Aquatic Pollution and Coastal Management

Unit 3 : Agricultural wastes and eutrophication

3.2.Nutrient Contents in Manure
The actual nutrient value of manure from a particular operation will differ considerably with the method of collection, storage facilities, and the species of animal. Chemical analysis on each sample should be obtained before applying manure in a field.

Factors Affecting Nutrient Composition of Manure
Nutrients in waste may be lost or converted to other forms during treatment or storage and handling, affecting their availability for use by growing plants. The type of animal housing system and/or waste handling method is known to affect the final nutrient composition of the waste. Bedding and water have a diluting effect on the final nutrient concentration of waste and result in less nutrient value per unit quantity. In addition, the type of housing and waste handling system can decrease the final nutrient composition of waste materials. For instance, there can be considerable loss of nitrogen to the air, and there is a potential for runoff and leeching when animal waste is exposed to weather conditions in an open lot system. In contrast, there is considerably less nitrogen loss from a completely covered feedlot with manure pack or a liquid lagoon.