ready, set, grow

Putting a seed in the soil is a pretty simple concept. But, as you might expect, in farming it is much more complex and precise than you might think.

By Pat Petzel

Not to say that you should, but one could, in theory, knock on the front door of a farmer and ask him to tell you how many kernels of seed corn are planted in a particular field.

Not to say that he would, but that farmer could walk to the edge of a field, look to the horizon and, after checking some records, say with near certainty how many seed kernels were planted there that spring. Not that you would and not that he should, mind you.

But it is interesting to think about. Most folks probably have no idea the amount of precision that goes into planting a crop. Prepare to learn about the most important task a grain farmer does all year -- spring planting.

Let's start with where it starts.

The Seed

Eric Borden, an agronomist with Agri Mark in Ashland County, helps farmers with the many decisions they have to make in the spring: what type of seed they need, what fertilizer to use and where, which chemicals to apply and so on.

He explained that seed corn is classified by maturities, which can range from 85 to 140 days.

Seed corn can also be of various hybrids, or crosses, that will grow into plants with certain characteristics: disease resistance, growth rate, stalk strength, hard or soft-shelled kernels and so on. Seed corn also looks different from other corn because the kernels are dyed red or some other color. This coloring marks the corn as treated with a fungicide and insecticide that protects the seed while it is underground. It typically takes a week or two after planting before the seed germinates and pops through the ground. If a year is exceptionally cold and wet, some seed corn will be in the ground three or four weeks before emergence. The longer a seed is in the ground, the more it is threatened by decay, mold and pests. And if there is anything that farmers hate, it's replanting.

For one, replanting is expensive. The seed is one of the major costs of spring planting. Prices for seed corn range from $45 to $150 per bag. Here's some "Jeopardy": trivia for you: Corn is sold per kernel. There are 80,000 kernels in a bag and one bag will seed three acres. So on a model 500-acre farm, even the cheapest seed corn will cost the farmer more than $7,000 and that doesn't include other expenses such as fertilizer, pesticides and fuel.

So how is $45 seed different from $150 seed? The $150 seed corn usually posses a special genetic trait such at Bt corn. It is corn that has been biologically engineered to be highly resistant to a devastating insect, the European corn borer. The $45 seed corn is usually "open-pollinated" corn, which generally doesn't yield as well as hybrid corn.

Soybean seed costs range from $10 to $23 per 50 to 60 pounds. Because many more soybean seeds are planted per acre compared to corn (33,000 corn seeds per acre compared to 200,000 soybeans), insects are not as much of a threat. The most expensive of soybean is called Roundup Ready soybeans. This seed is also genetically engineered so that the herbicide Roundup can be applied to kill weeds but not the soybean crop.

Planting and the Planter

When the soil is warm and dry enough, usually sometime in late April or early May, it's time to get the seed into the ground. The planters that farmers use today are a sort of assembly line on wheels. Hardin County farmer Chris Harrell helped explain.

First, of course, the seed is poured into the plastic hoppers on tope of the planter. How the seed makes its way through the planter and to its place in the soil involves a complex system that uses gravity and/or air pressure to force individual seeds into place.

But before the seed is dropped into the ground, the planter's v-shaped discs cut a trench through the soil. The trench's depth depends on soil temperature and moisture level in the soil, but the depth is usually about an inch-and-a-half to two-inches. The cooler the soil the shallower the seed is planted; the drier the soil, the deeper the seed is planted.

While the planter is cutting a trench for the seed, it may also be applying fertilizer nearby, two inches to the side and two inches below the seed to be precise. The nutrient composition of fertilizer for corn is generally phosphorus, potassium and nitrogen. Soybean fertilizer is usually just phosphorus and potassium (soybeans actually put nitrogen back into the soil). The salt content of the fertilizer is high so it cannot be applied too close or it will draw moisture away from the seed.

The final task as it passes over a field is for the planter's closing wheels to collapse the sides of the trench and lightly cover the seed. A dose of herbicide is sprayed over the field as well.

Now, this time of year, you might hear farmers talking about "drilling soybeans." To be truly hip to their jive, you should know that this means no more than planting soybeans, Harrell said.

There is a difference, however, in the way corn and soybeans are planted. Corn is planted in 30-to-40 inch rows (that is 30 inches between rows). Soybeans are usually planted much closer together in seven-to-ten inch rows.

One planter can be used to plant corn, soybeans and many other crops depending on the part of the country. But in Ohio , corn and soybeans are typically planted with two different pieces of machinery - a corn planter and a grain drill.

Some of the differences in how corn and soybeans are planted relate to the particular characteristics of the plants. Soybeans are planted closer together because they need to grow a quick canopy of foliage to help the plants "choke" out weeds. Corn, on the other hand, needs the extra space between plants so that sunlight can reach the lower leaves. Also, when fall comes, corn has to be in single-file rows to be harvested.

It sounds as if the farmer has no role at all as the planter glides over the soil surface doing all of these tasks. But up front in the cab of the tractor, the operator is keeping an eye on a variety of monitors that show everything from tractor speed to how many seeds have been planted per acre.

Even speed isn't as simple as it looks because it is monitored by ground speed radar similar to police radar guns. Regular speedometers like on your car are not accurate enough because they do not account for the times when the tractor's wheels may slip. Speed in important to know because a tractor that is moving too fast will cause excess vibration and jar seeds out of their proper position in the planter's chambers. Optimum speed, depending on conditions, is 5 to 6 mph.

Back in the planter, an infrared censor counts each seed as it goes by on its way to the soil. When a seed passes the censor it indicates on a monitor in the tractor cab a seed count for each row and then the average for the entire planter. It also can provide information on how far apart the seeds are, how many acres have been covered and an average of how many acres are covered per hour.

All of this information will eventually go into a computer back home and become part of the basic set of records most farmers keep. Some information, such as the amount of pesticides used is particularly important because the Environmental Protection Agency may have restricted uses on certain chemicals. In this case, the farmer must keep records on where, when and how much of that chemical was used. Producers also are required to have a license to buy these restricted use chemicals.

A basic planter on many farms plants 16 rows at a time, but planters can be as large as 30 rows. Today when fewer farmers are working more acres and when weather conditions allow only a short window of opportunity to complete planting, the need for larger and larger equipment becomes necessary. But that need is costly: A new 16-row planter can cost upwards of $80,000 and can become outdated in a matter of a few years.

The big mystery of planting, and a topic that can make a farmer the subject of relentless ribbing, is how to plant straight rows. Because, unfortunately, a grain farmer's mistake is there for all to see for the rest of the summer. Farmers may hate replanting, but they really hate crooked rows. What's the secret? "The secret is when you start," Harrell said. "You hope you have a straight side, such as a road or fence4row of the field, if you don't then you pick that point on the farm end of the field and you drive toward it. On occasion crooked rows can be the talk of the coffee shop depending on how bad you were. A lot of times in the first field of the year you try and find that back 40 (acres) for practice."

This article was reviewed by Dr. Peter R. Thomison, associate professor, horticulture and crop sciences, Ohio State University .

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