CRITERION FOR DESIGN AND SELECTION OF INJECTION TOOLS TO MINIMIZE LIQUID MANURE ON THE SOIL SURFACE

Abstract

Liquid manure injection can result in significant odor emissions and nutrient losses when manure is not containedin soil but instead overflows to the soil surface. A primary requirement, no overflow manure, was proposed for liquidmanure injection as a means to address these concerns. The relevance of the requirement was demonstrated by examiningthe ammonia volatilization and odor emissions associated with the manure injection operations with two existing injectors.Based on this requirement, a criterion for designing and selecting injection tools was established. The criterion addressesthe fact that sufficient tool capacity is necessary to avoid the occurrence of overflow manure. The tool capacity can bepredicted from the tools geometrical and/or operating parameters. The criterion has conservative characteristics whenapplied to a winged tool at deep injection depths, which would minimize the risk of overflow manure and favor higher targetmanure application rates. The level of overflow manure risk can be appraised from the tools injection performance graphfor different ranges of manure application rates and injection depths. The criterion and associated injection performancegraph were validated by examining overflow manure occurrences following manure injection by a winged tool andrunneropener tool.