How Do You Spell Out Bale Grazing Benefits? N, P, K, S

Paul Jungnitsch, a student from the University of Saskatchewan, in 2008 figured out a stunning back-of-the-envelope calculation on the potential benefits of wintering cattle on pasture in his master’s thesis.

Using a 130-day wintering period, and figuring that there were over five million beef cattle in Canada based on 2007 StatsCan numbers, if all those cows were taken out of dry lot pens, the total savings at 46 to 91 cents per head per day would be worth $620 million in savings per year for cow-calf operators.

Jungnitsch determined that the savings from wintering cows in the field would include 107 million litres of diesel, along with a net gain equal to 900,000 tonnes of commercial fertilizer.

“You’d swear that you put 100 pounds of nitrogen out there: dark, rich-green leaves, and tremendous growth.”

– LARRY FISCHER

If you’re driving around the countryside in the fall and see a field full of bales 30 feet apart, you might feel a stab of envy.

Wow! Look at that guy’s hay crop!

But once you mentally figure out that a hay yield of 40 big round bales to the acre is impossible, you’ll slap your forehead – it’s a bale grazing setup.

Come around the following July after some good rains and you might just slam on the brakes.

That’s because there’s lush green grass – stirrup high – growing where all those bales were last winter.

In a nutshell, that’s why bale grazing is catching on all over cattle country.

But still it makes you wonder, why aren’t more ranchers using the technique to restore fertility to their pastures and hayfields?

The reason, said MAFRI pasture and rangeland specialist Larry Fischer, is that some cattle ranchers still don’t realize that every bale of hay is chock full of organic fertilizer nutrients – money, in other words – if they put it where it will do them some good.

Fischer used to buy 250 heifer calves in the fall, bale graze them over the winter, then pasture them in summer and sell them to a feedlot. The heifers did just as well in the field as they did in the pens, and ended up much healthier with more exercise and less crowding, he added.

“I had a neighbour come and ask, ‘Aren’t you going to ruin your pasture by doing that?’” said Fischer, during a presentation on winter feeding options in Minnedosa sponsored by the local grazing club.

“I said, I don’t think so.”

It was a head-scratching moment for Fischer. If you run hay bales through a cow, 80 to 90 per cent of the nutrients come out the back end.

“When you first look at it in spring, you may wonder if the grass is ever going to come through, but it just gets better as you go on through the summer,” he said, adding that even on old beaten-up Kentucky bluegrass pasture, the results are startling.

“You’d swear that you put 100 pounds of nitrogen out there: dark, rich-green leaves, and tremendous growth.”

That’s because a cow’s hind end is a bit like Rumpelstiltskin’s spinning wheel. But instead of golden thread, it churns out two streams of gold: one solid and one liquid.

How much gold?

Researchers in Lanigan, Saskatchewan found that 32 cows, each of which deposited 0.23 pounds of N equivalent per head in solid manure every day, altogether plopped 805 pounds of N over a 109-day period.

Don’t forget the amber liquid, he added.

Their urine, at 0.22 pounds of N per head per day, meant that 767 pounds of N was poured onto the ground, too.

“Over a 200-day feeding period, that’s about $78 worth of fertilizer per cow that you’re putting on the pasture,” said Fischer.

They do that because a 1,400-pound alfalfa bale contains 43 pounds of nitrogen and seven pounds of phosphorus. A grass hay bale the same size represents 28 pounds of N and five of P.

Bale grazing 17 bales per acre puts 731 pounds of nitrogen and 119 pounds of phosphorus into the soil. Grass hay bales at the same rate put in slightly less: 476 pounds of N and 85 pound of P.

In the cold winter air, nitrogen volatilization losses are much lower than in summer, so more of that N-rich liquid gold stays put.

Grass needs nutrients to grow, just like any other crop, he added.

The Canadian Fertilizer Institute estimates that a three-tonne-per-acre grass crop uses up 92 to 113 lbs. of nitrogen, 27 to 33 lbs. of phosphorus, 117 to 143 lbs. of potash, and 11 to 14 lbs. of sulphur.

“Alfalfa would probably use up more than that,” he said.

What about access to water? Fischer says that he knows people who bale graze 500 to 600 cattle every winter and their cows lick snow.

Of course, a backup water source is necessary in case the snow is late, he said, adding that many ranchers have found that a half-to three-quarter-mile hike to water isn’t too much for a cow.

A researcher at the Western Beef Development Centre found that bale grazing recovered 34 per cent of the nitrogen compared to just one per cent if the cows were wintered in a pen and the manure was hauled out and spread on the pasture, Fischer added. [email protected]

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