More than biofuel? Jatropha curcas root system symmetry and potential for soil erosion control

One of the reasons why Jatropha curcas has recently been hailed as one of the world’s most sustainable biofuel crops, is its suitability to grow on arid land where it offers the additional benefit of erosion control. As arid lands are often very vulnerable to land use changes, it is nevertheless important to fully understand (belowground) plant functional and structural development before they are planted at large scale. Here we introduce possible measurement methods for the root system structure of J. curcas seedlings and adult plants, formulate a set of hypotheses on root system structure, and demonstrate these in the light of root structure stability. Initially developing one taproot and four perpendicularly oriented laterals, the root structure of Jatropha appears to be quite promising to control soil erosion by water and wind on arid land. The lateral roots could decrease soil erodibility through additional soil cohesion, while the taproot and sinkers may enable exploitation of subsurface soil moisture and thus enhance vegetative cover, even in very dry environments.