ABSTRACT: Ruzigrass (Urochola ruziziensis) has a large capacity to take up K from the soil, including non-exchangeable forms, and can play an important role in nutrient cycling in integrated production systems. However, K transport to roots of brachiarias is not well known, nor the nutrient dynamics in the rhizosphere, where a concentration gradient may be established towards the non-rhizospheric soil, creating a favorable environment for the release of non-exchangeable K. This study aimed to evaluate the effect of ruzigrass on […]

In recently fertilized soils, plants uptake nutrients mainly from around the granules, but little is known about the chemical composition of these zones. This study aimed to evaluate the K concentration gradient as well as the electrolyte concentration around KCl granules applied at different rates to five soils varying in clay (95 to 569 g kg-1) and organic matter (13 to 54 g kg-1) contents. Treatments consisted of four KCl rates (0, 50, 100, and 200 kg ha-1 K2O). These quantities were obtained by simulating a […]

A correct potassium fertilization management, using adequate fertilizer amounts, can minimize K losses and avoid soil K depletion. The objective of this study was to evaluate potassium dynamics in the soil profile as affected by different textures and exchangeable K levels resulting from previous soybean fertilizations. Soils with sandy loam and clayey texture previously planted with soybean and fertilized with 0, 60, 120 and 180 kg ha-1 K2O were sampled during 6 years. The experiment was carried out in a […]

Pot experiments are being used to study the potassium supplying capacity of soils. A greenhouse experiment with this objective evaluated samples of two Planosols, a Chernosol and a Gleisol, where flooded rice did not respond to potassium fertilization. The soils were cropped during 50 days with rice (Oriza sativa – BR-IRGA 409). Potassium uptake by the plant shoot, the exchangeable and non-exchangeable soil K, extracted by NH4OAc 1 mol L-1 and boiling HNO3 1 mol L-1, respectively, were evaluated, before […]