Deep tillage of soil causes release of a surge of nutrients due to the death and decomposition of large amount of soil organisms.

This surge of nutrients may give you an initial boost to crop growth. But if not taken immediately by plants, these nutrients will leach into groundwater or outgas to the air.

Meantime, the life cycles of many beneficial soil organisms are disrupted. It will take them quite some time to rebuild their population. If the next tillage happens before they can recover, the health and diversity of the soil is degrading.

Excess tillage also exposes the soil to too much oxygen, which oxidizes carbon content and leads to the loss of soil carbon to the air as carbon dioxide. This not only impairs the fertility of the soil, but also contributes to the increase of  greenhouse gas in the atmosphere.

To reverse carbon dioxide emission and to increase soil fertility with increased carbon content, try to reduce heavy tillage of the soil and add organic matter to it.