Uniformity of liquid manure application from existing land application systems

Land application ofliquid manure is currently creating significant environmental issues related to air and water quality. To reduce environmental impacts and to meet crop nutrient requirements, liquid manure must be applied at uniform controlled rates. The objective of this study was to evaluate the uniformity of current liquid manure application systems used in Southern Ontario. Existing single and multiple splash plate systems were evaluated at the field scale using three replicated continuous rows of sampling trays (0.126 m2 ) placed perpendicular to the direction of travel. Application rates, coefficients ofvariation (CV) and uniformity coefficients (Uc> were calculated from the masses of manure in the sample trays. The manure application equipment tested had CV values ranging from 30 to 68% with a mean value of 50%. Large CV values for uniformity are inadequate for crop production purposes when the manure is the primary nutrient source. The implications are significant for soil fertility management, crop productivity, and potential environmental impact to sensitive areas due to high hydraulic conductivity to subsurface waters.