Management of rice production systems to increase productivity

Necessary inputs for the nitrogen module consist of intended crop, crop yield,
plant N content, and, if you use organic inputs, the amount of manure or
residues that you apply. Depending on the location and crop, some other
necessary inputs can be accessed from the database. However, the precision
of the N recommendation improves dramatically with more information
supplied (Osmond et al., 2002).
The Nitrogen module is primarily designed to help you determine
appropriate N fertilizer rates after accounting for any organic applications.
NDSS depends on an extensive database of crop yields, soil N, HI etc, and can
be supplemented with local information. For each cropping and soil system
option you select, NuMaSS helps analyze projected costs and returns on
investment.
Diagnosis: N is almost always deficient in tropical soils unless a legume
is being grown or the crop is preceded by a fallow or green manure system.
Therefore, diagnosis of N deficiencies almost always produces the need to add
N.
Prediction: Unlike most other nutrients, there are few reliable soil tests
to determine crop N needs. This is particularly true in humid regions where
N can be readily transformed and moved below the rooting zone. Generally
N fertilizer recommendations are based on extensive data sets developed over
many years.
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