Corn silage growers will have several opportunities to test standing corn for whole plant moisture as fall approaches.  The Fond du Lac County Forage Council’s chopper will be set-up and open for business on Tuesdays, September 8th, 15th, and 22nd from 10 a.m. until noon at the Dave Schmitz farm located at N5236 River Rd., Fond du Lac.  The farm is located about one mile south of old Hwy. 151 (now County Rd. D/Military Rd.).  Whole plant corn samples will also be processed on the next two Tuesdays (September 9^th and 16^th) during the same 10 a.m. till noon time frame.   

     Any Fond du Lac County resident or crop professional is welcome to bring stalk samples for testing on any of the above dates.  Bring four stalks per field (cut at chopper height) and have the following information readily available:  name, city/town, contact information (phone #, e-mail or fax), hybrid planted, hybrid relative maturity, and planting date.   It’s suggested that samples be cut from inside the field to avoid field border and headland effects.  Corn stalks will be chopped and taken to the forage lab for moisture analysis.  We will then contact you with this information as soon as it is received (usually the next day). 

What’s the optimum whole plant moisture for harvesting corn silage? 

     Corn silage is complicated animal.  Total yield increases up to the point where kernel black layer is reached and the plant begins to desiccate, which is generally around 60 percent moisture.  However, delaying harvest until maximum dry matter yield is achieved reduces nutrient availability.  Often, kernels become hard and remain undigested by the animal.  Researchers often cite 65 to 68 percent moisture as optimum for maximizing corn silage quality.  Often silage that is over 70 percent or under 60 percent moisture results in the greatest problems from a feeding and storage standpoint.     

     Storage structure type dictates whole plant harvest moisture with the realization that some tradeoff is going to be made for quality and yield.  Corn silage put into upright silos is often done so at moisture levels between 60 and 65 percent to prevent seepage.  The thought process is sound but it comes with the realization that some loss of inherent feed quality may occur (less starch availability and higher lignin content).  Kernel processors help to alleviate some of these quality losses.  Corn silage is generally harvested at higher moisture levels for bunker silos to improve packing characteristics (ideally 65 to 70 percent moisture) but with the expense of maximizing dry matter yields.  Harvesting corn silage at over 70 percent moisture increases the chances for improper fermentation and the formation of butyric acid.