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Thinking of farming or growing groundnuts this season - hope you are ready for this comprehensive guide on how to grow groundnuts - it's the the full groundnut farming guide for beginners.To cultivate groundnut is easy and profitable too!
Groundnut
is a self-pollinating, indeterminate, annual, herbaceous legume. Natural
cross-pollination occurs at rates of less than 1% to greater than 6% owing to
typical flowers or the action of bees. The fruit is a pod with one to five
seeds that develops underground within a needlelike structure called a peg, an
elongated ovarian structure.
Groundnut
emergence is intermediate between the epigeal (hypocotyl elongates and
cotyledons emerge above ground as in soya beans) and hypogeal (cotyledons
remain below ground as in field pea types).
The
hypocotyl elongates, but it usually stops before the cotyledons emerge. Leaves
are alternate and pinnate with four leaflets (two pairs of leaflets per leaf).
The groundnut plant can be erect or prostrate (20–60 cm tall or more) with a
well-developed taproot and many lateral roots and nodules. Plants develop three
major stems, i.e. two stems from the cotyledonary axillary buds equal in size
to the central stem during early growth.
Bright
yellow flowers with both male and female parts are located on inflorescences
resembling spikes in the axils of leaves. One to several flowers may be present
at each node and they are usually more abundant at lower nodes.
The
first flowers appear at four to six weeks after planting and maximum flower
production occurs six to ten weeks after planting. Eight to fourteen days after
pollination, aerial pegs will grow 5 cm to 8 cm into the soil and then turn to
a horizontal orientation to mature into a peanut pod.
Pods
reach maximum size after two to three weeks in the soil, maximum oil content in
six to seven weeks, and maximum protein content after five to eight weeks. The
crop matures after seven to nine weeks in the soil, which is indicated by
maximum levels of protein, oil, and dry matter, and the presence of darkened
veining and brown splotching inside the pod.
Groundnuts
usually require a minimum of 100 to 150 days from planting to maturity,
depending on the variety planted. Flowering continues over a long period and
pods are in all stages of development at harvest.
Pegs
will eventually rot in the soil (25% after 12 weeks in the soil) and the
resulting loose pods are lost during the harvest. Because the pod wall is
needed to protect the seed, as it is moved through the various markets from
producer to processor or consumer, yields and farm prices are based on pods
rather than seeds.
Climatic requirements Temperature
Groundnuts
require a high temperature and a frost-free period of about 160 days.
They
will not reach optimum maturity for a marketable yield to justify commercial
production in areas with fewer heat units during the growing season. They are
very sensitive to low temperatures and seeds should only be planted when the
minimum temperature stabilises above 18 °C. Germination is 95% at soil
temperatures ranging from 18 °C to 30 °C. The suitable vegetative growth
temperature ranges from 20 °C to 35 °C. However, at 33 °C this declines to 84%.
A favourable temperature for flowering and pod formation is about 28 °C.
Higher
altitudes with cooler climates are not suitable for groundnut production. Avoid
planting in dry soil and irrigating during cold spells or planting in cold, wet
soil.
Water
Moisture is another critical factor for successful groundnut production.
Planting must be done on moist warm soils to speed-up the germination process.
Research
has shown poor germination in drier soils. Available soil moisture content is
also commensurate with row width. Wider rows are advisable in low-rainfall
areas while the opposite is true in higher-rainfall areas.
Rainfall
in the region of 500 to 700 mm per annum will be satisfactory for good yields
of groundnuts.
Soil requirements
Groundnuts
grow best in well-drained, red-coloured, yellow-red and red, fertile, sandy to
sandy loam soils with a pH range of 5, 5 to 7, 0. Saline soils are not suitable
because groundnuts have a very low salt tolerance.
Soils
with more than 20% clay and stones will result in poor yield and make
harvesting difficult. Shallow and compacted soils are not preferred as the
taproot of groundnuts can penetrate to the soil to a depth of about 2 m. The
most suitable soil forms are Avalon, Bainsvlei, Clovelly, Hutton, Pinedene and
Glencoe
CULTIVATION PRACTICES CULTIVATION
PRACTICES
Soil
preparation Seedbeds should be prepared either on flat or widely ridged fields.
Primary soil cultivation is necessary on virgin soils or any other soil type to
remove debris and break the plough layer.
A
uniform seedbed with sufficient planting depth and spacing, good germination,
weed control and sufficient moisture retention is imperative for good yields.
All plant residues should be incorporated well into the soil. Producers often
grow groundnuts in a minimum till system.
This
cannot be recommended as the soil layer where the pods develop should be devoid
of plant residue. Where plant residue is present, pods rot diseases increase,
influencing yield and quality. For successful groundnut production, deep
ploughing should be implemented.
Field layout and design
The
slope should be favourable and the field should be well-protected from soil
erosion through the construction of contours and field waterways.
Avoid
using fields with too much clay and fields that were planted to groundnuts the
previous year. The field should be protected from soil erosion by means of
contour ridges and waterway channels.
Planting
The planting
date for groundnuts should be as soon as enough rain has fallen and minimum
temperatures are met, usually from mid-October to mid-November. Late planting
(from December onwards) results in lower yields.
The
correct planting depth of 5 cm to 7, 5 cm ensures that the plant develops and
produces optimally.
The
preferred population density is 150 000 plants per hectare under dryland and
300 000 plants per hectare under irrigation.
The
best spacing between rows under rainfed conditions should be 90 cm with a
spacing of 4 cm to 7 cm between the plants; and 30 cm to 35 cm under
irrigation. The ideal intra row spacing is between 50 to 75 mm for all
available cultivars.
Fertilisation
Substantial
evidence exists to show that groundnuts respond well to additional fertiliser
applications, even though in rural situations this is not imperative.
Groundnuts are adapted to a soil with a pH (H20) of 5, 3 or higher.
If
the pH is higher than 3, 5 to 8, 0, certain elements become unavailable, e.g.
iron and zinc. Being a leguminous crop, groundnuts can fix atmospheric nitrogen
(N) with the aid of root bacteria.
For
this reason this crop is not dependent on nitrogen fertilisation. Root nodules,
which fix nitrogen effectively, have a pinkish appearance when dissected.
Groundnuts with effective root bacteria do not need additional nitrogen. It has
often been accepted that groundnuts prefer residual phosphorus to freshly
applied P.
In
rural fields, however, the level of P is usually low and it should be applied.
Like other crops, groundnuts require adequate levels of potassium for normal
growth and development. An oversupply of potassium in the soil can induce a
calcium deficiency, which is reflected in a lower yield and quality.
In
situations where the soil potassium level is low, additional potassium can be
applied. In most cases, approximately 10 kg/ha of potassium is probably
sufficient, although it is very seldom required. Calcium (Ca) is very important
for seed development and is regarded as an essential element in groundnut
production.
Groundnuts
are particularly susceptible to a calcium deficiency in the soil. Where a crop
is grown on calcium deficient soils, the producer will have a direct seed loss
as well as indirect damage to the seed, which is not always visible.
Seed
produced under such conditions is not suitable for planting. Seedlings are
often misshapen with a low vigour and the heart or embryonic axis is usually
damaged to such an extent that no germination takes place. In situations where
less than 100 mg/kg of Ca is present in the soil, gypsum is added at a rate of
200 kg/ha.
Boron
(B) deficiency symptoms occur in very sandy soils and can affect quality. In
cases where boron deficiency symptoms have been observed, boron could be
applied with or after planting at a rate of 1 kg/ha. In acid soils in which the
pH (KCl) is lower than 4, 8, molybdenum could be unavailable. In these
situations it is advisable to treat the seed with molybdenum by applying 50 g
sodium molybdate per 50 kg seed.
Molybdenum
can also be applied to the plant row 10 to 14 days post-emergence.
Irrigation
Most
of the cultivated groundnuts in Africa are under dry land. Irrigation can be
done in areas with limited soil moisture/low rainfall areas so that production
and quality can be maximised. The irrigation method will depend on the
available water resources and the available irrigation equipment.
Avoid
application of excess moisture by ensuring that scheduled irrigation is
practiced. A great deal of moisture is needed before flowering and during pod
filling (moderate during flowering and no application is required during
ripening).
Weed control
Groundnut
is susceptible to a wide range of weeds that are in severe competition with it
for available soil moisture, soil nutrients, light, space, etc., and others
which serve as hosts for diseases. Weeds can result in low yield and poor
quality of the groundnut seeds, as well as making harvesting difficult.
Therefore,
an integrated system, ranging from the chemical and mechanical to the
biological, should be used in order to prevent weed suppression. Effective weed
control implies good control of weeds throughout the growing season.
Mechanical: Three mechanical weeding operations
are important (assuming no herbicides are applied). The first is done prior to
emergence of seedlings, which is usually about seven days after planting. The
second one will be performed at 21 to 28 days after planting, while the last
cultivation is dependent on weed growth, but should not be delayed later than
60 days after planting.
Chemical: Chemical weed control is also
recommended on groundnuts. Several herbicides are registered for utilisation;
however, the choice of herbicide and the concentration applied will largely
depend on the species of weeds involved and the level of infestation.
Labels
on the herbicide should be studied carefully and emphasis should be placed on
the following:
•
Waiting period for both ensuing and previous crops
• Application
rate based on clay percentage of the soil
•
Application time, conditions, etc. Disease and pest control Diseases in
groundnuts can be classified as leaf, stem and pod diseases, and particular
viral diseases are also encountered. Insect pests such as termites could also
plague the groundnut farmer.
All
of these diseases can be identified using the Publication Groundnut Diseases
and Pests of the ARC-Grain Crops Institute. The most prevalent diseases remain
early leafspot and Sclerotium stem rot.
These
diseases are both difficult to control. Early leafspot is recognisable by the
brown spots on the leaves which are surrounded by a yellow halo. Stem rot may
be identified by the white mycelium (fungal growth) in the stems, pegs and
pods. Both diseases are particularly devastating when the weather is warm and
the soil is moist.
Other cultivation practices
Rotational
benefi ts Groundnuts, like other annual legumes in a rotation, offer several
cropping advantages for the producer.
Groundnut
yields often increase when the crop is planted after non-legumes because of the
following factors:
•
Disease and insect cycles become disrupted.
•
Alternative herbicides can be used to kill grassy weeds.
•
Soil nutrients are used efficiently. Inoculation Groundnut is a leguminous
crop, and it has the ability to fix 60% to 70% of its nitrogen requirement from
the atmosphere under ideal conditions.
Groundnut
has a very specific relationship with Rhizobium bacteria and it is essential
that an inoculant should be used. Under good growing conditions, groundnut is
considered a relatively good nitrogen fixer, provided that it is inoculated
with an appropriate strain of Rhizobium.
Other
practices include intercropping, use of good cover crops to improve the soil,
organic matter management, construction of diversion ditches, tilling and
planting along contours, construction of terraces, conservation tillage and
improving soil drainage.
Harvesting
Harvest
maturity In order to determine the best harvest date, a farmer must scout
his/her crops on a regular basis, as the groundnut plant usually gives an
indication of when to harvest. The number of days to maturity varies with
cultivars.
There
are some characteristics that require close attention and observation to
determine harvest maturity, namely:
•
Pod colour—inner walls display a dark-brown colour as a result of darkening of
the inner tissue of the hull. When 75% of the pods of the selected number of
plants have reached maturity by showing the dark discoloration, harvesting can
start. The outer wall of the pods should display various shades on the inner
cell layer when scraped with a knife. The colours are white on the immature and
yellow pods, and orange, light brown or black on mature pods. Harvesting can be
done if 70% of the pods show the other colours except white.
•
Seed colour—the colour of seeds in the pods can also be used as an indication.
Young, immature seed is usually white in colour and changes to pink and dull
pink as the seed matures. • Leaves—the leaves develop a yellow colour and are
dry at the tips.
•
Prevailing weather conditions—these can influence the determination of the
harvest date because they influence quality. Drought determines the harvest
date when the soil is desiccated to such an extent that the plant withers and
the seeds in the pods begin to shrivel and take on a ripe appearance. Such
groundnuts must be harvested immediately.
Harvesting methods
MECHANICAL: The digger-shaker-windrower is used
to lift groundnuts and detach them from the soil. Dig deep enough to prevent
cutting pegs. Windrow-inverting attachments orient plants as they leave the
shaker so pods are primarily on the top of windrows to permit greater air
circulation and exposure to sunlight for a shorter drying time.
Windrowed
groundnuts could be combine-harvested wet (35% to 50% moisture), semidry (18%
to 25%), or dry (8% to 10%). These pods could reach a semidry condition (seeds
rattle in pods) one to three days after digging. Drying in the windrow to a
moisture level of 8% to 10% requires five to ten days of good drying weather.
However,
groundnuts remaining in windrows for several days are more susceptible to
weather damage than those that are freshly extracted. Combining wet (green) or
preferably semidry groundnuts, followed by artificial drying, could result in
better-quality nuts.
Adjust
combines regularly to give better picking action when vines are tough, and
reduce picking action when vines are dry, to obtain good picking efficiency and
minimise mechanical damage to the hulls.
MANUAL: This method involves very careful
operations that, if improperly done, could result in some groundnuts being lost
in the soil.
•
Lifting or loosening the groundnuts: This involves severing of the taproot
below the soil surface with a “blade” implement normally at a depth of 10 cm to
15 cm.
•
The stacking process: After several hours, groundnuts can be packed into
bundles and stacked. It is important to shake off loose soil before stacking.
The stacks are formed with a core of 15 to 40 plants placed on their leaves
with the pods facing upward. A properly formed stack will not lodge or become
damp when it rains. The stacks are then left on the land for four to eight
weeks for final ripening and moisture loss before being picked.
•
Picking and shelling: This should be done with the correct picker. The method
of picking involves removing the pods from the entire plant. Plants are fed
into the picker and the shells are separated from the plants. Close monitoring
of the process is necessary in order to detect any defaults that could affect
the quality of the kernels.
•
Shelling: Hand-operated machines are available for shelling groundnuts pods.
Pods should be cleaned before being fed into the sheller. Close monitoring to
avoid quality loss is also important during shelling.
POST-HARVEST HANDLING OST-HARVEST
HANDLING
Sorting
Sorting
is done to ensure that foreign materials, weed seeds, undesired split seeds,
stones and leaves are removed from the desired seeds. Grades of groundnuts
should be sorted according to their colours and sizes so that market demands
can be met, and they must be free from insects and musty, sour and undesirable
odours; they must also not contain any substance which renders them unfit for
consumption and processing.
Sorted
groundnuts must comply with the requirements for permitted tolerances for total
Aflatoxin as well as Aflatoxin B1.
Grading
There
are five classes of groundnuts, namely Class A, Class B, Class C, Class D and
Class E.
Specifications
for classes A consignment of groundnuts is classified as:
- · Class A, if it contains at least 97% of the Red Spanish type of groundnuts (for example Harts)
- · Class B, if it contains at least 97% of the Spanish type of groundnuts (for example Natal Common, Selection 5, Sellie, Agaat, Jasper, Robbie, Akwa, Kwarts and Anel)
- · Class C, if it contains groundnuts that cannot be classified in accordance with the same standards and requirements as for Class A, Class B, Class D or Class E groundnuts
- · Class D, if it contains at least 97% of the runner-type of groundnuts (for example Norden) Class E, if it contains at least 97% of the Virginia runner-type of groundnuts (for example Selmani)
The
grades for the different classes of groundnuts are: • Choice grade • Standard
grade • Machine-cleaned choice grade • Machine-cleaned standard grade •
Machine-cleaned crushing 100/130 • Machine-cleaned splits • Hand-cleaned splits
• Crushing grade • Sundry machine-cleaned 80/100 • Sundry hand-cleaned 80/100 •
Crushing hand-cleaned 100/130 • Pods hand-cleaned • Grade other
Packaging
Groundnuts
of different classes (with the exception of Class C) and grades cannot be
packed in the same container.
For
the purposes of the application of the regulations a consignment of groundnuts
should be packed in containers that are suitable, intact, clean, dry, odourless
and strong enough.
Storage
The
seeds should be dried to a moisture content not exceeding 7%.
A
silo can be used to store the dry seeds. The storage structure should be free
of moisture to prevent moulding/micro-organism build-up. Groundnuts are usually
stored in the form of unshelled nuts.
Seven
to eight months’ storage is usually required for groundnuts used as seed, and
those intended for food uses can be stored until the start of the next harvesting
season.
The
stored seeds should be regularly inspected to maintain proper health and for
sanitary measures.
Transport
The
most frequent mode of transport for groundnuts is by road trucks or railway
wagons and ships, and in very rare instances air cargo can be used. The
tremendous increase in the fuel price in South Africa could affect the
producers’ profit if the seeds are to be sold in remote areas.
Marketing
Groundnuts
are sold mainly as edible groundnuts and crushed groundnuts, as seed and for
the animal feed industry.
Marketing
of groundnuts, like any other crop, is free of government intervention.
Producers are able to take advantage of the freemarket system through
techniques such as hedging and market research.
However,
the producer price for groundnuts is always fluctuating. Global trade requires
phytosanitary standards and quality, and several certificates. Locally and
internationally, an increase is expected in the demand for groundnuts as a
result of the biofuel initiatives worldwide.
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