manures, most adjustments to the total nitrogen applied to cropping systems
come by refining the quantity, location, and time of year that producers apply
synthetic fertilizers containing nitrogen. Applications of synthetic fertilizers
containing nitrogen are `much easier to manage because the amount of nitrogen
known with accuracy. More important, when livestock or legumes are
an important part of the farm enterprise, nitrogen additions from these sources
are a fixed part of the nitrogen budget for the enterprise, and adjustments in the
total amount of nitrogen applied will
be made by adjusting the amounts
synthetic fertilizers containing nitrogen that producers apply. Legumes and
applications of manure may be used to improve soil quality in addition to their
value as sources of nitrogen. The single most important way to improve nitrogen
management, therefore, is to reduce (or eliminate) supplemental applications of
nitrogen to account for nitrogen supplied by legumes and manures.
Recommendations for application of synthetic fertilizers containing nitrogen can
also be improved by setting realistic yield goals. As a crops-yield increases, the
crop`s need for nitrogen increases, at least initially. The dilemma for producers is
that nitrogen must be applied before the crop yield is known. Nitrogen
recommendations, therefore, must be based on some expectation of crop yield.
For many crops, nitrogen requirements and recommendations are based on yield
goals (the yield expected by the producer under optimum growing conditions).
Supplying the nitrogen needed for crop growth during the period when it is most
needed can be an important way to improve nitrogen management. Nitrogen is
needed most during the period when the crop is actively growing. Thus, fertilizers
containing nitrogen should be applied during and/or after planting whenever
possible.
An increased emphasis on nutrient management relative to structural practices is
essentially an investment in implementing education, technical assistance, and
improved management. Implementing structural practices requires relatively less
information and expertise but does not address the fundamental issue of needing
to reduce system inputs.
To improve nutrient management, technical assistance is needed to establish
appropriate nutrient budgets and application rates, based upon manure and soil
testing. The goal is to have no excess nutrients lost into the ecosystem.
Although there are associated technical assistance costs, nutrient management
plans can be expected to provide cost savings to the landowner, which makes the
concept attractive and enhances the potential for voluntary adoption.
control efforts, we found that a systematic
In reviewing current
institutional framework that captures all aspects of nutrient management does not
currently exist in the basin, although the Cooperative Extension Service has
recently begun training field staff. To ensure its long-term success, the parties
involved in the trading program will need to determine how improved nutrient
management can be administered.
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