Thursday, March 26, 2015

Ag and Soil: friends to the end

Dirt. Many of you have heard me go off on a tyraid about how dirt is not soil. To a soil scientist, dirt is a four letter word. I learned this my first day of Introductory Soils and it stuck, much like dirt to a shoe. Dirt is acceptable when talking about mud on your boots or dust on your jeans. This is perfectly fine! I'm not advocating to take the word out of the English language. However, its use needs to be modified as it implies a certain connotation. Specifically, dirt implies an unwanted substance hanging around, which is not what soil is at all! Soil is interwoven into our way of life, and it is insulting to call it something as degrading as "dirt."

This is dirt.
Soil is crucial in so many ways. For the month of March, the International Year of Soils theme is "Soils Support Agriculture." Soil and agriculture have had an interesting relationship over time. Soil and Ag grew up in a give and take relationship. Manures and substances were supplied to the soil, and soil produced plants for food and clothing. This process repeated itself over and over. The relationship was pretty tight, but has had its ups and down. Certain practices over the years have lead to decrease in soil quality.
Decreased soil quality leading to dispersion, sealing, and cracking. (

One of the most productive places on the planet way back in the day (let's go back several thousand years to ~9000 BCE) was Mesopotamia also known as the Fertile Crescent. The domestication of plants and animals allowed for a civilization to develop where the hunter/gather lifestyle was replaced by farmer. New approaches to farming developed specifically the use of irrigation water instead of waiting for the gods to provide precipitation from the sky. Mesopotamia was located between the Tigris and Euphrates rivers. This allowed for diversion of water to the cropland for improved production around 5500 BCE. However, this is where soil and Ag had their first dispute. The rivers contained salts that remained in the soil after evaporation. The accumulation of salts (aka salinization) in the soil destroyed soil quality by dispersing aggregates and decreasing infiltration. It also negatively affected plant production through severe osmotic imbalances (plant water uptake control). It is thought that this decrease in soil quality contributed to the downfall of the civilization in this area.

Salinization (
We see similar issues with salinization occurring in California. A decline in water availability and water quality has reduced soil quality and resulted in soils that are no longer arable. However, in general (not just California), we have added a whole other mess of issues as well. Through the invention of the Haber-Bosch process (early 1900's) we have been able to feed way more people than we thought possible. This creation and application of readily available nitrogen changed agriculture as we know it. However, when one partner in a relationship changes, so will the other. With the decrease in the use of manures and plant biomass to supply nutrients and organic matter, soil began to not quite get what it needed out of its relationship.  Things began to head in an unfavorable direction such as soil loss through water and wind erosion (see Drowing in Dust from October). This continued stress on soil will not likely end well.
Mollisol in California where a drainage ditch is causing severe erosion.

It has been projected that by 2050, there will be more people on the planet than we will be able to feed. If Ag and soil continue to treat each other with disrespect, we are headed for a whole lot of trouble. More and more farmers are starting to see that soil is the foundation for their livelihood and cannot be ignored any longer. The transition away from the "take, take, take" and back to "give and take" is happening, but needs more help. To bring this back it will likely mean paying more for food. Farmers must make a living just as we all do. Current practices have made synthetic fertilizers cheap and readily available. This approach is not sustainable for the soil, which needs much more than nitrogen to thrive. In order to switch to practices that improve soil quality, Ag needs a little encouragement and support from the rest of us, primarily through our wallets. We know Ag and Soil can find themselves in a good place again, but we all need to be involved in this. Your food choices can help change practices and make these less expensive for farmers. For the sake of our civilization, Soil and Ag need to be friends again, so that soils and agriculture support each other.