Multielement Extraction from Southern Brazilian Soils

To evaluate the effectiveness of multielement extraction of Mehlich 1 and Mehlich 3 solutions in soils from southern Brazil, correlation studies are needed. The amounts of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), and zinc (Zn) extracted with Mehlich 1 solution, 1.0 M potassium chloride (KCl), and 0.1 M hydrochloric acid (HCl) for representative soil types of the Rio Grande do Sul state (Brazil) were compared with those extracted with Mehlich 3 solution. The amount of nutrients extracted with different methods indicated high correlation coefficients. On average, Mehlich 3 solution extracted greater amounts of P (50%) and K (20%) than Mehlich 1 solution. Calcium amounts extracted with all solutions were similar. Magnesium amounts extracted with Mehlich 3 solution were on average 20% less than the amounts extracted with 1.0 M KCl solution. Mehlich 3 solution extracted similar amounts of Cu as the 0.1 M HCl but lesser amounts of Zn. Simultaneous multielement soil-test methods such as Mehlich 1 and Mehlich 3 solutions are efficient in soils from southern Brazil and are a feasible alternative to improving the efficiency of soil-testing laboratories.