Effectiveness of deep lime placement and tillage systems on aluminum fractions and soil chemical attributes in sugarcane cultivation

Combining deep soil tillage systems with lime application is a potential strategy for improving the sugarcane production in acidic soils. The authors evaluated the influence of tillage systems and lime application on sugarcane performance and soil attributes, including acidity. A field study in a clayey-textured Rhodic Hapludox soil was conducted with sugarcane for two growing seasons utilizing a 3 × 2 factorial scheme comprising three soil tillage systems with and without lime: conventional soil tillage system (CT), deep strip-tillage system (DT) and modified deep strip-tillage system (MDT). The soil tillage systems differed in the depth of soil disturbance and/or lime positioning. In addition to sugarcane stalk and sugar yields, pH, potential acidity (Pₐc), soil organic carbon (SOC), solid-phase and soil-solution calcium (Ca) and magnesium (Mg), the percentage distribution of exchangeable (%Alₑₓ) and non-exchangeable aluminum (%Alₙₑ) in the solid phase, and total monomeric (%TM-Al) in soil water extracts were analyzed and determined. The positioning of lime by the different tillage systems influenced the distribution of the Al fractions. TM-Al existed exclusively as organic monomeric Al (OM-Al) and showed little influence from treatments. In contrast, the distribution of Alₑₓ and Alₙₑ were highly influenced by lime and tillage system and varied according to the tillage efficiency of soil amendment. Soil chemical attributes and yield parameters were also influenced by the treatments in both growing seasons, highlighting the residual effect of liming. The soil chemical attributes influenced the Al fractions. Soil pH and exchangeable and soluble calcium (Caₑₓ and Caₛ) and magnesium (Mgₑₓ and Mgₛ) explained the variation of %Alₙₑ. Pₐc correlated with %Alₑₓ, whereas SOC explained the variation of %TM-Al. In general, the sucrose concentration, total recoverable sugar and stalk and sugar yields were increased by lime addition in plant cane and by lime addition and tillage systems in second ratoon. The stalk yield was highest in MDT, whereas the sugar yield was highest in both deep tillage systems.