

10.8 American bollworm, Heliothis armigera
The damage caused to groundnuts is not often important, but heavy outbreaks of the caterpillar
result in ragging of the leaves and defoliation of plants. Fully-grown caterpillars reach 40 mm in length
and vary considerably in colour from light to dark green in colour, or even brown. Markings vary in
intensity, but a broad pale stripe along each side is usual.
10.8.1 Control of American bollworm is the same for semi-loopers, Plusia spp. Section 10.6.

10.9 Leaf hoppers, Empoasca spp.
Leaf hoppers are very small green, wedge-shaped insects which may be numerous on groundnut
crops. They shelter on the undersides of the leaves, and are generally noticed taking swift, brief flights
away from the plants when they are disturbed. Closely related species in America have been observed
to cause yellowing of the tips of leaflets. A yellowing of the leaves in Rhodesia is als6 associated
with the presence of leaf hoppers.

Groundnuts
2 September, 1973














ERRATA


GROUNDNUTS

The relevant section in the Handbook should be replaced by
the following:
10.5.1. Hilda patruelis can be controlled by spot-spraying infected
plants, and plants within a radius of three metres around them,
with an appropriate insecticide. Alternatively, a band three metres
wide may be sprayed around the land. In cases of severe attack an
over-all application of insecticide may be necessary. Demeton-s-
methyl, monocrotophos and parathion have been used in the past
but only monocrotophos is registered for the control of Hilda
patruelis in groundnuts. Application rates are 155 ml monocrotophos
40 per cent. EC in 100 litres water per hectare, applied at the rate
of 80 to 400 litres per hectare depending upon plant size.
If demeton-s-methyl is to be used it may be applied at the rate
of 200 ml 50 per cent. EC in 100 litres water per hectare. Alter-
natively, 200 g parathion 25 per cent. may be applied at the rate of
200 g in 100 litres of water per hectare.
10.6.1. To control semi-loopers spray with:
600 to 1 200 ml monocrotophos 40 per cent. EC per hectare
in a convenient volume water; or
1 000 ml endosulfan 35 per cent. EC per hectare in a con-
venient volume water with 5 per cent. molasses (by
volume); or
1 kg carbaryl 85 per cent. WP per hectare in a convenient
volume water with 5 per cent. molasses (by volume).














Groundnuts,
March, 1975.





10.9.1 Control with carbaryl without molasses.

10.10 Weevil grubs, Systates exaptus and Mesoleurus deritipes
Occasionally, groundnut pods are penetrated by small, white, legless grubs, the immature stage of
weevils. Systates exaptus and Mesoleurus dentipes are the best-known. These species may be trouble-
some on red soils where they are better known to farmers as pests of maize. The grubs are very
difficult to control. Adults will leave notches in the leaves and lay eggs in a fold made at the edge of
the leaf.
10.10.1 Grubs can be controlled by spraying the adults in the preceding crop with 600 grams carbaryl
85 per cent. WP in 100 litres of water. There is no known control of grubs other than the inclusion of
non-host plants in the rotation.























































Groundnuts
September, 1973 3























SECTION 11

HARVESTING

Contributed by
G. Hutchison
and
G. J. Oliver,
Department of Conservation and Extension









SECTION 11


HARVESTING

11.1 General
Harvesting is a broad term used to describe the operations
necessary to remove groundnut pods from the soil and prepare them
for market. Probably no part of groundnut production calls for more
knowledge, skill, care and attention than harvesting. Losses are
probably greater at harvesting than at any other time.
Harvesting should commence when 50 to 70 per cent. of the
pods contain mature kernels. A delay in lifting beyond the 70 per
cent. kernel-maturity stage will result in pod loss and lower quality
as a result of excessive discoloration and mould (Figure 11.1). Mature
kernels have thin seed coats which are not easily rubbed off by hand,
and have attained the colour of the variety being grown. By com-
parison, immature kernels have thick fleshy seed coats which rub
off easily and are lighter in colour than mature kernels.


I I I I I
Kernels retained --Kernel dry matter
by No. 8 screen
-.**-***- Kernel discoloration



__ LIFT
100 10
90 9
80 i 8
Percentage kernel /*
dry matter 70 .t 7
or /
kernels retained by 60 / -' / 6
No. 8 screen/ I
50 7- --- 5
7
40 -- 4
30 s 3
20 -_- -_-_ __ 2
101 1 1


50 60 70
Percentage maturity


80 90


Percentage
kernel
discoloration


Fig. 11.1
Changes in groundnut yield, kernel size and discoloration during maturation.
(After H.R.R. Metelerkamp)

Actual timing of lifting will depend upon the size of the crop and
the time taken to plant it. To ensure that lifting is completed before
the crop reaches 70 per cent. maturity, an earlier start must be made
when lifting large areas of crops than when lifting small crops. Time
of maturity cannot be set accurately from the time of planting owing
to the fact that maturity is also influenced by other factors such as
altitude, and soil and weather conditions during plant growth.

Groundnuts,
October, 1976. 1


'


t


" --








Growers should examine plants in the field regularly to determine
the percentage maturity and the stage when harvesting should com-
mence. The crop must be lifted when it is 90 per cent. defoliated,
irrespective of kernel development.
Present harvesting methods can be divided into conventional
and mechanical, depending on methods used. The equipment used
will influence the further subdivision of mechanical harvesting.
Operations involved in conventional and mechanical harvesting
are shown in Table 11.1.

TABLE 11.1

Conventional Mechanical
(a) (b)
Loosening . . Loosening . Lifting
Lifting . Lifting . .. Wilting
Wilting .. . Wilting .. . Combining
Cocking (curing) . Picking (combine or picker) Artificial curing
Picking (hand or machine) Artificial curing

11.2 Conventional harvesting

11.2.1 Loosening
Loosening consists of cutting the tap root 100 to 150 mm below
the soil surface and loosening the soil by means of a groundnut
lifting blade. This is done to enable the plants to be lifted from the
soil without breaking the pods from the pegs and so leaving them
in the soil.

11.2.2 Lifting
Consists of pulling the plants by hand, shaking them to get rid
of excess soil and placing them in a window. At this stage the
moisture content is between 40 and 50 per cent.

11.2.3 Wilting
Plants are left in the window for two to three days until the
moisture content has dropped to 20 per cent.

11.2.4 Cocking
Cocks are constructed so that the groundnuts dry to 10 per
cent. without damage to the kernels. Various forms of cock con-
struction are being used by farmers. The main points to be borne
in mind in their construction are:
Plant material must be kept off the ground to prevent moisture
uptake, subsequent moulding and insect damage.
Construction must allow for air movement through the cock
to facilitate rapid drying.
The top of the cock must be constructed so that water cannot
penetrate the cock during rainy spells.
Groundnuts are normally left in the cocks for three or four
weeks before picking commences.

Groundnuts.
2 October, 1976.





























300 nun
I i .L. L .
Fig. 112
Tripod commonly used for drying groundnuts.


Fig. 11.3
The A frame commonly used for drying groundnuts in African areas.

11.2.5 Picking
Picking should commence when the kernels rattle inside the pods.
Picking can be done by machine or by hand. Hand picking has the
advantage that mouldy and damaged pods can be discarded during

Groundnuts,
October, 1976. 3







picking, thereby improving quality. Output should vary from one to
two bags of pods/labourer per day. Various devices will increase this
output to three or four or even 10 bags/labourer/day.
For crops of more than about 10 hectares, hand picking can be
extremely laborious and investment in a machine picker would there-
fore be worthwhile. Two South African machines are in limited
supply in Rhodesia, the most common to date being the "Slattery"
which has an output of about 10 bags/hour. This machine produces
a good clean sample on light sandveld but additional hand cleaning
is usually required for nuts grown in the heavier soils.
The "Nigel 5" picker has a claimed output in excess of 20 bags
of Valencia groundnuts per hour when grown on sandveld. The
machine has yet to be tested for Makulu Red and Valencia on
heavier soils.
A machine currently being built in Rhodesia should pick eight
to ten bags per hour and costs about one-fifth the price of imported
machines. Evaluation and further development of this machine will
be undertaken.
11.3 Mechanical harvesting
11.3.1 Lifting
Lifting with the digger-shaker machine commences as for hand
lifting when the crop is judged to be about 50 per cent. mature.
The digger-shaker should be adjusted correctly to avoid loss of
pods. Attention to the following points is important:
Set the blades to cut all roots across their full width, i.e. position
the back end points of the blades close enough together to ensure
that all plants are cut. The blades should cut the tap root just below
the cluster of nuts on each plant. Adjust the depth wheels and tractor
linkage setting to achieve the correct depth with the blades horizontal.
Adjust the height of the leading pick-up bars low enough to
allow the crop to flow without being so low as to dig the ground
below blade level.
Set the PTO drive speed carefully, depending on forward speed
of the machine. If the PTO runs too fast, plants will be ripped from
the ground and give rise to high pod losses. Too slow a PTO speed
will result in bulldozing ahead of the pickup, in which case damage
to the rattler bars is possible.
Dig only as much as can be handled by the combine up to
about four hectares a day.
11.3.2 Wilting
The moisture content of the nuts must not be too high when
placed in the drying bins. The crop should accordingly be wilted in
the window for two or three days. Avoid over-wilting in hot dry
weather.
11.3.3 Re-shaking
Re-shaking of windows may be necessary if soil separation was
poor during the initial lifting. This operation, which should only be
performed if absolutely necessary, should be done as soon after lifting
as possible delay will result in pod loss. To re-shake the crop
remove the cutting blades from the digger-shaker and use the machine
as a "pick-up".
Groundnuts,
4 October, 1976.







11.3.4 Combining
Nuts should be in the region of 20 to 25 per cent. moisture
after two or three days' wilting. This is the optimum moisture content
for least damage during combining. Careful adjustment to the
stationary fingers, the air blast and cleaning screens should be made
according to the instruction book.
To avoid picking up clods the pick-up head should run so that
the fingers are just above ground level. Again, the speed of the PTO
drive to the pick-up mechanism should be regulated in relation to
forward speed so that the crop flows evenly into the combine. A
constant check must be kept on the picked sample, the pneumatic
elevator and behind the combine where shelled nuts and other prob-
lems can be identified.
Adjustment to the combine may be necessary as harvesting
progresses during the day and the crop dries out.
At the time of writing the Lilleston Combine is the only type of
machine available in the country Messrs. Duly & Co. are the
agents.
Earlier combine models still in use are the bagger types but a
bulk type of machine has more recently been used. Wherever
harvesting is to be done by combine, the whole crop from land pre-
paration to drying and despatch should be specially planned to avoid
delays which can be expensive.
The combine is designed to pick a relatively green crop. Although
it has been used to pick a dry, cocked crop this usually results in a
high percentage of cracked pods and shelled kernels and so should
be avoided if possible.
11.4 Drying
Increasing numbers of farmers are now drying groundnuts arti-
ficially. Some of the benefits are-
reduced field losses from rodents, termites, mould damage,
shattering, etc., while the crop is in the cock and handled dry.
Earlier cash income.
Large quantity and very much better quality hay since the
tops will still be green and whole after picking. This high
quality roughage is worth in the region of $70 per hectare
for stockfeed.
Better use can be made of many existing drying installations.
Since the crop is taken off the land early, a quicker turn-round
for the winter irrigated crop is possible.
Drying systems can be simple and inexpensive. The simplest
form is the in-bag tunnel system using ambient air. A 300-bag tunnel
can, given ideal weather conditions, be brought from 15 per cent.
moisture content to 8 per cent. or 9 per cent. in two days, drying only
during the day and using a 285 m3 per min. (10 000 cfm) fan.
Drawbacks to this system are-
it demands a fairly large labour force to stack and unstack;
a power source is necessary for the fan; and
wet weather conditions will lengthen drying time considerably.

Groundnuts,
October, 1976. 5








The addition of solar heat to improve this system has been tried
and basic data involving the use of the "Solar Sock" are given below.
The solar sock should consist of at least 30 metres of black PVA
ducting within a similar length of clear ducting.
Black ducting should have a minimum wall thickness of 600
gauge (150 micron).
Wall thickness of the clear ducting is 300 gauge (75 micron). The
clear duct is approximately 75 mm larger in diameter than the black.
To avoid undue friction losses in the duct, air velocity should
not exceed 500 metres / minute (1 600 ft. / min.). Table 11.2 shows the
duct diameter recommended for various air flows.


TABLE 11.2

Air flow Diameter of black Air flow Diameter of black
m'/minute duct in mm cfm duct in inches
100 500 4000 21
150 620 5000 24
200 700 6000 26
250 800 8000 30
300 875 10000 34



Temperature rises of over 150 C above ambient are frequently
achieved during the midday period. These could be excessive for
groundnuts, and possibly for seed maize.
Provision for shade over the "sock" would be wise in the event
of excessive solar temperatures and also for when fans are not
operating. A simple frame to support a hessian cover should be
adequate.
These recommendations are based on preliminary observations
and should be used as a guide only.
Some farmers also use heated air to dry the crop, and standard
heat exchangers, but dangers exist in drying groundnuts too fast.
Until further local experience is available it would be wise, when
considering artificial drying, to use the figures below as a guide:
(i) Maximum drying air temperature of 350 C skin slipping
and reduced shelling quality are dangers when temperatures
rise above this point.
(ii) About 7m3 per minute per cubic metre of pods is
MINIMUM air flow required.
(iii) Static pressure in the plenum chamber will vary with depth
of nuts and moisture content. About 13 mm water gauge is
correct for pods 1,5 m deep at 15 per cent. moisture content.
(iv) Drying rate should not exceed 0,5 per cent. per hour.
(v) Heated air should not be used to reduce moisture below
9 per cent. Use cold air or stack and allow to dry naturally
to 6,5 per cent.

Groundnuts,
October, 1976.







11.5 Shelling
Existing prices encourage the sale of groundnuts in the pod and
permit shelling to be done by the GMB at centralized depots. Several
sellers are available, ranging from the small hand-operated machine
producing about 22 kilograms shelled nuts per hour, to the engine
driven and PTO driven machines capable of 250 to 1 300 kilograms
per hour. Basically, the settings which are important on a sheller are
screen hole size, which should be slightly larger than the larger kernels
in a representative sample, and the clearance between screen and
beater which should be about the width of two unshelled pods.
For best shelling quality the pre-grading of pods into three sizes
is desirable. The sheller must be reset for each size.







































Groundnuts,
October, 1976. 7
























SECTION 12


POST HARVEST OPERATIONS
12.1 Picking and shelling
12.2 Drying







SECTION 12


POST-HARVEST OPERATIONS
(To replace Page 1 of September, 1973)

By G. J. Oliver,
Depart ent eof Conservation-and-Extension

12.1 Picking
Numerous systems are available:
Hand picking has the advantage that mouldy and damaged pods
can be discarded, thereby improving quality. Output should vary
from one to two bags of pods/labourer per day. Various devices
have been devised which will increase this output to three or four
or even 10 bags labourer day. For crops of more than about 10
hectares, hand picking can be extremely laborious and investment
in a machine picker would therefore be worthwhile. Two South
African machines are in limited supply in Rhodesia, the most
common to date being the "Slattery" which costs about $2 500 to
$3 000 and which has an output of about 10 bags /hour. This machine
produces a good clean sample on light sandveld but additional hand
cleaning is usually required for nuts grown in the heavier soils.
The "Nigel 5" picker has a claimed output in excess of 20 bags
of Valencia groundnuts per hour when grown on sandveld. The
machine has yet to be tested for Makulu Red and Valencia on
heavier soils.
A machine currently being built in Rhodesia should pick eight
to 10 bags per hour and costs about one-fifth the price of imported
machines. Evaluation and further development of this machine will
be undertaken on the 1974/75 crop.
12.2 Drying
Increasing numbers of farmers are now drying groundnuts
artificially. Some of the benefits are-
reduced field losses from rodents, termites, mould damage,
shattering, etc., while the crop is in the cock and handled
dry.
earlier cash income.
large quantity and very much better quality hay since the
tops will still be green and whole after picking. This high
quality roughage is worth in the region of $70 per hectare
for stockfeed.
better use can be made of many existing drying installations.
since the crop is taken off the land early, a quicker turn-
round for the winter irrigated crop is possible.
Drying systems can be simple and inexpensive. The simplest
form is the in-bag tunnel system using ambient air. A 300-bag tunnel
can, given ideal weather conditions, be brought from 15 per cent.
moisture content to 8 per cent. or 9 per cent. in two days, drying
only during the day and using a 285 m' per min. (10 000 cfm) fan.

Groundnuts,
March, 1975.







Drawbacks to this system are-
it demands a fairly large labour force to stack and unstack;
a power source is necessary for the fan; and
wet weather conditions will lengthen drying time consider-
ably.
The addition of solar heat to improve this system has been tried
and more investigation is being done to establish the optimum
diameter of plastic piping in relation to air velocity. A 30-metre
length of 540 mm diameter black plastic (layfat)'tubing inside a
590 mm diameter clear plastic tube, and used with a 30 m' per
minute air flow, provided temperature rises of up to 15C above
ambient. Some farmers are also drying with heated air, using
standard heat exchangers, but dangers exist in drying groundnuts
too fast. Until further local experience is available it would be wise,
when considering artificial drying, to use the figures below as a guide:
(i) Maximum drying air temperature of 35C-skin slipping
and reduced shelling quality are dangers when temperatures
rise above this point.
(ii) About 7 m' per minute per cubic metre of pods is
MINIMUM air flow required.
(iii) Static pressure in the plenum chamber will vary with depth
of nuts and moisture content. About 13 mm water gauge is
correct for pods 1,5 m deep at 15 per cent. moisture con-
tent.
(iv) Drying rate should not exceed 0,5 per cent. per hour.
(v) Do not use heated air to dry below 9 per cent. Use cold
air or stack and allow to dry naturally to 6,5 per cent.
12.3 Shelling
Existing prices encourage the sale of groundnuts in the pod and
permit shelling to be done by the GMB at centralized depots.
Several sellers are available, ranging from the small hand-operated
machine producing about 22 kilograms shelled nuts per hour, to the
engine driven and PTO driven machines capable of 250 to 1 300
kilograms per hour. Basically, the settings which are important on a
sheller are screen hole size, which should be slightly larger than the
larger kernels in a representative sample, and the clearance between
screen and beater which should be about the width of two unshelled
pods.
For best shelling quality the pre-grading of pods into three sizes
is desirable. The sheller must be reset for each size.











Groundnuts,
March, 1975.




SECTION 12

POST-HARVEST OPERATIONS

12.1 Picking and shelling
Picking should commence three to four weeks after cocking, when the kernels rattle inside the pods,
and can be done by machine or by hand.
SHand picking has the advantage in that mouldy and damaged pods can be discarded, thereby
improving quality. Output should vary from one to four bags of pods per labourer per day, depending
on the method of picking adopted.
Machine picking is particularly suitable for large crops. Machines in current use are capable
of picking in excess of twenty bags per hour.
The shelling of Makulu Red and other late-maturing cultivars has proved more difficult than the
shelling of early maturing cultivars. In order to reduce breakages the pods must either be pre-graded
and shelled by size, or the sheller must be set to shell the large pods first followed by a second setting
for the small pods.
Sophisticated reaping methods used in other groundnut-producing countries incorporate digging,
windrowing, picking and artificial-drying.
Recently-announced prices encourage the sale of groundnuts in the pods, thus enabling shelling
to be done at centralized depots.













































Groundnuts
September, 1973 1

























SECTION 13


MARKETING
13.1 Regulations
Contributed by G. Fairlie,
Assistant Operations Manager,
Grain Marketing Board.




SECTION 13


MARKETING

13.1 Regulations
The quality standards applied to groundnuts delivered to the Grain Marketing Board are contained
in Grain Marketing (Groundnut Acceptance Standards) Rules which are, for the time being, in force.
These rules have from time-to-time been modified to accommodate a changing pattern of delivery by
producers, and have set standards for groundnuts which were delivered almost entirely in the shelled
state, suitable for the local ration trade and for oil expressing. More recently the standards have been
used to classify groundnuts which were marketed in the shell but which contained sufficient good-
quality edible kernels to justify the use of processing plant at central GMB depots.
The standards of quality laid down may be said to hold a reasonable balance between the standards
which a producer may achieve-having applied the principles of good management to a crop from
planting to presentation-and those established by the markets in which the products are finally
sold, whether as delivered or after processing. It is now accepted that the responsibility of a producer
ends when the unshelled groundnuts are dry enough for marketing. The work of decorticating and
Grading the edible content into grades acceptable by internal and external markets demand investment
in plant beyond the scope of individual growers. Furthermore, uniformity in an end product would
be unlikely were the processing operation to be spread over numerous small farm units. Given an
expanding supply of good raw material in the form of unshelled groundnuts, the central plants will
be able to extract the maximum possible quantity of valuable kernels; the Board, from its realisation
on the sales of the end products will thus be in a position to maintain satisfactory producer prices.
In marketing, nothing is more discouraging to a producer than to find that his consignment is
returned for some reason such as .excessive moisture, sub-standard sacks or incorrect sewing. The
Board's operations staff at Head Office, district office or depot are always available to give advice or
do trial grading on any controlled product. Producers are recommended to take a few sacks to the
nearest main depot for trial grading and assessment before commencing full-scale deliveries. This
will permit the grower to rectify anything necessary in advance, and get his deliveries off to a good start.
Far more deliveries of unshelled groundnuts have, to date, been placed in the higher grades than
was the case when shelled deliveries were the rule. It is true to say that a better return has been obtained
by the growers than had the same groundnuts been farm shelled and delivered as shelled groundnuts.
Where groundnuts have been downgraded or rejected it has principally been because of the
following reasons:
Excessive extraneous matter (over 8 per cent. ) The return to the farm and subsequent reprocessing
could have been avoided had trial grading and mechanical adjustments been made before several
hundreds of bags were filled.
Skin damage Since groundnuts are not shelled before delivery, this can only be the result of exposing
the pods over-long to hot sun between lifting and picking
Broken shells Incorrect operation of picking equipment will break shells and create loose-shelled
kernels, both of which will result in penalties when the consignment is being graded.
Markedly discoloured kernels (including purple staining) Kernels are excluded from the "SMK"
category if they are markedly discoloured or have any discoloration which affects the underlying flesh.
These defects are found in most samples, and where the groundnuts have been allowed to remain in the
soil beyond the proper lifting time, in quantities which can influence the grade. Even the SMK in such
a sample, which presently are accepted without penalty, have rather a dull dark appearance making
them unattractive to buyers of edible kernels.
Diseased kernels (mould) This problem is one for which there is no ready-made remedy. An excessively
mouldy crop must be shelled. Thereafter, it will be for the producer to decide whether it will be
practical to remove the excess mould and thereby obtain a higher grade, or to accept the low grade
laid down in the rules for such a sample.
General The points made above have, in the main, referred to Makulu Red but can apply equally
to Apollo, Valencia and Natal Common.













Groundnuts
September, 1973 1

















SECTION 13








SECTION 13


ADDITIONAL NOTES ON MARKETING

These additional notes deal with fairly common queries made by
producers in the past two years.

13.2 Extraneous matter penalty: unshelled groundnuts
The penalties, or deductions from the price paid to a producer,
are published annually in the GM (Producer Prices) Notice. For
deliveries containing up to 1,5% extraneous matter (EM) no deduction
is made. Where EM in excess of 1,5% is found, deductions are cal-
culated as follows.
Over 1,5% up to 3% EM 3% of the class/grade producer price
Over 3,0% up to 4% EM 6% of the class/grade producer price
Over 4,0% up to 5% EM 8% of the class/grade producer price
Over 5,0% up to 6% EM 10% of the class/grade producer price
Over 6,0% up to 7% EM 12% of the class/grade producer price
Over 7,0% up to 8% EM 14% of the class/grade producer price
Over 8,0% EM groundnuts are returned for re-cleaning.

13.3 Broken shells in unshelled deliveries
Producers have argued that to penalize broken and open shells
is unreasonable since the entire product will be shelled in due course.
Control is necessary for the following reasons.
(a) Kernels contained in broken shells are open to contamination
by dirt and, in addition, constitute a much higher Aflatoxin
risk than kernels contained in complete shells. In pre-cleaning
operations a sample high in broken shells produces loose
shelled kernels which are deliberately rejected from the edible
kernel production stream because of the Aflatoxin risk.
(b) The insect infestation risk which is low in sound unshelled
groundnuts becomes higher when stocks contain a significant
proportion of broken shells.
13.4 Pale-skinned versus red-skinned kernels
Marketing experience has shown that realizations on the sale of
a pale-skinned crop will be better than that obtained on red-skins.
From the 1976/77 marketing year lower prices will be paid for Reds
than Pales. Growers are recommended to switch to Apollo and
Spanish in all areas suitable to the production of these types.
13.5 Classification of groundnuts
First Schedule to GM (Groundnuts Acceptance Standards) Rules
1974 published as RG Notice 288 of 1974 is reproduced overleaf.






Groundnuts,
December, 1976. 1













TABLE 13.1
FIRST SCHEDULE (Sections 2 and 3)
STANDARDS OF CLASSIFICATION, GRADE, QUALITY AND MOISTURE CONTENT
PART 1
Shelled groundnuts


Class .


Pale-skinned


Red-skinned


Crushing


Grade .... PI P2 P3 P4 RI R2 R3 Cl C2

Maximum percentage moisture .. 6,5 6,5 6,5 6,5 6,5 6,5 6,5 6,5 6,5
Maximum percentage extraneous matter .1,0 1,0 1,5 1,5 1,0 1,0 1,5 1,5 5,0
Maximum percentage unshelled groundnuts .3,0 3,0 3,0 3,0 3,0 3,0 3,0 5,0 8,0
Maximum percentage diseased kernels 1,0 2,0 3,0 3,0 1,0 2,0 3,0 10,0 -
Maximum percentage kernels with concealed
disease .. .... 0,75 0,75 0,75 0,75 0,75 0,75 0,75 -
Minimum percentage SMK retained on 8 sieve in
case of Apollo and Makulu Red .... 60,0 50,0 40,0 60,0 50,0 40,0 -
Minimum percentage SMK retained on 6,75 sieve
in case of Spanish and Valencia ..... 60,0 50,0 40,0 35,0 60,0 50,0 40,0 -
Maximum percentage broken kernels 3,0 3,0 3,0 3,0 3,0 3,0 3,0 -
Maximum percentage split kernels .. 15,0 20,0 25,0 25,0 15,0 20,0 25,0 40,0 -
Maximum percentage broken, diseased, germi-
nated, insect-damaged and undeveloped kernels 25,0 -

Condition ......... Fresh Fresh Fresh Fresh Fresh Fresh Fresh Fresh Marketable

Variety or type .. Apollo Apollo Apollo Spanish Makulu Makulu Makulu Groundnuts failing to
or or or Red or Red or Red or comply with provisions
Spanish Spanish Spanish Valencia Valencia Valencia applicable to Classes
PI, P2, P3, P4, Rl, R2
and R3


00

02


I







SECTION 14


Bibliography

Alvord, E. D., (1967). Specialist advice on groundnuts. R.N.F.U.
Crops Conference. Rhodesian Farmer.
Broad, G. H., (1966). Groundnut pests. Rhodesia Agricultural Journal
Vol. 63 (5).

Collett, W. E., (1972). Irrigated groundnut recommendations. Rho-
desian Farmer, September 1st, 1972.
Collett, W. E. When should groundnuts be lifted? Rhodesian Farmer,
May 2nd, 1969.

Department of Conservation and Extension. Recommended variety
list for the more important crops in Rhodesia, Rhodesia
Agricultural Journal, Vol. 69 (5).

Elanco Products Company. It's impossible to eat only one.
Harper, J. C., (1966). The growing of groundnuts in Rhodesia.
Rhodesia Agricultural Journal, Vol. 63 (5).

Jones, M. E., (1967). Setting and adjusting your groundnut-sheller.
Departmentof Conservation and Extension.
Jones, M. E., (1969). Shelling of groundnuts for minimum breakages.
Modern Farming, June, 1969.

Meikle, J. O., (1965). A survey of African-grown groundnut varieties
in Rhodesia. Rhodesia Agricultural Journal, Vol. 62 (6).

Rothwell, A., (1972). Groundnut diseases in Rhodesia. Rhodesia
Agricultural Journal, Vol. 69 (2).
Stead, P. R., (1968). Work study on groundnut production. Depart-
ment of Conservation and Extension.
Whiteside, J. 0. and Bailey, R. A., (1967). Application of fungicides
for the control of cercospora and leaf-spot of groundnuts.
Rhodesia Agricultural Journal, Vol. 64 (6).

Wilson, K. J., (1962). Semi-looper caterpillars in Northern Rhodesia.
Occasional papers from Mount Makulu Research Station,
Government Printer, Lusaka.



Groundnuts,
September, 1973.




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