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This study examined the short-term response of rangeland to annual (1993/94 to 1996/97 seasons) application of fertilizer [all combinations of 0; 10; 30 and 50 kg ha(-1) nitrogen (N), with 0 and 10 kg ha(-1) of phosphorus (P)] in terms of aboveground phytomass production, crude protein content, seasonal rain-use efficiency (S-RUE), nutrient use efficiency, botanical composition, basal cover and soil compaction. After 4 years of fertilization, the botanical composition of the high N-fertilized plots changed from a climax to subclimax vegetation. Elionurus muticus showed the greatest decrease in frequency (62%) due to N fertilization. Phosphorus fertilization only, had an insignificant (p > 0.05) influence on species composition and basal cover over the 4 years. The production increased (p less than or equal to 0.01) with the application of N together with P, compared to applying only N (1074 vs. 823 kg ha(-1)). The more fertilizer applied, the more sensitive to drought the climax grasses became. Nitrogen and phosphorus fertilization significantly (p less than or equal to 0.01) affected S-RUE. The highest S-RUE of 6.64 kg phytomass ha(-1) mm(-1) and 0.23 kg crude protein ha(-1) mm(-1) were obtained with fertilizer application of 50 kg N plus 10 kg P ha(-1). On average over the 4 years, nutrient use efficiency with N + P application for all treatments was lower than without P. The increases in plant production per kg N applied, both with and without P were 28.00 and 29.81 kg respectively. Soil compaction increased with increase in N fertilization. These results confirm the vulnerability of native grasses in dry areas, following change in soil fertility. (C) 2002 Academic Press.