Grain storage requires the use of specialized containers which will help keep the grains intact and ready for use. Improvement in agricultural methods have expanded grain production in India, especially in rural areas. Better irrigation, modern farming techniques have resulted in larger yields. But the hard-earned produce is getting wasted due to storage inefficiencies.
It is estimated that 16% of the overall grain yield in India gets lost to insect-rodent manifestations, moisture and fungus attacks. That accounts for nearly 14-million tons of food grain worth Rs 7,000 crores getting destroyed to waste. Hence, when the harvesting season comes to an end, farmers and producers need to make sure of proper storage management.
What is a Silo?
A silo is a large mostly cylindrical container which can hold massive amounts of materials such as food grains, tea, fine wood particles, sawdust, coal, cement, etc. Silos are upgraded warehouses in the form of well-built structures. A warehouse can only to its best, store the material with no guarantee of moisture seepage, water leaks or animal hazard. Silos assure the farmers of an air tight containment in addition to having post-harvest functions like processing the sorting, cleaning, drying, fuming and aerating for longer preservation. There can be variations in size and types like Horizontal, vertical, hexagonal, octagonal, trench, tower or bunker silos. Silos help form an integral part of the agricultural value chain.
How are Grains stored in Silos?
The material stored inside the Silo is called silage. Silo storage systems always have sets of installations.
For example: A Silo setup for wheat will consist of one silo for processing the wheat, one silo will be for storing the wheat and another for removing the husk.
1. Loading of Grains
Each silo will have its own specific function of how to load grains, depending on the Silo the loading might differ. However, the two main loading methods are via augers or bucket loader.
Loading through Augers: Augers are metal tubes connecting to tractor vehicles containing the grains. Through this inexpensive method the grains load onto the top of the Silo with much difficulty in positioning the heavy metallic tube against gravity. These augers are not still, the rotating motion can be dangerous due to its size and may lead to injuries or loss of life.
Loading through Bucket loaders: Using Grain legs or simply Bucket loaders is a much more expensive but safer method of loading grains. There is an elevator installed which picks up the grains by buckets and transfers the grains into a fixed tube that leads to the opening of the silo storage. It is costlier to install due to its complex digital functions and design innovation.
2. Unloading of Grains
After the grains are transferred into the Silo, the grains fall into a pit, which protects it from external calamities and moisture. These grains in the pit are then elevated by conveyor belts to the top of the silo for further storage in containers or transportation of grains. They can also be emptied by unloading the grains through the bottom of the silo by an affixed auger. Due to gravity the grains fall into the bottom opening and are thus unloaded.
3. Temperature Maintenance
Depending on location and moveability, Silos can be made of various materials. Standalone Silos can be made from cheaper material other than metal like concrete. Moveable silos are made from metallic materials.
Aeration is the process of air moving in staggered amounts depending on the temperature inside the silo. Silos can reach up to 95 degrees Fahrenheit, so to prevent cross temperatures from outside cool air and inside hot air - Silos use aeration ventilation function for the prevention of spoilage in stored grain mass. Aeration controls and maintains uniform air temperature and pressure inside the Silo to match the external temperature. This prevents degradation due to the formation of moisture around the grains.
Conventional Open Top Silos: These are most commonly used Silos as they are cheaper and have easy functionality. Built from concrete, conventional silos are structured with an open lid which are easy to cover and let air circulation in and around the silo opening. This constant air flow ensures the grains don't get moist and are easily unloaded through the opening top.
Controlled Atmosphere Silos: This is opposite to an Open top silo as Controlled Atmosphere Silos main function is to cut out the external oxygen flow and pump in with a replacement of nitrogen or carbon dioxide; the large container can hold 50,000 tons and above capacity of grains and does not have openings but for the one at the bottom to unload.
Silos are especially good for a developing country like India, whose population demands the buffer stock requirement in the food grain market. From ancient wooden silos sighted during the Harappan Civilization to modern day Silos engineering the domain of grain management - Silos are the future in grain health and preservation until stocked out for sale.