Lucrecia Carolina Ludueña, Juan Fernández de Ullivarri, María Nuñez, Leandro Hidalgo, Eduardo Romero and María Laura Tortora
Estación Experimental Agroindustrial Obispo Colombres (EEAOC). W. Cross 3150. Las Talitas-Tucumán, Argentina; lluduena@eeaoc.org.ar
The global sugar industry is transitioning from pre-harvest burning of sugarcane fields to green harvesting, a sustainable alternative with multiple benefits. In a study conducted in 2011 in Simoca, Tucumán, Argentina on the variety LCP 85-384, the impact of burning (BR) and conservation as cover (CR) of the sugarcane harvest residue (HR) on different populations of soil microorganisms and on some key enzymatic activities was evaluated. Preliminary results showed early changes in biological parameters under both systems. To confirm these findings and identify new bioindicators, the experiment was extended for over 10 years under the same treatments (BR and CR). In the 2023-2024 cycle (plant cane and first ratoon), the following biological parameters were evaluated: i) total aerobic mesophiles, ii) Pseudomonas spp., iii) nitrogen-fixing bacteria, iv) total enzymatic activity (FDA), v) β-glucosidase (βGA), vi) phosphatase (PA), and vii) nitrate reductase (NR). Soil samples (0-10 cm) were collected pre- and post-harvest. Results showed that burning HR significantly reduced Pseudomonas, total aerobic mesophiles, and nitrogen-fixing bacteria, with Pseudomonas being the most sensitive. Enzymatic activities (FDA, βGA, NR) were also reduced, while phosphatase showed an inverse trend. These findings indicate that BR burning negatively impacts beneficial microorganisms and enzymatic activities, critical for system sustainability.