Absorption of primary macronutrients and soybean growth at different compactation densities and moisture levels in a silt loam soil¹

Absorção de macronutrientes primários e desenvolvimento da soja em solo franco-siltoso sob diferentes níveis de compactação e umidade

ABSTRACT

Soybean cultivation is increasing rapidly in the region of Alto Vale do Itajaí, State of Santa Catarina, where there is a predominance of silt soils. The objective of this work was to evaluate the content of primary macronutrients in shoots and shoot and root vegetative growth of soybean (Glicine max L. Merrill) grown in a silt-loam soil under different compactation densities and moisture levels. A randomized block design in a 4x4 factorial arrangement was used, with four compactation densities: 1.00; 1.20; 1.40 and 1.60 Mg m^-3, and four soil moisture levels: 0.130; 0.160; 0.190 and 0.220 kg kg^-1 and four replications. Each pot consisted of the overlapping of three 150-mm PVC rings, where soil was maintained in the higher and lower part of the pot with a density of 1.00 Mg m^-3 and in the intermediate ring, the compactation densities were increased. Values of soil density higher than 120 Mg m^-3 negatively affected N, P and K uptake by soybean plants, as well as the plant mass of the shoots and roots. The higher levels of soil moisture reduced the compaction effect and promoted better absorption of P and K.

Key words:
compactation density; nutrients uptake; root density; shoot system