A systems approach evolved from the product of sole crop land equivalent ratios (LER) yielded a non-linear and unified concept of land equivalent coefficient (LEC), which can also be expressed as a productivity coefficient (PC). Both the mixture LER, obtained by summation of sole crop LER, and the LEC, measure mixture productivity, while the latter, which also measures intercrop interaction, proved to be a superior index for the evaluation of mixture performance. The philosophy behind the LEC and the PC was satisfied from the geometric point of view and this showed that mixtures with stable potentials are superior to their components planted as sole crops on per unit area productivity. Mixture superiority also increases with increasing number of crop components. The formulation of this model and its advantages are discussed.
Ecological Modelling 05/1983; 19(1-19):27-39. DOI:10.1016/0304-3800(83)90068-6