John Kempf explains how to keep soil microbes alive and active. Bare soil hits 140°F at the surface, killing the enzymes microbes need. Most fields have a compaction layer 4 to 6 inches down that traps roots and water, so plants stay shallow. Fix it by breaking up the compaction and keeping living plants on the soil year-round.
Questions this video answers
About 140 degrees (°F) at the soil surface.
About 110 degrees (°F) down into the soil (reported as the threshold for enzyme denaturation).
Approximately 4–6 inches deep.
About 6–8 inches deep.
Chapters
When we want to develop a soil microbiome that is capable of delivering plant nutrition, we need to begin thinking about managing our soil as if though it were a petri dish in a laboratory. And what I mean by that is we want the absolute ideal environment for microbes. So an ideal environment means they need an optimal temperature range, they need an optimal moisture range, and they need a food source. And it's surprising how in many soils we do not have these pieces missing. So we have some of these pieces missing. So first, when we have bare soil that is exposed to sunlight and we have direct sunbeams beating on that soil, we know it's very common to get temperatures as much as 140 degrees. That didn't make sense as much as 140 degrees here on the soil surface. So right at the soil surface. It's not uncommon in sunny areas, particularly on darker soils, to have a soil surface temperature of 140 degrees. That usually translates to temperatures of 110 degrees. See if I can succeed this time of 110 degrees down to a depth. Depending on how conductive the soil is of temperatures and moisture levels and all that, you can have 110 degrees down to a depth easily of 2 to 3 inches. So 110 degrees is the temperature threshold at which you get enzymes denaturing. And you can extrapolate that that's going to have a very suppressive effect on the soil microbiome at that point. So now you've just taken the top couple inches of soil out of the microbially active zone. That soil is not microbially active as long as it is exposed to direct sunlight. And then we have this situation in far too many agricultural soils, particularly soils that have been no till for an extended period of time, particularly those that have been chemical no till, that haven't incorporated lots of COVID crops. We have a compaction zone that is usually anywhere from 4 to 6 inches deep. And this compaction zone is so compacted, roots have challenges getting through it. Moisture has a challenge getting through it. And there is no microbial activity below that zone. Because it's very, very simple. Biology has to breathe. If you would choke, if you would asphyxiate because of not getting enough oxygen, of having your head buried six inches deep in this zone, then the same is going to happen for biology. They have to be able to breathe. There has to be good gas exchange and good air exchange. We see far too many root systems particularly. Surprisingly, this is true even in dry land environments, where in the dry land environment, the root system is only 6 to 8 inches deep. And then we want that plant to survive two months of extended dry periods with limited moisture. If we want to get root systems deeper, and we want to get biology deeper, we have to solve compaction. So there is this ideology, this dogma, that soil should never be tilled in soils. In this situation, we need to remove that compaction. Tillage is the easy way to do it, the fast way to do it. You can also do it with root systems, but it's going to take a lot longer. But it has to be resolved. You should not expect to build soil microbial populations as long as you have this very dense compaction layer. And when you have bare soils exposed to the sun in this type of ecosystem and environment, you should not expect to establish good microbial populations that are going to be able to deliver nutrients for a crop. We need to fix the environment if we want the biology to thrive. And of course, the last piece is you have to give them a food source, which is lots of root exudates from COVID crops and from keeping the soil constantly covered with green growing plants. That combination of addressing these pieces will solve all problems.
