Soil Physical Properties in a Long-Term Conservation System for Onion

Abstract

The objective of this study was to evaluate soil physical properties under different cropping systems for onion. The study was conducted on an Inceptisol in Ituporanga, Santa Catarina state, Brazil. We evaluated eight cropping systems for onion: T1: maize-onion succession; T2: common vetch-maize/rye+fodder radish-onion-maize/rye+fodder radish-common bean; T3: rye-onionmaize/black oat-maize; T4: onion-velvet bean succession; T5: rye-onion-millet/black oat-onionmillet; T6: rye-onion-velvet bean succession; T7: onion-velvet bean+millet+sunflower succession.Treatments from T1 to T7 were conducted under no-tillage system (NTS) and T8: maize-onion succession under a conventional tillage system. We used the randomized complete block design, with five replications. Undisturbed soil samples were collected at the 0-5, 5-10 and 10-15 cm soil layers and we evaluated the following soil physical properties: geometric mean diameter of aggregates, total porosity, macroporosity, microporosity, bulk density and the ratio macroporosity/ total porosity. The data analysis was performed using univariate statistics, principal components analysis (PCA) and cluster analysis (CA). Based on the cropping systems characteristics, the CA divided them into three groups: group 1: T7; group 2: T1, T2, T3, T4, T5, T6; and group 3: T8. T8 showed evidence of soil physical quality deterioration at the soil surface, T7 presented the best soil physical properties.

Soil Organic Matter, N and P in a Soil Conservation System for Onion

“…For POC, at the 0-5 cm layer, all the treatments were similar, however, despite the absence of significant differences in this layer, it´s important to highlight that T4 (onion-velvet bean succession) presented the highest POC concentration, with a value corresponding to 2.8 times the T8 (maize-onion succession in CTS) value which presented the minimum concentration. The minimum POC concentration presented by T8 may be justified by the use of chisel and rotary tiller which deteriorates the soil structure mainly at the soil surface layer as also verified in this experiment by Muetanene et al (2021).…”

Soil exchangeable cations and acidity components in different cropping systems for onion

“…For onion, cover crop residues are deposited between plant rows, especially in late Winter and early Spring, residues protect the soil surface from the impact of raindrops and reduces erosion, suppresses the incidence of weeds, and increases water storage in the soil profile (Chen et al, 2014). Several long-term studies in different Brazilian regions, climates and soils have shown that the continuous use of NTS may improve the chemical (Rheinheimer et al, 2019), physical (Reichert et al, 2016;Pires et al, 2017;Muetanene et al, 2021;) and biological soil properties (Balota et al, 2014;Demetrio et al, 2020), and increase the soil organic matter stock (Ferreira et al, 2018;Veloso et al, 2020), with its corresponding social and environmental advantages (Freitas and Landers, 2014). Thus, NTS has proven to be a reference in soil and water conservation management in Brazilian agriculture (Freitas and Landers, 2014) as well as globally (Derpsch et al, 2010).…”