Fertilizing after Warm Season Cuttings
As the time of year comes to harvest warm season annuals, we have started receiving questions about adding fertility after taking the first cutting. Below are some answers…
Why you might need it -
Warm season annuals are efficient users of nitrogen, but they are still grasses that can require supplemental nitrogen when harvested. Even though nitrogen is the piece of fertility we focus most on for grasses, it is important to have your soil tests in mind to know what other amendments your soil may be looking for. Even if a warm season mix contains legumes, additional nitrogen may be needed. Those legumes are fixing nitrogen for you, but they are storing that as protein in the above ground growth that is removed as forage. This adds to the feed value, but not to the nitrogen content of the soil. Fertility after cuttings may not be needed if you have a lot of manure on the field ahead of time. It is also usually not necessary when grazing the forage as the livestock recycle the nutrients for you.
What to apply -
The type of fertilizer applied will vary from farm to farm based on your practices and what is available. Poultry litter can work well as a nitrogen source, but can be slower to release the nitrogen compared to others. Urea can be an option, but should be avoided in dry environments as it can be quick to volatilize. Ammonium sulfate and ESN (Environmentally Smart Nitrogen) are both stable forms that can work well to be applied after a cutting. A general recommendation for the amount of fertility needed is 30-50 pounds of actual nitrogen. We would not recommend any higher rates between cuttings
When to apply it -
The best timing for applying this fertilizer is directly after harvest in order to jump start you next cutting or grazing.
What other questions do you have about fertilizing warm season annuals?