NITRATE SAP ANALYSIS AS A TOOL TO ASSESS NITROGEN NUTRITION IN ARTICHOKE
The aim of this work was to assess the use of quick nitrate sap analysis, performed by a hand-held reflectometer and a portable selective ion-meter, to improve nitrogen management in artichoke grown in commercial fields. Experiments were conducted at four locations, in LHorta de Valencia, and nitrogen treatments were different amounts of available mineral nitrogen in soil. Petiole sap nitrate concentration as measured with both rapid methods was highly correlated with a laboratory method (r = 0.91 for the selective ion meter, and r = 0.97 for the reflectometer). A decline on sap nitrate content throughout the growing cycle was observed with both rapid methods. Readings obtained with the selective ion meter were higher than those with the other methods. Nitrate levels in plant sap varied with soil mineral nitrogen supply and with time throughout the growing season. Midrib sap nitrate concentration measurement either by the Cardy Meter® or the Rqflex© is a quick and simple tool to assess artichoke nitrogen status, and it can contribute to an environmentally sound N fertilization in artichoke.
Rodrigo, M.C. and Ramos, C. (2007). NITRATE SAP ANALYSIS AS A TOOL TO ASSESS NITROGEN NUTRITION IN ARTICHOKE. Acta Hortic. 730, 251-256
Cynara cardunculus var. scolymus, petiole sap, hand-held reflectometer, plant nutrition, nitrogen, tissue analysis