I was in a field recently that was just a few weeks out from being ready to chop for corn silage. I can remember a few months back when we thought we would never get there amidst the rain. Our wet spring resulted in varied planting dates and then we transitioned into a dry summer. These conditions leave a lot of questions on harvesting silage, whether it be immature or drought-stressed corn. A crop that is stressed can add challenges to successfully ensiling including:

• Fermentation complications because of forage that is too wet/dry
• Increased potential for mold and yeasts (already on the crop coming into the bunk)
• Lower energy content (which means less food for fermentation bugs)

While proper storage in the bunk should always be a priority, challenging growing seasons reinforce the importance of proper ensiling. John Wooden once said "It's the little details that are vital. Little things make big things happen." Why am I quoting a famous basketball coach you may ask? Because it takes doing all the little things correctly to have a quality forage that your production will be correlated to for the next year, which is a BIG deal.

One of the "little things" you could be doing is incorporating the use of silage inoculants, which work by shifting silage fermentation in a direction that better preserves the crop. There isn't a one-size-fits-all recommendation on when and how to use inoculants, it depends on the situation and your goals.

The main types of silage inoculants are homofermentative and heterofermentative. Typical homofermentative types include Lactobacillus plantarum, the Pediococcus species, and Enterococcus faecium, while heterofermentative bacteria includes Lactobacillus buchneri. There is also a third type that combines the two. Homofermenters turn carbon sugar molecules into one product - lactic acid. Heterofermenters produce multiple products, which could include any combination of lactic acid, ethanol, CO2, or acetic acid.

On the front end, bacterial inoculants enhance "good" bacteria that produce acid and drop pH, which speeds up the fermentation process and reduces dry matter losses from it. Back-end products (L. buchneri) can improve stability at feed out. This will also depend on your management of the bunk face, the heat of summer, and the success of fermentation. If you're looking to preserve crop quality as close to the point at ensiling, use a product that maximizes lactic acid production (homefermenters). If you don't want silage to heat, use a product that produces acetic acid (heterofermenters).

I have received the question before about whether wet or dry inoculants are better. Unfortunately, there doesn't appear to be any research that has specifically studied this. What does ring true, regardless of formulation, is that the product will only work if the bacteria are alive when placed on the crop. They need to be stored properly in a cool, dry place. This tends to be easier with wet products because the packages are small and can be stored in the refrigerator until they're needed. Some important notes for preparing inoculants:

• The water you use is important since it must support microbial life. Ideally, chlorine-free water should be used, but levels should be less than 1 part per million (ppm).
• The second thought on water; temperature. Research conducted by the University of Delaware showed that temperatures above 95?°F impacted bacteria populations. Water temperatures should remain below 85?°F, which can be accomplished by using insulated tanks or using frozen water bottles. Don't use ice as it will melt and dilute the concentration.
• These bacteria cannot move on their own. They need to be uniformly spread across the crop.

Regardless of whether you choose to apply a wet or dry product, it all depends on coverage and keeping those bacteria alive! In addition to these points, it's important to consider maintenance of the equipment applying the product. Nozzle function is important, and plugged or broken nozzles will impact coverage.

When picking out a product, we want to select products that have been researched and are proven to be effective. Make sure when comparing products that you are looking at "even" products, comparing apples to apples if you will. Look at the concentration (colony forming units or CFU's), cost, and rate of the different products. A product may look cheaper but have a lower concentration, requiring a higher application rate, making application costs the same as the "more expensive" option.

While there is data that supports that inoculants bring value and enhance silage management, they are not a silver bullet. At the end of the day, a quality crop needs to be harvested out of the field and managed using a variety of techniques to maintain quality and reduce losses.

Resources:

https://www.agproud.com/articles/31831-forage-inoculants-keep-them-alive#:~:text=Research%20conducted%20by%20the%20University,of%20CFU%20in%20the%20inoculant.

https://fyi.extension.wisc.edu/forage/silage-inoculants-what-the-research-tells-us-about-when-and-how-to-use-them/