Resumo

CARRANZA, Carlos; LANCHERO, Octavio; MIRANDA, Diego  e  CHAVES, Bernardo. Growth analysis of 'Batavia' lettuce (Lactuca sativa L.) cultivated in a saline soil of the Bogota Plateau  . Agron. colomb. [online]. 2009, vol.27, n.1, pp.41-48. ISSN 0120-9965.

Salinity is a worldwide restriction to horticultural crops, causing growth alterations, low absorption and distribution of nutrients to different organs of the plant, and quality changes. Detailed growth analyses of horticultural species such as lettuce had not been carried out yet for crops established in saline soils in the Bogota Plateau. The present experiment took place in Marengo Agricultural Center, which belongs to Universidad Nacional de Colombia, and is located 12 km from Bogota, on the way to Mosquera. Three plots of 300 m² each, allowing 8.3 plants/m², were treated with water from 'La Ramada' Irrigation District, and sampled every week for leaf area and dry weight measurements. Growth parameters were estimated with the logistic model and an equation fitted by means of a SAS software package. Using the functional approach, a series of growth indexes were derived: Relative Growth Rate (RGR), Leaf Area Index (LAI), Net Assimilation Rate (NAR), Crop Growth Rate (CGR), Specific Leaf Area (SLA), and Leaf Area Ratio (LAR). RGR was highest (0.1164 g g^-1 day^-1) 10 days after planting (dap). Likewise, maximum values were reached by LAI (6.78) 61 dap; NAR (0.00046 g cm^-2day^-1) 24 dap; CGR (0.0007 g cm^-2day^-1) 35 dap; SLA (497.55 cm² g^-1) at transplanting, and LAR (483.38 cm² g^-1) at transplanting as well. Soil salinity at Marengo farm was observed to cause reduction in lettuce growth parameters.

Palavras-chave : growth parameters; logistic model; growth rate; salinity.

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