Nitrogen replenishment using variable rate application technique in a small hand-harvested pear orchard

Anna Vatsanidou, George D. Nanos, Spyros Fountas, John Baras, Anamaria Castrignano, Theofanis A. Gemtos


Precision agriculture is a management approach for sustainable agriculture. It can be applied even in small fields. It aims to optimize inputs, improve profits, and reduce adverse environmental impacts. In this study, a series of measurements were conducted over three growing seasons to assess variability in a 0.55 ha pear orchard located in central Greece. Soil ECa was measured using EM38 sensor, while soil samples were taken from a grid 17 × 8 m and analysed for texture, pH, P, K, Mg, CaCO3, and organic matter content. Data analysis indicated that most of the nutrients were at sufficient levels. Soil and yield maps showed considerable variability while fruit quality presented small variations across the orchard. Yield fluctuations were observed, possibly due to climatic conditions. Prescription maps were developed for nitrogen variable rate application (VRA) for two years based on the replacement of the nutrients removed by the crop. VRA application resulted in 56% and 50% reduction of N fertiliser compared to uniform application.


precision agriculture; yield mapping; soil variability; site-specific management; fertilisation; Pyrus communis L.

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DOI: 10.5424/sjar/2017154-10986