Post Harvest

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kheteshwar borawat

Feb 4, 2009, 1:35:40 AM2/4/09

Post Harvest

Post Harvest Operations

Post-harvest operations are assuming importance due to higher yields and increased cropping intensity. Due to introduction of modern technology, yield levels have substantially increased resulting in a marketable surplus which has to be stored till prices are favorable for sale. With increase in irrigation facilities and easy availability of fertilizers, intensive cropping is being practiced.

Harvesting assumes considerable importance because the crop has to be harvested as early as possible to make way for another crop. Sometimes, harvesting time may also coincide with heavy rainfall or severe cyclone and floods. In view of these situations suitable technology is, therefore, necessary for reducing the harvesting time and safe storage at farm level. The post-harvest losses are estimated to be about 25 per cent.

A recent estimate by the Ministry of Food and Civil supplies put the total preventable post-harvest losses of food grains at about 20 million tons a year, which was nearly 10 per cent of the total production. The principal adviser, planning commission stated that food grains wasted during post-harvest period could have fed up 117 million people for a year.

The important operations carried out after harvesting of the crop are threshing, drying, storage and processing.


Out of the total food grain production, more than 70 percent is with the farmer and rest is stored by governmental organizations like central warehousing corporation and Food corporation of India and traders. The godowns are the most common structures for above ground bag storage.

The godowns have all the facilities for fumigation, providing aeration and rat proof. Each of the godown can hold 5000 tonnes of bagged food grains. Grain is also stored in bulk using large silos.

For want of required storage space in godowns food grains are also stored in the open and this method of storage is known as CAP storage. Cap stands for cover and plinth. Open spaces in warehouses and elsewhere are used for storing produce. Crates are placed on floor, mats are spread on the crates and finally bags are placed over the crates.

The stacks are built in the farm of domes. As protection against rain and sun the stacks are covered with thick (600 to 1000 guage) black polythene sheets and the cover is tied to the stack with the help of plastic ropes.


Harvesting of crop is seasonal, but consumption of food grain is continuous. The market value of the produce is generally low at harvesting time. So the grower need storage facility to hold a portion of produce to meet the feed and seed requirements in addition of selling surplus produce when the marketing price is favourable.

Traders and Co-operatives at market centres need storage structures to hold grains when the transport facility is inadequate.

The government also needs storage structures to maintain buffer reserves to offset the effects produced by the vagaries of nature. Hence, there is necessity to store the produce for different periods primarily for commercial reasons. The growers, processors, transporters and warehouse men have to develop storage facilities for proper storage of food grains, oilseeds, commercial crops like Chillies, vegetables and fruits etc., and seeds intended for sowing in the following seasons.

An ideal storage facility should satisfy the following requirements

  • It should provide maximum possible protection from ground moisture, rains, insect pests, moulds, rodents, birds, fire, 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.

Types of Storage

Holding grain in bulk in underground is an age old method of rural storage. Wheat, Paddy, Sorghum, Fingermillet, etc., can be stored underground for a period of 2 years. These structures are simple underground dig-outs upto a depth of 5 m varying in sizes to hold from a small quantity upto 50 tonnes.

The pits are lined with brick or concrete so that moisture from walls and bottom does not damage the grain. At the time of filling a layer of straw is placed on all sides.

After the pit is filled, straw is spread over the grain and then topped with a layer of soil. Insect infestation is less in the under ground storage and it is cheaper over above ground storage structures.

This underground structure is not suitable for high rainfall and high water-table areas. Further the grain stored underground have poor appearance and musty smell.

Several types of above ground storage structures mentioned below are also in use in our country,

Mud Bins

The mud bins are made of unburnt clay mixed with straw with 1 to 3 inch thick wall and are oval, rectangular or circular. A small hole is provided at the base for taking out the grain and a larger hole is provided at the top for filling it with grain. Both the inlet and outlet holes are plugged while grain is stored.

Straw Bins

For storing paddy in humid zones dried plants are used for making temporary structures, which after being filled with grain are further reinforced from outside by winding paddy straw ropes around the whole structure. Each structure holds 2 to 6 quintals of grain.

Bukhari Bins

This is a cylindrical structure and is made of mud and split bamboo's. The bin is always placed on a wooden or a massonary plat form to prevent its contact with the ground. The capacity may vary from 3 to 10 tonnes.


Type Bins These bins are very much similar to a timber box placed on a raised plat form, which is generally supported on pillars. Both the floor and walls are made of wooden planks, where the tiled or thatched roof is placed over it as a protection against sun and rains. The capacity may vary from 9 to 35 tonnes.

Metal Bins

Bins made of steel, alluminium 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 either steel, alluminium or concrete. Usually steel and alluminium bins are circular in shape. The capacity of silo ranges from 500 to 4000 tonnes. A silo has facilities for loading and unloading grains.

The storage structures in rural areas are not ideal from scientific-storage point of view, as substantial losses occur during storage of grain from insect pests, moulds, rodents, etc. ; keeping the requirements of the farmers in view the Indian grain storage institute (IGSI), Hapur with its branch at Ludhiana and Hyderabad have developed several metal bins of different capacities for scientific storage of grain in rural areas.

Methods of Storage

The grains are stored at three different levels, viz., at the producer's level (rural storage) trader's level and urban organizational storage. The urban organization uses modern facilities and structures like silos, warehouses and also undertaken periodical inspection, processing and treatment of grains for ensuring their quality during storage.

Generally, there are two ways of storing grains i.e.

Storage in bags and Loose or bulk storage.

In the tropical regions, the grain is stored in bags. Storage in bags requires considerable labour, but the minimum investment is enough on permanent structures and equipment. The storage in bags has the advantage of being short-term storage. Bag storage can be done under a roof of Galvanized Iron sheets, a plastic covering where grain is intended for very early onward movement. Usually no control measures against insects is needed for short-term storage. If bag storage produce is intended for long time, the control measures have to be taken against insect pests.

The bulk storage has an advantage of greater storage capacity per unit volume of space. Less labour is involved in loading and unloading and there is no need of investment in purchasing gunny bags. In bulk storage the insect infestation is also lower over bag storage. The grain can be kept for several years in bulk storage.


When once the grain is threshed and dried it will be transported from the field to store houses by bullock carts, or tractors by the growers. Sometimes if the market price is favourable the produce is disposed to the traders soon after drying.

The disposal of the produce, either at the village or at the market yard is, however often closely connected with financial needs of the growers and sometimes indebtedness. The traders on purchasing, transport the produce to go-down, or shops for sale to the consumers.

This transport mainly uses trucks i.e., lorries. Government agencies like Food Corporation of India etc., transport the produce from one place to another place either by road or rail (waggons) for long term storage and sometimes to export to other countries by sea (cargo). If the produce is not properly bagged and handled there will be some loss during transport.


In general most of the producers sell the grains at their door steps in villages, to avoid transport. At village level defective measures and weights are used by traders and also the prices paid to farmers are much lower than regulated market rates. Now-a-days farmers are encouraged to sell their produce in near by regulated markets, though some labour is involved in transport.

In regulated markets some amenities are provided for sellers and the growers can secure maximum value for their produce. In market yards several methods like cover system, open system and auction system are adopted depending on the type of produce sold. Since the rural banking system is improved the farmers to a large extent they are out of clutches of greedy private money lenders who exert pressure to dispose produce for lower price.

At present in some places the cold storage facilities are also available. Farmers can utilize these cold storage facilities for stocking their produce on payment of rent and the produce can be disposed when there is remunerative price in the market.

Though several measures are taken by government the marketing of agricultural produce is facing problems and growers are not getting the reasonable price for their produce. If production exceeds demand, price declines until the market is cleared. Prices raise when production fell short. Responses to lower or higher prices occur in the next production cycle.

Therefore, the acreage for a particular crop based on demand and the supporting prices for each commodity need to be monitored by the rulers based on demand and supply studies. The government has to bring buyers and sellers together, develop price information systems, establish consistent grades and product quality standards for better marketing of agricultural produce at all times.

The Low Cost Post Harvest Technology

These are some of the technologies suitable for small farmers

  1. Solar Dryers: Drying is the cheapest mode of preservation of fruits, vegetables and other items like fishSolar drying is practiced by mankind since times in memorable. This method of drying with solar energy is ideally practiced by many grape growers in Maharashtra to make Kishmish/ Manuka/ Bedana from grapes.

  2. Zero Energy Cold Storage: Many farmers cultivate fruits and vegetables, which are seasonal in nature. Produce of all the farmers come to the market yard at one go. As a result prices fall. There is a good technology catching up. This is Zero energy cold storage.

    Everybody knows water becomes cool in an earthen pot. The water oozing out of the pot gets evaporated. While this evaporation occurs, water inside the pot becomes cold this principle is called as evaporate cooling. This principle is used for zero energy cold storage. Just make a double walled room. Keep sand between the outer and inner wall. Keep the sand wet by watering. And your produce kept inside the inner room will be preserved longer. Government is giving subsidy to popularize this concept.

  3. Pickles: Pickling is one of the cheapest process of preservation of fruits and vegetables. Common salt and spices are used in conventional pickles. The process of pickling does not need energy. The process is so efficient that many people make pickles in their houses, which last even two to three years. And that too without any chemical preservatives. Pickled items are preserved because of fermentation.

  4. Fruit Juices: We can make juice from various fruits like Mango Pineapple, Grapes Lemons, tomatoes and many types of local specialties like Kokam, Jamun etc. Even Banana and Guava juice can be made. Banana, which is considered as poor man's fruit in India is considered as rich man's fancy in countries like Korea and Japan. We can make pulps out of he juices and use in off-season.

  5. Preservations in Salt solutions: Keeping in salt solutions can preserve vegetables. This process can be used to prolong the shelf life of various vegetables like cabbage, okra, spinach etc. In this process vegetables are kept in salt solutions and bottled. While using, just wash the vegetables in Water to remove salt solutions. Shelf life will vary according to various factors but you can prolong shelf life at least by one month in this process. Calcutta University has done considerable research in this field.

  6. Small-scale industry in farm: Farmers cannot get price for their produce because they have to depend upon middlemen for marketing. There is a solution to the problem. You can start manufacturing ketchups, sauces of various types and also Paste of Garlic, Ginger, Chilly etc. With a small investment in machinery and building, a unit can work profitably. The unit may give employment to others with a small investment of only 10 lakhs.

It can be stated with more confidence that such low cost technologies are more successful because there is more involvement of entrepreneurs in their projects.

Have a lot of fun and success.
yours kheteshwar
always with you...

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