RESUMO. A alfafaThe study aimed at evaluating the agronomic efficiency index (AEI) of Gafsa phosphate (GP) and of GP with gypsum application before and after liming compared to triple superphosphate (TS), at the rates of 50, 100 and 200 mg P dm -3 , as well as relating soil nutrients with the treatments and with the nutrient symptoms. Three sowings were made. All GP combinations presented a very low AEI during the first sowing and high in third sowing. A higher soil phosphorus concentration was obtained with GP than TS only after ultimate harvest. Liming before or after phosphate fertilization had similar responses on soil phosphorus concentration. Phosphorus deficiency occasioned reduced growth and purple stem. Symptoms of manganese toxicity were characterized by a yellow and purple color in the leave borders. The efficiency of GP increased with the time.