Potato (Solanum tuberosum L.) and Bean (Phaseolus vulgaris L.) in Sole Intercropping: Effects on Light Interception and Radiation Use Efficiency

An investigation was carried out during three crop growing seasons (2005; 2006 and 2007) at the Technical Center of Potato (CTP) situated in the low valley of Medjerda river at Saida (Tunisia) to find out how potato and bean can grow and develop in an intercropping system rather than in sole cropping. Crop productivity of potato and bean intercropping systems was evaluated in terms of total dry matter production. The light interception and radiation use efficiency by this system were calculated in sole cropping and intercropping. Results showed that the total dry matter production (TDM) by potato in sole intercropping was higher than in sole cropping. This increase occurred during the three experiments from 3.60 to 4.75% compared to the potato in sole cropping. However, for bean in sole intercropping the TDM was significantly lower (P < 0.05) than in sole cropping. This decrease had varied from 48.9 to 63.1%. Intercropping potato with bean had actually reduced the radiation interception by both crops. This reduction was in the three experiments (2005; 2006 and 2007), respectively equal to (20.9; 9.4 and 4.8%) for potato and equivalent to (50.4; 58.7 and 44.8%) for bean. Radiation Use Efficiency for potato in sole intercropping has improved from 7.7 to 23.6%.