Effect of cultivar on measurements of nitrate concentration in petiole sap and leaf N content in greenhouse soil-grown cucumber, melon, and sweet pepper crops

• Published in: Scientia horticulturae Vol. 320; p. 112200
• Main Authors: Rodríguez, Alejandra, Peña-Fleitas, M. Teresa, Padilla, Francisco M., Gallardo, Marisa, Thompson, Rodney B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023
• Subjects: Analysis; Capsicum annuum L; cucumbers; Cucumis melo L; Cucumis sativus L; cultivars; environmental impact; fertigation; greenhouses; melons; microirrigation; N fertilizer management; nitrates; nitrogen content; nitrogen fertilizers; pepper; petioles; sap; soil; Sufficiency values; sweet peppers; Vegetable crops; vegetable growing; Sufficiency values; Analysis; N fertilizer management; Vegetable crops; Cucumis melo L; Capsicum annuum L; Cucumis sativus L
• ISSN: 0304-4238
• DOI: 10.1016/j.scienta.2023.112200

•Effect of cultivar on petiole sap [NO3−] and leaf N content examined in cucumber, melon and pepper.•Appreciable and consistent differences in sap [NO3−] between cultivars in cucumber and melon.•Smaller consistent differences in leaf N between cultivars in cucumber and melon.•Consistent differences between cultivars not observed in pepper.•Strong relationship between leaf N and on petiole sap [NO3−] in the three species. Excessive N fertilizer applications in intensive vegetable production in soil is commonly associated with appreciable N losses causing negative environmental impact. Measuring petiole sap [NO3−‒N] and leaf N content (%) are simple and practical monitoring methods to assess crop N status for improving N fertilizer management. The effect of cultivar on petiole sap [NO3−‒N] and leaf N content was evaluated. One cucumber, two melon, and two sweet pepper crops were grown in different cropping periods, with three cultivars in each crop. Three N treatments, deficient (N1), sufficient (N2) and excessive (N3) N supply, were applied by combined fertigation with drip irrigation. For a given N supply, there were often significant differences between cultivars in petiole sap [NO3−‒N] and leaf N content in cucumber, the two melon crops and one pepper crop. This was, particularly so with the sufficient (N2) and excessive (N3) N supply. In the cucumber and two melon crops, there were consistent differences in petiole sap [NO3−‒N] between cultivars in two or three of the different N treatments. In some crops, very little petiole sap [NO3−‒N] was measured with deficient (N1) N supply. In the two pepper crops, the differences between cultivars were less clear than with cucumber and melon. In general, for the three species examined, petiole sap [NO3−‒N] was subject to more consistent and larger effects between cultivars, than was leaf N. Average differences between cultivars in petiole sap [NO3−‒N] of 200‒450 mg NO3−‒N L−1 were observed during periods of 4‒6 weeks in cucumber and melon. The differences between different cultivars of the same species in petiole sap [NO3−‒N] and leaf N content, when receiving the same N supply, has implications for the practical applications of these methods for monitoring crop N status.