Less plowing, more organic matter
Francisco Arriaga, Assistant Professor
Department of Soil Science
UW-Madison College of Agricultural and Life Sciences
3:04 – Total Time
0:17 – Why farmers plow the soil
0:28 – What happens when you plow
0:59 – Carbon is important organic matter
1:20 – Research says carbon can be restored
1:48 – Practices to improve soil health
2:14 – What direct seeding, no-till is
2:40 – Reduced tillage benefits
2:53 – Lead out
Sevie Kenyon: Francisco, tell us why farmers plow and till the soil.
Francisco Arriaga: So the need for plowing soils, when you plant you have a good seed to soil contact so your seeds can emerge and your crop can grow properly.
Sevie Kenyon: Francisco, what happens when people till the soil?
Francisco Arriaga: So you’re preparing a nice seed bed, viable soil, but at the same time you’re breaking soil aggregate. Soil aggregates are basically these clumps, if you will, of your sand, silt, and clay that stick together. What’s important about that is actually organic matter, it’s the glue that makes this aggregate stick together, and when you plow you incorporate a lot of air, a lot of oxygen in the soil. And these microbes use that and basically their population growth, and they just feed on this organic matter and we lose a lot of this carbon.
Sevie Kenyon: And why is the loss of that carbon so important?
Francisco Arriaga: Well organic matter and carbon, soil organic carbon in the soil is critical. That’s what gives you good infiltration so when it rains, you want that rainfall to go into the soil, so you need to have good infiltration for this to happen. And also to help water retention, so that water can be used for your plants to grow.
Sevie Kenyon: And Francisco, what are you learning from your research about this process?
Francisco Arriaga: A lot of the land that we’re farming used to be in prairie, so [it] had a very high organic matter and when you plow that, you know, you have very good growth, but over time that organic matter has been depleted. So now what we’re finding is that if we do certain management practices we can increase this organic matter and over time, it’s a long-term process, we can improve productivity and the resilience of those soils
Sevie Kenyon: And Francisco, what are some of the things that farmers and others can do to begin to improve soil health?
Francisco Arriaga: So one of the things is what we call reduced tillage, or conservation tillage. So these are tillage practices that minimize the amount of disturbance in the soil and so it reduces the amount of organic matter that we lose. The extreme of this is what we call “no till” so those are management systems where we actually don’t have any tillage. The only steel that actually touches the ground is your planter.
Sevie Kenyon: So maybe you could paint us a little picture of what no till looks like.
Francisco Arriaga: You know in Spanish, that’s my native language, we actually don’t call it no till, we actually call it siembra directo, which should translate to direct seeding, so that basically gives you the general idea of it. You don’t work the soil with any kind of tillage. You basically, all you do with that soil is plant directly your seeds directly into that soil. Basically you reduce almost one hundred percent the type of disturbance that you have on that soil.
Sevie Kenyon: What are the benefits of that reduced tillage?
Francisco Arriaga: So the benefits of reduced tillage include buildup in organic matter, but the other thing that it does is minimizes the disturbance of the soil, keeps a lot of cover on the soil surface so it reduces the amount of erosion that we have in the soil.
Sevie Kenyon: We’ve been visiting with Francisco Arriaga, Department of Soil Science, University of Wisconsin-Extension and the College of Agricultural and Life Sciences, Madison, Wisconsin, and I am Sevie Kenyon.