Sustainable Intensive Agriculture: Evidence from Aqueous Geochemistry

Geochemical and crop models allow for simulating the concentration of irrigation water (Durance River) by evapo- transpiration, equilibration with soil pCO2, dissolution/precipitation of calcite, dissolution of fertilizers (P-K, no N), and apatite precipitation. Nutrient absorption is simulated as removal of the corresponding ions from the solution. The results show that the crop system in the Crau plain has thus protected and ameliorated soils since the XVIth century, while sustaining production of high quality crops and a correct income for farmers. This has been made possible by investments in water control (irrigation and drainage). It is now endangered by urban sprawl.