Efecto de la cosecha y la labranza vertical en caña de azúcar sobre propiedades físicas del suelo en tres zonas agroecológicas del Valle del Cauca.

Abstract

The impact of mechanized harvesting and six vertical tillage treatments on bulk density (Da) and penetration resistance (Rp) was evaluated in soils from three agroecological zones (1H1, 5H3, and 15H1) cultivated with sugarcane. A Block Design in Plots with Repeated Measures was applied, and Da and Rp were measured before harvesting, after harvesting, and after tillage. The design was structured with six treatments in an arrangement of three blocks, one for each agroecological zone (ZA). The effect of using three different types of agricultural implements, commonly used in the region, named Subsoil Topo, Parabolic, Triple, and their combination, was evaluated. The results showed that mechanized harvesting caused a generalized increase in bulk density in the 0–20 cm and 20–40 cm layers of the three agroecological zones (1H1, 5H3, and 5H1), shifting initial optimal values (0.9–1.2 g/cm³) to moderate and limiting ranges (> 1.35 g/cm³), especially in the inter-row and in more clayey soils. The magnitude of this effect varied according to texture: in 1H1 (Typic Haplusterts), the greatest increases were recorded in the furrow at 20–40 cm; in 5H3 (Sodic Endoaquerts), the surface Da remained stable, but the interrow showed moderate elevations; and in 15H1 (Fluventic Haplustepts), both horizons reached critical values due to their high susceptibility to deep compaction. At the same time, penetration resistance increased significantly up to 80 cm depth: in the furrow, Rp went from < 1 MPa (0–10 cm) to > 2.5 MPa (20–40 cm), compromising the zone of maximum root proliferation; in the interrow, values reached 3 MPa at 20–40 cm. The vertical tillage implements showed soil-dependent efficacy: the triple subsoiler (T4) uniformly reduced Rp in 5H3; treatments T2 (parabolic subsoiler) and T3 (topo subsoiler) reduced Rp below the control to more than 50 cm in 15H1; and in zone 1H1, T4 and the combination T6 (topo + triple) stood out at 0–30 cm. Likewise, T3 and T6 increased surface Da, while none of the six treatments significantly modified subsurface Da, highlighting the need to adapt decompaction strategies to each agroecological zone.

The impact of mechanized harvesting and six vertical tillage treatments on bulk density (Da) and penetration resistance (Rp) was evaluated in soils from three agroecological zones (1H1, 5H3, and 15H1) cultivated with sugarcane. A Block Design in Plots with Repeated Measures was applied, and Da and Rp were measured before harvesting, after harvesting, and after tillage. The design was structured with six treatments in an arrangement of three blocks, one for each agroecological zone (ZA). The effect of using three different types of agricultural implements, commonly used in the region, named Subsoil Topo, Parabolic, Triple, and their combination, was evaluated. The results showed that mechanized harvesting caused a generalized increase in bulk density in the 0–20 cm and 20–40 cm layers of the three agroecological zones (1H1, 5H3, and 5H1), shifting initial optimal values (0.9–1.2 g/cm³) to moderate and limiting ranges (> 1.35 g/cm³), especially in the inter-row and in more clayey soils. The magnitude of this effect varied according to texture: in 1H1 (Typic Haplusterts), the greatest increases were recorded in the furrow at 20–40 cm; in 5H3 (Sodic Endoaquerts), the surface Da remained stable, but the interrow showed moderate elevations; and in 15H1 (Fluventic Haplustepts), both horizons reached critical values due to their high susceptibility to deep compaction. At the same time, penetration resistance increased significantly up to 80 cm depth: in the furrow, Rp went from < 1 MPa (0–10 cm) to > 2.5 MPa (20–40 cm), compromising the zone of maximum root proliferation; in the interrow, values reached 3 MPa at 20–40 cm. The vertical tillage implements showed soil-dependent efficacy: the triple subsoiler (T4) uniformly reduced Rp in 5H3; treatments T2 (parabolic subsoiler) and T3 (topo subsoiler) reduced Rp below the control to more than 50 cm in 15H1; and in zone 1H1, T4 and the combination T6 (topo + triple) stood out at 0–30 cm. Likewise, T3 and T6 increased surface Da, while none of the six treatments significantly modified subsurface Da, highlighting the need to adapt decompaction strategies to each agroecological zone.