A recent study has been completed that concludes plowing kills worms, damages soil fertility, reduces soil's ability to absorb water and diminishes worms' food supply.
It can take up to ten years to repair the damage done to soil by conventional plowing.
Now 34% of US cropland uses no-till farming according to the USDA. Additional benefits include using less fuel and fewer soil improvements.
Did you know that when summer heats up worms move 18-inches down into the soil to protect themselves from the heat? Here's an interesting Purdue U. article about worms.
The University College Dublin conducted similar research and reported similar findings in May, 2017. “What we see is a systematic decline in the earthworm population in the soil after continued ploughing and a significant increase in the abundance of earthworms in less disturbed soil,although some soils would need more than 10 years to show good signs of recovery” says Associate Professor Olaf Schmidt, from the UCD School of Agriculture and Food Science, University College Dublin.