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Grazing corn

I’ll say it right up front. The 2011 crop year didn’t start on the right foot. We were in trouble before we even got started. They say a little adversity builds character, but I’ve got enough character. Here’s to a normal growing year in 2012.

April 30, 2011 delivered a healthy dump of wet heavy snow. Just what we needed after going into winter with saturated soils, more water. We had 300 acres of fridge forage winter triticale seeded last fall, late, but still established. The plan was to seed 30 acres of corn, 20 acres of Shoshone sainfoin, 500 acres of soybeans and 300 acres of InVigor canola. That’s the fun part of making plans — changing them. Once the snow melted and we had more rain, there was water everywhere, including Mom and Dad’s basement. The new goal was to have the canola seeded by May 26. Then we’d seed soybeans until June 10.

Things looked grim for getting the corn in. Since our kids were kayaking in the field I’d planned to seed, I changed to plan C.

This plan was to seed the corn on last year’s corn field. Once the water started to drop we worked the field on May 31 with 4-inch spikes on 12-spacing, trying to dry out the soil. Of course, it rained again. After getting the soybeans in the ground, we worked the field again, drying it out enough to get on the land to seed corn. Because the land had been seeded to corn that was grazed for the last two years with supplemental alfalfa hay bales, nutrient levels were very high, so no fertilizer was required. The corn averaged 12.49 wet tonnes per acre or 2.75 dry tonnes in our trial. After grazing the numbers were a bit low. We averaged closer to 225 grazing days per acre, assuming 35 pounds of dry matter per day per cow, dry tonnes would have averaged closer to 3.5 tonnes.

The corn was seeded June 10 with our Kinze planter on 34-inch rows. Our trial consisted of four rows of each of the varieties. The seeding rate trial used lower seeding rates that the 27,451 seeds per acre, mainly because I took the wrong gear. This trial showed how different varieties respond to lower seeding rates, which I think is important for two reasons. First, lower seeding rates will keep costs down, and second, to see which varieties stay feminine at lower rates. The important two feminine traits are fine stems and long slender cobs.

One thing to watch when reducing seeding rates is maturity. Lower plant populations will hasten maturity and produce more cobs per plant. Under poor growing conditions — dry or cool — lower seeding rates will work well. Under good conditions, higher seeding rates will result in higher tonnes. Feminine plants will result in improved palatability.

Fertilizer and glyphosate

No fertilizer was added to the field because it was grazed for the last two years, so nutrition for the corn crop would be adequate. Because the animals never left the area during grazing, all of the manure and urine was left in the field. Cattle have evolved to fertilize grassland, and will retain only three to five per cent of the nutrients they consume.

We sprayed the field twice with RoundUp WeatherMax, making the crop clean. I found a couple of plants that survived the glyphosate. After further investigation, I realized they were RoundUp Ready sugar beets I’d seeded last year. They must have been dormant and germinated this spring. The cows will thank me later when they eat the sugar beets.

On July 22 our Tillage radish seed arrived from Oregon, so we seeded our first field to cover crop. Then we loaded up to deliver some seed to Alberta. When I came home, I went out to the corn field. There was a place in the field where a couple of runs in the planter ran out of seed, so I broadcasted some of the Tillage raddish on the soil without incorporating on August 1. It was amazing to see how quickly they germinated and grew.

The ultimate test

The next challenge was to see what the cows thought. The cows were turned into the corn field. After walking over them for the first day, once they tried them, they cleaned them right up.

On October 8 we did our trial. The trial consisted of LF 690R, LF 728R, LF 815R, LF 755RR/Bt MZ 1261R, PPS 2146, PPS 7871, PPS 8811, PPS 7811, PPS 8781, PPS 7781, 8098, BAXXOS, and HL SR 35.

We cut down 1/1,000 of an acre of each variety (15.4 feet long). The trial averaged 17.4 wet tonnes per acre, ranging from 12.8 to 24 wet tonnes per acre. Moisture content ranged from 68.5 per cent to 81.7 per cent.

The important numbers are the dry tonnes per acre. When talking to people about any forage production, always ask about dry tonnes, especially with highly variable moisture products or different moistures. Once the cows were grazing, there was very little difference in palatability. All of the varieties were very palatable.

The 8098 is a stacked variety, and the palatability, as predicted, was lower than other varieties but still respectable. Relative feed value averaged 118, and protein averaged 9.1 per cent. Lignin averaged 3.1 per cent and maintenance energy averaged 1.50 Mcal/kg along with a 63.7 per cent TDN. Grazing days per acre was calculated at 259 and the milk production per acre was calculated at 5,955 kg. Fifty cattle started grazing the field on September 24. By the end of November they were about half done; by Christmas they had about 10 acres left.

Grain overload

A few farmers at Agribition told me that corn grazing does not work — they lost cows due to grain overload. This is a result of seed retailers promoting corn varieties that mature too early, causing too much grain production.

Ideally, corn staging should be between blister and dough (R2 to R4). For silage, those varieties and staging works. For grazing, managing mature grain intake is more difficult. In my nine years of selling corn seed, I have not heard of any of our customers losing any of their herd due to grain overload. My quick rule of thumb is: just before freeze up, go out to your corn field and bite a cob. If it tastes starchy and bland, your starch content in the grain is high and most likely should be silage. If the kernels in the cob are still juicy and taste sweet, they’re safe to graze. They won’t be as sweet as sweet corn, but will taste relatively good.

Corn supplies are limited for a bunch of good grazing varieties for 2012, so picking varieties early this winter is important. Seed yields in 2011 were poor in the corn seed production areas, so if you’re thinking about corn for 2012, it’s best to book seed relatively soon. Your cows will thank you. †

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