TNAU Agritech Portal :: Crop Protection

Crop Protection:: Storage Structures

To cope with the current and future demand of the increasing population for the food grains, it is emphasized to reduce the loss of food during and after harvest.
Food grains are stored for varying periods to ensure proper and balanced public distribution throughout the year.
Post harvest losses in India are estimated to be around 10 per cent, of which the losses during storage alone are estimated to be 6.58 per cent.
But, with the advent of improved agricultural technology, the farmer can afford to store the grains for longer period with minimum loss.

For best storage performance

The produce must be thoroughly cleaned and graded,
Dried to the safe storage moisture level of 10-12 % for food grains and 7-9% for oil seeds (on wet basis) for a safe storage period of 6-12 months.
Storage structures should to be properly repaired, cleaned and disinfected,
Structures should bear the load of grain stored and do not permit contact/exchange with outside humid air,
Structures should be constructed in the coolest part of the house/ farm.

An ideal storage facility should satisfy the following requirements

It should provide maximum possible protection from ground moisture, rain, insect pests, moulds, rodents, birds, fore etc.,
It should provide the necessary facility for inspection, disinfection, loading, unloading, cleaning and reconditioning.
It should protect grain from excessive moisture and temperature favourable to both insect and mould development,
It should be economical and suitable for a particular situation

	Grains can be stored in bulk or in bags. (a) Bulk (open) storage: Farm products are sometimes stored in surface structures in a loose form. It is preferred over bag storage for the following reasons Large quantities of food grain can be stored No difficulty in loading and unloading of grain No need to purchase storage containers like gunnies Insect incidence is less than bag storage, even this can be eliminated by fumigation in situ Avoids waste from leaking bags Easy inspections- save labour and time.

	(b) Bag storage Storage farm products are stored after placing them in gunny bags made of jute. Advantages Each bag contains a definite quantity which can be bought, sold or dispatched without difficulty; Bags are easier to load or unload. Infested bags-can be removed and treated easily Problem of the sweating of grains does not arise because the surface of the bag is exposed to the atmosphere.

Storage structures used by the farmers are

Gunny bags of different capacities (35, 50, 75 and 100 kg) with or without inside
Plastic lining.
Mud bins having 100 – 1000 kg capacity
Baked earthen containers of 5- 100 kg capacity
In heaps on flat floor in the corner of houses (100- 1500 q).
Bamboo structures
Wooded bins and
Underground structures

CONVENTIONAL STORAGE STRUCTURES

Structures	Make	items	Capacity	Remarks
1.Bamboo Structures	Split bamboo woven in the form of a cylinder with wide base and narrow mouth	Paddy, wheat and sorghum	500 kg	Life 4-5 years. Weight loss due to insect attack is 5 % in paddy and 15 % in sorghum.
2. Mud and earthen structures	Clay, straw and cow dung- 3:3:1. earthen structures are made, sun dried and then burnt in fire	Paddy, wheat, sorghum, oil seeds and pulses	5 to 10 q	Life 8- 10 years. During rainy season develop cracks and moisture absorption followed by insect and mould infestation.
3.Wooden structures	Local wood is painted black. At the top, 30cm x 20 cm inlet and at the bottom 30 cm x15cm outlet is provided	Paddy	10 q	15- 20 years. Neither airtight nor moisture proof.
4. Brick structures	Rectangular, structures built as part of the house, with brick in cement or lime mortar having a wall thickness of 40 –50 cm. At the top 50x 50 cm inlet and at bottom 15 x15 cm outlet is provided.	Paddy, sorghum and wheat	25- 30 q	25- 30 years. High initial cost, not insect and moisture proof.
5.Underground structures	Circular pits vary from 100 – 400cm in depth and 50 – 100cm dia at neck and250 – 300 cm at the bottom. For filling and emptying there is an opening at the top. Before filling the sides and bottom are packed with straw and husk. After filling the pit is gain covered with straw and stone, the finally with mud.	Cereals	100 –200q	Safe against insects but, loss of seed viability and handling difficulties made it out of date
6. Miscellaneous plant materials a. Paddy straw b. Stem of vitex and pigeon pea stalks c. Bottle gourd shells	a. Paddy straw is wound in the form of rope to varying diameter b. stems wound like a bin and both sides are plastered with mud and cow dung c. empty shells are used	Paddy, other cereals and pulses Paddy and Other cereals Pulses, gourd seeds	30–100q 1-2 q 2-5 kg	Not insect and rat proof Temporary Only small quantity of seed lots.
7. Metal corrugated G.I. sheets	Sheets of about 3 m high are held vertically along one edge and edges of the other sheets are overlapped and bolted to each other. Thus the circle with 2-4 m dia. is completed with many such sheets. They are covered on the top with the plain M.S. or G.I. sheets.	Various types of grains	Vary	Temporary
8. Hessian cloth bags
9. Gunny bags

Improved rural-level storage structures

1. Bitumen/ coal tar drum

An alternate model of metal bin, low cost with similar technical performance.
These bins are of 520 mm dia and 900 mm height. They can store 1.5 q of wheat and 1.2q of Bengal gram.

2. Hapur bin/ Kothis

Circular bins of 2, 5, 7.2 and 10 q capacities and have potential to meet requirements of even large farmers.

3. Udaipur bin

These bins are made out of used coal tar drums.
These can stock 1.3 q of wheat and maize.
These bins can be made to have more airtight lid if the drum outlet end is given small cut to unload the bitumen.
These bins are suitable for storing of food grains for short duration and can be adopted by small farmers.

4. Stone bin

Stone bin (Chittore bin) is made of locally available 40 mm thick stone slabs with dimensions of 680 mm x 1200 mm with square cross-section.
The inlet and outlet are made of asbestos. This bin has a capacity of 3.8 q.

5. Bamboo bin

These bins are made of two walls of bamboo with polythene lining in between and have varying capacities.
These bins are suitable for short – duration storage and can be adopted by small and marginal farmers.

6. Baked clay bin

Baked clay bin of 7q capacity (paddy) is made of 16 burnt rings jointed by mud plaster; cement mortar and cow dung coatings one after another.
The ends of the rings are made in such a manner that they fit into each other.
These rings are kept on a polythene sheet covered and plastered platform of brick mansory and cement sand mortar.
An outlet is provided for the discharge of the grain.
The top is covered with a mild steel lid. Because of the low cost and good performance these are particularly useful for small and marginal farmers who do not store their produce for longer duration.

7. PKV bin

Made from green bamboo splits into suitable sizes.
The tunnel, outlet flap valve and complete stand can be fabricated in a workshop.

8. Pusa bin

It is a modification of the ordinary mud storage structure commonly used in villages.
To provide moisture proof and airtight conditions, polyethylene film of 700 gauge thickness has been embedded at the top, bottom and on all the sides of the mud bin.
The embedding process provides mechanical support and safety to polyethylene film.
The construction of outer walls with burnt bricks up to 45 cm height makes the structure rat proof as well.
The bin is constructed with un burnt bricks on burnt bricks or concrete floor to avoid rat burrowing.
The grain and seed both remain safe in the bin for more than one year with proper precautions.

9. Pusa Cubicle

This is a room like structure ( 3.95 x 3.15 x 2.60 m), a modification of Pusa bin to provide large storage capacity of 24 tonnes on a platform of 3.73 m x 2.93 m x 0.07 m is made with unburnt bricks on a concrete floor (except 22 cm of outer sides with burnt bricks).
A polyethylene sheet is placed on this platform and another platform of similar dimension is made with unburnt bricks.
The 22 cm thick inner walls are constructed upto 2.6 m height. A wooden frame of 1.89m x 1.06 m for door is fixed in the front side of 3.95 m wall.
The roof can be made by wooden beam placed at 15 cm distance and covered with unburnt bricks.

10. Pusa Kothar

Presently storage is practiced in small compartments of a room (5.3 m x 2 m x 4 m) called kothar.
The roof is constructed with the help of wooden poles and mud slabs, leaving near the front wall three filling holes each of 0.5 m x 0.5 m size.
Two out lets of G.I. sheets of 15 cm dia. and 30 cm length are fitted at the floor wall on the front side.

11. Metal bins

Bins made of steel, Aluminium R.C.C are used for storage of grains outside the house.
These bins are fire and moisture proof.
The bins have long durability and produced on commercial scale.
The capacity ranges from 1 to 10 tonnes. Silos are huge bins made with steel/ aluminium or concrete.
Usually steel and aluminium bins are circular in shape.
The capacity of silo ranges from 500 to 4000 tonnes. A silo has facilities for loading and unloading grains.

STACKING

Food grains have to be stored and preserved on scientific lines in godowns till they are issued to consumer.
Te bags containing food grains cannot be just dumped inside the godown, for it will not facilitate proper storage.
Proper stacking ensures free access to the stocks in all parts of the godown for inspection and helps in effective disinfestations work. Generally, three methods of stacking are being followed: 1. Simple, 2.Cross and 3. Block method.

Steps necessary for good storage practice in respect of all food grains

Stored product pests can be managed either behaviouraly (traps viz., probe traps, light traps, pitfall traps etc.,) or with several preventive and curative measures (both chemical and non-chemical methods).
Once a facility is obtained, a number of steps are to be taken to ensure safe storage of grains. These steps comprise

1. Before storage

Checking for leakage of rain water and sufficiency of drainage facilities
Cleanliness of the facility and environment
Assessment of capacity of the facility
Pesticidal treatment
Security and firefighting arrangements and
Repairs to available equipment

2. After receipt of grain

Inspection for variety and soundness of quality
Inspection carefully for infestation, it any, and when present, for type and extent
of infestation,
Inspection whether grain has excess moisture, whether it had been heated up in
earlier storage and has any musty or rancid odour
Any grain rendered wet or damaged to be segregated and salvaged with facilities
available and check the weight received

3. During storage

Maintenance of cleanliness
Ensuring aeration where necessary
Checking for leakage after rains
Inspection for insects, rats and mites at fortnightly intervals
Watch for advancement in deterioration, if any,
Pesticidal treatments necessarily based on observations
Ensuring disposal where called for, and
Arrangement for segregation, salvage and processing, wherever, damage owing to leakage of water and other causes might have taken place.

GRAIN PROTECTANTS
Chemicals that can be directly applied to grains are formulations of chemicals having residual toxic or repellent action or both. Those are applied directly to the grain to prevent damage by stored product pests. Eg., clay minerals (red earth, Kaolin) before 1950. Now their use is restricted only to seeds and grains meant for animal feed. These grain protectants can be applied in the form of spray/ dust on the uninfested grain.
Advantages over fumigants

Used as a prophylactic treatment
Can be effective when the grains are stored in loose containers where fumigation is not possible
Less dangerous than fumigants
Don’t affect germination adversely
One application at harvest time is sufficient for one year

Example
1. Pyrethrum synergized with PBO: safest of the grain protectants available and approved for use. Available as powder 1 % PBO +0.8 % pyrethrum, 0.83 lb synergist+ 0.6 % pyrethrum also be applied in the form of spray 3-5 gallons/ 1000 bushel, 0.6 lb synergist+0.066 lb pyrethrum.

2. Premium grade Malathion: Foul smell is removed. Can be directly applied over the grain as 1 % D or as a spray 57 EC. Other chemicals include: Carbaryl, Dichlorvos, Fenitrothion, Malathion, PBO, Pyrethroids (Deltamethrin, Fenvalerate).

Source

Balasubramani,V., S. Mohan and K.N. Ragumoorthi. 2003. Storage Entomology (An ntroduction). Department of Agricultural Entomology, Centre for Plant Protection Studies, Tamil Nadu Agricultural University, Coimbatore-3. 100p.
Pingale, S.V. 1976. Handling and storage of food grains. (Jaiswal, P.L. and Wadhwani,A.M. eds.)
Indian council of Agricultural research, New Delhi. 186p.
William Wilcke and Gary Wyat. 2002. Grain storage tips- Factors and formulas for
crop drying, storage and handling. (Accessed on 14.09.2007)
http://www.extension.umn.edu/distribution/cropsystems/M1080-FS.pdf .
Storage Structures And Insect Management With Respect To Modern Storage Structure . S. Suresh and K. Vanitha, Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore-3