Regular soil testing helps develop and maintain more productive soils for farming, gardening and landscaping. Soil tests indicate whether plant nutrients are deficient and, if so, what amounts are needed for optimum growth. Soil testing is also a useful diagnostic tool to identify problems related to excessive levels of nutrients and salts, low pH, low organic matter and poor drainage.
When properly interpreted, soil tests increase profits in agricultural production systems and promote more favorable conditions for productive and aesthetically pleasing gardens and landscapes.
The best windows of opportunity for soil sampling are early spring and late fall. Field, garden and landscape activities are limited during these periods, and samples can be collected and analyzed in time for fall or spring fertilization. Fall testing has the advantage of allowing the application and incorporation of fertilizers with fall tillage and winter precipitation.
Spring testing, however, often provides a better indication of nutrient availability immediately prior to plant growth. Regardless of when samples are collected, allow a minimum of two to three weeks for analyses, fertilizer purchase and application and any other corrective measures to be taken before planting.
Soil sampling can also be done during the growing season to aid in diagnosing plant growth problems. Landowners who observe a problem may want to sample the soil while symptoms are present to diagnose the problem and take corrective action during the current growing season.
For perennial plants such as turf, ornamentals, fruit trees and pastures, soil should be tested prior to planting and once every two to three years. Soil testing prior to establishing perennials is particularly important since it provides an opportunity to incorporate nutrients into the root zone before planting, and to diagnose and correct soil pH problems before the investment in planting is made.
For annuals such as corn, small grains and gardens, soil should be tested once every two years. Generally, as the intensity of management increases so should the frequency of soil testing. Highly productive growers making frequent fertilizer, manure or other soil amendment applications should test more frequently to monitor changing soil conditions and prevent the build-up of excess levels of nutrients or salts.
Commercial growers and home gardeners should keep soil test records for all areas sampled, as well as fertilizer application and plant yield and quality information. This allows growers to relate yield and plant performance to soil test results and fertilization practices. Since soils and grower management practices vary widely, knowing what soil test values correspond with optimum plant performance on a site allows the grower to customize a soil management program.
University of Georgia Cooperative Extension recommends a routine soil test package for general sampling situations. The routine package measures soil pH (acidity or alkalinity) and nutrient availability. Recommendations are made based on the test results and background site information you provide with the sample.
The cost of the routine test is $8 per sample.
Lime and nutrient recommendations are provided on the soil test report providing the grower or gardener with a detailed recipe for growing success.
For more information or to have your soil tested, contact your local County Extension office at 1-800-ASKUGA1.
Billy Skaggs is a Hall County extension agent. He can be reached at 770-531-6988. His column appears biweekly and at gainesvilletimes.com.