1Central Potato Research Institute Campus, Modipuram-250110, UP, India.
2Central Potato Research Institute, Shimla-171001, HP, India.
*Present address: Project Directorate of Cropping System Research, Modipuram-250 110, UP, India.
In order to optimize tuber yield in organic potato production systems, knowledge of crop growth in relation to N limitation is necessary. The SPAD Chlorophyll meter reading appears promising for rapid, on farm analysis of crop nitrogen status. Chlorophyll meter readings (using a Minolta SPAD-502 chlorophyll meter) and leaf N content were recorded during the growing season (from 28 to 70 DAS at 10–12 days interval) in existing experiments to assess the N status of potato crop. Highly significant linear and quadratic trends were obtained for the regression of leaf N content (R2 = 0.59 to 0.83) and tuber yields (R2 = 0.43 to 0.65) and chlorophyll meter readings. SPAD readings decreased as plants aged.
