Nitrogen cycling on intensively managed boreal dairy pastures

Summary

The aim of this study was to measure the main N processes and losses of the N cycle in boreal dairy pasture systems. The experiments were mostly conducted on 'lysimeter field' at MTT Agrifood Research, Maaninka. Pasture N utilization is ineffective compared to silage cutting especially when high amounts of concentrates or protein supplementation is used. Transformations and immobilisation/mineralization turnover of N are high due to short term ley conditions. When the management changes almost yearly, the soil N is in constant state of change and equilibrium is never achieved. Nitrogen is accumulated in soil during grass cover years and mineralized during the renewal year. Thus, N fertilization for newly sown sward and cover crop after pasture renewal is not needed. In winter microbial activity in soil slows down, but still continues even in temperatures below zero. Freezing prevents most water movement in soil and nitrate therefore accumulates.