A major constraint to agricultural production in acid soils of tropical regions is the low soil P availability, due to the high adsorption capacity, low P level in the source material and low efficiency of P uptake and use by most of the modern varieties grown commercially. This study was carried out to evaluate the biomass production and P use by forage grasses on two soils fertilized with two P sources of different solubility. Two experiments were carried out, one […]

The land use history and management of fertilization influence the soil phosphorus supply capacity. In this study, the P fractions in a Red Argisol (Ultissol) of the cerrado region were evaluated under different application methods and with phosphorus sources of different solubility, after three successive corn crops. The area had already been fertilized and cultivated in the past and remained covered with Brachiaria grass. A randomized block design with four replications was used, in a 4 x 3 + 1 factorial scheme, involving four […]

This study compared the residual effect of reactive natural phosphate originated from Morocco with that of triple superphosphate on the oat biomass production, soybean yield and yield components, availability of phosphorus and sulfur in the soil and determined these nutrient contents in soybean leaf tissue in response to the phosphorus and sulfur sources and doses. The study consisted of soybean and oat crops cultivated under minimum tillage cultivation system. The experiment had a complete randomized block design with four replications […]

The efficient use of phosphate fertilizers in soils of the tropical region is still a challenge, mainly regarding long-term soil management. Based on the cumulative response of three successive maize cultivations, alternatives of phosphorus supply combining P sources and application methods were compared in a formerly fertilized Red Argisol. Treatments arranged in a 4 x 3 + 1 factorial scheme represented by four P sources (180 kg ha-1 P2O5) as triple superphosphate – TS, magnesium termophosphate – MT, Arad reactive rock phosphate – RP, and Araxá […]

The sorbed P/ P in solution relation of the soil may be affected by the previously sorbed P (Ppre) content and by soil management systems. The objective of this study was to evaluate modifications in the maximum P sorption capacity (Pmax) and the constant related to the colloid linkage energy (k) of the Langmuir isotherm caused (a) by the inclusion of Ppre, and (b) by different soil tillage methods and crop sequences. In May 1997, samples of two Oxisols (Very […]

The objective of this work was to quantify the main forms of P derived from fertilizer in soils of varying physical and chemical properties, cultivated with sugar-cane, in Pernambuco. Soils from 11 commercial plantations were sampled following the harvest of the plant-cane (Jan. 1994), that had been fertilized in the furrow 18 months before. To find samples with fertilizer-derived P, a pit was opened perpendicular to the plant line and 28 soil samples were taken with the aid of a […]