AMMONIA EMISSION FROM A DOUBLE-SLOPED SOLID FLOOR IN A CUBICLE HOUSE FOR DAIRY-COWS

Two methods to reduce the ammonia emission from double-sloped solid fl oors, with a gutter at the bottom of the flat ''v'' and baffles dippin g into the slurry, in cow houses were investigated. The effect of two extra urine gutters in the sloping floor parts and the effect of spray ing water, at a rate of 6 l/d per cow after scraping with a frequency of 12 times per day, were studied. The experiment was performed over 1 9 weeks in two compartments of an experimental mechanically ventilated cow house, each housing ten non-lactating cows. In one compartment, a double-sloped solid floor with underfloor slurry pit and floor openin gs, to dump manure collected by a scraper, was constructed. A central urine gutter was permanently in use. Underfloor air flow was prevented by a high slurry level and vertical baffles dipping into the slurry; these also reduced air exchange between pit and house. The other compa rtment served as a reference and had a traditionally slatted floor, al so with underfloor slurry pit. Ammonia emissions from both compartment s were recorded continuously. Ammonia emission from the compartment wi th the double-sloped solid floor operating with one urine gutter and w ithout spraying water was, on average, reduced by 50% compared with th e reference compartment. Emission was further reduced, on average, by 65% compared with the reference compartment when water was sprayed. Th e use of three instead of one urine gutter had no significant effect o n the emission, despite the fact that the mean surface area covered by a single urination was reduced from 1.15 to 0.90m(2). It was conclude d that a further reduction of the distance between the urine gutters w ould not be expected to influence ammonia emission, since the mean sur face area covered by a urination was already close to the minimum of 0 .8 m(2) for slatted floors. (C) 1997 Silsoe Research Institute.