67 Agronomy research 11 (1), 67–72, 2013 Effect of site-based precision fertilisation on yield and oil content of spring oilseed rape seeds J. Kuht 1,* , T. Tõrra 1 , A. Makke 1 , J. Kilgi 1 and E. Nugis 2 1 Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 5, EE51014 Tartu, Estonia; * Correspondence: jaan.kuht@emu.ee 2 Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56, EE51014 Tartu, Estonia Abstract. The experiments using two fertilisation methods on the spring oilseed rape in 2012 were carried out in two places – on the Eerika experimental field of the Estonian University of Life Sciences and on the Erumäe producing field of the Pilsu farm. The aim of this work was to investigate site-based precision fertilisation on the spring oilseed rape yield and oil content in oilseed rape seeds. The preceding crop was spring wheat in both fields. Five treatments were used: control treatment (without fertilisers, C), common fertilising system (CvS), fertilisation by site-specific information (SI), fertilisation by site-specific information additionally with mineral nitrogen fertiliser (SI+MF), and site-specific fertilisation additionally with foliar nitrogen fertiliser (SI+FF). The highest seed and oil yield was achieved in treatments fertilised by site- specific information additionally with foliage nitrogen fertiliser. In the production field, the statistically significant seed and oil yield increase was achieved in treatment. Oil content of spring oilseed rape seeds was higher in treatments C and CvS. In both trials, additional fertilising with foliar nitrogen (including microelements, SI+FF) increased the oil content of oilseed rape seeds. There was a negative correlation between the oil content and seed yield of spring oilseed rape. Key words: spring oilseed rape, soil nutrient content, precision fertilising, foliar fertilising. INTRODUCTION Current applied methods in agriculture use precisely controlled movement of the machinery in the field conducted by exploitation of Global Positioning System (GPS). GPS navigation system gives operatively necessary information of the position of the agricultural machinery and the movement in the field (Ludowicy et al., 2002; Robinson 2007; Nugis et al., 2010; Võsa et al., 2009). While the ultimate goal in the field is crop yield, it is important to notice the yield potential of different parts in the specific field. Primary information for this purpose is obtained from the yield map. In addition to locating the position of the machinery, information on soil properties is also important. Thus the Geo Information System (GIS) database has become an inseparable part of precision farming (Jordan et al., 2005; Santhi et al., 2005). Collection of soil samples is the first step in monitoring soil nutrients and the creating of site-specific database (Crozier et al., 1998).