Alfalfa is extremely demanding in fertility, and an adequate supply of nutrients is important for forage production and is essential to maintain high forage quality and profitable yields. Tropical acid soils are naturally poor in plant nutrients, therefore, soil liming and balanced nutrient supply essential to ensure high yields and high alfalfa forage quality. The knowledge of soil properties spatial variability and forage yield is useful for the rational use of inputs, as in the variable rate application of lime and fertilizers. Precision agriculture requires methods to indicate the spatial variability of soil and plant parameters. The objective of this research was to map and evaluate the spatial variability of soil properties, yield, liming and fertilizer need and economical return of an alfalfa pasture. The study was conducted in a 5.3-ha-area of irrigated alfalfa pasture, directly grazed, intensive managed in a rotational system with 270 paddocks in Sao Carlos, SP, Brazil. Alfalfa shoot dry matter yield was evaluated when the crop has 10% of flowering and before the dairy cattle grazing. Soil samples were collected at 0-0.2m depth and each one represented a group of 5 paddocks. The values of soil pH, P, K, CEC and basis saturation were analyzed by traditional soil testing. Apparent soil electrical conductivity (ECa) was measured with a contact sensor. Data of liming and fertilizer needs were used to estimate the 1-ha-alfalfa cost of production and the total cost of production dairy system. Results of alfalfa dry matter yield were used to simulate pasture stocking rate, milk yield, gross revenue and net profit. The entire variable used at the estimation was based on a Brazilian intensive dairy cattle production systems based on grazing. Spatial variability soil properties and site specific liming and fertilizer need were modeled using semivariograms with Vesper software, and the soil fertility information and economic return were obtained by SPRING software. Results showed that the geostatistics and GIS use were decisive tools to show soil and pasture spatial variability and support management strategies. Soil nutrient were used to classify the soil spatial distribution map in order to design site-specific lime and fertilizer application maps. Spatial variation of forage and estimative of stocking and milk yield are adequate pasture management tools. Spatial variation of issue needs, forage availability and economic return are management tools to avoid economic and potential environmental problems form unbalanced nutrient supplying and over- or under-grazing pressure.