Potential causes of lower crude protein in small grain silage this year

Posted on June 7, 2021 in Forage Foundations
By Ashley Blackburn, Vita Plus agronomy and forage specialist

Colder soil temperatures, frost and less rain than a normal growing season plus other stressors can affect crops in different ways, especially crude protein levels in small grain silages.

Inadequate fertilization can lead to low crude protein in small grains.  Be sure the crop has been fertilized adequately with macro nutrients (nitrogen, phosphorus and potassium) and sulfur. These nutrients are vital to crop development.

  • Nitrogen (N) is a major component of chlorophyll and amino acids, the building blocks of protein.
  • Phosphorus (P) is involved in several key plant functions, including energy transfer, photosynthesis, transformation of sugars and starches, nutrient movement within the plant, and transfer of genetic characteristics.
  • Potassium (K) is associated with the movement of water (regulating opening and closing of stomata), nutrients and carbohydrates in plant tissue.
  • Sulfur (S) is used in chlorophyll formation and is a structural component of amino acids that form protein.

Forage-type small grains
Make sure the small grain variety planted was a forage-type small grain.  These varieties tend to have better forage quality than non-forage small grain varieties.

Temperature and moisture
This growing season has been both cold and dry.  Colder soil temperatures and frost can affect soil nutrients available for plant uptake.  This is because soil bacteria help convert applied nitrogen to an available form for the plants to take up through a process called nitrification.  For this process to occur, soil temperatures need to be at least 50 degrees F.  Colder temperatures and late frost can lead to depressed nutrients in the soil available for plant uptake, which then affects small grain silage crude protein content.

Rye planted in the fall for forage production can yield substantial dry matter (DM) in the spring.  The rule of thumb for harvesting small grains is to harvest at the boot stage or early head stage before pollination can occur. Harvesting at the boot stage can typically produce DM yields of about 2 to 3 ton per acre at quality levels for animal production feeds. The table below shows average and range of rye forage yield, quality, and nutrients removed by harvest. Getting a crude protein level analysis before or shortly after harvest is always a good idea to check the quality of the forage for feed.

Category: Crop varieties
Feed quality and nutrition
Forage Foundations