Dosis óptima económica de fósforo en el cultivo de papa en el sudeste bonaerense

Abstract

Asegurar una buena disponibilidad de fósforo (P) para el cultivo de papa, es tan importante como ajustar la estrategia de fertilización para producir el máximo rendimiento con la mayor eficiencia económica. El Avail, aditivo que puede aplicase como recubrimiento de fertilizantes fodforados, ha demostrado aumentar la eficiencia de uso en diversos cultivos, sin resultados consistentes en papa.

To ensure the phosphorus (P) availability in potato crop is as important as to adjust the fertilization strategy to achieve maximum yield with the greatest economic efficiency. Avail®, which is an additive that can be used to coat phosphorus fertilizers, was proven to increase P fertilizer efficiency in various crops, but without consistent results in potato. For potato crops in the Southeastern Buenos Aires, the objectives of this research were: 1- to compare potato yield at different rates of calcium triple superphosphate (TSP) with and without Avail® addition and, 2- to establish the phosphorus fertilization rate that produces the maximum economic benefit (DOE). Information of nine P fertilization trials (2005-14) were used. Bray1 and Mehlich3 tests were applied to soil samples taken before crop planting and total yield was determined. The DOE were calculated for different fertilizer/tuber price relationships. Fertilization increased yields with average values of 44 Mg ha-1 for the unfertilized plots and 52-69 Mg ha-1 for the fertilized treatments. There were no significant yield differences due to the use of different P sources (TSP or TSP +Avail®), for any of the tested rates. This result was consistent across all trials despite having different extractable P contents before planting. Determined DOE for Bray1 or Mehlich3 were similar (R2=0, 8). For both extractants, the DOE decreased with increasing P availability, specifically: DOE P (kg ha-1) = 176 - 5*Bray1; 216 - 6*Mehlich3. Even though both soil P availability and price relationships affected the DOE, the first was the determining factor to define the suitable phosphorus fertilizer rate for cost-effective production of potato crops.