Harrowing In The Fall – Matthew Smith

Why do we use this technique and what problem are we addressing?

On our farm we harrow in the fall to break up crop residue and also to initiate the winter annual weeds growth so they germinate then the first frost can kill them off. We were addressing the need to control our winter annual weeds.

How does this technique work?

Using a harrow bar can be a useful tool for weed control.  The technique works by pulling a harrow drawbar through the field with enough hydraulic pressure on the tines to break up the topsoil and cover crop.

Refinements

The only refinement we have done is adjusting the hydraulic pressure, as it is needed for the field conditions.

Limitations and Successes

Limitations of this technique are if the weeds don’t germinate it can really affect the amount of control needed in the spring. Therefore, it is necessary to be aware of the type of weeds present and have the knowledge of the stages of their life cycle. The farmer must be able to develop a management strategy in order to disrupt the weeds life cycle.  Successes of this method have worked well in our farming operation to help control winter annual weeds, it has also helped us get into the field sooner in the spring as it allows the soil to warm up faster with less residue covering the soil and holding the cold air in.

When is this method useful?

This method would be really useful when crops with heavy residue such as wheat are grown. That way you can reduce the amount of residue and eliminate some weeds. This method of weed control is effective as weeds can decrease yields by increasing competition for water, sunlight, and nutrients.

Would it work beyond our situation?

This could work beyond our situation as harrowing could help in the spring as a pre crop emergent weed control method. You could then seed your crop a couple days prior to emergence go over the crop with the harrows and remove other problem weeds as well.  Harrowing can help reduce the rate and spread of certain weeds and can kill weed seedlings.