Factors Affecting Soil Productivity

Soil Texture

• Soil texture refers to the size of the particles present in soil. Each type of soil is broken down into a textural class, which tells you the amount of sand, silt and clay present. Soil texture determines the amount of water the soil can hold, the soil's ability to retain nutrients, and the aeration of the soil. For example, finer textured soils hold more water but also further restrict the movement of air and water.

Soil Structure

• When soil particles become cemented together, they are called aggregates. These aggregates take on shapes that define the structure of the soil and affect the way air, water and roots move through the soil. For instance, a soil featuring blocky aggregates, which are as tall as they are wide, is ideal for the growth of roots and movement of air and water, whereas platey aggregates, which are wider than they are tall, impede water and air movement and root development.

Soil Depth

• Soil depth refers to how deep the roots of crops can penetrate into a soil to obtain nutrients and water. Given the chance, the roots of most crops will grow down 3 feet or more making an ideal soil depth 6 feet deep. High water tables, shale, coarse gravelly layers and impervious layers will limit the soil depth and are difficult if not impossible to change in an area.

Soil Slope

• The slope of the soil is determined by the topography of the land. Soil that is present on a steeply sloping hill is less stable in terms of productivity and is more likely to be subject to erosion and water runoff issues than soil that is located on a plateau.

Soil Fertility

• Soil fertility refers to the amount of nutrients available to plants in the soil. Soil fertility will vary year to year depending on crop rotation, erosion, organic life present and amendments added. The topic of soil fertility is familiar to most gardeners, and encompasses element and nutrient loads in the soil that are commonly addressed with organic and chemical amendments.