Soil

Mulching potato paddock

Soil is the loose mineral or organic matter surface of the earth’s crust that is capable of supporting plant growth. Soils may be a few centimetres to several meters thick (deep). The careful management and preservation of this soil mantle over time can be the difference between a prosperous society and poverty.

Soil is formed by break- down of parent rock into small particles and it forms at a rate of 20 to 30 mm per 100 years. One of the reasons to avoid soil erosion is this slow replacement of soil from parent rock. Another is to prevent the loss of nutrients contained in this soil that are important to vegetation growth.

Soils Workshop

As well as that, soil erosion is prevented where possible from entering waterways, as it buries the ground layers that provide living environments for aquatic organisms, makes streams shallow and treacherous to cross, reduces light within the water column and makes water unpalatable.

Soil properties important for production include soil nutrients, soil ph, soil structure and texture, soil biology and the soil’s ability to absorb and retain water.

A healthy soil feels soft and crumbles easily, drains well, does not crust after planting, soaks up heavy rains with little runoff, stores moisture, resists erosion, supports high populations of soil organisms and has a rich, earthy smell.