Is Tillage bad for the soil?
Yes, tillage, from a simple glance has many disadvantages to soil health most significantly reducing soil organic matter and opening up ground to erosion. Although there are many factors and circumstances where my opinion shifts to favor tillage over any no-till or no-dig methods.
What is tillage?
Tillage is the act of land preparation where the soil is mechanically agitated by machinery, animal, or human hands. Yes, in my opinion, taking a hoe out to the garden and weeding is a light form of tillage. Most commonly, people think about a high-speed tine tiller that chops up and mixes soil into a seedbed when thinking about tillage.
What is the purpose of Tillage?
Tillage is most often used to break up compaction and help with future water infiltration and gas exchange when preparing land for planting. Tillage has allowed the boom in population growth. Now we could produce a surplus of food and no longer rely on humans or horses to prepare our lands for planting.
Forms of Tillage
Forms of Tillage by Hand:
- Hoes
- Rakes
- Shoveling
- Picking
- Hilling
Forms of Tillage with either horse or motors pulling equipment:
- Moldboard plow & disc
- Field cultivators
- Chisel plow
- Disk plow
- Speed harrows
- No-till drills
Forms of Tillage using PTO ( The power take off, energy used from an engine to rotate an attachment on a tractor.)
- Rotary tiller
- Rotary spader
- Power harrow
Effects of Tillage
Whenever soil is disturbed and exposed we have changes in the physical properties of the soil and potential emission of carbon dioxide, nitrous oxide, and methane. A study in 2014 found tillage influences carbon and methane emissions but emissions of nitrous oxide had more to do with soil moisture and microbial mass than directly connected to tillage. (Mangalassery et al., 2014)
The different forms of tillage play a large role in the scale of these emissions. In combination, the total amount of tillage performed globally influences our global emission of carbon or methane.
Tillage also causes losses of biological activity and loss of ground cover. Tillage can lead to erosion when there is nothing to slow down the impact of falling rain.
Now that we understand a bit about why tillage can have a negative impact locally and globally, we must ask the question, “where can tillage be eliminated?”.
Elimination of Tillage
The elimination of tillage would lower our global spring gas emissions. If we never planted once again in the fall when they are harvested we would avoid more carbon and methane emissions. It may sound like a great solution for climate change, but where will our current food production pivot to make up for the loss in production?
Without going too deep into the systematic shortcomings of the global food system, it is important to first think about where tillage could be eliminated with proven methods of production.
Reduced tillage and implementation of grazing
Our current production system for meats separates animals and their feed production into two separate enterprises. We till massive areas to plant soybeans, corn, and other grains to then truck in and feed unexercised, unhealthy, and obese animals. This is a poor quality, unnatural product which then becomes our food.
A simple solution is to put ruminants back on pastures to eat a diet that they evolved to eat. A diet consisting of grass, legumes, and trees or shrubs leaves. This would reduce the amount of land growing these feed crops for feedlot animals. This reduction of tillage would only require more land to be used in grazing to meet the same protein quantities that the meat industry currently produces today. This is a huge simplification of a much more complex issue but grazing instead of growing feed should be a consideration for a future in sustainable meat production. Or at least a way to minimize feedlots and the amount of large-scale tillage necessary to keep the system running.
There are even hybrids of these systems where guys like Gabe Brown use no-till drills to grow commodity crops but also rotate cattle into their fields. The cattle graze cover crops and have led to decreased needs for fertilizers and more resilient production systems.
While reduced and no-till drill options exist when we look towards vegetable production it is a much more difficult issue to eliminate tillage from production.
No-till or no-dig systems
There are a lot of no-till or self-proclaimed no-till gardeners and even commodity crop growers out there. “What is tillage?”, will differ from one grower to another.
Large scale
Large-scale commodity crops can be grown under a no-till drill system. The no-till drill can cut through residue with a disc (which is still a form of tillage), and drop a seed into the furrow strip followed by a press wheel that closes the furrow back up.
Methods of no-till drills
- These operations rely on crimping, a method of laying down a cover crop before it has gone to seed and then running the no-till drill through the cover crop.
- Others use glyphosate (weed killer) to kill any vegetation before planting.
- Another method, a cover crop may be planted no-till after the commodity crop is harvested.
The no-till drill is a great innovation and has some promising uses. Growers are still experimenting with how to best optimize these drills to preserve our soils.
It would be a great incentive to require commodity crops of the future to be grown with no-till drills worldwide to help cut down on carbon emissions from agriculture. It would be great to see government subsidies to help farmers buy no-till drills, especially in poorer countries, as they are very expensive and educate newcomers on how to use them.
Small scale
On a small scale, a no-till or no-dig garden relies on mulching to avoid tillage. The most common no-till method is to spread 4+ inches of compost on top of cardboard or following a long period of occultation (covering the soil with a tarp to kill the existing vegetation). These systems usually call for 1″ yearly additions of compost.
When I started my farm we started in a no-till mindset using tarps and buying in compost by the truckload. We also made our compost, but a large pile of compost will only go so far when you need so much of it.
Why I moved away from completely no-till systems in vegetable production?
I think that no-till is great ideologically but is faulted by many issues:
- Time/Energy: Spreading so much compost is time and energy intensive. Not to mention, a very expensive material.
- Skips the Benefits of Soil: When we only plant our crops in the compost we are not able to take full advantage of the clay sheets in soils. We are now relying on compost to have all the minerals we need for a superior crop. Soil balancing is no longer applicable as we have an unrealistic sense of our TEC (total cation exchange capacity) of the native soil we buried in compost. The TEC helps us know how to load the positively charged ions before additions such as compost.
- Stuck in a category: Some instances work better than others with no-till. I never think it’s great to get so locked into an ideology that we are unable to experiment with our growing methods. True sustainability is a balancing act between the three P’s, Profit, Person, and Planet.
- Requires more water: While compost does a great job of holding water, in Virginia trying to start a no-till, fall garden at the end of July or early August without heavy irrigation is near impossible. The days are so hot and long and the ground is rather dry as a result. When we were no-till the only way to be able to transplant or seed into these conditions was to irrigate or add more compost. Now with smart tillage, we can perform secondary tillage which allows rain to penetrate deeply.
- Requires more fertilizers or compost: One of the most startling discoveries I made when converting some of our products to use tractors and tillage regarded our amendments. Our fall crop showed an overuse of Nitrogen with hairy root crops and excessive greens when using our amendment input numbers from the no-till system. This is because we utilized all the organic matter that was sitting on the surface from spring crops instead of raking it away with a no-till system. Also, the amendments that we do add if any for a fall crop are not lost to the air through nitrification but are instead mostly retained in the soil.
Why zero-tillage won’t work?
Eliminating tillage from our production of food is unwarranted unless there is a solution to take its place. As long as we have a globalized food network that operates on an economy of scale the majority of consumers will not pay for the higher costing produce or meats that are using more planet-friendly approaches to production. We are so used to convenience and often value spending our hard-earned money towards hobbies or leisure than towards our health or food.
The future of tillage
It is hard enough to run a farm and be profitable. It is becoming unfeasible for some productions that rely on energy inputs such as Greenhouse growers in Europe. In particular, the Netherlands is quite concerned about the future of the cut flower market as many growers decide not to continue to grow year-round. It is too costly to heat their production facilities in the coldest months of winter.
In my circumstance, we are already on quite small margins producing vegetables for market and now face less severe increases in energy about 3% starting in January. While we are not heavy users of energy for heating out-of-season crops, we are concerned about the uncertainty of diesel for the 2023 season.
I am wondering what the price will be in early spring, 2023, and whether or not there will be a diesel shortage.
My farm could switch back to systems that do not use tractors to produce food but we would quickly cut out a lot of the less profitable and more labor-intensive crops.
In Conclusion
The cost of labor is not proportionate to the cost to produce food on a small scale. The more that we see the effects of inflation the more people start to budget and niche food producers are going to have a hard time selling their products at above-average market prices. This is why I do not think that the elimination of tillage would work from a production standpoint. The market will not bear the increased costs associated with a more labor intense product of small producers. The cost of compost will only increase as well with its relationship to the diesel supply, in transport and production.
We would need more laborers with no-till to achieve the same output. This possibly means that we will become more reliant on larger operations to produce our vegetables if you are in the buyers’ market.
Homesteading
While it may not make sense to produce for the market at a small scale. Getting into homesteading or simply growing your garden could cut your food costs significantly and help you budget healthy food for your life. Now is a great time to learn how to grow your own and get into homesteading if you have access to land or have friends that you could help out with. You would be surprised at how much food you can grow on a small scale. At the end of the day, humans were able to get by before the Ag revolution, it was just a lot more effort than we even consider today.
It takes time to build a following of great customers but farming is a lot of hard work, trial, and error, and can be very satisfying to reap what you sow. I hope that our future supports more farmers and our consumer habits change to favor local businesses.
Sources
Mangalassery, S., Sjögersten, S., Sparkes, D. et al. To what extent can zero tillage lead to a reduction in greenhouse gas emissions from temperate soils?. Sci Rep 4, 4586 (2014). https://doi.org/10.1038/srep04586
