Check Herbicide History before Planting Barley

Darren Crawford, 535-3919 or dpc@montana.edu

In many cases this winter, quality feed barley has been worth more than malt barley in Montana. The increase in feed barley prices over the last six months is driving renewed interest in barley production, and many Montana producers are considering seeding more acres barley than they have for several years.

Nitrogen requirements, herbicide history, and seed quality are just a few of the things that need considering as a producer considers barley.

Barley requires less nitrogen than wheat, about 1.5 to 1.8 lbs of nitrogen for each expected bushel, while spring wheat requires about twice that for each expected bushel.

Herbicide history is one important factor. We often think about the herbicide history when switching to a broadleaf crop like peas, lentils or alfalfa, but it is important when planting grass crops as well. Some common wheat sulfonylurea herbicides have plant-back restrictions for barley along with restrictions on broadleaf crops. Soil texture, post application precipitation, organic matter, soil pH and other factors can influence the persistence of herbicides in the soil. Therefore, some herbicide labels specify conducting a bioassay to determine the suitability of seeding a particular crop. So in addition to checking the pesticide use history of each field, it is wise to review the labels of the pesticides you have used in the recent past as well as the labels of the chemicals you plan to use.

There are a few things to consider when conducting a field soil bioassay to ensure accurate results. Sample all the various soil types within the field. Consult a county soils map to assist in seeing where to sample a field. Also, try to sample those portions of the field which are most likely to have overlaps such as field ends and corners. If possible, keep the soil core intact rather than mixing across depth. Mixing may dilute a layer that might otherwise be toxic to the crop.

Use good quality seed. Good quality includes being free of weed seeds and able to produce a healthy seedling. Resist the temptation to use seed that has just a few wild oats. Using a seed lot with just a few weed seeds may contribute to the development and spread of herbicide resistant weed bio-types. The plants that produced those few weed seeds that contaminate a seed lot, may have been plants that were resistant to certain herbicides. The simple fact that they survived an application of herbicide in the past increases the chances that you would be introducing herbicide resistant weed biotypes to your farm or spreading them to other fields on your farm.

Other important things to consider are harvest timing and storage.

Most of Montana's barley acres end up being harvested between winter wheat and spring wheat. It is important to clean trucks and combines thoroughly when switching crops. Storage is very important for most farmers, since they usually have to keep the crop in their own bins until their market is able to take delivery. Be sure to have a bin that is clean and empty, since contamination with other crops is a serious fault if you are selling seed or malt barley.

Last but certainly not least in this discussion is marketing and market availability. It is important to remember that just because prices are high right now, doesn't mean that they will still be high at harvest this fall or next winter when many crops are hauled and delivered. Also, remember to think about when these crops will be delivered and how that fits into your operation. There are many tools out there to help manage this risk, such as production and delivery contracts and hedging corn against barley. Some other things producers can do to manage risks are to keep their inputs as low as reasonably possible and to have an alternative use for the crop, such as feeding it to their own livestock to reduce winter feed costs.

Rotating crops can be very beneficial to soil health, breaking disease and pest cycles and by spreading production risk over more diverse crops. It can also be profitable, as long as we plan properly and pay attention to the details.

Categories: Barley, Herbicide, Herbicide Injury

Date: 05/22/2007