Review of radiation interception and radiation use efficiency in intercropping in relation to the analysis of wheat/faba bean intercropping system

Growth and final total yields of crops and intercrops largely depends on the interception and the efficiency of use of growth resources namely water, nutrient and radiation. The literature indicates that provided water and nutrients are not limiting, growth and final yields of crops is mainly dependant on the amount of intercepted photosynthetically active radiation (PAR) and the efficiency of its use by the crops and/or the intercrops (i.e. Radiation use efficiency). However, PAR, which is a free natural resource, must be intercepted and utilized instantaneously, as it cannot be stored for later use. Empirical evidences abounds to indicate that it is possible to improve the interception of PAR by the crop through the manipulation of agronomic tools such as sowing date, seeding rate, fertilization, intercropping amongst others. Wheat (Triticum aestivum L.) plus faba bean (Vicia faba L.) intercropping system experiments are increasingly being carried out but only a few of these investigations studied PAR interception and RUE. This paper reviews PAR interception, RUE and associated variables with particular emphasises on the need to assess these variables in wheat/faba bean intercrop system.