Quantification of sugarcane active metabolism roots

The objective of this work was to evaluate a method to determine sugarcane roots with active metabolism and its distribution and growth in the soil profile, by using isotopic dilution technique with N-15. The experimental design was in randomized blocks, the split plot was considered in relation to time. The N-15 tracer was applied in the leaves of the plants as urea solution. After the harvest of the above ground part of sugarcane plants, trenches were opened and the soil + roots samples were taken by monolite. The isotopic dilution method with N-15 allowed evaluating active root mass and the root distribution in the soil. There is a larger percentual distribution of the roots with active metabolism in depth than in the surface of the profile, which stands for, respectively, 31% in the layer of 0.6-0.8 m and 23% in the layer of 0.0-0.2 m. The method also made possible to determine the roots with active metabolism that remained in the soil after sieve, that was 35%, showing the importance of determining these roots.