We have had enough calamities this year to leave an impression on our minds for a long time and we are still a ways from harvest. Judging from the number of pigweeds sticking up above the crops and the number of hoe crews in the fields, no doubt, this pest has thrived among the other disasters that have been occupying our time.
Some have indicated that they feel pigweed will eventually put them out of business, while others have attacked the problem with a renewed vengeance and determination to keep this aggressive pest at bay.
As I travel around the state, it is interesting to note the large number of fields with pigweeds sticking up above the crops. These catch my eye and are much more noticeable than the extremely large number of very clean fields. Certainly, there are more pigweed escapes this year than in any of the past 10 years, but we have also suffered a more severe spring than in any of the past 10 years. It only takes a blink of the eye or a few bad weather days to get behind and create difficulty in catching up with pigweed.
Judging from the calls coming in, it appears that most farmers have realized the importance of not allowing additional weeds to produce seed this year. Managing the soil seedbank is the only chance we have to get in front of pigweed.
Several have told me there is no such thing as Zero Tolerance on large acreage, and I fully agree. But that does not mean we should not strive to reduce the soil seedbank. We have made a real effort to insure that no weeds produced seed last year in the “Zero Tolerance” demonstration fields.
We sampled the soil seedbank last spring and again this spring to monitor our progress. Careful sampling with a sub-inch GPS unit showed a 65 percent reduction in seed over one field and we found no seed in our samples in the other field, but a 90 percent reduction in the number of weeds germinating.
Our sampling technique was to pull 4-inch cores from numerous locations throughout the fields. Even in the field with 65 percent reduction, all samples showed near 90 percent reduction in the number of seed except two cores. These two cores showed a slight increase in the number of seed from last spring. No doubt this was caused by a weed that matured enough to produce seed prior to being chopped.
In some recent research by Jason Norsworthy, it appears that mature seed can be produced in as little as 14 days after the seedhead appears on a pigweed. The fact we saw a slight increase in the number of seed in a couple of samples indicates there were not a large number of seed produced in this area, but yet too many to realize the 80-90 percent reduction we were expecting.
Step in right direction
However, a 65 percent reduction in the number of weeds we have to contend with this year from last is significant and certainly a step in the right direction and reinforces my thought that this is the only way to manage this pest. Many people are telling me they have more to contend with this year than ever before. This is not the right direction and certainly will not get better without drastic action.
Unfortunately, soil-applied herbicides are not as reliable as glyphosate once was over the top. Unfortunately, Ignite will not kill as large a pigweed as glyphosate once did. Unfortunately, the new technology coming down the pipe will not be as effective as glyphosate once was. Unfortunately, the herbicide programs we have available in cotton and soybeans do not offer the flexibility glyphosate once offered.
But, in spite of all this, we do have some very clean fields. I have walked several fields that were pretty bad last year, but are much cleaner this year. Maybe these farmers are just lucky or maybe they are simply good. As we all know, it takes a good deal of both to farm in today’s agriculture.
Pigweed will certainly test our skills and question our luck. Someone lamented the other day that he and all his family had been making a special effort to pay the preacher as much as possible and the pigweeds were growing and no rain was in the forecast to activate soil-applied herbicides. He said he was beginning to suspect the preacher was not reporting his contributions.
I fully understand the old adage: “It is hard to remember the objective was to drain the swamp when you are up to your neck in alligators.” However, we are probably at crossroads as to whether some of our fields will become too costly to farm or whether we can turn the train around and start to reduce the soil seedbank.
We will discuss many of the management techniques at the upcoming field days at Marvell, Ark., on July 19 and at Keiser, Ark., on July 21. We will even address best options for turning a train wreck into something that can be farmed. If you are interested in attending, call me or your county agent for additional information.
Pigweeds are not going away and glyphosate is not a pigweed herbicide. Even with an aggressive management program, pigweed escapes are not only possible, but probable. We have certainly turned the corner on many fields and still have an opportunity to remove escapes from others.
In a distorted way, I hope 2011 will be remembered as the year of the pigweed. This will mean that every year after this is better. I am optimistic we can make this happen on most farms and I am looking forward to writing an article for the Delta Farm Press in a few years referring to how bad the weeds once were back in 2011.