Liming in soils with plinthic materials of the Brazilian Savanna: potentials and limitations

Abstract

The expansion of agriculture has been taking place in marginal soils with low productive potential, such as Plinthosols. The liming can increase the economic and environmental sustainability of agriculture. However, there are no studies on the dissolution or recommendation of limestone for Plinthosols. The objective was to evaluate the effect of limestone doses on the chemical attributes of three soils with different gravel contents (ironstone concretions). The soils were collected (0-20 cm layer) in native areas of the central region of the Brazilian Savanna. They were classified as Red-Yellow Latosol (RYO) and two Concretionary Pétric Plinthosol (with 29% [CPP-29] and 72.8% [CPP-72] of soil volume with gravel). A factorial scheme (3x6) with the three soils (RYO, CPP-29, and CPP-72), six limestone doses, and four replications. The evolution of pH was verified at 10, 20, 30, and 40 days after the beginning of incubation (DAI), and determined the chemical attributes (Al, H+Al, Ca, Mg, BS, V%, P, and K) at 40 DAI. The doses to reach pH 6 were 1.4 t ha-1 for RYO, 3.9 t ha-1 for CPP-29, and 2.7 t ha-1 for CPP-72. Al3+ neutralization was 100% with doses above 3.5, 2.5 and 0.5 t ha-1 for CPP-29, CPP-72, RYO. There was a significant increase in Ca and Mg contents in all soils. However, the Soil CPP-72 did not reach a critical level for Ca (>2.41 cmolc dm-3) and Mg (>0.91 cmolc dm-3) for Plinthosols with higher plinthite content. Thus, we recommend using agricultural practices that increase the capacity of the soil to retain and recycle nutrients.