When working with perennial forages, soil fertility is vital because it affects the quality of the forage with the animal eats.  The animal health and production is related to the nutrients that the animal gets from the forage eaten.

The best way to determine the fertility level and fertilizer needs of a current or future pasture is from a soil test.  Soil tests tell us the soil pH: Nitrogen (N) recommendations; Phosphorus (P) and Potassium (K) levels and recommendations; as well as secondary and micronutrient status.  For a new pasture, soil test samples should be collected and analyzed well in advance so the types and quantities of recommended fertilizers can be incorporated into the soil at the time of field preparation.  At this same time, lime should be applied to achieve a soil pH of at least 6.3.  In addition to correcting pH, lime is a source of valuable calcium, which all living things need.

The pH of the soil is important, but why the pH is at that level, should be considered more important.  The base saturation levels of Calcium, Magnesium, Potassium, Sodium, and Hydrogen levels determine the pH.  You can have a high pH and still have a shortage of Calcium in the soil.  Calcium, however, is the one element that drives the production of quality forage.  A good source of Calcium is Gypsum, which is Calcium Sulfate.  Sulfur is very important for creating high quality proteins in forages.  Most soils are low in this element.

All grasses need nitrogen (N) on a continual basis to attain and maintain optimum production.  Nitrogen is a vital fuel component for the plant.  It is consumed daily as the plant grows.  This is true even when grasses are planted with clover or other nitrogen fixing Legumes.  Legumes are a money saving source of Nitrogen especially during the summer and should be used where possible.  Alice Barblanca white clover can provide up to 150 units of N/acre/year.

Even with clover in the pasture mix, 50-200 unit lbs (depending on the type of grass) of supplemental N/acre/year is about right for optimum production.  This assumes that the proper levels of phosphorus and calcium are present.  Without these, the performance of Nitrogen alone is greatly reduced.  The best way to apply Nitrogen is in 30-50 lbs applications, every three to five weeks depending on rainfall, weather, etc.  On established pastures, take a soil test every 2-3 years, then top dress add the recommended levels of Phosphorus and Potassium in the fall, allowing winter action to incorporate.

In Central IN during the past five years we’ve gained an average of 2.5% organic matter on the whole farm.  We use 150-200 lbs n/acre/year.  Some people will not believe that we can raise organic matter with that much Nitrogen.  The fact is we would not be able to do it without Nitrogen.  We are not applying 100lbs in 1 application on bare ground, but 30-50 lbs at a time on dense sod.

Remember that persistency of forages is related to balanced fertility.  A healthy plant is likely to over-winter or over summer.  All plants and animals need balanced fertility (nutrition).  That includes micronutrients as well.  Constant removal of nutrients with crop and pasture levels some soils very low in Copper, Zinc, Manganese, Boron, etc.  Do not let the word “micro” fool you.  You do not need much, but you do need enough.