Waste products are generally applied to the land because they contain nutrients or liming materials beneficial to plant growth. Waste analysis is the most accurate and efficient way to measure the nutrient or lime value of different waste products. Because the amount of these beneficial components can vary among waste products, laboratory analysis lets the producer know the proper amount of the waste material to apply to meet the specific plant needs for each site. Composting can reduce volume, improve uniformity, and sometimes alter the nutrient availability of waste products. Because of this, samples from the final material that will be applied must be analyzed.
Nutrient concentrations vary in most organic waste products.
Note that the maximum and minimum values for nitrogen, phosphate, and potash differ by more than 100-fold. Table 1 . Variations in poultry and swine manure nutrient levels. Because environmental damage and losses in plant yield and quality often happen before visible plant symptoms, growers and other users should always have their wastes analyzed by a competent laboratory and their application rates determined by a knowledgeable agronomist. The Waste Advisory Section of the NCDA Agronomic Division analyzes wastes, interprets analytical results, and provides management recommendations for citizens of North Carolina.