Spatial and temporal yield variation in three different clay soil fields

Recent farming machinery provides multiple ways to gather spatial information about soil and cultivated crop properties. However, collected information can not be used straight forward for decision making purposes due to complex relationships between crop growth, weather and soil properties.A quantitative analysis of yield data from three fields over three years was carried out to investigate the spatial and temporal trends. At first it was studied if varying soil water retention properties reflect the observed within-field yield variation of small grain cereals and whether the variations in weather conditions between growing seasons affect the within-field yield variation. Secondly, the potential biomass accumulation in existing soil with varying precipitation was simulated and analysed. The analysis results of the observed biomass yield and simulated biomass yield were compared.The variation in soil water retention properties was found to have an effect to yield variation. However, soil properties alone were concluded not to be enough to predict the yield and the yield variation correctly in case of high variations. There were other factors affecting the observed yield variation, e.g. lodging, cold summer, extremely high precipitation and the field topography. The prediction of site-specific biomass accumulation solely by soil properties was concluded to be impossible. Therefore crop observations were found necessary among the knowledge of soil properties in order to simulate the potential biomass accumulation for precision farming purposes.