Seeking strategies to increase soil phosphorus in organic farming

Many organic farmers tolerate negative phosphorus budgets and rely on biological activation of soil P reserves. Scientists Ohm et al. investigated long term soil P pools and enzymatic soil activities in organic cropping systems. They show that labile inorganic P fractions in soils decrease continuously and future mobilization forces for P from more stable fractions are insecure in practical use. Organic farming should be aware of the problem and develop P-fertilizing strategies.