Experience has taught us that three major concerns arise as to why everyone is not no-tilling. Let’s explore these areas and present some of the “reasons why.”
The three major concerns are unstructured soils; planters that are not set up or operated correctly; and the failure to use starter fertilizer. If we can take some actions to counter these problem areas, we will be able to demonstrate a much more successful transition to continuous no-till.
We are now able to transition a farm with well- to moderately well-drained silt loam soils to continuous no-till and experience improved crop yields the first year into the program. And it just keeps getting better.
The first concern centers around the “condition” of the soil. We will assume that soil fertility and pH have been corrected or will be addressed in the transition phase. The chemistry of nutrient levels and balances and proper pH are very important and will strongly influence how we apply starter fertilizer later in our discussion.
This first item is about soil structure. When soil has been regularly tilled, the structure of the soil is pulverized. This is catastrophic to natural soil health. Soil biology is altered by tillage as bacteria are favored over fungal organisms. The fungal organism network is much more efficient at cycling nutrients than bacteria.
Earthworm population dynamics are also greatly altered. Regular earthworms (the size of the lead in a pencil) tolerate tillage fairly well, as they spend most of their life in the top 18 inches or so of soil. Nightcrawlers (the size of the pencil), on the other hand, do not tolerate tillage, and in the presence of tillage, their numbers crash. Their burrows, which can be 40 to 48 inches deep, are cut off and they suffocate. Nightcrawler burrows provide rapid entry access for water into the soil. Water makes the crop.
When the soil is tilled, structure is pulverized and pore space is artificially created by the tillage as the soil is mechanically “loosened.” The artificial pore space may work for the current year with sufficient water. To have effective pore space in a pulverized soil, the same artificial pore space building has to occur every year.
When a soil is no longer disturbed by tillage, it will begin to revert to its native state as a structured soil with adequate pore space in the presence of soil aggregates. Pore space is all about water (and air) and a plant’s ability to get it.
This is the general year-to-year process:
- Year 1 (no-till this year, tilled last year): The soil becomes more dense, and holds water tighter with less available to the plants.
- Year 2 (2nd year no-till): The soil becomes even more dense with less water available to the plants.
- Year 3 (3rd year no-till): Soil remains dense but may begin to lessen as soil structure begins to reinitialize. Water stress continues.
- Year 4 forward: Soil structure redevelops in the soil and, with proper management, can approach good levels. Pore space in structured soil allows plants to utilize water, as it is not held as tight by the soil.
What can be done to manage this condition during the transition phase? We need to first, conserve soil moisture and second, aid in the re-creation of natural soil pore space.
- To conserve soil moisture by increasing water infiltration and reducing surface evaporation, we need to keep the soil covered with crop residues. This can be very threatening to a new no-tiller who is not accustomed to working with surface residues at planting time. When we need them most, we are most threatened by them in our inexperience. If we are going to transition to continuous no-till and have higher yields right away, the soil surface needs to be well covered with crop residues.
- To aid the re-creation of natural pore space and enhance the reinitialization and development of soil structure, we depend on cover crops and/or crop rotation to include close-growing, high-residue-producing crops such as small grains. Keeping living roots growing in the soil as much of the year as possible will help quicken the processes involved in soil structure development. When growing cover crops, we are again most threatened by all of that biomass when we need it most. We need to allow sufficient growth time to develop as large a root system as practical. This will provide natural pore space and is a “seedbed” for the reinitialization of soil structure.
With high levels of evenly distributed soil-covering crop residues and the use of cover crops and/or crop rotations to include close-growing crops, such as small grains, we can greatly improve the soil’s ability to supply sufficient amounts of water for high-yielding crops from the start as we transition to continuous no-till.
We have two other areas of concern to consider. Stay tuned. We will address them in upcoming months.