Abstract

CABEZAS, Marco  and  CORCHUELO, Germán. Estimating yellow potato (Solanum phureja Juz. et Buk.) solar radiation interception in three Colombian localities. Agron. colomb. [online]. 2005, vol.23, n.1, pp.62-73. ISSN 0120-9965.

Three experiments were simultaneously carried out in three Colombian localities (Firavitoba, Carmen de Carupa y Bogotá) to measure and compare photosynthetically active radiation (PAR) interception patterns in Solanum phureja. Three random complete block design planting densities (8,33, 4.17 and 2.67 plants/m²) were evaluated, having four replicates and an experimental unit consisting of five four-metre-long rows or planting lines. Overall PAR, reflected PAR, transmitted PAR and absorbed PAR were determined. The Monsie and Saeky model was used for establishing the PAR k extinction coefficient in canopies. Results revealed statistically significant differences within localities and plant densities, but not for LAI interaction. There was a higher overall incidence of radiation in those localities situated at high altitudes. PAR distribution was similar in high and low stratum in all cases, proving that plant architecture allows a suitable distribution of PAR within the canopy. The k extinction coefficient was mainly affected by leaf development. Values ranged from 0.39 to 0.61. It was revealed that plants may become quickly saturated above 2,800 m a.s.l. due to effects of luminescence, thus inducing stressful conditions interfering with leaf development and therefore distribution of tuber photo-assimilation, so affecting agronomic yield

Keywords : Photosinthesys; extintion; plant-density; canopy.

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