What Is Nutrient Managemnet?

Chickens in houses. (Image)

Many people do not know exactly what nutrient management actually means. This article will attempt to shed some light on the subject.

Before one can understand what is nutrient management, he must first understand what are nutrients. Nutrients are substances that are essential for plant growth such as Nitrogen, Phosphorus and Potassium (potash). These three nutrients are the main ingredients in any mixed commercial fertilizer. Consider "triple thirteen" (13-13-13) and understand what each number symbolizes. In commercial fertilizer, the first number is the percentage of nitrogen (N) that the mix contains, therefore this mix will contain 13 % nitrogen or 13 pounds of nitrogen per one-hundred pounds of fertilizer. The second number represents the percentage of Phosphorus (P) that the mix contains and the third number is the percentage of Potassium (K) that the mix contains. So, if someone applies two-hundred pounds of triple thirteen, his field is receiving twenty-six pounds of each nutrient.

Plants use different amounts of each nutrient in order to produce fruit, fiber, forage, etc.. Producers must first know the needs of the plants before he can determine what and how much fertilizer is needed. Since plants can utilize only so much of each nutrient, all excess nutrients either accumulate in the soil, leaches through the soil or runs off the field with water. What happens to the excess nutrients depends on many factors such as soil type, slope, water table, ground cover, etc..

Each particular nutrient affects plant growth in different ways. The following is a short description of each nutrient’s function in forage production.

Nitrogen is the element which is usually most limiting in hay production. It is an constituent of protein. Proper rates of nitrogen increase growth rate and photosynthesis. Nitrogen deficiencies are characterized by a light green color and poor growth. Hybrid bermudagrass hay requires high rates of nitrogen to maximize yields. Nitrogen losses are due to volatilization, leaching and runoff.

Phosphorus is critical in establishment of a root system. It is essential in the storage and transfer of energy and is a component of several biochemical actions that control plant growth and development. Phosphorus deficiency in warm season grasses is exhibited as small, unthrifty plants. Phosphorus is used in much smaller amounts by hay than are nitrogen and potash.

Potassium (potash) is indirectly related to many cell functions. Some sixty enzymes require the presence of potassium. Plants sufficient in potassium are much more "winter hardy" than those plants that are deficient. Plants that are deficient in potassium are more prone to drought stress, certain diseases and winter kill. Bermudagrass hay removes tremendous amounts of potassium from the soil.

As previously stated, plants remove different amounts of each nutrient per unit of measure (ie. tons, bushels, bales, etc.). The following is the amount of nutrients removed per ton of hay. Therefore, once a producer knows how many tons of hay is removed from a pasture, he can calculate how many pounds of nutrients are removed.

Nitrogen - Hybrid Bermuda .....46 lb/ton of hay

Bahia.......................43 lb/ton of hay

Phosphorus - Hybrid Bermuda...12 lb/ton of hay

Bahia....................12 lb/ton of hay

Potassium - Hybrid Bermuda....50 lb/ton of hay

Bahia.....................35 lb/ton of hay

Once a producer understands the amounts of nutrients that are utilized by the plants, he should then determine the amounts of nutrients that need to be added to the fields. The only way to determine the amounts need to add to the field, is to know the amount of nutrients that exists in the soil. This is done through a soil test which can be obtained through the local LSU AgCenter’s Cooperative Extension Office. A soil test will indicate the nutrients present in the soil in order to determine what added nutrients are required. Each field should be considered on a "case by case" basis.

Poultry litter has an average of sixty pounds of nitrogen, sixty pounds of phosphorus, and forty pounds of potassium per ton. This equates to a commercial fertilizer mix of 3 - 3 - 2 or 3% nitrogen, 3% phosphorus and 2% potassium. These amounts are averages and will vary with different farms or production units. It is recommended that a litter analysis be conducted for each farm.

Once a producer knows what is needed to produce the hay and the amount of nutrients that are present in the field, he can decide how much is needed to produce amount of desired forage.

Although there are many more factors in nutrient management, this has been a short explanation of the major points of managing a producer’s fertilization costs. With production costs rising at a steady pace, producers must consider ways to maximize yields while minimizing costs.

For more information on maximizing yields while minimizing costs through fertilizing, contact Matt Stephens at 318-644-5865 or your local County Agent.