ABSTRACT: There are several globally accepted methods to chemically characterize P-fertilizers, but not all are suitable to predict the agronomic efficiency of the P sources in terms of plant nutrition. Our aim was to investigate the performance of P extractors for fertilizers, investigating the consistency of different methods for P sources of varying properties and the related plant responses. The experiment was carried out in a greenhouse, using corn as a model plant. Phosphorus values extractable in water, 2 % […]

Despite the large number of studies addressing the quantification of phosphorus (P) availability by different extraction methods, many questions remain unanswered. The aim of this paper was to compare the effectiveness of the extractors Mehlich-1, Anionic Resin (AR) and Mixed Resin (MR), to determine the availability of P under different experimental conditions. The laboratory study was arranged in randomized blocks in a [(3 x 3 x 2) + 3] x 4 factorial design, with four replications, testing the response of […]

The change of cultivation systems from conventional to no-tillage, the change in soil sampling depth and the higher crop yields over time can influence the critical P content, fertility ranges and fertilizer doses recommended for crops. The objective of this work was to calibrate the soil P tests, Mehlich-1, Mehlich-3 and anion-exchange (AER) resin for soybean, wheat and corn plants cultivated under no-tillage system, and to estimate the P fertilizer amounts for a maximum economic yield. For this purpose soil […]