Resumen

HERNANDEZ, María; CHAILLOUX, Marisa  y  AROZARENA, N. J. Critical range of nitrogen and potassium in indicator leaves from the protected tomato (Solanum lycopersicum L.) crop HA-3019 hybrid for two planting seasons. cultrop [online]. 2009, vol.30, n.4, pp. 00-00. ISSN 1819-4087.

This study was carried out at Liliana Dimitrova Horticultural Research Institute, with the objective of proposing critical N and K ranges to protected tomato crop for its different growth and developing cycle stages. Four N/K ratios (1:1.5, 1:2.0, 1:2.5 y 1:3.0) were studied at two planting times, spring-summer (EPV) and winter (EI), on a compacted Red Ferralitic soil. Treatments started to differentiate after the third bunch setting (beginning phase III) and up to the end of planting. Yield per commercial quality category and percentage of N and K were determined in indicator leaves five times during cropping cycle, comprising a period from the beginning of phase III to the end of phase IV (full production). The best behavior regarding yield structure was obtained with N/K ratios 1:2.0 and 1:2.5 in EPV, whereas 1:2.5 for EI. Leaf N and K concentrations tend to decrease with crop age, independently of the treatments and seasons studied; a similar performance is recorded at the critical nutrient range (RCN). Concerning 90-100 % of top yield, a critical N range was calculated at the beginning of phase III of 4.71-4.90 % (EPV) and 5.09-5.20 % (EI), meanwhile at full production values were 2.56-2.84 % (EPV) and 3.24-3.22 % (EI). RCN for K in phase III ranged from 4.90 to 4.96 % (EPV) and 4.29-4.35 % (EI), while in full production they were from 3.34 to 3.47 % (EPV) and 3.69-3.96 % (EI).

Palabras clave : tomatoes; protected cultivation; nitrogen; potassium; leaves.

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