Tighty Whities Can Tell You About Your Soil Health

This is a fun experiment you can try with your own pastures and fields. It comes to us from Anthony Bly and Sara Berg of South Dakota State University Extension. Just remember that different areas will have different kinds of soils and you may get different results.

Soil microorganisms require carbon to survive. Men’s cotton underwear briefs contain high amounts of carbon. Therefore, briefs can be buried in the soil and retrieved later to see and evaluate soil microbiological activity and ultimately, soil health status. During the South Dakota Soil Health Coalition’s first Soil Health School in the Aberdeen and Ipswich areas, a “Tighty Whities” demonstration was conducted. The briefs were buried to about the waistline in the soil five weeks ahead of the school at 3 sites that included: corn with conventional tillage, soybeans under mulch tillage, and no-till soil currently with growing cover crops. Soil health school participants had the opportunity to extract the briefs and view the results of five replicates in each field. Results were revealing…to say the least.

A new brief was compared to one brief from each field.

The first soiled brief in the picture above (second from the left) was from the no-till field with cover crops. Hardly anything remained of the brief, indicating extensive soil microbiological activity. The brief from the mulch (reduced) tillage soybean field (third from the left) had more material remaining when compared with the no-till/cover cropped soil, and the conventional tilled corn (for right) had the most material which indicated the least soil microbial activity. All 5 briefs buried at each site were weighed, with the results matching the degradation observed in the photo (Table 1).

Kathy’s Note: If the lower case letters and some of the other data is as confusing to you as it sometimes is to me, here’s a translation: “Significance” is derived from statistics to help us see if a practice really makes a difference. The difference is something that you can see, that you can acknowledge and that you can expect again (under the same conditions). Probability (PR>F in the table above) indicates how certain you are that you’ll get this same result again. So what the statistics here show us is that there was a significant difference seen, and after 5 replications (5 pairs of underwear buried in each field) the chances that you won’t get these same results are 1 in 1,000.