The following article was submitted by Chris Hicks, Smith County Extension Agent: 

Over the last few weeks as temperatures have warmed, it has been a common sight to see pickup trucks hooked to fertilizer buggies headed to and from fields. Yes, fertilizer season is in full swing here in Smith County as farmers are replacing nutrients used by last year’s crops. 

Hay is the number one crop in Smith County with over 20,000 acres harvested each year. At an average yield of 2.25 tons per acre and an average price of $115/ton, that’s nearly $5.3 million dollars’ worth of hay produced each year. 

Obviously hay is big business in Smith County, not only from a production standpoint, but also from the input side. One of the costliest, and most important of those inputs is fertilizer. 

The haymaking process moves nutrients from one place to another. The nutrients stored in the aboveground portion of grass in one field are cut off at the ground, dried in the sun, baled up and hauled off for storage. 

Then, those nutrients will be fed during the winter, typically in another field. Those stored nutrients are fed through livestock and deposited around hay rings and in pastures. That’s great for those pastures, but what about that hayfield where the nutrients came from? Do we stop to think about how many nutrients we are removing when we harvest hay?

According to the Southern Forages 4th Edition, an annual tall fescue yield of 3.5 tons/ acre will remove 135 lbs. of nitrogen, 65 lbs. of phosphate, and 185 lbs. of potash. Bermudagrass hay production is even more startling in its removal rate with 258 lbs. of nitrogen, 60 lbs. of phosphate, and 288 lbs. of potash being removed with a 6 ton/acre yield. 

These nutrients may ultimately be recycled through livestock and benefit pastures if hay feeding areas are rotated, but their absence in the hayfields will manifest itself through weaker grass, decreased yield, and more weeds. 

In order to know what nutrients are available in your hayfields and how much may be lacking for optimum yield, a soil test should be taken. It is a good idea to test hayfields every two years to make sure they are not deficient in one or more nutrients. 

Your soil test results will be used to formulate research-based, cost-effective lime and fertilizer recommendations specific to your situation. For more information about soil testing or UT fertilizer recommendations, stop by the University of Tennessee Extension office at 125 Gordonsville Hwy. in Carthage, or call us at 615-735-2900.