How does a no-till corn planter work?

The calendar turned the page to April, the sun came out, soil temperature headed to 50 degrees F, the red bud trees started blooming and the corn planter started rolling.  The dry conditions the last couple of weeks have given way to great corn planting progress in our area.  We have about 2/3 of the corn in the ground.  The cooler temps have slowed germination but we expect some corn to start "spiking" through the ground any day now.  Jake Mitchel is pictured below on the opening day of corn planting.

All of our corn is planted no-till.  Specialized attachments to the planter allow us to plant the corn directly into the residue from last year's wheat and double crop soybean crops.  The field shown in the pictures had a 5 way cover crop mix planted to keep the rolling landscape green through the winter to help reduce soil erosion.  The cover crop was killed about 2 weeks prior to the planting of the corn crop.  No-till ground is generally somewhat harder than conventionally tilled ground.  The planter is equipped with a pneumatic down-force system that holds pressure on the row unit to keep it in the ground and provide an even "ride" to optimize the performance of each row unit.

The picture above shows the row unit of the planter.  The spike wheels on the front of the unit are "Martin Row Cleaners" they gently sweep wheat straw and soybean stubble out of the way of the wavy no-till coulter blade (between the black frame).  Getting the residue out of the row keeps the no-till blade from "hair-pinning" the stubble into the row furrow.  If "hair-pinning" occurs in the row furrow it can reduce seed to soil contact and hinder germination of the corn seed.  Cleaning the row off allows the sunlight to warm the soil directly in the row furrow to speed up germination.

Following the no-till coulter is a set of "double disc openers."  These openers create a V slot for the seed tube that's directly between the two openers to drop the seed in.  The large black wheels on either side of the row unit are called "gauge wheels."  They are used to set the depth of the unit when planting.  They ride up to a point and will raise the unit up if the depth goes past a desired set point.  We generally try to plant the seeds about 1 & 1/2 " to 1 & 3/4" deep.  If you plant too deep the seeds won't germinate evenly and may have trouble pushing through the crust of the soil.  Plant too shallow and the corn may suffer from "shallow root syndrome" and not be able to get established because the root system may have trouble developing.  Shallow planted corn may also have a greater tendency to blow down before harvest since the roots aren't as deep and sturdy in the ground.  

At the back of the row unit are the closing wheels.  One is spiked and the other a cast iron wheel.  These wheels are spring loaded and "close" the seed furrow up covering the planted seeds.  If the ground is too wet the ground won't close over the furrow leaving the seed exposed and can cause problems for the young plants as they grow.  In ideal planting conditions the ground crumbles over the top of the furrow as the closing wheels work the soil over the row furrow as pictured below.  

The only way to determine the planter performance is to dig in the seed furrow to gauge the soil moisture and the depth of the seeds.  It usually takes a day of planting to get all the planting metrics dialed in the way we want them.  The technology on the planter makes the adjustments fairly quick but old-fashioned know how and technique are still keys to getting a "picket fence stand" of corn!  My youngest son points out the seed in the V trench furrow below.

All the planter settings and metrics I have discussed in this post are displayed to the operator in the cab of the tractor pulling the planter.  We use yield zones to determine how much fertilizer to place in different areas of the fields as I have discussed in previous posts.  We build seeding prescriptions for these same zones with higher and lower seed populations according to the productivity in a zone in the field.  The more productive zones get higher rates of fertility and seed.  The lesser productive, thinner soils receive less fertility and seed.  This keeps us from over applying  nutrients and seed where they won't yield an increased return.  This makes us better stewards of the soil and water in the environment and makes us more efficient producers.  The prescriptions for the seed are loaded to the tractor controller via Wireless Data Transfer from a desktop computer to the screen on the left.  The iPad on the right logs all the different data as we plant a field.  The different population zones as applied, seed variety, date, down pressure target and margin, ride, elevation, speed, direction of each pass and many other metrics about the planting operation are logged wireless through the Climate Field View app and sent to the cloud for storage.  We can later access all the data in the MyJohnDeere or Climate Field View platforms for analysis and later use.