Eficiencia en el uso de la radiación en papa estimada a partir de la cobertura del follaje

the radiation use efficiency (rue) of a crop is the relationship between dry matter produced and the intercepted photosynthetically active radiation (ipar) during the growth cycle. the ipar can be determined by applying beer’s traditional method, that uses leaf area index (lai), or taking ground cover (f) as a surrogate of ipar. when potato lai exceeds 3, the ipar values change very little, making it very difficult to detect differences due to variations in crop conditions. the aim of this study was to determine the rue in potato (solanum tuberosum l.) cv. spunta, comparing the use of lai and f values to obtain ipar. the trial was conducted in the green belt of cordoba, argentina, on a late season crop from february to may 2008. the use of f values overestimates rue, as a result of a systematic underestimation of ipar, but when ipar values where correctly taken according to the previously established relationship with f, rue was similar to that obtained through the reference method which presented a value of 2.90 g mj-1 par.