URBAN AG
The importance of soil fertility
Key to having healthy landscape plants by Timothy Daly, UGA Extension Gwinnett
Large sums of money are spent installing new landscapes, and sometimes the plants perish. Many problems can be the source of the difficulty, but one sticks out in particular: the condition of the soil, which is the most critical component of a plant's environment. From soil, the plant obtains water, nutrients, and even air. The ideal type of soil for a plant is fertile, deep, well-drained, and has high organic matter. Many essential nutrients are necessary for optimal plant growth. The major nutrients, which the plants require most, are nitrogen, phosphorus, and potassium. The secondary major nutrients are sulfur, calcium, and magnesium. Then plants require micronutrients, which are only needed in small quantities. Zinc, iron, manganese, molybdenum, boron, and copper are some of the micronutrients. Regardless of the type of nutrient, if any are deficient, the entire plant will suffer. Different plants have differing fertility requirements.
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The importance of pH
Of the many factors that affect nutrient availability, the most important is the soil pH, which measures the soil's acidity. The pH scale ranges from one to fourteen. Seven is considered neutral, and below it, the soil is acidic, and above it is alkaline or basic. The scale is logarithmic, meaning that a pH of six is ten times more acidic than seven, a pH of five is 100 times more acidic, and so forth. Most plants require a pH of 6.0 to 6.5, which is the level at which most essential elements a plant needs are available and can be absorbed. Outside that range, their levels are too low for the plant to take up. However, several exceptions exist. Iron, zinc, and manganese are in higher quantities at a pH below six. Some plants
