Building better biology

Your soil is alive beneath your feet. The soil biology plays a key role in residue breakdown and nutrient cycling, not to mention suppression of many pests. Want to build a better biology in your soil? Think rotation and reduced tillage.

There are lots of ways to measure soil biology but earthworms are probably one of the most familiar in terms of soil biology. This spring we performed a series of earthworm counts and measurements on the long term plots at the Ridgetown Campus of the University of Guelph. Yes I know this is a field crop plot and the soil is a bit heavier than many horticultural soils but the basic principles hold true.

Rotation/Tillage Middens*
per m2
Earthworm #s
per m2
Continuous soys/ conventional tillage
0
41
Continuous Corn/No-Till
10.3
40.3
Corn-soy/ No-till
35
161
Corn-soy-wheat with red clover/No-till
50
317

2 *Middens are the residue covers that dew worms make over their vertical burrows, basically little residue caps that shade and protect the earthworm. It is a convenient way to count worms spring or fall.

You can see that as we reduce tillage we see more middens and higher numbers of earthworms. As the crop rotation becomes more varied - the different residues and root systems support more soil life. Add in a cover crop like red clover and the worm numbers rise again. This may be a field crop rotation but many vegetable soils also grow field crops like corn, soys and wheat. Build better soil biology by making good rotation and tillage choices during the non-vegetable portion of the rotation - your soil will thank you!

The white golf tees mark the earthworm middens - 10 in continuous corn no-till versus 0 in continuous corn conventional tillage.

The white golf tees mark the earthworm middens - 10 in continuous corn no-till versus 0 in continuous corn conventional tillage.


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