Encouraged by recent European Union recommendations to lower nitrate content of vegetables, the present paper reviews research aimed at reducing nitrate levels in endive (Chicorium endivia L, var. crispum Hegi) through cultural methods. Endive plants were grown under controlled conditions at two N levels (8 and 16 mM), five N form ratios (NH(4)(+):NO(3)(-) = 100:0; 70:30; 50:50; 30:70; 0:100), and in nutrient solutions from which N was withdrawn one week prior to harvest. Endive grown with 8 mM of N yielded better (+22 %) and contained less nitrate (-39 %) as compared withthat grown with 16mM N. Endive also grew well with high ammonium percentages in the nutrient solution, which sharply decreased nitrates in leaves. By the elimination of 90 % of N from the solution in the last week before harvest, nitrates were reduced by 42 %. Supplying N in mixed form, NO(3)(-) concentration of endive leaves decreased linearly during the light period. Temperature of nutrient solution and molybdenum concentration in the nutrient solution had no effect on nitrate accumulation.
Growing nitrate free endive head in soilless systems.
ELIA, ANTONIO;
1999-01-01
Abstract
Encouraged by recent European Union recommendations to lower nitrate content of vegetables, the present paper reviews research aimed at reducing nitrate levels in endive (Chicorium endivia L, var. crispum Hegi) through cultural methods. Endive plants were grown under controlled conditions at two N levels (8 and 16 mM), five N form ratios (NH(4)(+):NO(3)(-) = 100:0; 70:30; 50:50; 30:70; 0:100), and in nutrient solutions from which N was withdrawn one week prior to harvest. Endive grown with 8 mM of N yielded better (+22 %) and contained less nitrate (-39 %) as compared withthat grown with 16mM N. Endive also grew well with high ammonium percentages in the nutrient solution, which sharply decreased nitrates in leaves. By the elimination of 90 % of N from the solution in the last week before harvest, nitrates were reduced by 42 %. Supplying N in mixed form, NO(3)(-) concentration of endive leaves decreased linearly during the light period. Temperature of nutrient solution and molybdenum concentration in the nutrient solution had no effect on nitrate accumulation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
