Q. What is the ideal pH for corn silage?
A. There is no single number! The final pH should be between 3.7 and 4.7, depending on the forage and the dry matter (DM) of the crop. Relying on the pH value alone is not a good measurement for determining high-quality silage. There are many variables that can affect pH, including the type of forage, DM level, the filling/packing/sealing program, the “age” of the silage at sampling and even the type of inoculant used.
The pH will start to fall after the silage storage structure has been filled, packed and sealed. Once silage becomes anaerobic, the conversion of forage to silage begins. To achieve successful fermentation, and prevent bad fermentations, the pH must rapidly be reduced to below 5.
Forage inoculants can help ensure silage hits the correct pH targets and acid profile to promote stability, retain DM and maximize nutrient preservation. For example, the lactic acid bacteria (LAB) Pediococcus pentosaceus 12455, provides an efficient, fast fermentation fueled by sugars generated by high activity enzymes.
Once feedout begins, pH may rise again due to the activity of spoilage yeasts. Specific forage inoculants can help prevent this. The high dose rate Lactobacillus buchneri 40788 is the only inoculant microbial reviewed by the FDA and allowed to claim improved aerobic stability of silages and HMC.