Ammonia Emission for US Poultry Houses: Laying Hens

Abstract

Ammonia (NH3) emissions were monitored from ten commercial layer houses in Iowa (IA, six)and Pennsylvania (PA, four) for a full year, with two different housing and management schemes. Highriselayer houses (four in IA and two in PA) stored manure in the lower levels for a year, whereas manurebelt houses (two in each state) had the manure removed either daily (IA) or twice a week (PA). Dietarymanipulation consisting of two levels of crude protein (CP): standard CP (Ctrl) and essential amino acids(AA) supplemented lower CP (Trt), was evaluated with the four high-rise houses in IA, two houses pertype of diet. Ammonia and carbon dioxide (CO2) concentrations of exhaust air in each house weremeasured weekly or bi-weekly using portable monitoring units (PMUs), with each data collection episodelasting two consecutive days. Ammonia levels were measured using periodically purged electrochemicalsensors. Ventilation rates were determined by calibrated carbon dioxide mass balance method, based onthe latest metabolic rate data for the laying hens. There existed substantial diurnal variations in ammonia emission rate (ER) for the high-rise layer houses but less variation for the manure-belt houses. Incomparison, seasonal variations in ER were relatively small. Manure handling practices and dietmanipulation all demonstrated effects of various degrees on ammonia emissions rate. Specifically, NH3emission rates during 12-month monitoring period averaged 0.90 and 0.81 g/d-hen, respectively, for thehigh-rise layer houses with Ctrl and Trt diet in Iowa; 0.83 g/d-hen for the high-rise layer houses inPennsylvania; and 0.068 and 0.084 g/d-hen, respectively, for the belt houses in Iowa and Pennsylvania.The results contribute to the U.S. national inventory on ammonia emissions from animal productionoperations, and quantify the dynamics and magnitude of ammonia emissions from U.S. layer houses asaffected by housing type, manure management, diet manipulation and geographical location.