intensive salmon farming generates organic residues which have a potential use in agricultural soils. the objective of this study was to evaluate the effect of three salmon sludge rates on potato (solanum tuberosum) crop development and its residual effect on annual ryegrass (lolium multiflorum). the field experiment was carried out on an andisoil from osorno serie (hapludands), located in osorno (40o35？s, 73o08？w), chile. treatment were three salmon sludge rates (50, 100, 200 t ha-1), a control (no fertilizer), and an inorganic fertilizer treatment. the salmon sludge was incorporated into the soil and then potato tubers cv. yagana-inia were planted. after the harvest, an annual ryegrass was seeded. total potato yield with inorganic fertilizer was 64.3 t ha-1, significantly superior to the results with the salmon sludge rates and the control (p ≤ 0.05). there were no differences (p > 0.05) among the fish sludge rates (45.6 to 47.5 t ha-1) and the control treatment (39.4 t ha-1). in addition, there were no differences (p > 0.05) on tuber weight, but the number of tubers per plant was different (p ≤ 0.05). annual ryegrass yield was significantly different (p ≤ 0.05) between fertilizer treatments and the control. salmon sludge did not affect potato or ryegrass yield or development and increased p olsen and cation exchange capacity in the soil.