Conservation Tillage: Sustainable Soil Management

When I first heard about no/low till systems of agriculture, the concept didn’t quite click.

How am I supposed to plant something in the ground if it isn’t tilled first?

Soon after, I signed up for a local master gardener’s course. There I was introduced to a wide new world of agricultural theories. The more I studied organic farming practices, I became gradually clued in to a different line of thinking. There was an emphasis placed on the intricate relationship of nutrients, enzymes and microbes in the soil. It was eye-opening.

I learned microscopic networks that exist in the soil must not be overlooked. Their proper functioning is critical to the health of the soil, which in turn affects its ability to nourish the plants grown in it. What a novel idea!

And as it turns out, conventional tillage destroys the symbiotic systems of the soil by displacing them and oxidating organic material. On the other hand, conservation tillage seeks to minimize the destruction of soil health. It achieves this by tilling less and establishing a beneficial surface layer of crop residue to prevent erosion. 

That master gardener’s course taught me that popular and conventional practices are not always best. Sometimes we have to investigate and look below the surface (literally) to find the truth.

Let’s dig a little deeper to explore the detailed depths of conservation tillage.

Conservation Tillage Explained

The ultimate goal of conservation tillage is to prevent soil loss by leaving a portion of the previous year’s crops in the field to decompose. The leftover material eventually breaks down, feeding the soil and covering the surface. Water runoff is substantially reduced, which preserves resources and minimizes pollution. The crop residue should make up at least 30% of the planting area’s total surface.

In areas of large-scale conventional farming, the earth has been depleted of its nutrients and organic material. This makes it light and dusty, easily washed or blown away. These conditions lead to calamities like crop losses and food shortages.

To further clarify the objective of conservation tillage, I must mention the NRCS (Natural Resources Conservation Service) of the USDA (United States Department of Agriculture.) The NRCS lays out four basic principles to assist farmers in managing, protecting, and feeding their soil.

1. Keep the soil covered (protect)
2. Reduce soil disturbance (protect)
3. Keep living roots in the soil (feed)
4. Diversify using rotations and cover crops (feed)

These pillars of conservation tillage can be implemented to drastically improve soil health, reduce erosion and minimize loss of nutrients.

But before we dive into the wonderful world of conservation tillage, let’s quickly touch on some downfalls of the practice.

The Disadvantages of Conservation Tillage

Some disadvantages associated with conservation tillage are inherent in the practice, while others are avoidable through proper implementation.

• Soil compaction is a problem when equipment isn’t used appropriately or if crop rotation doesn’t follow the correct succession.
• A good deal of intense labor is required in conservation tillage, especially in the beginning stages. Specialty equipment is required on a large scale and a lot of time-consuming physical labor is needed on a small scale.
• Extra time and labor lead to higher start-up costs. Without initial investment capital, the expense of starting a conservation tillage practice can deter many farmers from beginning in the first place.
• There is no immediate payoff when using conservation tillage practices. Almost all of the benefits are realized in the long term. Over time, soil condition vastly improves. However, observing these positive gains will take at least a few seasons.
• Incorporating fertilizer and organic material into the soil can be challenging, due to the low till nature of the practice.
• Certain greenhouse gases, other than carbon, may be produced inadvertently by increased moisture retention and microbial activity.
• Some farms that practice conservation tillage employ herbicides to control weeds. It’s an unfortunate byproduct of choosing not to till.

Now we can move on to the brighter side of the specific types of conservation tillage and their advantages.

Conservation Tillage Methods

There are many types of conservation tillage practices. They are based on the same ultimate objective but have slight variances in their approach.

1. No-Till

The no-till method is the least disruptive form of conservation tillage. Seeding and fertilizing are done in a single pass. Seedbeds are specifically dug shallow to preserve the soil’s integrity. Crop residue is used to cover and effectively plant the seeds. This will keep the seeds in place and feed them over time as they sprout and grow. High-quality fertilizer is applied to further feed the crops and establish productive topsoil.

No-till is also known as zero-till, direct seeding and slot planting.

Benefits of No-Till

• No-till significantly reduces erosion.
• All crop residue stays on the surface, protecting topsoil from wind and rain damage.
• Crop residue minimizes runoff and retains moisture.
• Time and fuel are saved due to less time spent in the field. Less compaction occurs as a result.
• Money is saved without expensive equipment like plows and cultivators.
• Crops from the previous season remain in the field throughout the winter. This leftover organic matter reduces erosion and evaporation while providing shelter for beneficial wildlife.
• No-till builds fresh organic matter into the soil.

2. Strip-Tillage

The strip-tillage technique divides fields into two halves. One side is seeded with a cash crop and the other is reserved for soil conditioning. Only the soil on the first side is tilled to prepare for easy crop planting. The other half is not tilled but sown with a cover crop. Throughout the season, the cover crop achieves the same results as tilling. On top of loosening the soil, cover crops produce biomass and fix nutrients into the soil.

Strip tillage, sometimes referred to as zone tillage, sets up a type of crop rotation. It’s an efficient way to set up a field for planting and set it up for long-term success. It works exceptionally well for fields that haven’t been worked in a long time and need initial plowing to loosen the soil. The following season cover crops can be used as a surface residue to enrich the first half. The second half’s remnants are turned into the soil and a no-till strategy can be implemented for successive seasons.

Benefits of Strip-Tillage

• The freshly tilled field warms up more quickly in the spring.
• Tilled soil achieves better seed-soil contact.
• The herbicides that are used are concentrated in one area, minimizing the total amount applied.
• Fewer passes in the field are needed, resulting in less soil compaction.

3. Mulch-Till

Mulch-tilling involves completely working the soil before planting. Special tools such as cultivators and chisels are then used to partially mix organic mulch into the field. The soil is only minimally disturbed while moisture retention and organic material content are vastly improved.

Benefits of Mulch-Till

• Plenty of residue is left on the soil surface, even though it’s completely tilled.
• Crop residue is mixed into the topsoil.
• Mulch-tillage dramatically improves the quality of poorly drained soils.
• Water, fertilizer and organic matter can penetrate the soil more easily.
• Mulch-tillage can be used on many different soil types. It’s appealing to most farmers, as it’s most similar to conventional tillage.

4. Ridge-Till

The ridge-till method forms and maintains permanent raised beds. Special machinery is required to form these ridges. The residue is applied to the ridges in the off-season. This supports the structure of the bed and helps improve its fertility. Before planting in the beds the residue is removed and left between the ridges to help control weeds. Bed maintenance and weed management are controlled by cultivation.

Benefits of Ridge-Till

• Ridge-till substantially reduces erosion.
• Residue is set in rows between ridges, fertilizing the soil and smothering weeds.
• Ridges make earlier planting possible because they drain and warm up more quickly in the spring.
• Ridges make great raised beds, perfect for planting seeds.
• Crops remain in the field throughout the winter. Leftover organic matter reduces erosion and evaporation while providing shelter for beneficial wildlife.
• The herbicides that are used are concentrated in one area, minimizing the total amount applied.
• Cultivation controls weeds and maintains ridges.
• Less traffic in the area leads to less compaction.

The Systems That Benefit From Conservation Tillage

Conservation tillage affects agricultural systems on every level. Sustainable practices that don’t disturb the soil, provide soil coverage, increase surface residues, include crop rotation, reduce the need for inputs and improve soil quality can’t be overstated.

Environmental Responsibility

The environment as a whole benefits from conservation tillage. What is taken from the earth is reintroduced back into the soil, keeping the cycle unbroken. The farmers that adhere to this philosophy decrease the demand and prevalence of chemical herbicides and fertilizers. Native plants and pollinators flourish when they aren’t being eradicated by these poisons.

Resources are preserved due to the ability of the crop residue to retain water and prevent runoff. Because of the minimal amount of tilling, less energy is consumed, while the need for fertilizer is greatly reduced. All of these factors contribute to cleaner air, soil and waterways.

Conventional agricultural practices tend to be more intense. Excessive tilling increases the demand for fuel and fertilizer. The depleted soil has no means of retaining water due to its lack of fresh organic matter. This results in large amounts of runoff that carries pesticides and chemical fertilizers into neighboring waterways.

Conservation tillage is the obvious choice for the eco-friendly farmer.

Farm Prosperity

The practice of conservation tillage makes a farm more resilient to extreme climate conditions. The incorporation of organic matter and residues captures and retains moisture and slows down the rate of evaporation. This protects crops from drying out during times of drought.

Less capital is spent on fertilizers, pesticides, water and fuel because farmers use what they produce themselves to feed and sustain their crops. These savings can add up to a small fortune by the end of a season.

By adding fresh organic matter, the life force in the soil ecology is outstanding. The presence of beneficial microbes, enzymes and minerals helps to produce substantial yields that net higher profits. 

Conservation tillage may require a bit more work but certainly costs less and yields more. A win-win situation for any farmer.

Agricultural Sustainability

We can safely state that society at large benefits from agricultural sustainability, stemming from practices like conservation tillage. Simply put, an efficient farm consumes less while producing more. The study and implementation of conservation tillage on every level could permanently fix the problems of the agricultural industrial complex.

Frequently Asked Questions (FAQ)