Rod Weeding Tertiary Tillage – Miles Crooks
An important aspect of our weed control on our farm is tertiary tillage with a rod weeder. We use a rod weeder because of its effectiveness on weeds in all different life stages. Rod weeding is great way to upset sprouting weed seeds and also effectively uproots older weeds. Another greater advantage we gain from using the rod weeder is that it can till very shallow so it does not disturb dormant weed seeds that are deeper in the soil and we can easily till above our sprouting crop.
We mainly use the rod weeder to control wild oats in our Kamut crop. Kamut has a longer growing season then wheat, so to make up for the longer season we try to seed early. With seeding earlier in organics we don’t get a good kill on the wild oats before seeding. Kamut needs to get well established before it can compete with the wild oats. We have found that by using a rod weeder after seeding gives our Kamut the advantage it needs against wild oats and other weeds.
Using dicers to seed we can plant the Kamut seed fairly deep. This is an advantage as well as a disadvantage. It’s a disadvantage since it takes the Kamut seed longer to emerge from the soil, and the seedling will not have as much strength as seed that is seeded shallower. With Kamut being a big seed we are able to seed it deeper and it will not have trouble reaching the soil surface from the greater depth. Seeding deeper also gives us the advantage to wait more days after seeding to rod weed, giving us a much better kill on the wild oats and giving the Kamut a head start advantage.
With seeding deep, we can wait usually wait till the fourth day after seeding to rod weed. We typically check to see where our crop is at and try to rod weed when it has a sprout around a centimeter in length. Often by this time wild oats and weeds have already sprouted and started to emerge from the soil. At this time we make two passes with the rod weeder in different direction above the sprouted Kamut. With making two passes we can maximize the effectiveness against the weeds still while minimizing the damage to the crop. With the shallow tillage, the rod weeder doesn’t disturb deeper dormant weed seeds allowing the Kamut to emerge with little or no competition five to six days after rod weeding. This allows the Kamut to get a head start and become competitive against weeds.
Modifications and Limitations
We have not made any major modifications to this operation. We have recently purchased a rod weeder with a one inch diameter bar instead of the three quarter inch bar we have used in the past. This bigger bar allows a more aggressive tilling, and needs more careful operation to minimize crop damage. Depending on the Kamut seed depth and stage we can now choice between using the bigger or smaller bar to maximize weed damage and minimize crop damage.
The rod weeder’s high aggression tillage can really limit its use in tertiary tillage. With crops that are seeded shallow, the rod weeder is not the recommended tool to use. As the rod weeder could cause a lot of damage to crops that are seeded too shallow. The rod weeder is limited to pre-emergence tertiary tilling so there is a very narrow time frame between maximizing weed damage and minimizing crop damage. This time frame can be hard to hit, as we are busy with seeding other crops and pre-working. If we do miss the time that we are able to rod weed in, we usually we go with the harrows. Rod weeding doesn’t limit us to one kind of tertiary weed control. Another limitation of the rod weeder is that it needs dryer soil to be effective and not make a mess of the field. This has proven tricky in the past couple years of high moisture. Rod weeding also has one major disadvantage it leaves the soil very prone to erosion. The rod weeder tends to turn the soil into powder which is very susceptible to wind.
Rod weeding has many uses beyond the one I have just described. It can be used as pre-seeding tillage, where it would effectively kill the weeds, without it going too deep and disturbing dormant seeds. The rod weeder is more effective on well-established annuals, because it does a good job of loosening and knocking the dirt off the roots of weeds. It also turns up the root and brings it to the soil surface unlike other tillage equipment that tends to bury the plant more.
The rod weeder works better than most other equipment against grasses and other plants with fibrous roots. It works well against grasses because it can knock the dirt off fibrous roots effectively which is so important when trying to kill grasses. At the right speed and depth rod weeding is can flip up the roots and expose them to the sun allowing them to dry out quickly and not allowing them to reestablish in the soil.
One example of this on farm was after we grew winter rye, in the fallowing year we could not kill the volunteer rye with cultivators. The cultivator’s would just loosen the rye from the soil and move it around a bit, which allowed the rye to reestablish its roots into the soil. After trying cultivating a couple of times which was ineffective, we used the rod weeded. The rod weeded effectively brought the roots to the soil surface, knocking much of the dirt from the roots and often flipping over the rye completely exposing the rye roots to the sun. The rod weeder was very effective in killing volunteer rye.
The rod weeder works for us in weed control. It’s an important piece of equipment to our farm and in our operation. I suggest that all organic farmers have one around; as they come in handle in many different situations.