JI Romero, A Sanzano and ER Romero
Estación Experimental Agroindustrial Obispo Colombres (EEAOC), Tucumán, Argentina; juanromerojir@gmail.com
In sugarcane, insufficient levels of available P result in reduced yields and ratoon longevity. Approximately 20% of Tucumán sugarcane area soils shows P deficiency. Traditionally, P fertilizers are applied in a single high dose at planting. Recommended P doses were established following sufficiency criteria and range between 20 and 35 kg of P2O5/ha/year depending on soil P levels and expected yield. Subsequent studies indicate that in high-yielding plots and/or with crop residue burning, these doses are insufficient to cover P outputs, affecting yields and longevity. Significant responses to P were observed in ratoon cane. Additionally, local experiences have shown improvements in fertilizer use efficiency (N and P) in ratoon cane when sulfur (S) was added in low P and organic matter soils. These results suggest potential alternatives to traditional P fertilization management. To evaluate some of these alternatives, a trial was established during the 2022-2023 growing season with different P-splitting strategies and S addition. A four replication microplot trial was established with five treatments in a randomized complete-block design. Planting and treatment application into the furrow were carried out in July 2022. No nitrogen was added to plant cane. In the first ratoon, P was incorporated, while N and S were applied over the furrow line. For the variables measured (foliar nutrient %, stalk number and weight) in each season, linear models were adjusted with treatment and block fixed effects. Treatment means were compared using Fisher’s LSD test (p<0.05). Foliar P% showed significant responses. P application increased significantly stalk number. For both seasons, the yield response to P ranged from 13% to 22% depending on the dose. In addition, a 10% yield response to sulfur was observed. These results support the development of new fertilization strategies with potential agronomic, operational, economic, and environmental advantages.