Macronutrients in Soil

Major Elements The major essential nutrients supplied through soil are nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. We will be testing for nitrogen, phosphorus, potassium, and pH.

Nutrient Origins: Where do these macronutrients come from? Minerals released from decomposition or rocks and organic matter. (Biogeochemical Cycles) Deposition from flood water. Application of limestone and soil based fertilizing materials. Use of animal fertilizers (manure). Which method happens in our plot areas?

Nitrogen 80% of the Earths atmosphere is made of Nitrogen. Atmospheric nitrogen can only be converted into a usable form by plants called legumes. Some common ones are beans, peas, and peanuts. Nitrogen is involved in all biochemical processes to sustain life.

Nitrogen's Importance Component of chlorophyll which gives plants it’s green color (Photosynthesis). Increases succulence, or a plants ability to store water to survive though drought. Promotes above ground growth of plants. Increases plant’s fruit size. Allows plant to take in more of other nutrients.

Too much Nitrogen Delays crop maturity. Weakens stems which can increase bending of plants. Causes the plant itself to grow more, at the expense of the fruit it’s producing.

Too Little Nitrogen Yellowing of leaves from chlorophyll deficiencies. Slower/less growth of plant overall. Smaller fruits and flowers.

Phosphorous Necessary for hardy growth and root development. Causes increase in cell activity. High cell activity causes resistance to disease. Too much Phosphorous is not harmful to the plant.

Too Little Phosphorous Can be caused by excessive farming without returning it to the soil by using fertilizers. Lacking Phosphorous resources result in less growth in both the plant and the animal that consumes it.

Potassium Not a structural competent of plants, but helps with physiological and biochemical functions. Increases disease resistance by strengthening stems, and thicken a waxy layer called the cuticle. Activates enzyme systems within plants. Controls Turgor pressure within plants to prevent from wilting. Enhances fruit size, flavor, texture, and development.

pH pH is a measure of acidity or alkalinity of a substance. pH stands for potential hydronium. pH is a logarithmic scale, so one unit on the scale is ten times greater than the last.

pH Too low of a pH causes low calcium levels and negatively effects growth. Too high of a pH enhances bacteria growth within the soil, which negatively effects the plant. The optimum pH level in soil is between 6.0 and 6.5.