ABSTRACT Recently, Brazilian agriculture and the mechanization process have been improved and developed, particularly in sugarcane cultivation. The developed processes should adopt suitable management practices in terms of the technical, economic, and operational logistical aspects. As a management tool, the present study aimed to measure the impact of the accumulated use of harvesters (life in h) and agricultural productivity (Mg · ha−1) on the harvesting operational capacity (HOC). Mathematical modeling was performed on data obtained from eight sugarcane production units, and equations corresponding to the HOC as a function of the harvester's life and the crop agricultural productivity were developed. The equation that best represented the phenomenon was selected. The values of the HOC depend on operational conditions and range from (17 to 44) Mg · h−1, thereby demonstrating significant operational and economic discrepancies. When the mean life of the harvester was 10,000 h and the mean productivity of the cane field was 80.0 Mg · ha−1, an HOC of 31.7 Mg · h−1 was obtained. It was found that agricultural productivity is directly proportional to the HOC, whereas the harvester's life is inversely proportional to the HOC; the parameters are not linear in both cases.

RESUMO A agricultura brasileira tem expandido e melhorado suas técnicas nas últimas décadas, assim como a mecanização da cultura de cana-de-açúcar. Em geral, o custo da mecanização dessa cultura é o mais elevado dentre o custo total de produção em relação a outras culturas. Este custo é composto de vários componentes, tais como o custo da colhedora. Este trabalho teve por objetivo desenvolver um modelo matemático que represente o custo operacional da colhedora em função de sua vida e da produtividade agrícola, parâmetros esses associados à capacidade operacional da colhedora. Foram realizadas simulações deste custo, variando a vida útil das colhedoras entre 0 e 17.900 h e a produtividade agrícola da cultura variou de 50 a 130 Mg ha-1. Os resultados apresentaram um custo operacional entre R$ 7,23 e R$ 26,43 Mg-1. Verificou-se que o custo operacional é inversamente proporcional e não linear à produtividade e também diretamente proporcional e não linear à idade da colhedora.

ABSTRACT The brazilian agriculture has expanded and improved its techniques in the last decades as well as the mechanization of sugarcane cultivation. Overall, the mechanization cost of this cultivation is the highest of the total cost of production in relation to other crops. That cost consists of several elements such as the cost of the harvester. This study aimed to develop a mathematical model that represents the operational cost of the harvester in relation to its operating life and agricultural productivity, parameters that are associated with its operational capacity. Simulations of this cost were conducted, raging the operating life of harvesters between 0 and 17,900 h, and the agricultural productivity of the cultivation from 50 to 130 Mg ha-1. The results indicated an operating cost between R$ 7.23 (BRL) and R$ 26.43 Mg-1. It was verified that the operational cost is inversely proportional and nonlinear to productivity, and also directly proportional and nonlinear in relation to the age of the harvester.