Hydrated Lime to Reduce Manurial Nitrogen Losses in Dairy Barns

Abstract

ABSTRACT HYDRATED lime was tested in both laboratory and barn experiments as a possible compound to reduce manurial nitrogen (N) losses in free-stall barns by preventing the hydrolysis of organic N to ammonia. In laboratory experiments, increasing liming rates increased the time before hydrolysis started and decreased the rate of hydrolysis. At 8 kg calcium oxide/t manure, little or no hydrolysis occurred in a 24 h period. Analysis of the data revealed that the effect of lime on organic N hydrolysis appeared to be one of altering the pH. At pH's greater than 10, no hydrolysis occurred, independent of temperature. In barn experiments, hydrated lime was applied at various rates in two experiments to a feed alley and a rest alley that were scraped once daily and that housed 30 to 37 yearling heifers. Low levels of lime increased manurial N losses over the unlimed treatments whereas if the final manure pH were above 9, urea and total N levels increased proportionally with pH. At final pH's of 9.6 to 9.8, there was no appreciable loss of total N or urea.