Halophyte-Fodder Species Association May Improve Nutrient Availability And Biomass Production Of The Sabkha Ecosystem
Published 2010 · Environmental Science
Sabkhas are often regarded as marginal non productive areas. Yet, a wide range of halophytes together with less salt-tolerant fodder species thrive in these ecosystems. In the present study, the potential of halophytes in improving biomass production and nutrient uptake ofan un-grazed parcel edging an inland sabkha (100 km south-east of Tunis) was addressed. The vegetation of studied area was characterised by perennial halophytes tufts in association with fodder annuals, mainly Medicago species. Halophytes grew slowly and accumulated low contents of mineral nutrients (N, Pi, K+) and high Na+ concentrations in their shoots. Depending on the precipitation, the annual fodder species showed high growth activity (up to 40% of the plant annual biomass production of the ecosystem), which was sustained by a high capacity of nutrient uptake (up to 70% of the total nutrient uptake). The annuals were almost exclusively clustered under the halophyte tufts, or at their immediate vicinity, where soil N and Pi levels were significantly higher, and salinity significantly lower than between the tufts. The perennial halophytes provided optimal conditions for the growth of these annual Leguminosae, which valorised the nutrients accumulated around the halophytes, owing to their high growth rate, nutrient-absorption rate and use-efficiency. These data are of high ecological significance and suggest that the salt tolerant-fodder species association may constitute a low-cost and valuable approach for the restoration and reclamation of the marginal saline ecosystems.