Evaluating Soil Quality

Soil Texture The percentages of sand, silt and clay present in soil helps determine fertility. Examples: + charged clay particles attract – charged nutrient ions. Too much sand decreases the water holding capacity of soil. The best soil is loamy with a balance of clay, sand, and silt. Clay (less than .002mm), silt (.002-.05mm), sand (.05-1.0mm).

Organic Matter Organic matter adds nutrients as it is decomposed. Organic matter is also + charged.

Soil Porosity/Retention Ability of soil to hold water. Clay soils hold water while sandy soils do not. Mixture is best.

Soil pH Above 7 is alkaline and below 7 is acidic. Optimum plant growth at 6 – 6.5. How acid or base a soil is effects what plants can live in it. Lime is used to adjust soil pH. Aluminum increases acidity.

Soil Nutrients Necessary for plant growth. Different plants like different levels of nutrients. Macronutrients are required in large quantities. N, P, K. Trace nutrients are necessary but can be detrimental in large quantities.

Plant Nutrients Water from soil and Carbon dioxide from air are broken up and rearranged into carbohydrate during photosynthesis.

Nitrogen from soil- proper leaf growth and color. Phosphorus from soil- DNA production, root, stem, flower, and leaf production. Potassium from soil- help make proteins and carbohydrates in plants. Calcium from soil- cell metabolism, growth and reproduction.

Magnesium from soil- part of the chlorophyl molecule. Trace elements- sulfur, iron, zinc, molybdenum, boron, copper, manganese, chorine.