GASEOUS LOSSES OF FERTILIZER - N FROM SPORTSTURF SOILS

Compaction of sportsturf soils can result in poor aeration and the creation of reducing conditions. At shallow depths oxidation and reduction may be favoured at adjacent locations. Experiments were carried out to investigate the fate of applied nitrate and urea fertilizers on a sportsfield under moist soil conditions. It was found that from 60% to 85% water-filled porespace there was a very substantial increase in the loss of NO₃-N through denitrification. It was shown using ¹⁵N labeled urea under soil moisture conditions similar to those experienced frequently during the soccer season that nitrification and denitrification can occur concurrently leading to the gaseous loss of N from ammonium-type fertilizers. The potential rate of denitrification is greater than nitrification so N losses under conditions that favour concurrent processes are likely to be controlled by nitrification rate.