Fertility

Image 1. Additions of nitrogen and potassium drastically reduced broomsedge in this Kentucky hayfield.

by Jimmy Henning

• Select fields for stockpiling fescue for fall and winter grazing. Apply nitrogen in early to mid-August and remember to mow or graze forage to three to four inches of height prior to nitrogen application.
• Plan ahead for any fall seedings. Plan details such as soil testing, no till or conventional till, fertilizing requirements and removing animals from the field to allow time for establishment.
• Follow up with any soil test results to decide on fertilizer needed for the fall. To take a soil test, contact your local county extension agent.

Many producers have already started planning pasture and hayfield fertilization. Pastures require nutrients to reach peak productivity. These nutrients are derived from several sources including residual nutrients in the soil, the breakdown of manure and soil organic matter, and nitrogen produced by N-fixation in legumes. Most importantly, nutrients are supplied to plants through the application of commercial fertilizer and lime.

By S. Ray Smith Extension Forage Specialist, University of Kentucky - Have you ever given advice and then not taken that advice yourself. I’m sure my kids could tell you a few stories about that. At almost every forage meeting I speak at I emphasize the importance of soil testing hay and pasture fields. I say something like: “if you do not take a soil test, then how do you know if you are over-fertilizing or under-fertilizing.” If you over-fertilize, then you are spending money that could be used for other things.

Plants require several minerals and nutrients for growth and production. The three primary nutrients required for plant growth are nitrogen, phosphorous, and potassium. Nitrogen (N) is an essential nutrient necessary for photosynthesis, enzymatic reactions, and creating amino acids, the building blocks of protein. Increasing nitrogen in the soil has been proven to greatly increase pasture production. 

Fertilizer is one of the main expenses in a productive grazing system. It is important to apply fertilizer and lime in accurate amounts for best forage production and financial and environmental reasons. Performing a soil test on pastures and utilizing the results to evaluate pasture fertility is strongly advised. Analysis of a soil sample will determine nutrient content of the soil including phosphorus, potassium, magnesium, sodium, sulfur, manganese, copper, and zinc. Soil pH, organic matter, and exchangeable acidity will also be included in the results.

Cool-season grasses show dramatic responses to nitrogen fertilizer applications. Benefits include stimulating growth, improving yields, and increasing protein content. Applying nitrogen in mid-February to mid-April can promote early grass growth which can increase overall forage production.

Fertilizer application is often needed for a healthy forage stand. Having a soil test done before applying fertilizer to pastures is strongly encouraged. Apply only what is needed according to the soil test results. The University of Kentucky recommends phosphorus (P) applications starting when the soil test P level drops below 60 lbs/acre and potassium (K) when soil test K drops below 300 lbs/acre. Ideal soil pH levels are dependent on the forage type and usually range between 6.0 and 5.5.