As we all know, until the last decade or so, conventional tillage operations like the moldboard plow was the primary method utilized. Utilizing conventional tillage practices brings with it the following negative consequences:
- Increases soil erosion - This one impact alone has a very negative impact on your farm. Some of these impacts are:
- lower fertility levels
- development of rills and gullies in the field
- poorer crop yields
- less water infiltration into the soil
- more soil crusting
- more runoff in the spring and after storms
- Buries crop residues so that there is slow decay and no surface mulch effect.
- Exposes bare soil to water and wind erosion. May compact the soil beneath the plow.
- Minimal ridging effect.
- High cost per acre
Given the above factors, it makes sense to investigate adopting conservation tillage practices on your farm. Conservation tillage is defined as any tillage system that reduces the number of passes over the field for land preparation and increases the surface residues to protect soil and water loss. That definition is enticing in and of itself as it inherently shows the major benefits you can obtain. But, the question remains, why would I want to adopt conservation tillage? I would start with some very basic questions put together by the US Environmental Protection Agency (EPA):
- Is soil erosion a problem on your farm?
- Is the organic matter level content of your soil being depleted?
- Is soil compaction becoming a major problem on your farm?
- Are you experiencing reduced yields?
- Are high operational costs eating away at your profits?
If you answered yes to any of these questions, then you should definitely be thinking about adopting a conservation tillage plan. If you are new to conservation tillage, then try adopting a plan for a few fields to get the feel for it and then adopt farm-wide. This minimizes your risk and allows you to learn what works best for you.
Conservation tillage has a few different approaches; none being wrong or better than the other.
Types of Conservation Tillage
No-Till
This approach means the the soil is left untouched from harvest to planting and from planting to harvest. The only soil "disturbance" is with an implement that is able to cut through and penetrate the residue like a drill or seed furrow opener.
No-till beans into corn
Image by: Iowa State
Strip-Till
This method only disturbs the portion of the soil that the seed will come into contact with when planted. There are benefits to strip-till when compared to no-till. Strip-till warms the soil by creating an aerobic condition. It also allows for better seed-to-soil contact while still maintaining a suitable environment to prevent erosion by leaving residue between the rows.
Researchers at NDSU looking at Strip Till Field
Image by NDSU
Ridge-Till
This method leaves the soil undisturbed from harvest to planting. You then plant the crops in ridges you form using a row cultivator. It is similar to strip-till in that it leaves residue between the rows.
Ridge-Till Cotton planted in No-Till Corn Residue
Image by University of California
Mulch-Till
This method only allows the soil to be disturbed prior to planting. You can use cultivators, discs, harrows, sweeps, etc. You may even perform deep tillage using a subsoiler. Whatever equipment you use be sure you have at least 30% residue cover or it isn't considered conservation tillage.
Now that we have a broad overview of the methods of conservation tillage, let's look at the factors, or BMP's, to guide you in developing a conservation tillage plan specific to your farm.
Best Management Practices
Soil Characteristics
It is important to match your tillage with your soil. Failure to adhere to this could lead to loss of soil productivity due to erosion and decrease in crop yields. The best way to obtain this information is through a soil analysis at your soil laboratory. When evaluating your soil, pay attention to the following:
- Internal Drainage: If your soil doesn't drain well and you have a high amount of residue, the soil remains cool and wet for too long. This can cause a reduction in yield for certain intolerant crops like corn.
- Soil Fertility: In conservation tillage systems, it is imperative that you have a high soil fertility level. As stated above, be sure to obtain a soil analysis and evaluate the levels of Phosphorous (P) and Potassium (K). If they are low, be sure to raise these levels up to where they should be, otherwise your efforts to adopt conservation tillage will result in decrease in yields.
- Compaction: This is quite a difficult value to measure; however, it is known that field activities performed on wetter soils increases the compaction. This can result in poor seed-to-soil contact causing decreases in yield and other issues related to the crop vigor in your field. Be on the lookout for indicators such as spindly, short corn.
- Erosion: The potential is, for the most part, dependent upon the soil texture and rise and run of the slope of you field.
Image by: Carleton College
Science Education Resource Center
If your field is considered highly erodible you must have at least 30% residue cover to be in compliance with conservation tillage guidelines. Agriculture has made great strides to date in our efforts to reduce soil erosion, but we still need to continue the research and increase adoption rates.
Graph by: USDA-NRCS
We covered this topic in our previous posts (links in the first paragraph of this posting).
Herbicide Program
With conservation tillage comes an increase in weed pressure. You must adjust your herbicide program to fit your tillage plans; just like you do with soil. A good approach, if possible is to incorporate your herbice application with your tillage operations to minimize runoff.
Equipment
The adoption of conservation tillage practices requires new, state-of-the-art equipment; especially planters. Planters will be required to place seed in soil with heavy residue. The challenge is to maintain good seed-to-soil contact and solid stands. A row cleaner can assist in ensuring you get the proper stand.
Have you started to look into conservation tillage? Have you adopted it already? How long and what are you seeing on your farm? We would really love to hear from you.
Next up in the conservation tillage series is crop production with conservation tillage. Stay tuned and share with your friends.
Resources:
No-Till and Sustainability
NRCS Web Soil Survey
EPA - Soil Preparation
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