Effect of liming in plinthic and petroplinthic soils for soybean cultivation in the Brazilian Savanna

Abstract

Agricultural expansion is advancing on marginal soils (Plinthic soils), but the liming recommendation for this soil, especially for soybean cultivation, remains unknown. This study aimed to evaluate soybean (Glycine max) responses to limestone doses in concretionary soils (plinthic and/or petroplinthic). The experiment was carried out in the greenhouse, in randomized blocks, with four soil types and six limestone doses (4x6 factorial scheme), with four replicates. Soils were: RYO: Red-Yellow Oxisols; CPP-29, CPP-72, CPP-82 corresponds to the Concretionary Petric Plinthosol with 29, 72, and 82% concretions, respectively. Limestone doses varied from 0 to 4 times for each soil, based on the recommendation of regional bulletins. Soil temperature, crop emergence, development, and soybean yield characteristics were evaluated. Results were evaluated by ANOVA, followed by the LSD test or polynomial regression adjustment (p ≤ 0.05). Soybean response to liming varied with soil types. Seedlings showed lower vigor in Plinthic soils with plinthite contents ≥72%. These soils showed higher thermal accumulation (°C), and this increase showed a strong negative correlation with soybean development and reproductive characteristics. Evidence of liming response was observed after crop stage V5. Limestone substantially improved soybean growth and development in Plinthic soils with high plinthite levels, although they had lower yield potential than low plinthite levels and Oxisol. In general, the maximum response of the crop occurred at doses ~2 times higher than that practiced in the Brazilian Savanna region, especially in Plinthic soils