July 27, 2017

28/07/2017: The grain chain: Grain storage on farms

by Chief Industries, UK

No one can deny grain storage is necessary on farms


The producer needs to store the large quantities of grain coming off the land at harvest time. The stock farmer needs to store sufficient grain to ensure he has stocks to provide reliable reserves of grain for his cattle, pigs, chicken, etc. But what are the options for storage, and what are the considerations for storage? Well there are two basic considerations: cost and security.  


 
Image credit: Chief Industries, UK
Cost
When considering the cost, one must take into account obvious capital cost and whilst this is one’s first main focus, it has to be evaluated in terms of the annual cost. What is the lifetime of the plant or equipment? What is the maintenance cost and running cost? Is there a resale value? What are the associate labour costs?

All of these questions should be asked in the mind of the farmer prior to making a decision. Then finally, review that cost in relation to the value of the crop being stored. What can seem like a lot of money may be comparatively small in relation to the contents of the storage system.

Security

Security actually covers a wide range of factors that are very important to consider. Of prime importance is to keep the grain in safe and good condition. What grain you put into storage should come out in almost exactly the same condition. That is of paramount importance. The most expensive loss you can have is to have stored grain spoiled.

Of course the method of storage should also be designed to accommodate the stresses of holding grain in the storage method and the forces associated with stored grain are substantial. Ignore them at your peril, or someone else’s since failed storage systems can easily result in loss of life. Of course you need to consider damage and losses due to rodents, birds, and insects.

How secure will the grain be against moisture, from rain entry, ground water, condensation, or simply being put into storage at too high a moisture content? Finally maybe the first thing anyone thinks about when you mention “security” is how safe is the grain against theft. Unfortunately it is an aspect that also has to be borne in mind.

Storage methods

Bags
Thankfully the days of storing in bags are coming to an end, but only slowly in Africa. It is labour intensive work. Bag life is short, so although it may not be a high cost, it is ongoing and an annual. Bags are susceptible to damage from rodents and other pests, and need protection from rain and surface water.

There are some reasonably successful insecticide treatments nowadays that can be administered under reasonable sealed tarpaulins a task that needs to be taken with significant care. Bagged grain is relatively easy to steal in small quantities of a few bags at a time, necessitating the need to count and control every movement of bags, which becomes extra administrative time.

Warehouse
If one already has a suitable storage shed this is a relatively cheap method of storing grain and well suited to storing a single crop. Ventilation of the grain is not easy and will require temporary ventilation ducts that need lifting up as the store is emptied and relaying down again as the store is filled. Alternatively one can use small fans on spear shaped ducts that you push down into the grain. They work but are not ideal. Filling and emptying existing shed is always a problem. Usually the most effective way is with a front-end loader with a decent size bucket on the front. If you already have one then it is the simplest way. If you have to buy one simply to use an existing shed then the economics are doubtful.

Firstly, the capital cost of these units is not cheap, and then when you add on the running and maintenance cost it can be very expensive to use. Alternatively you can use a pneumatic conveying suction blower. They can work quite well but take a lot of kW power either electric or tractor driven.

They are not suitable for sensitive crops like edible beans, but are very versatile with normal grain. When using an existing shed take great care with the walls. They are unlikely to be retaining walls and will not be built to withstand the pressure of grain, which is considerable. If they are not retaining walls, then plan to have the natural angle of incline of the grain at floor level when it reaches the walls.

You need to allow for some slippage of the grain during storage so in any event it can end up resting against the bottom 300-400mm of wall in any case. Alternatively you can purchase retaining wall panels to stand inside the existing walls, or you can have your existing walls reinforced by a civil engineer to accommodate the loads.

Of course you could consider having a purpose built grain storage shed to store your grain. This has many advantages over using and existing shed. A purpose built storage shed can have level floor ventilation channels already built in. You can have dividing walls between bays, allowing you to store different crops and you can have retaining walls already built into the design.

If you are still going to use your front-end loader for filling and emptying, then you can still be competitive with silo storage, but you have high running costs with your loader. You also do not have good environmental control, difficult insect control, and possible access by rodents and birds.

Of course with a purpose-specific designed warehouse for grain storage, you can also have a good mechanical filling and unloading system but then your costs could easily be 20 percent higher than a silo storage system and you do not have such good alternative use of the warehouse when not storing grain. Your area of land occupation will also be much larger than with grain silo storage.


Read the full article, HERE.

Visit the Chief Industries, UK website, HERE.
 

The Global Miller
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which is published by Perendale Publishers Limited.


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