ECONOMIC AND TECHNICAL IMPACT IN SOIL AND NUTRIENT LOSS THROUGH EROSION IN THE CULTIVATION OF SUGAR CANE

The general objective was to show the economic and technical impact in soil and nutrient loss through erosion in the cultivation of sugar cane. It was specifically to evaluate the nutrient loss through erosion (P, K, Ca and Mg), the cost of replacing the nutrients and the production of sugar cane in two harvesting systems (raw and burned sugar cane) in Catanduva, state of Sao Paulo, Brazil. An area of 100 ha was studied for each system, formed and harvested in the same period (2002 and 2007), with similarities in the type of soil, variety, topography, and the number of cuts. The methodology was based on the universal equation of soil loss and the theory of production costs and the replacement of nutrients. The greatest loss of soil nutrients and erosion occurred in the areas of the burned sugar cane; the burned sugar cane (cut by hand), the average of five cuts, losses 48.82% per hectare of land, 56.45% of potassium (K) and 60.78% of phosphorus (P) than the raw sugarcane (mechanical harvesting), the replacement cost of nutrients, on average, by the burned cane (R$ 33.92 ha(-1) year(-1)) was higher that the raw sugarcane (R$ 21.12 ha(-1) year(-1)), the raw sugar cane had lower production cost (R$ 29.60 Mg-1) compared to the burned sugar cane (R$ 32.71 Mg-1); the raw sugar cane had a higher average return (R$ 5.70 Mg(-1)year(-1)) with respect to the burned sugar cane (R$ 2.59 Mg-1).