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Getting the most out of pasture fertilization

Nicole Richardson for Progressive Forage Published on 01 June 2020

Throwing stock onto a pasture and hoping they are getting the correct nutrients is like a shot in the dark. Pasture maintenance and rehabilitation can be a daunting task; establishing a fertilization plan can help take the guesswork and burden out of the equation.

Soil testing

The first step to establishing a healthy fertilization plan is to gather a soil test of the pastureground. Going out and grabbing a handful of soil to send in is not going to get the accurate results needed.

Less than a teaspoon of soil is used during the laboratory analysis. This minute amount of sample must be an accurate representation of that 40 acres. Retrieving a meticulous sample is somewhat of an art form: Depth, pattern and location are key components to being able to paint the perfect picture in the end. Chrome-plated or stainless steel sampling equipment should be used, avoiding galvanized, bronze and brass tools along with clean plastic buckets.

To choose location for samples, a general method of each plot should be divided into sample areas. Color is a good place to start when sectioning off sample areas; ASCS photos can also be used to determine sections. Surface debris should always be removed prior to sampling, and the following types of odd areas should be excluded: fencerows (new or old), old roadbeds, windbreaks, turn-rows, spill areas, etc.

Sample depth is also highly essential and should be consistent throughout each core taken. Ideal sample depth is between 6 and 8 inches, and ideally a majority of laboratories recommend 6.66 inches. In hand with sample depth, quantity of samples plays a large factor in accuracy of results. Ten to 15 samples per section, with each group of samples representing no more than 5 acres. Samples should be selected in a zigzag pattern throughout each section, giving the most accurate representation of each type of soil.


Following laboratory results from an accurate soil sample collection will determine which fertilizer to apply and when. Secondly, keep in mind that to see high monetary results in the end, the soil must be deficient in a nutrient. Soils that are high in nutrients will likely not see profitable results from adding fertilizer, though it remains key to continue adding maintenance amounts of fertilizer to ensure productivity and longevity continue at high levels.

For grass-based pastures, early spring nitrogen application will aid in creating stronger and more resilient grass strands, whereas for legume-based pastures, splitting nitrogen application between early spring and late summer will benefit the strength of legumes. Adding phosphorus and potassium can be a hefty investment, so care should be taken when amortizing the projected ownership/lease of the land.

If it is a short-term situation, it may not be profitable to begin the buildup of phosphorus and potassium. These nutrients are to be built up over a lengthy timeframe and can be monetarily tasking. Maintaining a pH level between 6.0 and 7.0 for grasses, and 6.5 and 7.0 for legumes is comfortably achieved by adding lime.

What to plant

Most pastures are grass blends, and while this can suffice ruminants, there are better alternatives. Adding legumes to a grass pasture blend can increase efficiency because they provide a more readily available energy. While climate location should dictate what type of legume is overseeded, there are different options.

In Southern regions, annual legumes such as crimson clover are oftentimes added to grass pastures, while in more temperate climates perennial legumes are utilized such as white clover or alfalfa. By blending these legumes into a grass pasture, it provides a more dynamic nutrient profile, allowing stock to increase feed efficiency during grazing months. This, in turn, can assist in ensuring the dollars spent on seed and fertilizer become profitable.


A detailed grazing plan is necessary to ensure the dollars and work put into fertilizing and seeding acres does not go to waste. While everything could be done correctly before turning stock out for grazing, if they are allowed on forages too soon, it could destroy the integrity of the pasture. It is critically important to allow grasses and legumes ample time to grow and establish themselves before they start taking damage from livestock; 4 to 6 inches of growth is a good head start for them.

Rotational grazing is an ideal way to protect forages during grazing season. A strong rotational grazing program can add 25% to 50% plant production in the first year and nearly double production by year three. The rest time for the plant allows it to recover from leaf removal and maintain vigor to restore itself. If rotational grazing is not an option, this same concept is applied to fall rest periods. Pulling the herd off the pasture for the fall allows the pasture time to rest and recover, leaving increased root reserves which promotes earlier green growth in the spring.

Forages are highly susceptible to damage during dry periods. This can be combated by supplementing during these periods with grain. Providing additional nutrients takes a load off of the grasses and legumes and allows them to still recover and continue growth even during drought seasons.

A well-maintained pasture is indispensable when it comes to ensuring dollars input are profitable on output. From testing through seeding and grazing, each step is indicative to how successful the nutrient output will be. The ultimate goal is to increase availability and feed efficiency in the stock that will be consuming the forages. By providing them with a high-quality and nutrient-dense grass and legume, it can ensure the investment put into the property will yield profitable results.  end mark

Nicole Richardson is a freelancer from Missouri.