Fertilizing for making hay in ‘22


Tony Nye - OSU Extension



I hope everyone is ready for a wonderful Thanksgiving and I hope you can share with family and friends.

In this current crazy, mixed-up world we live in, lets look at this next week through the words of Charlie Brown, “What if today, we were just grateful for everything?”

Before getting into the column for this week I will leave you with this Thanksgiving quote to all the cooks: “A new survey found that 80 percent of men claim they help cook Thanksgiving dinner. Which makes sense, when you hear them consider saying, ‘That smells good’ to be helping.” — Jimmy Fallon.

Once the Thanksgiving feast is over next Thursday, we can all get back to reality, I guess. In the agricultural sector this could mean finishing harvest (not a lot left, thank goodness), doing some necessary tillage, starting to work on taxes, or trying to figure what inputs I will need for next year and worry if they will be available when needed.

One hot topic of course is increasing fertilizer costs. Here are some recent Ohio fertilizer cost averages: 28% nitrogen — $559/ton; ammonia — $960/ton; MAP — $854/ton; and potash — $732/ton.

These costs are at levels we have not seen in years — if at all — and many producers are wondering, “Will I be able to get by on lower levels, or not applying at all in certain situations?”

This question might be “real life” for livestock and hay producers, but I think the answer will be the same no matter what we grow when considering crops and/or animals.

Answer: Can we afford not to? Bottom line is we can not starve animals or crops.

In a recent Ohio State University BEEF cattle newsletter, OSU Extension Educators Stan Smith, Fairfield County and Chris Penrose, Morgan County talk about strategies when addressing hay fertilization.

They both agree that first and foremost, now more than ever is the time to make sure we have up to date soil tests. We can’t manage what we haven’t measured and knowing the nutrient content of forage fields is critical to knowing which soil nutrients will offer the most return on investment.

Don’t forget the value of manure if available. Perhaps having your manure analyzed for nutrient content this year might be dollars well spent.

Lime has gone up little if any, in price, in recent years. To optimize the efficiency of the fertility we do have, correcting soil pH should be high priority during times of expensive soil nutrients.

Understanding the type of hay being grown will help in determining fertilizer needs; such as, are you growing alfalfa or a grass mix? If it’s a field full of legume or field heavily mixed with legume, nitrogen is likely not needed at all.

On the other hand, if the goal is to optimize the productivity of stands that are predominantly grass, yields will be benefited by properly timing the application of a correct amount and source of nitrogen.

Strategically timing nitrogen might mean foregoing an early spring application since it’s not uncommon to grow more first cutting hay than we can make and harvest in a timely fashion.

However, 50 units of nitrogen applied to a grass hay field immediately after first or second cutting can significantly boost yield of the subsequent cutting.

Applying nitrogen after a first cutting onto warm soils at times of high air temperatures increases the risk of volatilization of urea-based nitrogen sources. Use a stable source of nitrogen such as ammonium sulfate. If using urea and rainfall is not on the horizon, including a nitrogen stabilizer or urease inhibitor is likely warranted.

If phosphorus is being applied at the same time, the nitrogen that comes along with a phosphorus source like 18-46-0 is stable and effective.

Perhaps the most difficult decision will be what to do about phosphorus and potash needs.

Each ton of harvested hay removes with it 12 pounds of P2O5 phosphorus and 49 pounds of K2O potash. If soil nutrient levels of phosphorus and potash are at critical minimum levels, perhaps the only phosphorus and potash that needs to be applied this year are the amounts removed through harvest.

If levels are at the minimum critical levels of 30 ppm for phosphorus when using the Mehlich-3 extraction method, and 120 ppm for potash on loam and clay soils, phosphorus and potash could wait to be replaced at the end of next growing season if you are of the opinion fertilizer prices may moderate before then.

Smith and Penrose continue in the article noting that If soil test results indicate phosphorus and potash levels are above the minimum critical level mentioned above for forages, it may be cost effective to skip a year of phosphorus and potash application. Regardless, now may not be the best time to proceed with an aggressive soil nutrient build up program.

And, if you do choose to replace all the phosphorus and potash removed by a hay crop, how much will that cost per ton of hay removed?

Using crop removal rates suggested earlier and when assuming phosphorus and potash cost near 60 cents per pound, a ton of forage is removing from the field between $35 and $40 dollars’ worth of fertility. If it’s predominantly grass hay and you add 20 units of N per ton of hay produced, at today’s fertilizer prices you’ll add about $15 to that total.

If you value hay at $100 or more per ton and harvesting optimum yields of high-quality hay is essential to the success of your operation, fertilization, even despite very high soil nutrient cost becomes a no-brainer.

You can’t starve profit into an animal, or a hay field!

Tony Nye is the state coordinator for the Ohio State University Extension Small Farm Program and has been an OSU Extension Educator for agriculture and natural resources for over 30 years, currently serving Clinton County and the Miami Valley EERA.

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Tony Nye

OSU Extension