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Abstract
A rapid sap nitrate test for field use was evaluated for kiwi fruit. Good relationships were found between petiole sap nitrate concentration (SN) and total leaf nitrogen concentration (TN) in all trials, and between both SN and TN and shoot extension in young plants. Desirable values for optimum shoot growth were >800 ppm SN and >3.0% TN. Both SN and TN had a significant effect on fruit size, with small fruit being associated with low N levels. Desirable values for minimum percentage of undersize fruit were >2.9% TN and >400 ppm SN, sampled in December. There was a close relationship between SN (but not TN) at harvest and rate of fruit softening in all trials, with high SN levels associated with earlier softening. The desirable value for maximum fruit storage life was zero ppm SN at harvest.