It's not dirt!

Following practices that build and maintain good levels of soil organic matter will help you grow healthier and higher yielding crops in your garden, according to soil scientists Fred Magdoff and Harold van Es, authors of "Building Soil for Better Crops." Plants grown in soils high in organic matter are better able to withstand drought, insects, and diseases. A healthy soil also requires less fertilizer.

Are you a reactive or a proactive gardener when it comes to soil health? Reactive gardeners respond after seeing a problem in their gardens. If the soil doesn't hold moisture, they irrigate more. If plants don't seem to be growing well, they add fertilizer. If insects attack, they spray with pesticides. Proactive gardeners realize that low nutrients, poor water-holding capacity, soil compaction, or insect damage may all be due to a degraded, poor quality, almost dead soil.

Gardeners sometimes think that a lot of fertilizer is all that is needed to have a productive vegetable garden, but "feeding the soil, not the plant" is the key to higher yields and more sustainable gardening.

Soil fertility can be maintained by adding organic material. What is organic material? Organic material has living and nonliving components. The living parts include microorganisms, such as bacteria, fungi, and viruses, most of which are beneficial. Worms, plant roots, and animals comprise other living portions. The microorganisms and worms help to break down leafy residues and manures into usable nutrients for plants. In fact, Charles Darwin called worms the natural plows of the soil. John Malcom, a Vermont dairy farmer, states, "The microscopic flora and fauna in our soils give soil its fertility; otherwise, it is just dirt."

The nonliving parts of the soil include the dead microorganisms mentioned above and old roots, leaves, sticks, and any added manures. Organic matter ranges from very fresh material, yet to be broken down, to "humus," which is very decomposed and most useful for plants.

Organic matter is lost from soil each year through decay, leaching, and plant use. Building a high quality soil requires action. Add organic matter to the soil; use a variety of organic materials; and decrease loss of organic material. Different types of material include disease- and insect-free crop residues, compost, well-aged manures, leaves, straw, grass clippings, etc.

If you are a soil lover, you may want to order "Building Soils for Better Crops," by Magdoff and van Es, a USDA publication, ISBN 1-888626-05-4. We also have helpful handouts available at University of Nevada Cooperative Extension.

For more information, e-mail skellyj@unce.unr.edu or call me at 887-2252. You can "Ask a Master Gardener" by e-mailing mastergardeners@unce.unr.edu or call your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at www.unce.unr.edu.

• JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.