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The University of the Philippines (UP) is the country’s national university. This premier institution of higher learning was established in 1908 and is now a university system composed of eight constituent universities and one autonomous college spread throughout 17 campuses in the archipelago.



Application of rapid nitrate test in papaya (Carica papaya L.)  [1994]

Tantung, R.L.; Philippines Univ., Los Banos, College, Laguna (Philippines) [Corporate Author]

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There were big differences in nitrate concentration with leaf positions. The recently matured leaves exhibited the highest nitrate concentration which was observed at 0930 hours. Sap nitrate was responsive to changing external N levels indicating the sensitivity of the test. Petiole NO3-N concentration was also affected by plant age. It was highest at vegetative stage and lowest at reproductive stage. Petiole sap nitrate as determined by quick test and dry tissue nitrate was found to be highly correlated (R=0.80) indicating that sap test provided a reasonably precise measure of monitoring the current nitrate concentration. Using regression equation, the critical sap NO3-N value was 350ppm, tissue NO3-N was 2518 ppm and total N was 1.3 percent