Surface application of lime-silicate-phosphogypsum mixtures for improving tropical soil properties and irrigated common bean yield

Abstract

The movement of surface-applied lime to subsurface soil layers is slow, and,consequently, liming requires a long period of time to become effective.Thus, it is important to develop strategies to increase the efficiency ofacidity amendments practices in order to improve the chemical propertiesof tropical acid soils in no-till systems. The aim of this study was to evaluatethe effects of applying mixtures of silicate, lime, and phosphogypsum to thesoil surface in tropical no-till systems on soil chemical properties and leafnutrient concentrations, yield components, and grain yield of the commonbean (Phaseolus vulgaris l.). A field experiment was performed during twogrowing seasons (2004 and 2005) in a field with Typic Acrustox soils. Amongthe treatments, the silicate–phosphogypsum mixture was more effectivefor ameliorating soil acidity at a depth of 0 to 0.20 m over a short periodof time (6 mo). The application of soil amendments separately or in mixturesincreased the soil pH to 0.40 m depth 18 mo after application. Combiningthe surface application of phosphogypsum with lime and/or silicateeffectively increased the NO3-–N, SO42-–S, and Ca2+ levels at soil depthsof up to 0.40 m over a relatively short period of time, resulting in a higherbase saturation in the deepest layer evaluated (0.20–0.40 m). Comparedwith the control treatment, the mixtures of soil acidity amendments andphosphogypsum resulted in greater Ca, S, and Si concentrations in theleaves and increased the grain yield of the common bean by >22% over twogrowing seasons. long-term studies are required to establish the frequency ofreapplication and the residual effects of soil amendment mixtures.