Using a Rotary Hoe, Spiked Harrow and Heavy-Duty Cultivator for Organic Soybean Crops

April 29, 2022

As a soybean farmer, you can choose from different types of equipment to help you effectively weed your crops. These tools include rotary hoes, spiked harrows and heavy-duty cultivators. Let’s take a look at what they do and how to use them. 

Using a rotary hoe

Rotary hoes are made for weeding an entire cultivated surface. This kind of machinery churns small lumps of soil that containing weed seedlings, directly uprooting them using spoons attached to the star wheels. 

In addition to simple rotary hoes, there are versions with two and three rows of star wheels for more aggressive weeding. 

Strategy for using a rotary hoe for weeds

Rotary hoes allow you to carry out “post-emergence” weeding of weeds that have sprouted early. These machines should not be used when the weeds have reached a more advanced stage (over 1.5 cm), i.e., when first or second trifoliate leaves have developed. 

Since they’re less effective once weeds have reached the stage of the second trifoliate leaf, this equipment should ideally be used when the weeds are in the cotyledon stage. It’s therefore a good idea to act early, as soon as the crop can withstand this kind of operation.

Strategy for post-emergence rotary hoeing of organic soybean crops

One to three passes with the rotary hoe are recommended between the cotyledon and first unifoliate leaf stages. The area may need further hoeing depending on the weed pressure.

Using a spiked harrow

Using a spiked harrow is similar to using a rotary hoe as it is a way of weeding the entire cultivated surface. This is a type of “blind cultivation,” because precise weeding is not possible with this tool. Using the spiked harrow stops weeds from advancing into the crop row, at which point they become difficult to reach with other tools like light-, medium-heavy- and heavy-duty cultivators.

Strategy for using spiked harrows for weeds

One feature of the spiked harrow is that it is more “aggressive” than the rotary hoe. It is know for destroying weeds at a slightly more advanced stage (less than 2 cm) and work more effectively than the rotary hoe in sandy soil.

The spiked harrow is used at both pre-emergence of the crop (5 days after seeding) to early post-emergence. Pre-emergence harrowing is an effective way to eliminate weeds that have sprouted early. 

This equipment ensures effective weed control when the soybean seedlings are deep enough and have not yet emerged. It is a good idea to work with a spiked harrow in early post-emergence as this is when the weeds are still small and often at the same stage as the crop.

Strategy for post-emergence harrowing of organic soybean crops

One to five passes with the spiked harrow are recommended between the cotyledon stage and the first trifoliate leaf stages. Depending on how many weeds you find, you can then do more passes up to three weeks after the start of the flowering stage.

Using a heavy-duty cultivator

Heavy-duty cultivators are useful for inter-row weeding of widely spaced crops like soybeans. With a heavy-duty cultivator, you can cultivate hard and crusted soil and create ridges. The heavy-duty cultivator is always used with a self-guiding system to increase precision and reduce potential seedling loss.

Strategy for using a heavy-duty cultivator for weeds

The heavy-duty cultivator cuts and buries the stems and roots of weeds located in the middle of rows using long horizontal tines. This equipment must be adjusted to control the amount of soil thrown onto the row to avoid damaging the crop. 

Ridging is the main way of controlling weeds in the row when using a spiked harrow or rotary hoe is no longer possible or effective. The heavy-duty cultivator can handle more residue and as such can be used to save a field overrun with weeds.

Strategy for using a heavy-duty cultivator for organic soybean crops

Farmers can carry out two to three passes of the heavy-duty cultivator at the following stages:

  • First unifoliate leaf
  • First trifoliate leaf
  • Three to four trifoliate leaves

A ridge of 2.5 to 5 cm is recommended from the unifoliate growth stage depending on the crop’s height. At the trifoliate stages, larger ridges can be made if combined with one pass of the spiked harrow to level them.

Rotary hoes, spiked harrows and heavy-duty cultivators for weed control in organic farming

There you have it! You should now have a better understanding of how to use rotary hoes, spiked harrows and heavy-duty cultivators for organic soybean crops. To learn even more about soybeans and weed control methods, you can check out these articles: