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Soil Management
Row of plants growingSoils from the Ground Up
Nutrients, organic matter, and water in the soil are the raw materials that give life to the landscape. Yet soil fertility is not just a matter of nutrients, but also of chemical, physical and biological factors, including soil texture, composition, structure, pH, and living organisms.

Few soils are of only one texture, with most being combinations of particle types. The best soil, called loam, is a combination of sand, silt, and clay. Its mixture of sizes permits penetration and drainage of water while retaining moisture.

The addition of organic matter brings more nutrients and stimulates microbial activity. Organic matter creates a stable, open structure that improves drainage and water retention; it lightens heavy soils and firms up light ones. It also helps create the optimum acid-alkaline balance in which the most nutrients become readily available to plants.

Successful landscapes are just as dependent upon successful management as they are upon the necessary raw materials. Site management is the same whether using recycled or potable water.

Evaluating Drainage
Begin the process of evaluating drainage by examining your site, both surface and underground. At its simplest, assessing soil drainage involves excavating a test hole four to six inches deep, filling it with water, allowing it to drain, filling it again and then measuring the rate at which the water level drops with a ruler placed vertically inside the hole.

The drainage rate will be highly variable depending on the soil type and moisture content, so the measurement is meaningful only if determined when the soil is completely saturated with water. The drainage rate should be no less than one-quarter inch per hour and should not exceed two inches per hour. Soils with drainage rates outside of this range may require soil modifications for optimal growth.

Good Drainage
Good drainage is essential for aeration, nutrient cycling, and root growth. It also prevents problems caused by standing water. Good drainage is especially important when using recycled water because it makes it much easier to keep the potential accumulation of salts at manageable levels.

Essentials for improving drainage
  • Aerate the soil.
  • Add organic matter to the soil.
  • Add soil amendments such as gypsum (only if necessary).