The intense and successive use of mechanization in modern cropping systems has increased soil compaction under no-till areas. In this study, we aimed to assess the performance of a fixed shank coupled with a seeder for the mitigation of soil compaction induced by machinery traffic as an efficient alternative to replacing the chiseling and subsoiling operations in no-till areas. We evaluated a long-term experiment conducted in clay loam (Rhodic Haplustox) soil in southern Brazil. The experiment was conducted under a randomized block design, whose treatments consisted of three wheel-traffic intensities: 0 wheel-traffic (0 WT), 14 wheel-traffic (14 WT), and 28 wheel-traffic (28 WT), combined with four soil tillage mechanical interventions under a no-till field: no-till (NT), no-till with a fixed shank (NT + FS), soil chiseling (SC), and soil subsoiling (SS). The soil physical attributes evaluated were the soil penetration resistance (SPR), macroporosity (MaP), microporosity (MiP), total porosity (TP), bulk density (BD), field-saturated hydraulic conductivity (K_fs), S index, and plant-available water capacity (PAWC). In addition, three critical soil physical functions were evaluated by using a soil physical quality index (SPQI). The results showed that SPR was sensitive to soil compaction and captured differences among the mechanical intervention methods. Machinery traffic caused soil compaction, increasing SPR and reducing PAWC. Soil chiseling and subsoiling promoted lower BD, a higher TP, MaP, Kfs, and higher S index at the 0.05–0.15 m soil layer. Based on the SPQI, no changes were detected in the soil physical functions between NT and NT + FS. On the other hand, SC and SS enhanced soil physical functioning by 10%. We concluded that a 15-cm deep fixed shank could not mitigate the soil compaction induced by machinery traffic at the seeder operation. Therefore, this method is less effective in improving the soil’s physical environment than chiseling and subsoiling operations. Finally, we encourage monitoring the persistence of these benefits on the soil over the subsequent crop seasons and in years with an intense water deficit along with the crop cycle.

Soil health has been used worldwide for soil monitoring in different soil use and management. The objective of the study was to evaluate, in a Subtropical Oxisol of the Campos Gerais region in Paraná state, if the Visual Evaluation of Soil structure (VESS) and Soil Management Assessment Framework (SMAF) approaches allow evaluate soil response to various land uses or soil tillage used in the region. The land use and tillage practices consist of conventional tillage, minimum tillage, no-tillage, and secondary forest. The SMAF was used as a tool to evaluate the soil health using five indicators: pH, phosphorus, potassium, bulk density, and soil organic carbon. The VESS was used to determine the soil structural quality. The secondary forest showed the best soil structure and tillage practices declined soil structure quality. Similarly, the soil health index was higher in secondary forest compared to tillage practices, and the tillage had little effect on soil health. The SMAF showed differences between land use and tillage practices. The VESS method could be used as a complementary tool for monitoring the soil health.

The soil tillage practiced over a long period of time impacts soil quality. The first step in soil quality assessment is to select which indicators should be used. The objective of this study was to identify the soil attributes that discriminate soil tillage systems and can be used as indicators for soil quality assessments. Sixteen soil physical and chemical attributes were evaluated: macroporosity (MaP), microporosity (MiP), total porosity (TP), bulk density (BD), field-saturated hydraulic conductivity (Kfs), soil resistance to penetration (SRP), pH (H2O), pH (CaCl2), aluminium (Al), calcium (Ca), magnesium (Mg), potassium (K), available phosphorus (P), total organic carbon (TOC), cation exchange capacity (CEC) and base saturation (BS), of a very clayey Red Latosol, cultivated for a long period in no-till (NT), conventional tillage (CT) and minimum tillage (MT). The soil attributes (indicators) were selected using canonical discriminant analysis. MiP, Kfs, pH (CaCl2), Ca, Mg, CEC e BS were the most efficient indicators to discriminate soil tillage systems. In the indicator interpretation step was sustained MiP as the indicator that represents the function of physical stability and support, Kfs as the indicator that represents the function of water relations, BS as the indicator that represents the function of nutrient cycling and pH (CaCl2) as the indicator that represents the function of filtering and buffering. These indicators can be used for future soil quality assessment and monitoring of tillage systems in similar regions and conditions.

Soil fertility and conservation tillage systems play important roles in agro–ecosystem productivity and preservation. Soil spatial variability of phosphorus (P) and potassium (K) was studied in different tillage systems. The objectives of this research included: (i) to assess the variability of P and K in three tillage systems: minimum tillage (MT), conventional tillage (CT) and no–till (NT), and depth of 0–0.1 m and 0.1–0.2 m, and (ii) to map their spatial distribution. The field experiment was conducted in a Rhodic Haplustox. The samples were collected in a regular grid of 10 × 5 m with regularly spaced lines of 10 m, resulting in 50 samples on each soil tillage system, in the depth of 0–0.1 m and 0.1–0.2 m. The spatial variability of P and K was determined by using the kriging maps. In the NT (depth of 0–0.1 m), the distribution and concentration P and K was more uniform in the area, and in the CT, due to inadequate management of the soil and topography of the terrain influenced the displacement of P via leaching and erosion. In the MT there were large patches of P and K pulverized by the area and a tendency of nutrient loss that occurs due to the erosive process of the soil, decreasing the nutrient of the soil. In the CT and MT, the altitude influenced the concentration of P and K in the 0–0.1 and 0.1–0.2 m layer, that is, the higher the altitude, the lower the concentration of P and K. Spatial variability of P and K in soil depends on both factors, degrees of mobility of nutrient, altitude and on management practices. Altitude (e.g. topography) and tillage systems variability in soil P and K concentration are potentially of agronomic importance.