Plants need soil to contain a certain amount of life to function more efficiently. Bacteria, fungi, and earthworms make the
nutrients available to the plant to thrive, and protect it from disease. Turning over the soil through cultivation causes much of this soil life to die periodically (as does compaction, pesticides, herbicides and chemical fertilizers). When the soil biology is lost through whatever means, the plants require more inputs (often about 70% more) in the form of fertilizer and water (Elaine Ingham, PhD, Soil Science).
Here are some of the main problems:
- Co2 emissions: when soil is exposed to oxygen (plowing, tillage), organic matter and pockets of CO2 (decomposed organic matter) stored in the soil get released into the atmosphere. Read more. T
- Soil Health: Cultivating destroys soil structure, causing reduced habitat for beneficial insects and soil microrizhal and fungi. This causes a multitude of problems including: These soil organisms convert applied nutrients into soluble plant food. Losing them causes many of the nutrients to be lost, leaching into groundwater or oxidizing. Lack of soil structure contributes to soil erosion, capping of soil surface causing water and applied nutrients to runoff into the groundwater.
- Compaction: Regularly cultivating to a certain depth, combined with the weight and vibration of a tractor, causes the layer just under the cultivation depth to become compacted*. Plant roots (including annual cover crops) are less likely to grow below the compacted soil, causing reduced health,and reduced access to water in drought seasons. Only disase causing organisms grow in compacted soil (anaerobic).
- Erosion: Loss of top soil has frequently been implicated in the collapse of civilizations. When rain drops hit bare and cultivated soil, they can dislodge the soil, carrying it out to rivers where it causes more damage to fish habitat.