title: Water addition, evaporation and water holding capacity of poultry litter.
abstract: Litter moisture content has been related to ammonia, dust and odour emissions as well as bird health and welfare. Improved understanding of the water holding properties of poultry litter as well as water additions to litter and evaporation from litter will contribute to improved litter moisture management during the meat chicken grow-out. The purpose of this paper is to demonstrate how management and environmental conditions over the course of a grow-out affect the volume of water A) applied to litter, B) able to be stored in litter, and C) evaporated from litter on a daily basis. The same unit of measurement has been used to enable direct comparison-litres of water per square metre of poultry shed floor area, L/m(2), assuming a litter depth of 5cm. An equation was developed to estimate the amount of water added to litter from bird excretion and drinking spillage, which are sources of regular water application to the litter. Using this equation showed that water applied to litter from these sources changes over the course of a grow-out, and can be as much as 3.2L/m(2)/day. Over a 56day grow-out, the total quantity of water added to the litter was estimated to be 104L/m(2). Litter porosity, water holding capacity and water evaporation rates from litter were measured experimentally. Litter porosity decreased and water holding capacity increased over the course of a grow-out due to manure addition. Water evaporation rates at 25°C and 50% relative humidity ranged from 0.5 to 10L/m(2)/day. Evaporation rates increased with litter moisture content and air speed. Maintaining dry litter at the peak of a grow-out is likely to be challenging because evaporation rates from dry litter may be insufficient to remove the quantity of water added to the litter on a daily basis.
authors.affiliation: Department of Agriculture and Fisheries, QLD Government, Toowoomba 4350, Australia; University of NSW, School of Civil and Environmental Engineering, Sydney 2052, Australia; Poultry CRC, PO Box U242, University of New England, Armidale, NSW 2351, Australia. Electronic address: mark.dunlop@daf.qld.gov.au.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Dunlop
authors.affiliation: Poultry CRC, PO Box U242, University of New England, Armidale, NSW 2351, Australia; The University of Queensland, QLD Alliance for Agriculture and Food Innovation, Dutton Park, Brisbane 4102, Australia.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Blackall
authors.affiliation: University of NSW, School of Civil and Environmental Engineering, Sydney 2052, Australia.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Stuetz
mesh_terms: D000818:Animals; D004784:Environmental Monitoring; D006799:Housing, Animal; D011200:Poultry; D058438:Water Cycle; D014881:Water Supply / Q000706:statistics & numerical data*
keywords: Broiler; Litter moisture content; Wet litter