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Man doing tillage in his garden

Primary and Secondary Tillage-Which One is Best

Tillage is the manipulation of soil to prepare the ground for growing crops. This process changes the soil characteristics, such as temperature, infiltration, evaporation, and water retention. Many people new to growing on a larger scale don’t know that there are two forms of tillage: primary tillage and secondary tillage. These tillage methods are very different, and understanding the differences is important.

What is Primary Tillage?

 Secondary vs Primary Tillage

Primary tillage is deep soil manipulation, it’s intensive plowing, and it tends to take place right at the start of a fresh cropping season. This is how the farmer prepares the ground to sow fresh seeds to improve the health and yield of their crops.

These primary tillage operations use a variety of technologies including harrows, tandem disks, off-set disks, packers, and field cultivators.

Importance of Primary Tillage

Primary tillage creates a more ideal environment for the establishment of seedlings. This is also an ideal way to incorporate herbicides and fertilizers into the ground to control weed growth.

There are five reasons to carry out primary tillage:

●      Digging into crop residues.

●      Increasing soil aeration and water retention characteristics,

●      Deeper layer aeration and water retention for rainfall seasons.

●      Cutting and exposing weed roots.

●      Creating soft soil down to a depth of around 10-15 cm for planting.

What is Secondary Tillage?

Secondary tillage is a less aggressive and shallower process than primary tillage operations. There are three ways to approach secondary tillage depending on your unique circumstances:

1.    Animal Powered

If the tillage is animal powered, a moldboard plow on a saturated field followed by peg and tooth harrows works well. The soil is puddled, and the level surface is ideal for the planting of crops.

2.    2-Wheel Tractors

A 2-wheel tractor system will use a moldboard, disk, and rotavator for the second tillage operations. It is possible to use pet tooth harrows if a rotavator is not available for this task.

The tractor cage wheels are deployed to improve traction on all soil types, and as an added benefit, this will puddle the soil at the same time.

3.    4-Wheel Tractors

A 4-wheel tractor system uses seven disks and offsets plows, rotavators, and tined cultivators for secondary tillage. These systems puddle the field mechanically with a leveling board and rotavator or a tractor with large cage wheels and a harrow system.

Why Is Secondary Tillage Important?

Following primary tillage with secondary tillage gives the soil a structure that’s optimal for seed planting. Secondary tillage takes place after primary tillage operations, and there are five main reasons to do this:

  • Additional weed control.
  • The reduction of clod sizes.
  • Leveling the soil surfaces.
  • The promotion of puddling.
  • Incorporating fertilizers efficiently.

When Do You Use Secondary Tillage?

Man doing secondary tillage in garden

After primary tillage, there are usually 2-3 secondary tillage operations that occur before planting. The exact number will be determined by the stage of the soil. If there are large numbers of weeds and the soil is filled with clods, more tilling is necessary.

This will make the soil ready for fertilizers, and the puddling is improved. In many nations, the primary and the first secondary tillage operations are carried out with tractor systems. This may be followed with 1-2 secondary tillage operations carried out by animals and towed harrows.

Primary and Secondary Tillage Implements

For primary tillage, the most common implementation is a moldboard plow. If the soil has hardpan layers, it may be necessary to saturate the field regularly before tilling. If the soil has a lighter texture, tillage can be done to match the field moisture conditions.

A 2-wheel tractor-powered system will use a disk plow fitted with one-way disks and a moldboard plow.

Disk plow is an ideal implement for the rocky, hard, and heavily rooted ground because these obstacles can be removed efficiently with a lower power requirement. Another common configuration is a 3-7 disk and offsets plow fitted to a tractor for efficient primary tillage operations.

Because secondary tillage is less aggressive and lighter than primary tillage, the implements vary. A moldboard plow, rotavator, and disk harrow are commonly used and in certain cases, a disk harrow may be preferable to a rotavator. Other secondary tillage implements include rotavators, offset disk plows and tined cultivators.

Pros and Cons of Primary and Secondary Tillage

 PrimarySecondary
Pros●       Aerates the soil
●       Encourages deeper root penetration
●       Controls weeds
●       Incorporates fertilizer
●       Destroys weeds
Cons●       High moisture loss
●       May enhance soil erosion
●       Could disrupt the lifecycle or any beneficial soil organisms
●       May compact wet soil
●       Could enhance wind and water erosion
●       Potential to consume significant fuel 

Difference Between Primary and Secondary Tillage

 PrimarySecondary
ToolsPloughHarrow, cultivator, etc
AimTo open and loosen the soilWeed control, break clods, and prepare seedbeds
TimingAfter the last harvestAfter primary tilling
Till depthDeepUpper surface
ResultsRough surface finishFine finish

FAQ’s

How deep is primary and secondary tillage?

The purpose of primary tillage is to create soft soil down to a depth of 10-15 cm. This will vary depending on the soil clod sizes and other ground conditions. Secondary tillage takes place at a shallower depth, and an evaluation after primary tilling is advisable.

Which type of tillage disturbs the soil the least?

This may seem like a strange question to answer because the primary focus of this article has been to show the benefits of primary and secondary tillage for cultivation.

Lady using tiller to prepare soil

Tillage does enhance the nutrients present in the soil, but some recent studies have found that there can be a negative impact on soil quality.

During tillage operations, the soil is disrupted and fractured, which will accelerate the surface runoff and increase the risk of soil erosion. This is a drawback for farmers working in low-rainfall environments. The increase in surface runoff can lower the water table and this will intensify the impact of drought conditions.

When the soil is churned up, it’s vulnerable to rain and wind that can blow away weak soil structures. This can seriously degrade the overall soil quality, which will become obvious over subsequent years.

Tillage also removes the existing crop residue, which protects the toil soil from the down-force that occurs during rainfall. This can increase the percentage of removed topsoil, and the soil quality is degraded.

When the overall quality of the soil is lowered, fertility is reduced, and any planted crops will suffer. Another problem caused by eroded soil deposits is the pollution of nearby surface and groundwater sources.

For these reasons, many farmers have turned to no-till or conservation farming methods that don’t disturb the soil.

The crop residue is left on the surface of the soil to protect it against weather conditions. This can be an effective way to conserve the soil, but the crop yield may be lower. That said, if primary and secondary tillage is reduced or stopped altogether, there are fuel savings of around 3.9 gallons per acre.

Conclusion

As you can see, there are significant differences between primary tillage and secondary tillage operations. They serve different needs, but there are some drawbacks to tilling that need to be considered carefully depending on where you work.

In conclusion, primary and secondary tillage are both important agricultural practices that play a crucial role in preparing soil for planting. Primary tillage involves deep plowing, which breaks up the soil and loosens it for planting, while secondary tillage involves shallower cultivation to create a finer seedbed and remove weeds. These practices help to improve soil structure, water retention, and nutrient availability, leading to better crop yields and overall agricultural productivity.

However, it is important to note that over-tilling can lead to soil compaction, erosion, and loss of soil organic matter. Therefore, farmers and agricultural practitioners must carefully manage tillage practices to balance soil health with crop production needs.

In summary, primary and secondary tillage are valuable tools in modern agriculture, but their application must be thoughtful and tailored to individual farming systems to ensure long-term sustainability and success.