Productividad primaria y aprovechamiento ovino de "atriplex nummularia", arbusto forrajero introducido en el S.E. español.

Abstract

The cultivation of saltbushes (Atriplex sp.pl.) as protein-rich supplementary feed for periods of nutritional stress (summer, fall, drought, montane winters, etc) is being studied in S.E. Spain. Atriplex nummularia, native of Australia, because its production and persistance, it has been selected as the more promissing saltbush for future cultivation. The primary production of Oldman saltbush was measured in two years oíd shrubs and the results were: a) its total aerial biomass. Was 6,6 Kg of dry matter, of which a 40% was browsing biomass (2,6 KgDM) and the rest was woody material; b) a 70% of its browsing biomass was under 1,2 meters, the height up to which sheep reach browsing; c) a 57% of its dry browsing biomass was made up of leaves and the rest of fine steams ñor yet lignified. When browsed by local race Segureña sheeps, they consumed 99% of its browsing biomass and compared with other saltbushes, A. repanda was consumed fáster than A. nummularia but others like A. halimus and A. canescens were less palatable than oldman saltbush. Under controled grazing triáis in oldman saltbush plantations were the browsing biomass available was estimated between 1,2-1,4 Tm DM/ha the number of sheep grazing days per ha were between 900-1.400, a result equivalent to a stocking rate of 3 sheep/ha, a value well over the average 0,5 sheep/ha of native rangelands in south-east Spain.