On-Farm Evaluation of Variable Rate Fertilizer Applications Using Yield-Based Mathematical Formulae in a Greek Apple Orchard
Vasileios Liakos, Erick Smith, Spyros Fountas, G.D. Nanos, D. Kalfountzos, Theofanis Gemtos
Abstract
The objectives of this study were to compare variable rate and uniform fertilizer applications in apple (Malus domestica Borkh.) and its effect on production and economic return. In the study, 59.6% and 63.4% less fertilizer were applied in the variable rate treatments (VRT) in 2011 and 2012, respectively, with less than 4% difference in yield. Soil properties did not significantly affect yield and fruit quality. The VRT fertilizer cost was reduced by 2.3% and 7.6% in 2011 and 2012, respectively, and fruit quality was not significantly affected. Assessing yield to calculate fertilizer demand suggests variable rate fertilizer inputs can potentially increase the profitability of an apple orchard.