Storage of High Moisture Barley

Grains reach maturity several days before harvest. To prevent spoilage, harvesting is normally delayed to allow the grain drying time in the field. If barley could be harvested when it reached maturity, rather than having to let it dry in the field, then harvests could be completed earlier with reduced field losses.

Tough grain with a moisture content of 15.5 to 17.0 per cent when bin stored may rot. Damp grain with a moisture content greater than 17.1 per cent will rot quickly, often producing enough heat to start a fire. Spoiled grain is useless as feed since there is a risk of toxic chemical build-up during spoilage from aflatoxins, which are produced by soil micro-organisms. Aflatoxins endanger the health of both people and animals.

Micro-organic contamination occurs during both the growing season and harvest when dust becomes mixed with the grain. If damp grain is to be stored successfully, you must prevent micro-organic growth or kill micro-organisms before growth begins.

Ensiling

To prevent micro-organic growth, grain must be handled like silage, which means promoting the growth of acid-producing bacteria in the absence of oxygen. These bacteria produce acids by fermenting barley sugars and carbohydrates. The acids (mainly lactic acid) produced stop further bacterial action. A state of preservation results when the acids, produced without oxygen, kill the micro-organisms that cause spoilage. A pH of 4 – 5 will ensure safe storage of the silage.

Moisture content and packing of barley when stored are the most important factors in determining the final products. Barley that is too dry and/or not packed properly will have excess oxygen present, and this condition will allow moulds and yeasts to continue to work, resulting in ruined feed from excessive mould and rotting.

Packing can be improved by rolling or hammering the grain before it is placed in the silo. Combined rolling and packing result in the rapid exclusion of oxygen, which creates a favourable environment for acid forming micro-organisms. The open kernels of barley provide a ready source of carbohydrates for acid-forming bacteria to feed on, and rolling at harvest time will eliminate the need for this operation when the grain is fed. At that time, grain can be fed directly from the silo.

The best moisture content for barley is 25 to 35 per cent. To determine the correct moisture content, a simple hand test is suggested. When squeezed in the hand, some whole barley kernels will stick together, while rolled barley will remain in clumps. If the grain is too dry (less than 25 per cent), it will fall apart in the palm. As combining progresses, it may be necessary to add water to harvest grain to meet the 25% moisture level. In warm weather, grain can easily lose several percent of moisture over a day.

Horizontal or pit silo
Silo sides should be air tight with a good surface seal maintained until the grain is fed. If air can enter, some moulding will take place. In horizontal bunker or pit silos, line the top three feet of silo walls with plastic sheeting, which extends over the top surface. However, unless the plastic is held down properly, it can pump air into the silage. Cover the plastic with old silage, hay, straw, fish netting or bales placed very close together. Old tires are usually a poor choice as plastic flapping still occurs, causing air movement.

After fermentation, high moisture barley is a brownish-yellow color with an occasional light brown kernel. It has a distinctive fermented odour - a combination malt-alcohol odour. Rolled grain will be more uniform in color and will appear darker.

Freezing temperatures do not affect the feed quality of high moisture barley. At freezing temperatures, some caking will occur on the faces and sides of bunker silos. This condition will be more pronounced if the grain has been rolled before ensiling. The cakes are not solid and fall apart when the grain is moved since the moisture content is not high enough to form a solid block.

When high moisture barley is exposed to oxygen in warm weather, it will begin to heat and spoilage will occur. Matching the exposed surface area to daily feed requirements by removing three inches of grain daily will reduce spoilage. Once a silo has been opened and barley exposed to oxygen, it should not be re-covered. Re-covering the pit face after it has been disturbed will only accelerate spoilage.

Upright silo
The best storage method is in the oxygen-limiting upright silo. This type of storage reduces the need for grain to contain over 25 per cent moisture. Oxygen-limiting silos eliminate both the need to roll barley before storing and the need to remove three inches per day across the face.

Acid Preservation

Organic acids (propionic and acetic) are effective when applied to damp grain at recommended concentrations. These acids will kill about 90 per cent of the spoilage organisms and will prevent the remaining 10 per cent from growing. Organic acids preserve damp grain without deterioration, although germination is drastically reduced.

Organic acid-treated grain can be stored in any non-corrosive structure. It may be stored in grain bins, on barn floors or in sheds, when other facilities are not available. Treated grain can even be piled on the ground outside if it is protected from moisture. Protection can be provided by first laying plastic on the ground and then covering the pile with more plastic.
The moulding of stored grain is enhanced if the grain is exposed to moisture, dirt or exposed wood surfaces. Floors and all other wood surfaces, concrete floors and walls that come into contact with stored grain should be painted or covered with plastic. Steel or galvanized bins must be coated to prevent corrosion.

The amount of organic acid needed to preserve grain increases as the moisture content of the grain increases. If treating barley with organic acids, the most economical level of moisture content is between 18 and 25 per cent.

Table 1 gives the recommended rates of propionic and acetic acid to apply to high moisture barley. The recommended amount of organic acid must be used. Lesser amounts will permit spoilage and greater amounts will add to the cost of treatment.

Table 1. Recommended rates for acid preservation

• In trials extending over four years in Montana, harvesting high moisture barley resulted in a 12-day earlier harvest date. In wetter areas, the harvest date would be advanced still further.
• Yield of dry matter per acre increased by 16.7 per cent when compared to mature field-dried barley.
  
  1. increased yield was due to earlier swathing or elimination of swathing entirely, resulting in:
  • less shattering and head breakage by machines
  • a larger harvest of wild oats
  • a reduced loss due to bird damage
  • reduced losses due to lodging
  2. increased yield was due to a reduced exposure to risks, including:
  • damage due to hail, wind, and snow
  • yield loss due to barley sprouting in a wet swath
  • loss from fire in the field
  • serious bird damage
  3. increased yield was due to reduced combine loss because:
  • small kernels do not blow out and are utilized
  • fewer kernels are cracked or damaged
  • more kernels are saved
  • less flour production during combining

• When the moisture content of barley is between 25 and 40 per cent, the grain threshes readily. When the moisture content is 15 to 25 per cent, threshing is more difficult as the awns do not break off.
• It is not necessary to wait for late maturing patches or second growth to ripen.
• Areas that were wet in the spring can be seeded late and the grain taken off as high moisture feed.
• Combining can continue under more adverse weather conditions, humid periods and morning and evenings when the crop is soaked with dew, and even during light showers.
• Since the stubble is left longer in high moisture barley, there is less volume to combine.
• Harvesting high moisture barley aids in controlling weeds:
  
  

  1.	more weed seeds are harvested, especially wild oats, which normally shatter before the barley is mature enough to combine safely.
  2.	acid treatment or fermentation in the silo reduces the germination of weed seeds that may be returned to the field in manure.
  3.	there is a longer post-harvest period, which will permit fall weed control measures. .

• The crop is on the field for a shorter time. This result allows more time for post harvest cultivation or for grazing of the stubble.

• for high moisture barley to be stored satisfactorily, all oxygen must be excluded or the grain treated with an organic acid
• high moisture barley must be treated, dried or properly stored immediately after harvesting
• high moisture grain should be rolled or hammered if it is being stored in a horizontal silo, and this operation could create delays at harvest time

• high moisture barley is 20 to 25 per cent heavier than dry barley
• grain with more than 24 per cent moisture content does not flow readily. Some bridging in the combine and in truck boxes will occur
• if high moisture barley is straight combined and only the heads are harvested, then an excess of straw is left standing. Turning this excess straw back into the soil may be difficult
• when combining high moisture barley, the combine ground speed will be at least 25 per cent less than if dry grain were being handled. This reduction in speed is necessary to prevent straw walker losses. High moisture straw can carry significant quantities of grain through the combine; high moisture grain does not sift through the straw as readily as does dry grain
• high moisture barley can only be used for livestock feed. Elevators will not accept either high moisture barley or acid treated grain
• all bins used to hold acid-treated grain must be painted or covered to prevent corrosion or the presence of moisture, which would dilute the preservative
• as with any chemical, care is required in the use of acid treated materials