Interrelations in Phosphorus and Potassium Accumulation Characteristics of Plants Grown in Different Soil Types

Abstract

Nutrient accumulation characteristics and mineral content of plants depend on several factors such as crop and site characteristics, environmental conditions, and soil nutrient levels. Nutrient interactions are rather complex and may have an important role in this context. It is evident that phosphorus (P)–potassium (K) interaction is a part of cation–anion balance in plants. Although several authors demostrated the positive P-K interaction in plants, results are still inadequate. Studies on P-K interaction and adequate P/K ratios are needed to improve nutrient efficiency. Pot experiments were carried out under greenhouse conditions with perennial ryegrass (Lolium perenne L.) grown in three soils different in texture, soil organic matter (OM), pH, and available nutrient levels: an Eutric cambisol, a Calcaric fluvisol, and a Haplic phaeosem. Soil samples were taken from selected plots of National Long-Term Fertilization Trials (NLFT) after 30 years of fertilization. Besides the unfertilized control, increasing rates of P were applied in four replicates at four levels of P supply resulting from long-term P fertilization. Dry-matter (DM) production, P and K accumulation characteristics, nutrient concentrations, and K/P ratios of perennial ryegrass were studied for 4 months by taking four cuts. From the results, it was evident that both P and K accumulation of plants were closely related to DM accumulation. Phosphorus accumulation characteristics and amounts of P taken up by plants responded both to the level of long-term P supply and to rates of freshly applied P. Better levels of P supply had a beneficial influence on K uptake and K concentrations in plants. Phosphorus concentrations ranged between 0.20% and 0.53% P, whereas concentrations of K were between 1.63% and 5.64%. As the interaction between P and K may influence that of other nutrients, further research is needed to identify these relationships.