Phosphorus Retention Materials In Outdoor Laying Hen Paddocks For Reduced Environmental Impact And Increased Nutrient Use Efficiency

This study investigated phosphorus (P) retention materials of sand and limestone outside houses in paddocks for organic laying hens, as a measure to retain P and reduce leaching. When manure P, accumulated in the materials during 6 months, was exposed to rain simulations in a lysimeter study, P concentrations in drainage water were high from all treatments (58-136 and 130-197 mg L-1 of PO4-P and total-P respectively). On average, 14% of the manure P, captured in the materials was leached after 100 mm of simulated rainfall. The conclusion is that these materials may efficiently retain P during the outdoor season (May to October), but in order to reduce the risk of losses to waters during the following winter they need to be removed from the paddocks, preferably to arable fields. The materials can be regarded as potential P fertilizers and may thereby combine increased P use efficiency and environmental performance of organic outdoor poultry systems

Phosphorus Retention Materials In Outdoor Paddocks And Distribution Of Laying Hens During The Grazing Period

This study compared the P retention materials sand and limestone with gravel in a randomized block design with three replicates to evaluate the effect on hens’ distribution in the paddock between 1 May and 31 October. Each flock included 76 animals having access to a paddock (3.4 x 19.9 m), where material (3.4 x 3.0 x 0.2 m) was placed outside the pop-hole. The average amounts of hens’ outdoors were documented at 9 am and 3 pm each day. There was no significant difference between the materials concerning hens’ distribution and they seemed to be equally comfortable. Instead weather conditions influenced hen distribution. The sub-area with material close to the house was more frequently used by hens during the hot and dry summer. The hen’s choice was promoted by a roof above the pop-hole giving shade. With lower temperatures and rain showers later the hens’ distribution pattern changed significantly (P<0.001) and they were more evenly distributed over the paddock area during autumn