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(Article of periodic en Français - 1983)

Document title

Phytomasse et production végétale en Tunisie présaharienne

Authors(s) and Affiliation(s)

FLORET C. ; LE FLOC'H E. ; PONTANIER R. ;

Abstract

Phytomass measurements were carried out within about thirty ecological systems (mainly steppe vegetation types) of the Presaharian zone of Tunisia. The mean above-ground phytomass of perennial species is between 500 and 700 kg dry matter/ha. About thirty species contribute to it. 90 % of this phytomass is constituted by chamaephytes and small phanerophytes. The belowground phytomass seems to be slightly inferior to the above-ground one. The fluctuations of above-ground phytomass were studied during several years. Depending on the system and the year, the production (without grazing) ranged from about zero to 2,250 kg dry matter/ha/year. This production is a function of the total annual rainfall, but chiefly of the seasonal distribution of rainfall: the variation in production changes from 1 to 3 for the same annual rainfall. The water use efficiency is between 2 and 5 g dry matter/kg HO that is lost due to evapotranspiration. Due to the low soil nutrient level, water is not the principal limiting factor in very wet years. The above-ground phytomass decreases greatly in summer. There is no accumulation of litter from one year to the following one.

Source

Article of periodic

published at : Acta oecologica. Série Oecologia plantarum Montreuil

Editor :

Millesime : 1983, vol. 4, no2 [pp. 133-152]

Bibliographic references : 39 réf.

Language

Français

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