Until recently in human agricultural history, soil tilling was done by hand. Eventually, machine technology advanced so that tilling machines could be manually pulled by animals. Today, a wide variety of motorized and fully mechanical tilling machines exist. While these machines have helped cultivate nutritional soil for millennia, is tilling necessary? Today, let’s take a look at the history of tilling and better understand: what is no-till farming?
Plant Biology Basics
Plant science is complicated, but the basics are not. At the end of the day, plants only need a few key ingredients to grow. Let’s take a look at some plant biology basics to get a better understanding of why tilling may be useful.
Unlike animals, plans do not “eat” other organisms for their nutrients. Well, some do, but that is a rare exception. In order for plants to survive, they still need to take in essential elements. Among the most important are nitrogen (N), phosphorus (P), and potassium (K). These are commonly referred to as a group, NPK. Most fertilizers will have all three of these elements in varying amounts, depending on the type and purpose of the fertilizer. Nitrogen is present in abundant amounts in all proteins and is an important element in chlorophyll. Phosphorus is necessary for the main source of chemical energy in plants, ATP. Last, potassium is necessary for water movement and salt retention.
Very obviously, plants need water. Some plants require a minimum amount of water. Others require a massive amount of H2O. Regardless of how much water a plant needs, they all use it for the same basic purposes: rigidity, transportation, and electrons. First, the water helps plants to stand upright so their leaves can be exposed to the sunlight. Second, important salts and sugars dissolve in the water allowing the plant to traffic them to various locations. Third, in order to carry out photosynthesis, plants need a source of electrons. All of these vital functions are accomplished by water.
Sunlight and CO2
Like water, sunlight is another plant necessity that is required in varying degrees for different plants. Like you learned in high school biology, plants use the energy of the sun’s rays to turn the carbon from CO2 into glucose and O2. The plant will use this sugar both to build itself (cellulose) and for energy.
Why Till, Anyway?
Before we dive into no-till farming, we need to understand why farmers and gardeners would employ tilling in the first place.
- Break up hard soil: Plants need loose, malleable soil to grow! The roots must be able to penetrate the soil. Tilling can aid in this process by breaking up dense chunks of dirt that stand in the way.
- Deep nutrients: Tilling can be a very effective means of delivering nutrients (NPK) deep into the soil. The turning action is able to blend the soil, and when combined with fertilizer, this process helps to create healthier soil.
- Kill weeds: The tilling process also helps to destroy weeds. The churning action grinds them up, leaving more nutrients for the plants you want to grow.
Cons of Tilling
While there can be many benefits, tilling doesn’t come without its downsides. There are several reasons why farmers may shy away from religiously tilling their fields.
- Soil structure: Natural soil is different than dirt. Soil, according to the University of California Agriculture and Natural Resources department, is “composed of bedrock and mountain stones broken down over eons by wind and rain.” Soil contains nutrients, minerals, and microorganisms that help plants grow. Tilling can disturb the physical structure of the soil. Over time, this can lead to soil becoming compacted, i.e. dense. This provides a poor environment for the roots and starves microorganisms of much-needed oxygen.
- Soil moisture: Tilling has the tendency to dry out otherwise-moist soil. This is obviously not ideal for any plant, especially young ones.
- Helps weeds: This may seem counterintuitive as we just discussed tilling as a means of killing weeds! Sometimes, tilling can have the opposite effect. Instead of grinding up fledgling weeds, the tilling actually brings weed seeds closer to the surface, allowing them to germinate.
So then, what causes some farmers to employ no-till techniques? There are many reasons why farms of all sizes may choose to go no-till.
- Time: Quite obviously, tilling soil takes time. With a bonafide tractor, tilling can go as fast as about five acres per hour. The issue is that the average farm in the United States is 444 acres. At even 10 acres per hour, that is an entire week’s worth of just tilling.
- Erosion: Over the course of many seasons of tilling, the results can be catastrophic. According to Iowa State University, “Producers… may experience high erosion rates and degradation of topsoil, where nearly all organic matter is located. Removal of topsoil by erosion contributes to a loss of inherent soil fertility levels.”
- Microbiome: By and large, plants are unable to use naturally occurring nitrogen in the soil. Plants need the help of bacteria that assist with the process of nitrogen fixation, whereby nitrogen is broken down into usable forms. Tilling has the tendency to disrupt the soil microbiome. This leads not only to decreased nitrogen fixation but decreased soil health overall.
In short, tilling represents part of a short-term solution to a long-term problem. Issues such as monocropping, slash-and-burn, and fertilizer run-off all contribute to the degradation of our soil. Tilling is no different. No-till farming may yield fewer crops in the immediate future, but it is a positive step towards sustainable farming.
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