Lime and Gypsum Management for No-till Common Bean Production in Tropical Acid Soil.

In tropical regions, soil acidity is the most limiting crop production factor. Poor chemical fertility, resulting from aluminum (Al3+) toxicity and scarce of exchangeable bases has damaged root growth and the absorption of water and nutrients by Phaseolus vulgaris plants. However, the aim of this study was to evaluate the effect of lime and gypsum surface application on common bean growth and yield in a long-term experiment under no-tillage system (NTS). A field experiment has been conducted since the agricultural year 2002/2003 in a sandy clay loam, kaolinitic, thermic Typic. Four treatments were evaluated: 1 – Control (without application of limestone and gypsum), 2 – Gypsum (2,100 kg ha-1), 3 – Dolomite (2,000 kg ha-1), 4 – Dolomite plus gypsum (2,000 + 2,100 kg ha-1, respectively), which were applied in establishment of the experiment, and re-applicated in 2004 and 2010. The results attest that only surface liming was effective in alleviating soil acidity, providing an increase of 81% in plant population and improving common bean grain yield in 292% (1,383 kg ha-1). The use of lime and gypsum, concurrently, becomes more viable, since the number of pods per plants and productivity increased 18% and 15%, respectively, compared solely to dolomite surface application. In general, the differences in plant development was stimulated by gypsum application, which increased availability of exchangeable Ca2+ and Mg2+ and by neutralization of toxic ions such as Al3+ throughout the soil profile, providing better conditions for root development. However, the isolated use of gypsum is not viable to maximize crop grain production under a long-term NTS.