A Revista Ciência Agronômica é voltada para estudos relacionados com as Ciências Rurais e Recursos Naturais

Operational conditions of mechanized harvesting can affect the quality of harvested sugarcane. Therefore, the aim of this study was to assess the influence of the displacement speed and cutting height on the quality of the raw material during the mechanized harvest of sugarcane. Vegetable losses were accounted for in the field by manual collection of the fractions left after harvest. Vegetable and mineral impurities were determined at the processing stage in the laboratory. Both the displacement speed and cutting height did not affect vegetable losses. However, the increase in vegetal impurities occurred at higher displacement speeds, whereas lower cutting heights resulted in higher amounts of mineral impurities.

Soil compaction between crop rows can increase a machine’s performance by reducing rolling resistance and fuel demand. Controlled Traffic Farm (CTF) stands out among modern techniques for increasing agricultural sustainability because the machines continuously travel along the same path in the field, reducing plant crush and compacting the soil in the traffic line. This study evaluated fuel consumption and CO₂ emissions at different CTF intensities in different soil management strategies for soybean crop. The experimental design involved randomized blocks in a split-plot scheme with four replications. The plots constituted the three types of soil management: conventional tillage, no-tillage with straw millet cover, and no-tillage with brachiária straw cover. The subplots constituted for agricultural tractors were passed over in traffic lines (2, 4, and 8 times). We evaluated agricultural tractor fuel consumption, CO₂ emissions, and soybean productivity. The straw cover and tractor-pass significantly affected the fuel consumption and greenhouse gas emissions of the soybean cultivation. Fuel consumption and CO₂ emissions were reduced due to the machine-pass increase, regardless of soil management. Thus, a CTF reduces rolling resistance and increases crop environmental efficiency. Bare-soil areas increased by 20.8% and 27.9% with respect to fuel consumption, compared to straw-cover systems. Brachiária straw and millet reduce CO₂ emissions per hectare by 20% and 28% compared to bare soil. Lower traffic intensities (two passes) showed (13.72%) higher soybean yields (of 4.04 Mg ha⁻¹). Investigating these effects in other types of soil and mechanized operations then becomes essential.

The quality of sugarcane broth can be affected by soil management. In compacted soils the productivity is reduced, and the raw material is poor. This research aimed to evaluate productivity and quality of sugarcane for four soil management types: (CT) heavy harrow + light harrow; (CTI) Subsoiler + light harrow; (MT) Subsoiler and (NT) no soil movement. The variables investigated were resistance to soil penetration (SPR), the chemical raw material quality (broth) and crop yield. In crop rows, SPR did not reach severe levels up to 0.3 m for sugarcane root development. However, below this layer, MT, NT, and CTI reached SPR limiting values of 2.50, 2.35 and 1.95 MPa, respectively. In inter-crop rows, compaction was concentrated in soil surface layers (0–0.3 m). In addition, all adopted managements presented SPR above the critical value (2 MPa). The soil preparation forms qualitatively affected the sugarcane broth, showing higher fiber and protein contents in NT, MT, and CT. The PS, Brix, TRS, and Pol were not affected by soil management. Still, higher absolute values were found in the NT, indicating an increase in broth quality when applying conservation management. The highest yields were obtained by reduced tillage (MT), surpassing the lowest yield management (NT) with an increase of 10.5 Mg ha⁻¹.