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August 2001 LOCATION AND FORM OF APPLYING A MICROBIAL INOCULANT CAN MAKE A DIFFERENCELimin Kung, Jr. and A. G. Whiter
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Microbial inoculants have been used to improve the fermentation of silages for many years. They help by encouraging a more efficient fermentation and by increasing the rate of acid formation. The later causes a more rapid decline in pH that spares plant protein from degradation and is needed to preserve the crop. Recent research has shown that under certain conditions, the form of application can alter the effectiveness of an inoculant. In addition, although not well studied, the location of application may also affect how well an inoculant works. |
Form of application…. |
Silage inoculants are applied in a dry or liquid form and thus a logical question is: does the form of application change the effectiveness of an inoculant? A recent study from our lab showed that both a dry granular or liquid application of a commercially available silage inoculant were equally effective in improving the rate of fermentation of alfalfa with 30% DM. In alfalfa from the same field, but wilted to about 54% DM, again both forms of inoculation stimulated the fermentation process when compared to untreated silage. However, the liquid-applied inoculant caused an even faster decline in pH than did the dry-applied inoculant. Similar results have been reported by German researchers on grass silage with a dry matter content of about 40%. |
Why did this happen? Inoculants applied in a dry form rely solely on moisture in or on the crop to resuscitate the organisms. In contrast, dried bacteria begin to resuscitate in the water used for a liquid application. Thus, it may take longer for the bacteria in an inoculant applied in a dry form to revive, resulting in a slower rate of fermentation than with an inoculant applied in water. We suggest that if all other things are equal, apply an inoculant that has been mixed in water to forage with ³ 40% DM. To help with this recommendation, new high pressure/low volume liquid applicators require fewer refilling of inoculant tanks. (Do not mix an inoculant that has been designed for a dry application into water for a liquid application.) |
Location of application…. |
Another question commonly asked is: does the location of applying an inoculant make any difference on its effectiveness? Common sense would suggest that there are preferred locations for applying an inoculant depending on the situation a producer is faced with. For example, if silage is to be stored in a bunk, pile or pit silo I would recommend that the inoculant be applied at the chopper for a more even distribution. Remember, these bugs don’t have legs, nor do they swim! If all the inoculant gets put on in one spot, it will probably stay there. (Some distribution will occur during tractor movement and packing, but this is not efficient.) For silage that will be stored in a tower or bag silo, application at the chopper or blower/bagger will probably make a difference. (In a few instances, forage is chopped and harvested far away from where it is ensiled. Under these circumstances, I would prefer to have the inoculant applied at the chopper so that the microorganisms can begin their work right away.) Don’t forget to properly calibrate your applicators to match forage delivery and don’t increase the dilution or reducing the application rate! |
Help yourself…. |
Microbial inoculants can improve silage fermentation. Following some simple guidelines as discussed in this article will help you to make the most of your investment. |
L. Kung, Jr. is a Professor in the Department of Animal & Food Science at the University of Delaware. A. G. Whiter was a Science & Engineering Scholar in the senior author’s lab. |