Ammonia emissions from chopped willow versus pine shavings as bedding for broiler chickens

Studies show that amendments to poultry litter reduce ammonia emissions by reducing pH and moisture content. However these amendments require multiple applications to be successful. Salix (willow) naturally contains salicylic acid which has the potential to maintain a low pH thereby yielding low ammonia. The goal of this study was to compare chopped willow with pine shavings as bedding for broiler chickens during two trials comprising 42 day grow out periods. Day old chicks were placed (533 cm² bird^-1) in six pens each prepared with 16 kg of pine shavings and six pens each prepared with 23 kg of chopped willow. Litter moisture, pH and ammonia emissions were measured, the latter using a flux chamber technique. The first trial exhibited a decrease in average ammonia emission rates by 47% and 41% in weeks two and four, respectively. However these results showed no statistically significant difference. Moisture content for willow was 1.6% compared to 13.6% for pine during week two for the first trial. No significant moisture or pH effects occurred during the fourth or sixth weeks of the first trial. High variability indicated a need for a second trial that again yielded no significant differences among bedding treatments. Moisture content and pH comparisons left no indication of a mechanism for willow to reduce ammonia emissions. Neither trial confirmed any reduction of ammonia emissions from willow litter when compared to pine litter. High variability in ammonia emission from the litter surface suggests a need for a more comprehensive measurement technique to validate the ammonia emissions from willow litter.