Fertilizer Per Acre For Hay Calculator

Here’s what happens: When it comes time to make hay, you have a dilemma common to all farmers. There’s a bagful of fertilizer sitting in your truck. Do you topdress to help your crop grow, or overapply and waste money? Or do nothing, and wonder whether you’re helping or hurting?

It’s stressful, that’s why hay is considered a cash crop. Hay take more nutrients out of the ground per acre than almost any other agricultural system. And if you don’t fertilize enough, yield goes down and the grass stand weakens. If you over-fertilize, well, then you lose money and possibly contaminate groundwater. You want to be right between those two points so that every dollar you spend add the same amount of dry matter.

How to Fertilize Your Hay Crop

The myth: Nitrogen fertilizer is a one-and-done deal; many producers simply apply it early in the season, and that’s it. The truth is that timothy, fescue, bermudagrass (and most other types of hay) need a season-long supply of nitrogen. Every time you cut your plants, they has to put out fresh foliage, so they need some.

The key is to spread those applications… Rather than “dosing” with them all at once. Applying all the nitrogen at once might burn grass or wash away before the next cuttings. A gradual approach ensures the plant stays fueled when it needs fuel most; a gradual approach supply a slow drip instead of a big gulp.

Another key nutrient that affects profitability is potassium. When nitrogen gets too low it shows up (the plant doesn’t grow well and turns yellow). The effect of potassium are less obvious, but also very important. Potassium gives structural strength to the plants. It controls disease resistance and uptake of water.

Large amounts of potassium is taken out of soil by high-yielding stands. And no amount of nitrogen will make up for a lack of potassium. For example, some hay crops remove more than fifty pounds of potassium per ton of hay harvested. Replace those nutrients if you want to continue to have a good stand.

The long story is that phosphorus promotes good plant health over time. Unlike nitrogen, which has visible effects right away, you will not see any response immediate from adding phosphorus. Phosphorus is essential for a plant’s energy transfer system and root growth. For newly-planted stands, phosphorus is necessary for getting established. For established stands, phosphorus help them stay in tip-top shape.

Knowing your soil test information about phosphorus is important. Don’t guess at rates from last year or years past. Management practices and weather affect the soil chemistry so a three-year old soil test doesn’t count anymore. Know what you have now so you can decide whether to keep your good fields fertile or improve your poor ones.

Adding manure complicates fertilizer math. When you spread manure, it delivers not just N but P and K as well. If you don’t account for those other nutrients, you’ll be applying too little of them and too much of something else.

This page’s calculator factors in these offsets. It takes your soil test results into account (subtracting out contributions from manure). Then it calculates how much commercial fertilizer to apply to fill those holes. It also figures in efficiency rates. Not all the pounds of fertilizer you apply will end up in the roots; some will turn into gas, or get washed away, or lock onto soil particles that can’t be released. Taking those losses into account gives us a plan that works, instead of just a theoretical plan.

Remember that you want to match the product to the need. For maintenance, a balanced mix of everything works well. But if you have a deficiency in one particular nutrient, you’ll want something targeted at that. A low-phosphorus field might need a higher phosphate analysis to build up reserves quickly. Potassium might be low, or even nitrogen (and then just potash or just nitrogen). It’s not a one-size-fits-all deal. Target the specific needs identified on your soil test report.

Remember to consider soil balance when feeding hay. For each bale you cut, you’re mining the nutrients from the soil. Without replacing them, ground will deteriorate over time. Fortunately, math is done for you. All you need to do is plug in your soil test results, yield goals, and any manure credits. It’ll show you the gaps. From there, you can feel confident spreading fertilizer based off the life of the soil.

That’s how you match your input to what the crop needs. With a plan, you get consistency in your hay production. Consistency means fewer guesses.