Spatial and temporal stability of soil phosphate concentration and pasture dry matter yield

Several methods are described that could be used by a farm manager to define the spatial and temporal stability within a field from a series of yield maps. A quantitative analysis of soil phosphate concentration and pasture dry matter yield data over 4 years (2004–2007) were investigated to identify the spatial and temporal stability in a 6 ha pasture field. The data were combined into two maps that characterize the spatial and temporal variation recorded over the 4 years. The two maps were then combined to create a single map with five management classes, each with different characteristics that can have an impact on the way the field is managed. These categories are: high yielding and stable, high yielding and moderately stable, low yielding and stable, low yielding and moderately stable and unstable. The unstable class represents 83 and 93% of the total area with regard to soil phosphate concentration and pasture dry matter yield, respectively. Results from this study show that the significant temporal stability found cancels out over time, leaving a relatively homogenous map of spatial variation. The implication of the findings is that each pasture field should be managed according to the current year’s conditions. These results also justify a further study that evaluates the soil phosphorous dynamics under Mediterranean conditions.