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Report 3 (of 5): Prime Time
- Bangladesh
Introduction
In Bangladesh, agriculture plays a
vital role in the growth and stability of the economy,
and pulses in particular are an important part of
people's diets. Pulses such as lentil, chickpea and
mungbean are grown extensively, making the country
the world's fourth largest producer. Large areas of
land are nevertheless often left fallow after staple
rice crops have been harvested, due to the quick-drying
surface of the soil. There is a plentiful supply of
water stored deep below the soil's surface, however,
so farmers have been missing an opportunity to earn
more income and improve their livelihoods.
Research into seed priming - soaking
seeds before planting - is being carried out in countries
like Bangladesh in an attempt to make better use of
fallow land. The Centre for Arid Zone Studies (CAZS)
at the University of Bangor, Wales, funded by the
Plant Sciences Research Programme of the UK's Department
for International Development (DFID), has been carrying
out field trials with poor farmers around the world
to establish ways of reducing the time it takes crops
to grow. The research is proving that seed priming
can help to reduce growing time and potentially increase
yields, and the maximum length of time for which seeds
can be soaked is being calculated for maize, upland
rice, wheat, chickpea and sorghum.
Bangladesh
In the High Barind Tract area of north-western
Bangladesh, farmers traditionally grew only one crop
of rice a year during the kharif or rainy season (July
to October or November), then left the land fallow
until the following year. This area, covering approximately
2200 square kilometres, could be used to grow another
crop, helping farmers to increase incomes and food
supplies. Finding a crop that could chase the receding
soil moisture after the rains have stopped, one with
roots that penetrate deep and quickly and so would
be able to survive, has been part of the ongoing project
for over 20 years.
The primed chickpea on the right is mature and
ready to harvest. The non-primed crop, still
green in this photo, eventually ran out of water
and produced no grain.
© DFID Plant Sciences Research Programme
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In Bangladesh, research has shown chickpea
to be a particularly suitable crop because of its strong
rooting characteristics and its short duration. The
benefits of priming chickpea seed have been shown by
on-farm trials, which have demonstrated that soaking
the seed in water overnight before sowing improved crop
establishment and plant strength. Crop yields were shown
to increase by up to 50 per cent and the risk of crop
failure was reduced by half. This simple, low-cost,
low-risk technology has proved very effective and has
made chickpea a much more attractive crop for farmers
in this region.
Seed Priming
The cycle of plant growth - of seeds
growing into plants, which then produce seeds - is
a very important yet fragile process. Seeds must grow
and seedlings emerge quickly and consistently throughout
a field so that light, water and soil nutrients can
be used for maximum growth. In semi-arid environments
in the tropics, unpredictable rainfall, poor soil
and poor quality seed can often mean that crops fail
or are of poor quality.
A seed germinates when it absorbs
sufficient moisture from the surrounding soil. In
drought years, moisture absorption by the seed is
uncertain, if not impossible. Providing moisture directly
to the seed through soaking it in water before sowing
in order to give it a head start is not a new idea,
and farmers and their families in countries such as
India, Nepal, Pakistan, and Zimbabwe have long soaked
seed.
How to...
Seeds are primed by placing them in
a suitable container and covering them with clean
water, usually overnight (about 8 hours), so that
they can soak up the water before planting. Farmers
can prime their own seeds if they know the maximum
length of time for which their seeds can be soaked
before seed or seedling damage occurs. These limits
are calculated for each variety so that germination
will not continue once seeds are removed from the
water. Recommended safe limits tested in over 100
farm trials (with only minor differences depending
on variety and country) include:
- Rice: 24 hours
- Wheat and Barley: 12 hours
- Upland Rice and Maize: 16 to 18
hours
- Sorghum and Pearl Millet: 10 hours
- Chickpea and Mungbean: 8 hours
After the seeds have been soaked for
the appropriate length of time, the water is drained
off and the seeds are surface-dried by placing them
on a cloth or plastic sheet on the ground for 15 to
30 minutes or, for small amounts of seeds, rolled
gently in a dry cloth so that they do not stick together.
In most cases, seeds can be primed
overnight and simply surface-dried and sown on the
same day. Apart from a slight increase in size, primed
seeds are virtually identical to non-primed seeds
and can be treated in the same way. If primed seeds
are surface-dried and kept dry they can be stored
for several days, then sown as usual, and still perform
better than non-primed seeds. However, primed seeds
will only grow if they take up additional moisture
from the soil after sowing. Sowing pre-germinated
seeds where there is little or no water can therefore
be disastrous.
Improving Crop Yields
In Bangladesh, farmers were encouraged
to soak some of their seeds overnight, surface-dry
them, and sow using traditional methods. Groups of
farmers visited each other's fields to see the performance
of primed seed where different soil types and management
were being used. The groups then discussed the strengths
and weaknesses of the technique and made constructive
criticisms and improvements.
The participatory approach was very
successful in enabling farmers to test, develop and
adapt seed priming and to appreciate its effects.
As a result there was rapid farmer-to-farmer and village-to-village
spread of knowledge about seed priming. On-farm seed
priming in areas where farmers have tried the technology
for themselves is now well under way.
Crops
In marginal environments, crops often
grow slowly and are vulnerable to stresses such as
drought, pests and diseases. Farmers can choose to
re-sow seeds, but this involves a large physical and
financial burden that many simply cannot afford. The
seed priming project has field-tested a wide range
of tropical and sub-tropical crops, all considered
important food crops that are valuable to poor farmers'
livelihoods. These include wheat, barley, maize, rice,
sorghum, millet and chickpea.
Chickpea
Chickpeas (Cicer arietinum
L.) are grown from India, the world's largest producer,
to Australia and Turkey, which are now major exporters
of chickpeas. Chickpea is an increasingly popular
pulse, and much research has been carried out to understand
more about it. The focus has turned to allowing farmers
to achieve greater yields and boost production of
chickpeas around the world. Two types of chickpea
are grown, desi and kabuli:
- desi is thought to
have originated first and is mostly grown in Bangladesh,
India and Pakistan. It produces small, coloured
(mostly brown) seeds. Desi chickpeas must be dehulled,
split and ground into flour. In these countries
the flour from desis is a staple in the diet.
- kabuli produces a
larger, cream-coloured seed grown mainly in Turkey,
Syria, Iran, Mexico and Morocco. Almost all the
countries with high chickpea yields are producers
of kabuli and yet it is often more prone
to climatic and disease stresses. Major uses are
for salad bars, humus, falafel and vegetarian dishes.
Mr Musa points to a plot established using primed
chickpea seeds. Seeds failed to establish
properly in the non-primed plot to his left.
© DFID Plant Sciences Research Programme
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The chickpea plant is technically
classed as a garbanzo bean, and acts more like a
bean plant than a pea plant. It has a deep tap-root,
2-6 feet deep, is drought tolerant and stands about
50 centimetres (20 inches) tall. Chickpeas produce
1-2 peas per pod and require stress to set seed.
They like daytime temperatures of 20-30șC and night
temperatures of 18-20șC. The plant matures in 120
days and is relatively easy to harvest with conventional
equipment.
Diseases
- Ascochyta blight (Ascochyta
rabiei) is the most destructive fungal disease
of chickpea and 100 per cent losses are known
to occur in vulnerable varieties.
- Fusarium wilt (F. oxysporum
f.sp ciceri) is a major disease that
affects crops grown in tropical regions. The
wilt pathogen is both seed- and soil-borne and
can survive in the soil, in the absence of chickpea,
for more than six years.
- Botrytis grey mould (B.
cinerea Pers.) affects crops grown in the
sub-tropics and has caused devastation in parts
of Bangladesh, Nepal and northern India. For
varieties that are not resistant to this fungus
it is recommended that chickpea is intercropped
with linseed, which is resistant to the disease.
Pests
Nearly sixty insect pests are
known to attack chickpea, including pod borers,
leaf miners, aphids and bruchids.
- Helicoverpa pod borers (H.
armigera) are the most devastating insect
pests of chickpea in the tropics and subtropics.
Mixed cropping of chickpea with other crops
such as wheat and mustard can help to reduce
losses. In many areas, early sown crops suffer
less damage than late sown crops. Biological
control of H. armigera is possible using
sprays made from the naturally occurring nuclear
polyhydrosis virus (NPV).
- In the Mediterranean and Eastern
Europe, the leaf miner (Liriomyza cicerina)
causes the most insect damage. Spraying with
neem seed extract is relatively effective but
does not last for long periods of time. Sowing
crops early is recommended as this produces
higher yields than late sown crops, and early
crops are also less prone to leaf miner damage.
Natural threats
The major natural threats to chickpea
are cold, heat and drought. Drought can limit
productivity, particularly as chickpea is usually
grown as a post rainy season crop. Sowing seeds
earlier in certain regions can alleviate the effect
of water stress and increase seed yield but the
best results are achieved through growing drought-resistant
plants that are generally early maturing.
Chickpea crops are also sensitive
to salt which is a major problem in India and
Pakistan, where over 85 per cent of the world's
chickpeas are grown. Improved drainage can be
effective in areas where the water table is high;
otherwise it is recommended that chickpea should
not be grown in salt-affected areas.
N.B E-mail addresses for all contacts
in the table can be found in the further information
section.
Priming the Future
Seed priming provides a low-cost
practical solution to using fallow land, independent
of the crop variety used. The project has shown
that with all the crops, and particularly rice
and maize, seeds soaked in water overnight produced
better results than seeds not soaked. The initial
trials in the High Barind Tract of Bangladesh
have been successful, and the technology is being
applied elsewhere in other rice fallow systems
in Bangladesh and over extensive areas in Nepal,
India and Pakistan.
For further information, please
contact:
Dr David Harris
DFID Plant Sciences Research Programme
Centre for Arid Zone Studies
University of Wales
Bangor
Gwynedd LL57 2UW
United Kingdom
Tel. +44 1248 382 922
Fax +44 1248 371 533
Email: D.Harris@Bangor.ac.uk
Website: http://www.seedpriming.org/
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| Country Contacts:
Dr Azam-Ali: sayed.azam-ali@nottingham.ac.uk
Mr Bam: Rbam@forig.org
Mr Bittaye: bittayea@yahoo.com
Dr Chaitep: sptrest@loxinfo.co.th
Dr Fademi: ncri@skannet.com
Mr Gangwar: gvteirfp@vitalmail.com
Dr Harris: D.Harris@bangor.ac.uk
Dr Heinrich: G.Heinrich@cgiar.org
Dr Jones: r.jones@cgiar.org
Dr Joshi: kdjoshi@mos.com.np
Mr Mian: undp@brain.net.pk
Mr Mondal: asa@satyam.net.in
Dr Monde: cban@sierratel.sl
Mr Musa: musaprova@rajbd.com
Prof. Rashid: eusp@netzone.net.pk
Dr Riches: charlie.riches@bbsrc.ac.uk
Dr Roy-Macauley: ceraas@sentoo.sn
Mr Sodhi: gvtbhopal@sify.com
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Bangladesh Agricultural
Research Institute (BARI)
Joydebpur
Gazipur 1701
Bangladesh
Tel. +880 2 9252715, 9252087
Fax +880 2 9252087, 9252713
Email: barires@bttb.net.bd
BARI is a multicrop research
institute devoted to research on a wide
variety of crops other than rice, jute,
sugarcane, and tea. Crops include cereals,
oilseed, pulses, tuber crops, horticulture
crops, and spices and condiments. |
Websites
http://www.seedpriming.org/
http://www.dfid-psp.org/
UK Department for International Development's
Plant Sciences Research Programme (PSP)
http://www.cazs.bangor.ac.uk/
Centre for Arid Zone Studies, Bangor
This document is an output
from a project funded by the UK Department for
International Development (DFID) and the European
Commission (EC) for the benefit of developing
countries. The views expressed are not necessarily
those of DFID or the EC.
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