Phosphorus availability in hydromorphic soils of Eastern Croatia

The phosphorus (P) availability was tested on hydromorphic soils located in the Sava valley. 480 soil profiles covering the area of 31 227 ha was analysed in our study. The plant available P was determined by the Ammonium-Lactate meth-od. The P availability in the surface layer (0–30 cm) is very low (up to 5 mg P2O5/100 g of soil) in about 30 % of the tested agricultural land (9 440 ha), next 32 % (9 897 ha) is in the range of a low P availability (from 5.1 to 10 mg), while only 17 % (5 445 ha) has a good or very good P availability (above 20 mg). Especially high frequency of low P availability was found in vertic gley, amphygley and hypogley soils (total 8 680 ha or 28 % of tested agricultural land)