2015 First Cover Crop and No-Till Corn

Well, this is where our transition began from minimum-till to no-till production. We didn't have much information to draw from but we took the plunge on one field. A little time has passed but I will fill in as many details as I can.

The field was a bean field for the 2014 crop year and is irrigated with a pivot. After the bean harvest we had a fertilizer truck blow on our cover crop seed along with a load of sulfur and a little nitrogen fertilizer. We were able to get 1 or 2 quick irrigations on it probably in the first few days of October before the water district shut down for the year. Our cover crop mix was:
-30 lb cereal rye
-2 lb daikon radish
-2 lb kale
-2 lb purple top turnip
-2 lb mustard



The following spring in late March our soon to be corn field looked vastly different than any other in the neighborhood. We didn't have the ground fully covered and some species had clearly winter killed (daikon and mustard) but the process was started. The field also gained a healthy population of wild mustards to help fill in the spaces between cover crop.



Not the best photo but after just one cover crop the ground is full of worm holes, roots, and fungi.



A better picture showing our growing ecosystem. We had never seen anything like this before in a production row crop field.

Some where around the 1st of April we went in with paraquat (Grammoxone) to terminate our cover crop. At first it looked like we were going to have a very high success rate. However, as a couple weeks went by it became obvious some species killed fairly well while others were still hanging on. In particular the rye, kale, and wild mustards did not die and started slowly growing again by planting time.

Watching this field after our attempted termination, it was clear further action would be required to get a complete kill on the remaining cover crop.



At planting time, the rye was the most alarming remainder since it already had notable size and would obviously out-compete the corn once it overcame the paraquat.



Having read about the concept of a roller-crimper to naturally terminate cover crops, especially cereal rye, we realized there was a similar machine sitting in our neighbor's yard. This machine was designed as a tillage crumbler but with it's front roller made from narrow blades it looked to us like a crimper. So we put "Termination Plan B" into action.



We felt like our roller was doing a fair job of applying it's weight to the vegetation and creating the crimping effect. It also had the tendency to lay the stalks in one direction which we thought was important to keeping the planting from creating a wad. Of course only time would tell how successful it was.



From the internet research we had done and watching another local no-till corn the previous year, we knew coulters were key to getting the planter in the ground. Our solution to this was a shank that mounted to a rigid bar in front of each row with a small diameter wavy coulter to cut the residue.



A look at the field after crimping and planting. Compared to a conventional field it was hard to tell anything had happened in that field.



A closeup of a planted row of corn. If you look closely, you can just see the seed trench vertically up the center of the photo.

As one might expect given our expansion into no-till this project was a success. However, there were certainly some learning elements to improve upon in the future.

Further research has highlighted the need for cereals to be well headed out before crimping has a chance to kill the plant. Since our rye was barely into the boot on surviving plants it is obvious in hind-sight that the crimping step was a waste of time in this situation.

The surviving brassica species (turnips and kale) were extremely hard to kill with chemicals in the spring. Some plants survived the paraquat burn down and a post-emergent application of glyphosate and dicamba. I urge caution when using these species in cover mixes with a chemical termination. Those turnips also created a small problem getting the seed to a consistent depth because the planted had to roll over 3" bulbs on a regular basis. The trash wheels on the planter helped by tossing some bulbs to the side but it was not 100% and far from ideal.

In a strange twist of fortune, those surviving kale plants hosted a strong aphid population early in the year. The two-fold benefit to that was the aphids kept the kale from competing with the corn and provided a food source for an incredible lacewing population, the likes of which we had not seen on our farm for many years. While harvesting the corn that fall my red combine turned green with lacewings at times.

This spring was one of our drier at planting time. However, because we hadn't disturbed the soil and had some cover to protect from the sun and wind, our corn was able to establish a uniform population without irrigation while our conventional neighbors struggled or irrigated. Not all the benefits of cover crops/no-till are delayed gratification.

I found this photo of the corn field after emergence. The corn is ratty thanks to a hail storm the day before but you can see our continued battle to terminate the rye cover crop. We also have a flush of redroot pigweed coming in this field which makes me thing we haven't completed our post-emergence herbicide yet. Also I see there really isn't much residue left from the cover to protect the soil through the summer.