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When To Bale Hay

The advent of the large square (rectangular) baler has seen the number of hay stack fires substantially increase in recent years, although they still occur in small square and round bales too.

By Department of Primary Industries - 14th November 2005 - Back to News

Baling should occur when the moisture content in the plant reaches the point where heating, due to continued plant respiration and microbial activity, will not occur once baled. However, as we all know either the incorrect timing or use of equipment can lead to poor and/or uneven curing resulting in hay being baled too wet, or with wet patches throughout the bales. Then we throw in the worst and often unpredictable problem of all, the weather!

In the ideal world, the optimum moisture content for baling small rectangular bales should be in the range of 18 - 20 %. Large round bales should be baled in the range of 14 – 18% moisture content and large rectangular bales 12 – 14% for conserved feed. If hay preservatives are used (not common in Australia) these limits could be a few percent higher although extreme caution is still required for large rectangular bales.

There are several techniques for determining when hay is dry enough to bale.

One technique is to take a handful of hay from the underside of the windrow and twist it. If there is no free moisture present and the stems are brittle, the hay should be in good condition for baling. If it is very dry and brittle, it may be too dry to bale. When the stems appear too dry, allow the plants to absorb some dew during the late evening or early morning before baling.

Scraping the outside layer of the stem is another method used to help determine when to bale. If the stem skin can be peeled off, the hay is too wet. If it doesn't peel away, the hay is dry enough to bale. Many producers also bale when the nodes (lumps along the stem) are shrivelled and break easily.

A more accurate, albeit time consuming technique is to use a microwave oven test. To do this, cut up representative samples from the windrow into approximately 5 cm lengths. Weigh 100 grams using a small set of scales accurate to 1 gram. This is the WET weight. Place the forage in the microwave oven with a half full glass of water, placed at the rear. Keep the water level constant during drying. Heat on high for 3 minutes. Remove and reweigh the sample, stir it and redry for another 0.5 – 1 minute. Reweigh again. Continue this procedure every 20 – 30 seconds until the dry weight does not reduce by more than 2 grams from the previous weighing or until the sample begins to char! In the latter case, use the previous weight to calculate the moisture content.

To calculate the moisture content (% moisture) of the original sample, subtract the dry weight from the original wet weight, divide the answer by the wet weight, and multiply by 100.

ie. % moisture = wet weight – dry weight X 100

wet weight

Warning: Continue to refill the glass with water and NEVER leave the room unattended while the microwave oven is in action.

The last, although more expensive method, is to use a hay moisture meter. This can be a useful tool for determining proper moisture content at baling but is not fool proof. These may be used by pushing the probes into the windrow or a bucket of the curing material but are much more reliable when a bale has been baled.

Push the probe in from the end of rectangular bales and through the rounded circumference of round bales. Take at least 5 probes of each bale and average the readings. If the readings vary more than 3 percentage points, take several more probes and re-calculate the average. Do several bales to account for paddock variations.

However many factors can affect a meter’s accuracy. These are bale density and the use of chemical conditioners. Probing bales that are very ‘tight’ may yield readings over 2 points higher than the actual moisture content. Some preservatives, such as propionic acid, can increase readings as much as 4 percentage points. If preservatives are used and the instruction manual does not provide information on the effects of chemicals on meter performance, contact the manufacturer for additional information.

Electronic forage moisture meters can also be valuable tools during baling. Use moisture meters to supplement your personal experience when making management decisions.

Source: http://gippsland.com/

Published by: news@gippsland.com