Calculate the leaching of iron (in mol Fe/ha.year) at a pH =5 in the case of a coniferous and deciduous forest. The leaching of organic material in a deciduous forest is 5kmolC/ha.year and in a coniferous forest this is twice as much. The total amount of C is approximately comparable (20gC/kg DS). The association constant of Fe3+ with fulvates is 1013 (reaction: Fe3++SOFeSO++ ). The pKa of organic acids is 8 (reaction: Ht++SOSOH ). The pKsp of Fe(OH)3 is 39