Resumo

ZAMUNE, Ester Cristina; LLOVERAS, Jaume  e  ECHEVERRIA, Hernán Eduardo. Dosis óptima económica de fósforo en el cultivo de papa en el sudeste bonaerense. Cienc. suelo [online]. 2016, vol.34, n.1, pp.57-65. ISSN 1850-2067.

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.

Palavras-chave : Avail^®; Yield; Bray; Mehlich.

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