Soil Nitrocxn and Pasture Management

The. seasonal pattern of nitrogen mineralization is described and compared with the potential demand for nitrogen by grasses. Peak mineralization rates occur in spring but are quite inadequate for expression of potential grass growth. Nitrogen fixation by clovers provides a significant input into the system over a short period. Consideration of the fate of fixed nitrogen shows that losses largely o&et this input unless it is maintained at a high level. The role of pasture management and fertilizer practice in this maintenance is stressed. Seasonal differences in nitrogen transformations and their influences on nitrogen losses are discussed.