Vertical distribution of the root system of linseed (Linum usitatissimum L.) and legumes in pure and mixed sowing

Root competition for below-ground resources between edible plants may provide for long-term sustainability of agriculture systems. Intercropping can be more productive than a pure crop due to taking advantage of the morphological differences between species. In pure cropping, all biophysical interactions between plants occur through soil conditions. In intercropping, competition for water and nutrients is of major importance, but if the roots of one species occupy the zone just underneath the roots of the other crop, they can better use the resources of the root zone of the crop. The root system demonstrates a high degree of plasticity in its development in response to local heterogeneity of the soil profile and plant density. This study aimed at determining: (i) the morphological characteristics of the root systems of linseed, pea and vetch depending on the method of sowing; (ii) the root distribution in various soil types and at different soil profile depths (0–15 cm, 15–30 cm). Two three-year field experiments were conducted on two soil types in south Poland: soil A – Luvic Phaeozem (s1) and soil B – Eutric Cambisol (s2). These results show that linseed was more aggressive toward both legumes in mixture, but it produced lower yield compared to pure cropping. The environmental stress of plants in mixtures increased the relative weight of roots, which resulted in decreasing the root-shoot ratio (RSR)