Pakistan is facing grain storage problems at large
scale throughout the country, due to either traditional methods of seed
storage or short of commercial grain storages and their management. The
people often store their grains in godowns due to protection from hidden
enemies like birds, rats and insect pests, which cause time to time
damage to the seed.
Food grain storage is sensitive problem for the
Farmers, Grain merchants and is a serious issue to the Government all
over the country for safe storage under hygienic conditions. The
increase in production of major commodities like wheat, rice, cotton and
oilseeds of traditional and non-traditional varieties has emerged
dramatic services problem of retention for long period. The existing
storage facilities available are insufficient at various level to come
with large increase in production.
The storage of wheat and rice and seeds of pulses and
oilseed crops due to food value is important. There are seed hazards
which occur due to poor storage facilities. Wheat is only a grain crop
that is produced with low-cost technology due to minimum use of
pesticides except the inputs such as seed, fertilizer and farm machinery
etc. While crops like Rice, Cotton and Sugarcane are cost effective and
need proper care for handling and storage. Thus, hundreds of thousand of
tonnes of wheat and other food and cash crops. Such as Rice, Sugarcane
and Cotton, oilseeds and pulses had to be stored in temporary facilities
that afforded inadequate protection and pilferage.
The self sufficiency in food grain and adequate
arrangements for its storage go hand in hand. The ancient history showed
the arrangements for the storage of grain made by prophet of God Hazart
Yousif, when a worst famine hit Egypt for seven years. The prophet
Hazrat Yousif was appointed as the officer incharge over the storehouses
of the land as he was skilled custodian of food grains.
BASIC CONCEPT OF SEED STORAGE
The storage is the practice of keeping seed in store
houses, heaps, bulks and bags in such a way that seeds should retain
both food and seedling value, provided with certain conditions like
ventilation, fumigation and optimum temperature and humidity etc.
Whereas, the purpose of storing seeds is to preserve planting stocks
from one season until the next.
In cereal crops, post harvest losses are divided into
two parts, where first kinds of grain losses start from birds, rats,
insect pests and diseases, rain, delay in threshing and storage etc. The
losses of grain depends upon crop variety, grain moisture content, humid
climate and high temperature. Whereas such grain losses may be reduced
by threshing, cleanings, drying and storing of grain immediately after
harvest of the crop. The moisture content should be brought at 10-12%
The proper storage of wheat grains depends upon
timely harvest and post-harvest practices including threshing, cleaning
and drying of seeds. The wheat grains are obtained from golden ears of
this crop, which is sign of ripening due to rise in temperature in early
summer days, that are days of maturity. Wheat grain harvest must be
started in a well planned manner to avoid the rainy season. This is
amongst the good struggle of farmers who manage to produce high yields
of the best quality wheat. The most important steps which will come up
to store the grain without their spoilage of viability and nutritional
The dry wheat grain is one of the objective to have
proper procedure of storage to reduce chances of grain spoilage.
However, admixture or any adulteration in the grain including trash,
straw, dust, soil particles and grovels, may increase chances of store
grain pest attack. The storage losses due to insects, rats and moulds go
upto 10-18%. The seed quality is affected at many stages such as weather
condition before harvest at maturity, the condition between harvest and
processing, storage condition and pest problem in storage and precaution
in the causes of losses in storages may be of transport pre-storage,
storage and post storage nature. Where seeds are either admixtures,
eaten by rats and other pest, destroyed by insect pests, moulds, seeds
may be heated up and loose viability and germination capacity, which
adversely affect the next year sowing. The seeds also carry infection
and serve as source of disease for next crop.
The harvested material of any seed or variety should
be kept separately in a bulk to avoid admixtures of seed. The
precautionary measures must be taken during threshing and cleaning of
seeds. The seed graders and sieves may be used to clean and screen out
inert matter and small or undersize seeds for maintaining seed quality.
Such harvest and post-harvest practices lead to the grains which are
clean and free from inert materials. The proper storage of seeds under
hygienic condition is a measure for quality control. The storage period
starts from physiological maturity of seed to the time germination
begins. During this time period, a serious to complete deterioration in
seed quality can occur at such stages and seeds may lose their
viability. The basic reason for various storage practices is the effort
to maintain the physiological quality of seed by minimizing the rate of
The hazards may occur because of improper
ventilation, lack of control over temperature and humidity, high
moisture content in seeds, lack of control over rain due to broken
walls, floors and ceilings, spoil and uncleaned Godowns, use of old
bags, patches of insects and fungus, lack of spray and fumigation etc.
Which results in increase number of dormant seeds, sprouting, moulding
and rotting, increase of insect damage and bird contamination. However,
chemical and biological changes like loss of germination, development of
acidity, gluten deterioration and loss of nutritive quality, may also
Low capacity stores.
of local Mud bins for storage.
Uncleaned and filthy store houses.
Improper ventilation, leaky and dampness in store houses.
Inconvenient storages (with broken walls, ceilings and floors).
Unproof store houses to insect pests, rodents and birds.
Stores are unproof to gas .
Improper spray and fumigation to store houses.
Use of old gunny bags.
Seed storage in open bulks and heaps.
Insect nest and disease problems in store houses.
High temperature and humidity problems in stores.
Storing seeds with high impurities (including inert matter, dead bodies
of insects and fungus).
Unhygienic conditions of stores.
AND NEW STORAGE SYSTEM
The safe grain storage is dependent upon safe
environment. The ecological and climatic conditions in different parts
of the country consisted a warm and humid climate, which is inclined to
all kinds of biological and environmental hazards in stored grains.
There are certain new methods and techniques developed that decrease the
rate and chances of grain spoilage. The establishment of seed cleaning
and drying machineries, storage buildings, ware houses, silos, store
rooms, outside piles or bulks etc which can be used for keeping stored
grains dry and hygienic.
In rural areas of Pakistan, farmers still use Bins or
gundis, palis, kotha, khumba and barolla etc for the storage of food
grains on small scale, which are easy in handling and maintenance in
terms of store grain pest control. But, on commercial level, warehouses,
godowns, bunker, tower silos and flat-type concrete storage buildings
are used for storage purposes. Such type of storages are well equipped
with ventilation facilities for passing of air through the grain and
control the temperature to keep them dry.
In old system, small-scale farmers use clay or mud
silos for this purpose. Whereas, cylindrical metal bins are hard and are
better in preservation of grain quality, and are cost effective and
durable. At the time of selection of storages, some factors must be
considered to keep grain dry, withstand grain pressure (means more
capacious for storage), and ease of in-out movement of grain, which
determines the filling and emptying of the storage resource. This all
depends upon how economical is storage for grain storage purposes. If
the storage costs are higher than farmer capacity, it would be
impossible for small-scale growers to utilize such facilities.
The betterment in handling and storage of
agricultural produce by the use of modern scientific and technological
principles will reduce losses and improve the quality. The losses as a
result of faulty harvesting and handling methods, and above all of bad
storage are often under rated. Such losses might go upto 100% for
produce that is entirely spoiled due to lack of proper storage
However, a small cost and a little effort in this
regard, can save a lot of foreign exchange, and prevent grain spoilage
through proper planning and implementation strategies by educating
farmers to use scientific methods. The commercial Government storages
are more capacious with proper ventilation, control over temperature and
humidity, and are insect pests rodent and bird proof.
The seed is key element of the agricultural system,
which depends upon certain factors for establishing seed quality
including purity, germination capacity, vigor, seed size and health. A
large quantity of seed is damaged by fungi and insect pests during
storage, if not handled properly. After harvest and drying the seed is
packed in gunny bags and/or stored in Godowns properly. The moisture
content of seed should not exceed 14%. The seeds maintain their vigor
and germination capacity for a period of weeks to years only if storage
conditions fulfil the particular requirements for safe storage of seeds.
The storage life of cereal seeds stored at different seed moisture
contents may be as under:
The germination and vigor are influenced by the
storage conditions under which farmers store their seeds at village
level. When the farmer store his own seed, only small quantity is stored
at home or on the farm. At the mean time, some quantity of seed has to
be carried over for coming years. The purpose of storage is to maintain
the germination capacity. The life of seed comes to an end, when the
germination capacity begins to fall. The hard coat seeds such as peas,
beans, Alfalfa, Beet, Maize, Millet etc have long storage life.
SAFE STORAGE CONDITIONS
For least seed damage in storage, the seed should be
properly kept dry and cool to maintain its viability after the required
storage period. Seed respires, which produces heat and moisture. It also
absorbs heat and moisture from its surroundings and this cause
deterioration of the seed. For safe storage, temperature, humidity and
moisture content of the seed should be kept minimum. There are some
factors affecting seed storage and longevity which include temperature,
humidity, air or gases (Oz and COz) light, kind of seed, seed coat,
maturity and dormancy of seeds, seed treatment, fumigations etc. The
seeds may be stored safe at 5 per cent moisture content with a
temperature of 18°C or less. The storage under such conditions, the
loss of viability is very low. Whereas, life of seed decreases as
storage increase from O to 50°C, each 5°C increase in storage
temperature normally halves the life of seed.
The low temperature prolongs seed life, therefore
temperatures in storage areas should be kept as low as possible, in view
of storage period and economic value. The temperature range of 21-27°C
is most conducive to insect and fungal activity. In a general
phenomenon, temperature and humidity account much for the life span of
seed. The seeds containing high moisture are more susceptible to damage
at high temperature. If seeds come into contact with moist air, their
viability deteriorates sooner than if they are kept in dry storage. The
cereal seeds should never be stored with 14% or more moisture content,
but for ideal storage moisture content below 9% is necessary. There are
two sample rules which quantify the effect of moisture and temperature
on seeds. (1) For every decrease 1% in seed moisture content, the life
of the seed is doubled. (2) For every decrease of 5°C in storage
temperature, the life of the seed is doubled. The high moisture content
in the seed accelerates respiration causing accumulation of toxic
wastage products, resulting in loss of viability.
However, the moisture content of seed depends on its
chemical composition. The starchy seeds readily absorb and retain
moisture and seeds to have high moisture content. Whereas oilseeds on
the other hand, neither absorbs nor retain moisture content. It is
observed that high moisture containing seeds deteriorate faster and are
more susceptible to damage from extreme temperature, storage fungi,
insects, heating and mechanical injury. Whereas, at high relative
humidity, the life of seed is reduced, while the viability capacity
decreases and number of abnormal seedlings increases.
The seed is a source of food for insects, rodents and
other living organisms. A sufficient quantity of seed is damaged by
fungi, insect pests and rodents. The larger part of grain loss may be
saved by certain methods. Thus, the stored seed can never be quite as
good as it was before storing, so if poor seed is stored, it will be
even poorer in quality at the time of sowing.
The fungi adversely affect the quality of grain,
through increase in fat, acidity, reduction in germination, mustiness
and finally spoilage of grain. Some species of Moulds, produce toxins on
cereal- grain under certain favourable conditions, which is responsible
for human hazards and death of animals, after their use as food.
The stored grains are damaged by many insects which
due to their small size and stealthy habits, remained hidden in the
seed. The insects like Grain weevil, Red flour beetle, Grain moth,
Sawtoothed grain beetle etc. are important store-grain pests, which
cause great damage to the grain by eating away embryo of grain or seed.
Precautionary measures for safe storage
maintain high standard of godowns cleanliness. Where the proper cleaning
of storehouses should be done and rubbish should be wiped out.
The seed to be stored should be sound, healthy and free of trash.
Store house should be at such a place where grain remain safe from
insect pests, rats and humidity.
The mud plaster should be done at least one month before storage of
grains, by cementing ceiling cracks and leakages.
The proper ventilation for air crossing should be maintained in store
The seed must be dried before storage in the godowns and store houses
must be kept dry and well aerated (it means the seed and storage area
should be kept dry) before use.
The moisture content of seed should be minimized upto 8-12% or below,
for safe storage purposes.
The storage area should be safe from rain.
Pest control must be ensured at adequate level in the storage area.
Use of rodent and bird proof godowns having controlled ventilation, high
plinth and leakage free floors, doors and windows. The slope should be
given to the floors of the store for removal of water.
The bags should be kept on the raised floor or high plinth of the
stores. The bags should not come in direct contact with floor which may
damage the seed.
The insect pest proof gunny bags should be used for storing seeds.
The old bags must be avoided and new ones should be dried before use.
old gunny bags, cloth bags and containers are required to be used to
store seed, the same should be fumigated.
The bags should be kept in row stacks at high plinth build up by bricks.
The fumigation in storehouses needs air tight arrangements.
The coal smoke should be diffused in the bins, palis and store houses
while keeping the doors off for killing the insect pests.
The spray and fumigation of the storehouses should be done well before
grain storage. Before storage of grain, the Godown must be disinfected
by spraying Malathion (50% EC).
The wheat grains stored in bins and bags should be added neem leaves as
natural repellant, which must be dried first under shade before use.
The stores should be provided with electricity, offices and staff
The storage area should not be heat trap. The temperature should be low
if necessary to keep the storage as cool as possible.
Before storage of grain, the Godown must be disinfected by spraying
Malathion (50% EC).
The periodical inspection of the seed should be carried out and control
measures must be taken to avoid losses.
The measures for keeping in and taking out grain, easy access and
inspection of grain in the store houses and control over incidence of
fire should be properly managed.