For the first time ever, my farmer husband is letting me take over my very own 60 acres - for the first post on obtaining land, read here.
All plants, including corn, need nitrogen to grow. Nitrogen is a chemical, the seventh element on the periodic table, and literally surrounds us wherever we go. It is an odorless, colorless gas that makes up nearly 80% of our atmosphere.
With so much of it in the air, it was surprising to me to learn the challenges that come with getting enough nitrogen for our food and fuel crops. Washington State University explains here that nitrogen is likely the most limiting factor in our ability to grow more food globally.
The nitrogen that is in the air is not usable by most plants - we have to get that nitrogen into the soil. And that is exactly what I got to do today on my 60 acres!
When a plant grows on our farms, it takes up both micro and macro nutrients. When we harvest the crop and remove it from the farm, we also take away those nutrients such as nitrogen. To keep our farm sustainable and profitable, we have to manage those nutrients each year to make sure we are putting back into our soils whatever we have taken away.
So to prepare my 60 acres for corn that will be planted this spring, today I applied Anhydrous Ammonia (AA) - NH3. This is a colorless gas that is made up of one part nitrogen to three parts hydrogen. We also use N-serve, a nitrogen stabilizer that helps to keep the nitrogen where my corn will need it.
We elect to use AA as one of our sources for nitrogen because it's readily available, efficient and cost effective. The downside to using AA is that when it is applied it does kill off many of our organisms living in the soil, in the immediate vicinity of where it is applied. This is because it shocks the pH of the soil so quickly, but this is only in an oval shaped area right around where the gas is applied in the soil.
We spend a lot of time growing our soil bugs and earthworms so this feels like it's setting us back a little. Luckily, studies show that by the time we go to plant, the soil will have recovered back to its thriving state.
Organic farmers do not have the option of using AA because it is synthetic. They instead rely heavily on animal manure to add back in nitrogen. Washington State explains how even organic farms are still dependent on chemically fixed nitrogen because of the nitrogen cycle. Most manure applied comes from animals fed diets that were grown using chemically fixed nitrogen. For the food and fuel production we need today, chemically fixing nitrogen is necessary - but safe as well.
I used a tractor - a John Deere 8640 - to pull an applicator bar, and behind it the tank. The tank contains the AA. It runs through a hose, into the applicator bar where it is injected down into the soil.
A knife leads the injector, cutting the gas down into the soil, and then two closing wheels come behind to cover the soil back up. It's important that the soil gets covered back up otherwise all the nitrogen will escape right back into the atmosphere - where my corn can't use it!
It's also important that we try to put AA on when the soil is around 20% moisture. The soil should form a weak ball at the right moisture levels. For more application tips, read here! If there are no water particles to react with, the AA will travel further down into the soil to find water - possibly out of reach of my corn!
Today we put on 120 pounds to the acre. This is a lower application rate than normal - usually between 150 - 200 pounds per acre. This is because I have something else working for me as well.
My sixty acres actually started being prepared for this corn crop last fall when Matt planted a cover crop - a combination of radishes, turnips, cereal rye, alfalfa, and crimson clover. These plants grew all fall, even into the winter. We never harvested them because they worked in different ways.
For more information on how our cover crops work, read my post here!
Focusing on nitrogen, three of those cover crops helped us to be able to lower our rate of AA. First, the radishes have very long tap roots - a root sent straight down into the soil, sometimes up to six feet in length. These tap roots grab onto nitrogen further down in the soil and then bring it up to the radish. Because we do not harvest the radishes (they decay right back into our soils) that nitrogen will now be available to my corn.
The alfalfa and crimson clover also helps with our nitrogen. Alfalfa and clover, like our other main cash crop soybeans, are a legume and legumes can actually fix their own nitrogen. Clover is known as one of the best nitrogen fixing crops available. These plants actually grab onto nitrogen from the air and “fix” it onto the plant. Again, because we did not harvest the alfalfa or clover and it is still there in my soil, all of the nitrogen it fixed is now available to my corn as well.
For now, my 60 acres should have adequate nitrogen to get my corn started off right! We will apply a booster of nitrogen later in the growing season with a practice called side-dressing.
The next piece of equipment to run over my field will be the sprayer! Stay tuned!
(Today was also our 7th wedding anniversary so we had to take a picture together in the tractor!)
Kate Lambert grew up in northern Illinois, not on a farm but active in FFA and showing livestock.
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