Correlation between Soil P Test Results and P Contents of Young Spring Barley Studied in Long-Term Experiments

Interpretation of soil test results and plant analysis data are important for the further development of nutrient management in cereal production. The main objective of our pot experiments was to study the effects of increasing rates of phosphorus (P) fertilization (including agronomic and extreme P levels) and responses of young spring barley (Hordeum vulgare L.) grown in two soil types: a sandy loam (FAO taxonomy: Eutric cambisol, USA taxonomy: Orthic Eutrochrept) and a silt loam (FAO taxonomy: Stagnic luvisol, USA taxonomy: Typic Albaqualf). Ten-year intensive fertilization resulted in three P levels (referred as P0, P1, and P2). Soil samples were taken from selected plots 30 years after stopping fertilization. Available soil P was determined in the ammonium lactate (AL P) and sodium bicarbonate (Olsen P) extract. Relationships between soil P tests, dry-matter (DM) production, and P contents of young barley plants were evaluated. Significant correlations were found between soil P test values and both DM production and shoot P contents (R2 values ranged between 0.5047*** and 0.9751***). Correlations were closest between AL P and Olsen P values in both soils (R2 = 0.9748 and 0.9739, respectively).