Changes of Inorganic Active P Forms in Two Calcareous Soils and Maize Growth in Pot Culture in Sterile and Unsterile Conditions

Abstract

Plants and microorganisms can change phosphorus (P) forms and its availability in soil significantly. Two soils with different calcium carbonate and P forms were sampled and the experiment used a completely randomized design considered as factorial. The factors were soil (Sulan and Bahar), sterilization (sterile and unsterile soils), and maize planting (unplanted and planted soil with Zea mays). Plants were grown in greenhouse condition and harvested at flowering. Shoot and root dry weights and the ratio of root/shoot biomass were greater in Bahar soil especially in unsterile conditions than in Sulan soil. After plant harvest the effect of soil sterilization on soluble P was significant and it was greater in sterile soil compared to that in unsterile soil. The effect of maize planting on available P, dicalcium phosphate P (DCP-P), and octcalcium phosphate P (OCP-P) was significant. They were greater in unplanted soil, especially in unsterile conditions. Although the greatest apatite P was measured in unplanted soil in sterile conditions, this form of soil P did not change significantly.