report: cover crop fields showed reduced yields

[Mike Thayer]

An article in a recent Graze magazine reported that yields were reduced for corn and soybeans grown after cover crops. It affected corn more than soybeans. The data was collected by satellite imagery and was adjusted to account for some differences such as moisture. It did not state if the comparison with the control was in previous years, or nearby fields. No mention was made as to the inputs that were used for each trial field comparisons.

I think cover crops are viable in a cropping system, but we may need to adjust our technology to the proper timing, species of cover crops, and means of terminating the cover crops to find a system that works the best in the long term. It took several years before no-till practices were perfected before it was widely adapted.

 

[Linda Poole]

That's such a good point, Mike, about the learning curve for new practices. It's exciting and expensive to try out new practices, so when discouraging results occur with the first attempt, it's sure easy to say the whole idea was a bad one and quit the exploration. The example you gave of the evolution of no-till is a good thing to keep in mind.

I like the idea of small trials of new practices so we can learn without taking on too much risk. These safe-to-learn trials can really speed up learning, especially if we share information widely with other producers. That type of sharing is a main purpose of this forum -- and you've opened the door to talk about cover crops. I don't farm but do work with farmers in the arid West and I hear many different ideas.

What's your experience with cover crops? Do you have ideas on "the proper timing, species of cover crops, and means of terminating the cover crops to find a system that works the best in the long term"? I'm eager to hear more!

 

[Mike Thayer]

I have very limited experience with using cover crops in a complete cropping system, since I have cash leased most of my cropland out. I am trying to use cover crops on the remaining cropland, to grow forage. I am hoping to "harvest" the forage with livestock, instead of using equipment. I think utilizing livestock in the cropping system may be a key factor in increasing soil health, and there for maintaining long term acceptable yields, without heavy doses of other inputs. It could be the biggest benefit to producers is the reduction of other inputs needed to grow a crop. It astounds me how little of the dollar received by producers are left for profit.

My starting point for using cover crops, would be identifying quick growing crops that will establish a canopy early on in the growing season, and be one of low water requirement. If possible the cover crop should provide added nutrients such as nitrogen and make the soil phous available to the companion crop or succeeding crop. The report I referenced stated that using rye as a companion crop, has the most decrease in yields. So maybe there is a toxic effect to other crops.

And if herbicides were used to terminate a cover crop, is there toxic effect to soil microbes or the next crop? Maybe using a roller crimper to crush the cover crop would be a better way to terminate it. I had considered just mowing the cover crop to terminate it, but some reports show the cover crop will grow back and compete with the main crop. But crimping, crushing the cover will lay the crop down for a good mulch, but the plant will not grow back. I even wonder if this would work in conventional summer fallow systems, instead of tillage or spraying.

My real goal is to find something that works well, to show my tenant, so that he could have success using it, for all the above reasons.