The Grain Saver ™ concept

In the early 1980’s, a method of storing forage crops such as alfalfa and corn in large sausage shaped plastic bags was developed in North America. These air-tight polyethylene tubes were also suited for storing of whole dry grain. However, due to large amount of storage capacity available and the widespread set-aside in the US, the need for such technology was not in great demand. 

In Argentina, however, the situation was different. Stationary storage capacities was scarce when the farming sector was deregulated in the early 90’s, modern farming practices was introduced, and the growth in production increased by around ten per cent annually. It soon became evident that the shortage of grain storages and handling facilities was a major stumbling block for further expansion and those innovative solutions were requested. In 1996, 10.000 tons was stored in grain bags in Argentina, passing 20 million tons of stored grain in 2004 and reaching close to 55 million tons in 2008 having developed at an accelerating pace. The view changed entirely, suddenly areas in the interior, where delivery cost at harvest was high and trucking capacities scarce at harvest could be used for grain production, using the grain sausages for seasonal storages and later being moved to export harbors when the availability – and cost of – trucks was cheaper. Major grain storages along the coast developed around the center of stationary driers and metal silos and large buffer capacities of plastic sausages evolved due to its cost-efficiency.  

Around the world, similar situations now occur, from South Africa, where major grain trader Dreufus have built up numerous mobile grain storages without a single fixed investment, using grain carts, grain baggers and extractors, to handle large volumes of the domestic grain production, to Australia, North America, Asia and central and Eastern Europe where availability of grain storages are scarce and in times of globalization, becomes a critical factor for worldwide competitiveness. The advantages of the grain bagging technique are numerous and its appeal is so widespread that its users range from small producers who operate a few hundred hectares of land, to huge international grain traders such as Cargill, Bunge and Dreyfus. Remember that the pay-back of fixed installments often superseed more than a famers lifetime, compared to fixed investments in the Grain Saver ™ concept!

Grain Saver ™

The Grain Saver ™ can be used for storing any commodity that can be handled with an auger such as grain, oilseeds, fertilizers, seeds, dry fruits, dried sewage sludge, compost etc. It is a very flexible solution, irrespective if one is to handle 25 or 10.000 tons of grain or more. In Northern conditions, existing grain driers can be used longer time periods annually, thus creating greater use and lower running costs, when grain bags are used for intermediate storage.

By means of the grain bagger, expansion is flexible and taking over more land has become much less expensive in the expansion phase. By being able to bag huge volumes of grain directly at the field, the need for trucks becomes less in harvest season, thus each combiner can be used much more efficiently.

Especially in Eastern Europe, this creates excellent opportunities for the entrepreneur – the risk of high transport cost and the need to supervise these to guarantee your income, in addition to greater capacities of the combine fleet, makes the system outstanding. Due to the great capacity of absorbing great quantities of grain in short time, high capacity combines can be rented in at low cost on all farms, Different quality at harvest can now be stored flexible and placed in different bags already at sight, making sales activities much easier later on.

It is easy to mark up the plastic sausage by means of a simple pen, to create full knowledge of quality inside the bag, in addition to dividing different qualities of grain separately in smaller bags. It is very easy to supervise the bags by regular testing of temperature and moisture, two critical factors for securing grain quality. Normally one can store grain for longer period at 2-3% above the water content used as trading factor, i.e. at around 16 per cent. For oil seeds such as rapeseed, sunflowers and soya, a 12 % moisture level is preferred. 

Storing grain in sausage bags means storing in a modified atmosphere with low oxygen and a high carbon dioxide concentration. The bags are stabilized after about 30-32 days of storage, when CO2 has developed through respiration of stored grain and oxygen has been consumed. See graph below. In such atmosphere, the problem with storage insects and fungus problems are normally reduced.

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It is also recognized that the risk of contamination of the grain is reduced. Often, grain is stored outside in the open air, prior to drying. In this condition, the risk of contamination by birds and insects are great, raising the risk of for example salmonella infection of the grain, creating risks for animal breeders onwards.  

The working condition is greatly improved compared to stationary facilities – the amount of dust is greatly reduced. Thus, cleaning, that in stationary driers and storage facilities normally is a very time consuming activity, is more or less a thing of the past. Compared to stationary installments, maintenance costs and time spent on service of chains, augers, greasing spots and necessity to constantly clean the facility, is greatly reduced. In Northern conditions – where grain normally have to be dried due to unfavorable harvest conditions – grain bagging is cost-effectively incorporated together with a mobile drier, reducing investment needs at farm level. 

The capacity is high, with a Mainero grain bagger, one can bag more than 200 tons/h and with the extractor, one can take out 100-120 tons per hour, thus filling some 3-5 trucks per hour! Our experience is that the amount of spoilt grain is much less in a grain bag, as compared to storing in silos or flat storages. 

One general rule recommended as a safeguard is that the moisture level with which grain is stored in bags not be greater than base moisture standard used for commercialization purposes. The lower the grain’s moisture, the better it will keep and the longer the period of time it can remain in storage. In the case of seeds, the conditions are stricter.

As the moisture levels of the grain to be bagged increase, so too does the risk of damage. Testing carried out by INTA (acronym for the Argentine National Agro-Technology Institute, or National Institute of Agriculture) has shown that the quality of grain with high moisture content tends to decrease when it is stored in plastic silo bags for long periods of time. Grain that is damp runs of course far more risks. Damp grain should only be stored in plastic bags in an emergency, when there is no available alternative. In such cases, trials have shown that installing an 80% sun-blocking mesh as a protective sunroof about 40 centimeters (some 12 inches) above the bag in the spring and summer months, in order to block direct sunlight, will result in lower temperatures inside the bag and sharply reduce the risk of damage.

It should always be remembered that although this is a simple technology, extreme care must be exercised in protecting and maintaining the bags’ integrity. Monitoring should be permanent so that any ruptures in the bag can be repaired immediately, thus preventing air or water from entering.

Particular care should be taken to pick up all remains of plastic after emptying the bag. Plastic remains can contaminate the environment in many ways and are also an eyesore. The polyethylene the bags are made of is a highly recyclable material, so generally arrangements can be made to sell it or at least to have it picked up free of charge.