What makes a health soil?
Soil health is the capacity of soil to function as a living system. Healthy soils maintain a diverse community of soil organisms that help to control plant disease, insect and weed pests, and form beneficial symbiotic associations with plant roots. Healthy soils recycle essential plant nutrients, improve soil structure with positive repercussions for soil water and nutrient holding capacity, and ultimately improve crop production. A healthy soil does not pollute the environment; rather, it contributes to mitigate climate change by maintaining or increasing its organic carbon content.
The characteristics of soil health are:
Good soil tilth
Sufficient depth
Sufficient but not excess supply of nutrients
Small population of plant pathogens and insect pests
Good soil drainage
Large population of beneficial organism
Low weed pressure
Free of chemicals and toxins that may harm vegetation / crops
Resistance to degradation
Resilience when unfavorable conditions occur
Having living roots all year is essential to soil health. Roots by themselves provide diversity. Fibrous roots reduce bulk density, tap roots loosen compaction, deep roots uptake or scavenge N, P, and other nutrients. Also, the rhizosphere (area around roots) are areas highest of concentration for soil life. Roots release exudates and soil life feeds off these proteins and sugars.
Some keys to improving soil health are: consistently adding organic matter (compost), decreasing distrubance, increasing cover crops, increasing biodiversity, being sure to have living roots in the soil all year.
What is soil tilth? Tilth generally refers to the physical condition of the soil as it relates to plant growth. Favorable tilth implies good conditions for seed germination and root proliferation, allowing crops to thrive. Also, a soil with good tilth facilitates other processes, such as water infiltration and aeration, which benefit both crop and environment. Good soil tilth is usually equated with aggregation (presence of soil crumbs), because stable aggregates promote these favorable processes. Crop rotations can have a positive impact on soil tilth, depending on the crops that are being alternated. Additional ways to improve soil tilth include reducing tillage and using cover crops. There are thus a number of approaches to improving the physical quality of the soil, and often a combined approach produces the greatest improvement.