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Use of Leaf Area Index and Ground Cover to Estimate Intercepted Radiation in Potato

Antonio de la Casa1*, Gustavo Ovando1, Luciano Bressanini1, Ángel Rodríguez1 y Jorge Martínez1

Since there is no information in the green belt of Córdoba, Argentine, about the use of instruments to measure leaf area index (IAF) through light interception in potato crop (Solanum tuberosum L.), a study was developed with the objectives of: i) evaluating the employment and capacity of an optic instrument to determine IAF in a potato crop; ii) verifying IAF and ground cover (%C) using alternative measurements of crop canopy development to estimate intercepted radiation (fAPAR). The measurements were carried out during 2005 (from February 4 to June 1), in a plantation density experiment near Córdoba (31º30' S lat, 64º08' W long, 402 m.a.s.l.), with three treatments, in pl m-2: 6.0 ± 0.6 (TDC); 3.9 ± 0.2 (TDB) and 7.9 ± 0.7 (TDA). IAF was estimated by means of an optic instrument (ceptometer) and ground cover (%C) through digital pictures. The IAF values measured with the ceptometer were compared with photogrametric determinations obtaining an acceptable correlation (R2 = 0.80; P < 0.01). The relationship between IAF and fAPAR remained uniform, in the sense of comparing plantation densities, likewise during different moments of the cycle. Until the crop reaches maximum covering, the relationship between %C and fAPAR was linear, with a highly significant (R2 = 0.93; P < 0.01) coefficient of adjustment, although it shifts slightly away from a 1:1 relationship.

Key words: potato, plant density, ground cover, intercepted radiation, Solanum tuberosum L.

1 Universidad Nacional de Córdoba, Facultad de Ciencias Agropecuarias, CC 509-Ciudad Universitaria, 5000 Córdoba, Argentina. E-mail: delacasa@agro.uncor.edu * Corresponding author.

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