Transplanting shrubs for revegetation of salt-affected soils

Abstract

Vegetation (secondary) succession is extremely slow on soils contaminated with soluble salts by petroleum exploration activities in arid and semiarid areas. Excessive salt accumulations interfere with seed germination and seedling establishment of most species used for revegetation. Establishment and growth of transplanted fourwing saltbush ( Atriplex canescens) seedlings and rooted stem cuttings, and seedlings of oldman saltbush ( Atriplex nummularia), winterfat ( Ceratoides lanata), and prostrate kochia ( Kochia prostrata) were evaluated on three saline-sodic (EC (electrical conductivity) = 23 − 93 dS m -1, ESP (exchangeable sodium percentage) = 13−46%) oil well reserve pits over a three-year period. Survival of fourwing saltbush seedlings from an accession not adapted to saline soils was only 32%, compared with ⩾ 73% for seedlings or stem cuttings from an accession adapted to saline soil. Oldman saltbush suffered 100% mortality subsequent to subfreezing temperatures during the first winter following planting. Survival of winterfat and prostrate kochia transplants was 61 and 48%, respectively, after three years, and growth of these species was acceptable on the saline-sodic soils. Selection or specific accessions of species adapted to the existing conditions of the site to be revegetated appeared most promising for revegetation under extremely harsh environmental conditions.