Bioscience Journal · 2022
Physical attributes and organic material in pastures of Brachiaria brizantha at degradation levels
Rocha Junior, P. R. D., Donagemma, G. K., Andrade, F. V., Passos, R. R., Balieiro, F. D. C.
Export
Physical attributes and organic material in pastures of Brac…
Abstract
Pastures cover, in Brazil, around 165 million ha, most of them are at some degradation level. Recovering these pastures is essential. The objective of this study was to evaluate the sensibility of soil organic matter (SOM) and its physical attributes in pasture soil at different degradation levels (1 to 4), Capoeiras (1 and 2) and secondary Forest (Control). Samples were collected at four depths (0.00-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.40 m). We verified higher values for SOM and hydraulic conductivity (Ko) in Forest, especially in the most superficial layer (0.00-0.05). We noted low values for macroporosity in this area. In all areas under Pastures lower values for Ko were observed in the superficial layer (0.00-0.05 m) when compared to layers 0.05-0.10 and 0.10-0.20 m, which indicates that the pasture management and cattle trampling negatively affect the physical quality of the pastures. For field capacity and wilting point the average values were observed in Pasture 4 (more degraded), which caused higher values for water availability. According to the principal components analysis, except for SOM at 0.20-0.40 m, all variables studied presented correlation above 0.6. From grouping analysis, we separated 3 groups: Forest; Capoeiras 1 and Capoeira 2 and Pastures 1 to 4.
Show all
Pastures cover, in Brazil, around 165 million ha, most of them are at some degradation level. Recovering these pastures is essential. The objective of this study was to evaluate the sensibility of soil organic matter (SOM) and its physical attributes in pasture soil at different degradation levels (1 to 4), Capoeiras (1 and 2) and secondary Forest (Control). Samples were collected at four depths (0.00-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.40 m). We verified higher values for SOM and hydraulic conductivity (Ko) in Forest, especially in the most superficial layer (0.00-0.05). We noted low values for macroporosity in this area. In all areas under Pastures lower values for Ko were observed in the superficial layer (0.00-0.05 m) when compared to layers 0.05-0.10 and 0.10-0.20 m, which indicates that the pasture management and cattle trampling negatively affect the physical quality of the pastures. For field capacity and wilting point the average values were observed in Pasture 4 (more degraded), which caused higher values for water availability. According to the principal components analysis, except for SOM at 0.20-0.40 m, all variables studied presented correlation above 0.6. From grouping analysis, we separated 3 groups: Forest; Capoeiras 1 and Capoeira 2 and Pastures 1 to 4.
Pastures cover, in Brazil, around 165 million ha, most of them are at some degradation level. Recovering these pastures is essential. The objective of this study was to evaluate the sensibility of soil organic matter (SOM) and its physical attributes in pasture soil at different degradation levels (1 to 4), Capoeiras (1 and 2) and secondary Forest (Control). Samples were collected at four depths (0.00-0.05, 0.05-0.10, 0.10-0.20 and 0.20-0.40 m). We verified higher values for SOM and hydraulic conductivity (Ko) in Forest, especially in the most superficial layer (0.00-0.05). We noted low values for macroporosity in this area. In all areas under Pastures lower values for Ko were observed in the superficial layer (0.00-0.05 m) when compared to layers 0.05-0.10 and 0.10-0.20 m, which indicates that the pasture management and cattle trampling negatively affect the physical quality of the pastures. For field capacity and wilting point the average values were observed in Pasture 4 (more degraded), which caused higher values for water availability. According to the principal components analysis, except for SOM at 0.20-0.40 m, all variables studied presented correlation above 0.6. From grouping analysis, we separated 3 groups: Forest; Capoeiras 1 and Capoeira 2 and Pastures 1 to 4.
Findings
What changed what, as the paper reports it. Grouped by the measured property. The largest groups are open; open the others as you need them.
soil organic matter (SOM)
2
- decrease
Pastures1–4 (agreeing land-use variants) vs. secondary Forest (Control)significance not stated · 0–40 cm · November, rainy season (year unstated) · Guzerá Duas Meninas farm · 0–40cm, four sampled layers0–5,5–10,10–20,20–40cm; Pastures1–4 each below forest, largest surface contrast. Observational land uses,15 spatial samples/use/depth; no treatment-pair significance test.
Source · p. 7 “better quality under Forest due to higher contents of SOM in all the depths studied”
Source · p. 3 “there was a rapid tendency to decrease SOM contents with a small increase in the soil exposure rate.”
- decrease
Capoeiras1–2 (agreeing regeneration variants) vs. secondary Forest (Control)significance not stated · 0–40 cm · November, rainy season (year unstated) · Guzerá Duas Meninas farm · 0–40cm, four sampled layers; Capoeiras1–2 regenerating former pasture6/8years versus secondaryforest reference. Figure3 and discussion indicate incomplete SOM recovery; no pairwise tests.
Source · p. 7 “higher contents of SOM in all the depths studied”
Source · p. 6 “6 and 8 years are not yet the time required to recover soil organic matter in areas that were previously degraded pastures, especially when dealing with deeper layers. Even recomposition with capoeiras.”
hydraulic conductivity in saturated medium (Ko)
2
- decrease
Pastures1–4 (agreeing land-use variants) vs. secondary Forest (Control)significance not stated · 0–40 cm · November, rainy season (year unstated) · Guzerá Duas Meninas farm · 0–40cm, four sampled layers; Pastures1–4 versus secondaryforest. No pairwise test; exposure-fit reductions not treated as individual pasture effects.
Source · p. 7 “substitution of forest for pasture at any intensity reduces hydraulic conductivity in the soil”
Source · p. 7 “In the other areas, Capoeiras (1 and 2) and Pastures (1 to 4), the results verified were contrary to the forest, where higher Ma and lower Ko were observed.”
- decrease
Capoeiras1–2 (agreeing regeneration variants) vs. secondary Forest (Control)significance not stated · 0–40 cm · November, rainy season (year unstated) · Guzerá Duas Meninas farm · 0–40cm, four sampled layers; Capoeiras1–2 versus secondaryforest. Figure5 confirms lower Ko; observational, no treatment pair tests.
Source · p. 7 “In the other areas, Capoeiras (1 and 2) and Pastures (1 to 4), the results verified were contrary to the forest, where higher Ma and lower Ko were observed.”
macroporosity (Ma)
1
- increase
Pastures1–4 (agreeing land-use variants) vs. secondary Forest (Control)significance not stated · 5–10 cm · November, rainy season (year unstated) · Guzerá Duas Meninas farm · 5–10cm only; Figure4B direction agrees with explicit discussion. Other layers have contradictory narrative versus graph, omitted; no errorbar-overlap significance inference.
Source · p. 6 “the smaller values of forest porosity in the layer 0.05-0.10m”
Source · p. 7 “In the other areas, Capoeiras (1 and 2) and Pastures (1 to 4), the results verified were contrary to the forest, where higher Ma and lower Ko were observed.”
available water (WTC)
1
- increase
Pasture4 vs. Pastures1–3 (agreeing less degraded variants)significance not stated · 0–20 cm · November, rainy season (year unstated) · Guzerá Duas Meninas farm · 0–20cm (0–5,5–10,10–20cm), most degradedPasture4 versus less degradedPastures1–3; Figure6a–c confirms comparison.20–40cm unclear among variants, excluded. No pairwise tests, no cause assigned to grazing intensity.
Source · p. 7 “Pasture 4 presented higher retention of water”
Source · p. 7 “The higher level of degradation, the higher water retention.”
Source · p. 7 “pastures 1, 2 and 3, because they have a higher availability of grass, may be suffering with higher intensity of trampling, reducing the capacity of retention of water in the soil.”
Set-up
Treatments
- land uses and pasture degradation levels
- Pastures1–4 (agreeing land-use variants)Pastures and managed grasslandCapoeiras1–2 (agreeing regeneration variants)Transitional woodland shrubsecondary Forest (Control)Broad-leaved forestPasture4Pastures and managed grasslandPastures1–3 (agreeing less degraded variants)Pastures and managed grassland
Measured
- soil organic matter (SOM)Soil organic matter
- Unit
- dag kg-1 (text), g kg-1 (Figure3)
- Method
- Dry oxidation elementalC, PerkimElmer2400; authors multiply C by1.724 to obtain SOM. Units conflict text/figure; no chart estimates.
- hydraulic conductivity in saturated medium (Ko)Saturated hydraulic conductivity
- Unit
- mm h-1
- Method
- Undisturbed volumetric rings, Ruiz2004 saturated medium.
- macroporosity (Ma)Macroporosity
- Unit
- m3 m-3
- Method
- Water retention at0.006MPa, porous plate extractor.
- available water (WTC)Available water capacity
- Unit
- m3 m-3
- Method
- Fieldcapacity at0.033MPa minus wiltingpoint at1.5MPa; text WTC/WTF, Figure6AW.
Sites
Guzerá Duas Meninas farm
- Location
- Governador Valadares-MG, Doce River Valley, Brazil
- Land use
- PasturesPastures and managed grassland, secondary forestBroad-leaved forest, capoeirasTransitional woodland shrub
- Management on the whole site
- Bos taurus grazing extensivelyGrazing management
| Depth | Texture | Clay | pH | Organic C | Bulk density |
|---|---|---|---|---|---|
| general texture (depth not stated) | clay (argil texture) | – | – | – | – |
Similar papers
Changes in Soil Hydro-Physical Properties and SOM Due to Pine Afforestation and Grazing in Andean Environments Cannot Be Generalized
Marín et al. · 2018 · Forests
5 shared concepts
27 findings7 sites
Assessing Temporal Changes of the Soil Mechanical Strength of a Volcanic Ash Soil at Different Bulk Densities Under Pasture
Dorner et al. · 2023 · Journal of Soil Science and Plant Nutrition
4 shared concepts
11 findings1 site
Effects of Land Use on Soil Physical-Hydric Attributes in Two Watersheds in the Southern Amazon, Brazil
Moratelli et al. · 2023 · Soil Systems
4 shared concepts
11 findings2 sites
Soil Pore Architecture and Hydraulic Functioning of Native Forest and Sugarcane Systems with and Without Cover Crop Intercropping Revealed by X-Ray Computed Tomography
Awe et al. · 2026 · Forests
4 shared concepts
31 findings1 site
Soil physico-hydraulic properties under organic conilon coffee intercropped with tree and fruit species
Souza et al. · 2017 · Pesquisa Agropecuária Brasileira
3 shared concepts
19 findings1 site