Temporal changes of manure chemical compositions and environmental awareness in the Southern Great Plains

Abstract

Knowing the nutrient contents of animal manure is important in nutrient management plan development. Nutrient contents of manure may have been changed over time due to improvement of breeding, feeding, and manure handling. Therefore, the major characteristics of beef feedlot manure, dairy manure, poultry litter, and swine effluent were summarized using the data from two service laboratories in Kansas and Oklahoma. In general, dry matter contents, pH, and macro- and micronutrient contents of the manures had little changes over time in the last 5 to 20 yr. Only a trend of phosphorus decrease over time in swine effluent was observed. The nutrient contents of various manures largely depend on the dry matter contents. The nitrogen (N), phosphorus (P) and potassium (K) contents are in the following order: broiler litter > beef feedlot manure > dairy manure > swine effluent. Various environmental regulations related to animal manure management have been established and implemented in most parts of the world. The awareness of sustainable manure application to cropland has greatly improved in the last twenty years. More efforts need to be made to further improve nutrient use efficiency of animal manure, protect soil health, and environmental quality.