Recent estimates by the U.S. Geological Survey indicate that more than 700,000 tons are produced annually in Delaware alone. Agricultural producers have used this material as a nutrient source for decades, especially as a nitrogen source for corn, small grains and sorghum production. Those crops are relatively high users of nitrogen, and judicious use of poultry manure has been beneficial. Vegetable producers, however, have refrained from using this nutrient source for several reasons. First, unknown or unreliable analyses of poultry manure's nutrient content have limited its use by vegetable producers, who want a more exact fertilizer.
Most vegetables are quick-growing crops.
Maturity and quality are often as important as yield in determining profitability, which legitimizes vegetable producers' concerns about poultry manure and its effect on these variables. Second, the inability to spread manure accurately at lower rates has limited its use. Recent improvements in spreader technology and local availability of more precise equipment have answered these concerns. Third, growers believed a widely held misconception that poultry manure introduced weed seeds to their fields. To address these concerns and to determine the suitability of poultry manure as a nutrient source for vegetable crops, in 1995 University of Delaware Cooperative Extension initiated field research on four vegetable crops that represent a cross section of crops widely grown on our lighter, sandier soils, including watermelons, pickling cucumbers, peas and limas.