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Nutritional changes in petiole sap over space and time in a tomato crop greenhouse

Abstract:

The aims of this trial were to determine the spatial and temporal variability of the nutrients in petiole sap in a tomato crop under greenhouse and to determine the number of sub-samples for a representative sample. The experiment consisted of the selection of 20 sampling points. Petiole of fully expanded leaf was collected weekly in order to determine Cl, NO3-N, H2PO4-P, SO4-S, Na, K, Ca and Mg concentrations. Our results showed that variations of NO3-N, Na, Ca and K concentrations in sap were affected by the spatial distribution, whereas SO4-S and Mg concentrations in sap were affected by their temporal distribution. The spatial variability of our experiment could be related to radiation, yield and antagonism between nutrients, whereas the time variability could be related to the phenological stage of the plant and the antagonism between nutrients. The suggested number of petiole sub-sample ranging from 25 to 113 depending on nutrient.