Maize-N Version & Updates Status

Beta Version 2009.1

• Released on Aug 18, 2009 .
• Currently available for download by collaborators of MaizeN development.
• Updates include:
  • N mineralization for tropical soil. The user no longer needs to adjust the reference temperature to reasonably simulate uptake from indigenous N supply.
  • Updates were made in the response of fertilizer N recovery efficiency (RE) to the timing of N application and doses of in-season applications. In general greater fraction of in-season applications and greater number of in-season doses results in an increase in RE.
    

Prototype Version 2009.2

• Released on April 6, 2009.
• The version was distributed during the MaizeN collaborators meeting in April at University of Nebraska-Lincoln.
• Updates include:
  • Correction in the relationship between time of N application and the fertilzier N recovery efficiency (RE)
  • Yield-based approach in simulation of EONR
    • Yield without nitrogen was calculated based on the indigenous N uptake (IN) and recovery efficiency for indigenous N. IN was simulated mechanistically using the C & N mineralization component (DK model).
    • Various efficiency terms were estimated semi-mechanistically using the generic QUEFTS relationships and empirical data from Maize Global Database.
    • Such a change from the uptake to yield-based approach significantly improved the accuracy of the model in predicting economically optimum N rates (EONR).

Prototype Version 2009.1

• Released on May 30, 2008.
• The first prototype version of MaizeN.
• Features:
  • Uptake-based approach in simulation of EONR.
  • Indigenous N uptake was simulated mechanistically using the C & N mineralization component (DK model).
  • Efficiency terms were held constant or estimated empirically.
  • This version did not simulate economically optimum N rates (EONR) with a reasonable accuracy.