Strip Intercropping Promotes Nutrient-Snatching By Deep Roots

Summary

The potential of intercropping systems for acquisition of deep-placed nutrients is still not well-known. We examined root growth and nutrient uptake potential of a strip intercropping system with a deep-rooted perennial and a shallow-rooted annual crop species. We compared root growth of sole-cropped winter rye (Rye), rye “intercropped” with an adjacent lucerne strip (Rye|Luc), and sole-cropped lucerne (Luc). Tracer uptake of the crops were measured, including tracer uptake of lucerne grown adjacent to winter rye (Luc-Rye) was determined to reveal the possibility of nutrient-snatching. Our results showed that roots recovered from below the rye in the Rye|Luc intercropping contained roots from both crop species and did not reduce overall root growth. Nutrient uptake potential by Rye|Luc was equivalent to rye as a sole crop, meaning that no competition were observed. Lucerne grown adjacent to labelled rye (Luc-Rye) was able to reach the nutrient source under winter rye by its deep roots. We conclude that strip intercropping shall consider the contrasting root systems of cropping components in order to maximize the resource use efficiency from deep-soil layers.