Eucalyptus growth and phosphorus nutritional efficiency as affected by soil compaction and phosphorus fertilization

ABSTRACT

Soil compaction interferes in soil nutrient transport and root growth. The aim of this work was to evaluate eucalypt growth and phosphorus (P) nutritional efficiency as affected by soil compaction and P rates. The treatments were composed of a 3 × 4 factorial scheme (soil bulk densities levels versus P fertilization rates) for two weathered tropical soils, a clayey Ferralsol (F_Clayey) and a sandy Ferralsol (F_Sandy). The soil bulk densities assessed were 0.90, 1.10 and 1.30 g cm⁻³ for F_Clayey, and 1.35, 1.55 and 1.75 g cm⁻³ for F_Sandy. The P rates were 0, 150, 300 and 600 mg kg⁻¹ for F_Clayey, and 0, 100, 200 and 400 mg kg⁻¹ for F_Sandy. Soil compaction reduced root growth, P content in the plant, P utilization efficiency and P recovery efficiency; and increased average root diameter. Phosphorus fertilization increased root length density, root surface area, dry matter, P content in the plant, P utilization efficiency and P uptake efficiency; and decreased P recovery efficiency. It was concluded that P fertilization is not effective to offset the deleterious effects of soil compaction on eucalypt growth and nutrition.

Abbreviations: F_Clayey: clayey Ferralsol; F_Sandy: sandy Ferralsol; R_Dens: root length density; R_Diam: root diameter; R_Surf: root surface area; R_DM: root dry matter; S_DM: shoot dry matter; WP_DM: whole-plant dry matter; R_P: root P content; S_P: shoot P content; WP_P: whole-plant P content; PU_tE: P utilization efficiency; PU_pE: P uptake efficiency; PRE: P recovery efficiency.

KEYWORDS:

• Eucalyptus camaldulensis
• phosphorus nutrition
• phosphorus utilization efficiency
• root growth
• soil bulk density