Biomass growth fertilizer requirements

The problem with this fixed nitrogen is that its use as a fertilizer requires land application. While some of the nitrogen is retained by the plants, much is carried off the land as stormwater runoff This increases the concentration of DIN in groundwater and river-water. Drainage of these waters into the coastal ocean supplies nutrients that stimulate plankton growth. Remineralization of the plankton biomass can lead to development of hypoxic and anoxic conditions in coastal waters. 

For cases where irrigation will not be used, application of fertilizer will occur once per rotation. This is envisioned to occur after harvest when the site will be most easily accessible. This design predicts the fertilizer requirement for only that portion of the plantation being harvested in a given year. Fertilizer requirements are first estimated based upon biomass growth only and then... 

Second, the model does not predict the growth response to fertilization above levels required to compensate for nutrients removed in the harvested material. The parameters for wood and leaf growth are currently put into the nutrient balance model from the growth model as independent parameters. Growth is only indirectly related to the nutrient balance through the use of land class productivity data in the growth model for the prediction of biomass production. Any fertilization necessary to raise the fertility of the site to a level required to sustain a desired amount of productivity would be included in the transition period costs. The necessary detailed data required to estimate optimum fertilizer schemes are not presently available. 

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