ECONOMIC-EVALUATION OF LIMING AND PHOSPHA TE FERTILIZATION IN ALFALFAON THE HIGHLANDS OF SANTA-CATARINA STATE, BRAZIL

Economic evaluation of liming and phosphate fertilization in alfalfa ( Medicago sativa L.) was realized based on a trial carried out in acid soils with low phosphorus availability on the highlands of Santa Catar ina State, Brazil. A linear programming model was developed to find-th e optimum strategy of liming and phosphate fertilization which maximiz es the net present value according to different production levels in a six year period. The results showed the economic viability of produci ng alfalfa in this soil type, considering the high investment ratios a nd net present values obtained. However, due to high liming costs (whi ch occur only in the first year), the cummulative net revenue only sta rts to be positive in the third year, involving a high financial risk related to the investment. Sensitivity analysis studied the influence on the technical and economic results as a function of variations in y ields as well as prices. Finally, risk analysis indicated the liming a nd phosphorus fertilization strategy related to the 90% production Lev el as the least risky.