Soil Testing (cont)
By: Charlie Nardozzi
Do-it-yourself soil tests
A laboratory soil test has definite advantages, but it takes time to get the results. For a quick look at your soil, many home tests are available. These rely on color charts to match the nutrient levels in a soil solution. Unless you buy an expensive test kit, the specific nutrient tests aren't, in general, as accurate as in a professional soil test. Their usefulness is limited to a basic guide of the pH and nutrients that are immediately available, and they're best for gardeners who are knowledgeable and inquisitive about soil chemistry.
Alternative soil tests
Some private labs are responding to the need of organic gardeners and farmers to go beyond testing the mineral content of the soil to offer tests for biological content (fungi and bacteria). These labs, such as Soil Food Web Laboratory in Oregon, believe that the soil's biological life is just as important as the mineral content in determining soil and plant health.
It's believed that the more diverse the microorganism population in the soil, the better the soil structure, the more nutrients available to plants, and the less disease on the plants. Some labs, such as Woods End Laboratory in Maine, have a home test kit (Solvita) that tests biological and textural components in the soil, with a special emphasis on organic matter management. These tests, though more expensive than traditional university tests, give gardeners and farmers valuable information about their soil's microbial life. Since these tests are relatively new, cropping and fertilizer recommendations based on them don't have a long history of experience.
Charlie Nardozzi is a senior horticulturist at National Gardening.