Impact of water stress on the fodder value of Atriplex halimus L

Abstract

In Morocco, biomass productivity of Atriplex nummularia has previously been studied, but information on the impact of water stress on native saltbushes Atriplex halimus is lacking. The present study was conducted to assess the impact of water stress on morphological parameters, chemical composition and in vitro organic matter digestibility (IVOMD) of three Tunisian clones of Atriplex halimus (G1, G2, and G3) and two Moroccan ecotypes of the same species (G4 and G5). The experiment was conducted under greenhouse conditions. Container‐grown plants were subjected to two levels of water stress: low level T75 (75% moisture at field capacity) compared to high level T50 (50% moisture at field capacity). The T100 control (maintained at 100% moisture at field capacity) of each clone or ecotype was used to compare the effect of water stress on the studied parameters. Because the results obtained in the case of the low water stress (T75) were highly similar to those of the control, this treatment was later omitted. The results showed that biomass dry matter (BDM) production was significantly reduced in G4, G1, and G5 when water was limited in the T50 treatment. Nitrogen content was higher (8%) in G4 and G2. The BDM reduction induced by water stress was 26% compared to the control. Ash and crude fibre contents increased significantly on a dry matter basis (P < 0.05) under water stress (T50). Hemi‐cellulose, a significant parameter that expresses well the genotype under water stress conditions, increased by 62%. Dry matter digestibility was reduced by water stress except for the G2 genotype. On the basis of these results, the G4 ecotype and G1 clone can be proposed for range improvement because of their high nutritive value under water stress conditions.