The issue of soils and land use in agriculture is very hot at the moment. Lots of projects looking at these issues using remote sensing. Coming either from an environmental, often water quality approach, or from an agronmetric/extension approach, trying to improve outputs and profitability of irish farming ( for example the Harvest 2020 report). Sometimes an image pops up that really emphasises that ultimately we are heavily influenced by geography. Below is an image I’m using in a project looking at grassland and it really emphasies the effect of soil on short and long-term land use choices in farming.
Its a September 2009 Landsat TM5 image (Bands 3,4,5-rgb) in kilkenny-carlow region, with soil associations from the general Soil map overladen. The colours are not “true” colours – The general light green areas are grassland, the light pink is bare soil, the darker, lusher greens are forestry and deep russet red on the left are the exploited bogs, the built up areas of Kilkenny and Carlow show up are purple blotches.
Its a fascinating image we can see that the pink crescent stretching from Kilkenny to Carlow that the harvest is in – the fields are bare, but we can also see how that land use choice of tillage is determined by the soil type – the blue polygons are areas of grey-brown podzolics (light textured well-drained sandy loams) soils in this , where as the white polygon in the centre the association is dominated by gleys (poorly drained soils). So the poorly drained soils constrain the choices made – their physical structure is unsuited for tillage – but we can also see in play longer term landuse choices as the percentage of forestry in the gley area is much higher than the GBP areas. Though the forests would grow even better in the GBP areas, the economic return for the farmer favors tillage.