Scientific and technical knowledge of sugarcane cover-management USLE/RUSLE factor

Sugarcane covers 10.6 Mha of Brazilian agricultural land (13 % of all cropland), mainly in the south-central region. In tropical climate conditions, the physiological characteristics of sugarcane allow a wide range of management systems with contrasting soil erosion outcomes. Models can assess these differences and the Universal Soil Loss Equation (USLE) based models are the most frequently used. The cover-management factor (C Factor) is the USLE input variable that represents the changes in soil cover and management. We collected, compared, and evaluated sugarcane C Factor values reported in technical and scientific literature to support modelers and soil scientists on the adequate choice of these values. We analyzed references reporting primary C Factor values and sources that applied these values or described them. We found 50 references, showing a wide value variation ranging from 0.0012 to 0.5800. Thirteen references were primary sources. We found seven primary sources for Brazilian sugarcane growing conditions, but only two papers were peer-reviewed. Sugarcane C Factor modelers frequently used C values based on a poor understanding and description of the methodological and geographical origin of these values and out of the context of the specific crop management systems of application. Therefore, the results may not be compatible with the study site conditions. The primary sources lack clarity in the description of the site-specific environmental and management conditions in which the C Factors were obtained, hindering the use of these specificities by the end user.

Automated summary

The study collected and compared sugarcane C Factor values reported in literature to support modelers and soil scientists in choosing appropriate values. A wide variation in C Factor values was found in 50 references, indicating a lack of understanding of the methodological and geographical origin of these values in existing research.