Uniformity of liquid manure application from existing land application systems

Land application of liquid manure is currently creating significant environ mental issues related to air and water quality. To reduce environmental imp acts and to meet crop nutrient requirements, liquid manure must be applied at uniform controlled rates. The objective of this study was to evaluate th e uniformity of current liquid manure application systems used in Southern Ontario. Existing single and multiple splash plate systems were evaluated a t the field scale using three replicated continuous rows of sampling trays (0.126 m(2)) placed perpendicular to the direction of travel. Application r ates, coefficients of variation (CV) and uniformity coefficients (U-C) were calculated from the masses of manure in the sample trays. The manure appli cation equipment tested had CV values ranging from 30 to 68% with a mean va lue of 50%. Large CV values for uniformity are inadequate for crop producti on purposes when the manure is the primary nutrient source. The implication s are significant for soil fertility management, crop productivity, and pot ential environmental impact to sensitive areas due to high hydraulic conduc tivity to subsurface waters.