Effect of Phosphate Rocks on Spring Barley Shoot Yield and Phosphorus Uptake in a Pot Trial

The effect of five rock phosphates (from Algeria, Florida, North Carolina, Senegal, and Morocco) and hyperphosphate on the shoot yield, phosphorus (P) concentration, and P uptake of spring barley was studied in a pot experiment on acidic sandy soil (Nyirlugos) and acidic clay loam soil (Ragaly), with superphosphate as the standard P source. The effect of adding calcium carbonate (CaCO3) in combination with superphosphate (SSP) was also investigated. Averaged over the whole experiment, the shoot yield of barley was almost twice as high (3.69 g pot−1) on the clay loam soil from Ragaly, which was rich in colloids, than on the colloid‐poor sandy soil from Nyirlugos (1.90 g pot−1). The P uptake, however, was only 25% higher (13.0 mg P pot−1) on the clay loam soil, averaged over the whole experiment, than on the sandy soil (10.4 mg P pot−1). This could be attributed to the fact that the P concentration of barley at tillering was almost 0.1% higher on average in the rock phosphate treatments and 0.2–0.3% higher ...