Rangeland degradation in a semi-arid South Africa—II: influence on soil quality

Snyman, H.A.; Preez, C. C. du

doi:10.1016/j.jaridenv.2004.06.005

Cited by 102 publications

(70 citation statements)

References 91 publications

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“…These results showed that grazing depresses SOC content and storage, which is in accordance with some previous studies (Snyman andDu Preez 2005, Wu et al 2010). They are, however, in contrast to studies of Gao et al (2007Gao et al ( , 2009, who conducted experiments in an alpine meadow that were used as winter pasture (October to May).…”

Section: Resultssupporting

confidence: 93%

Grazing depresses soil carbon storage through changing plant biomass and composition in a Tibetan alpine meadow

Sun¹,

Wesche²,

Chen³

et al. 2011

Plant Soil Environ.

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Grazing-induced variations in vegetation may either accelerate or reduce soil carbon storage through changes in litter quantity and quality. Here, a three-year field study (2005)(2006)(2007) was conducted in Tibetan alpine meadow to address the responses of surface soil (0-15 cm) organic carbon (SOC) storage in the plant growing season (from May to September) to varying grazing intensity (represented by the residual aboveground biomass, with G 0 , G 1 , G 2 , and G 3 standing for 100%, 66%, 55%, and 30% biomass residual, respectively), and to explore whether grazinginduced vegetation changes depress or facilitate SOC storage. Our results showed that: (i) Higher grazing intensity resulted in lower biomass of grasses and sedges, lower root biomass, and in a change in plant community composition from palatable grasses and sedges to less palatable forbs. (ii) Increased grazing reduced the SOC content and storage with only G 3 showing an SOC loss during the plant growing season. (iii) Soil organic carbon storage exhibited a highly positive correlation with the residual aboveground biomass and root biomass. Our results imply that a grazing-induced reduction in plant biomass productivity and changes in species composition would depress soil carbon storage, and that an increase in grazing pressure can lead to a gradual change of alpine meadow soils from being 'carbon sinks' to become 'carbon sources' .

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Section: Resultssupporting

confidence: 93%

Grazing depresses soil carbon storage through changing plant biomass and composition in a Tibetan alpine meadow

Sun¹,

Wesche²,

Chen³

et al. 2011

Plant Soil Environ.

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“…Loss of vegetation cover and removal of leaf litter led to the formation of soil seals (Singer and Bissonnais 1998) and exposure of soil particles to the direct impact of raindrops (Mohammad and Mohammad 2010), both of which enhance runoff and soil erosion (Descroix et al 2001(Descroix et al , 2008Snyman and duPreez 2005;Al-Seikh 2006). Overgrazing and cattle movement were the main causes of gully erosion in mountainous areas (Descroix et al 2008).…”

Section: Discussionmentioning

confidence: 99%

Linking fine root and understory vegetation to channel erosion in forested hillslopes of southwestern China

Zhou

et al. 2014

Plant Soil

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Aims The forestland understory vegetation reduces concentrated overland flow through infiltration improvement by roots and raindrop interception by surface cover. However, little has been done to quantify the linkages between understory vegetation cover, roots, and channel erosion, and such information can help assessing the role of the reforestation in soil erosion control. In this study, we evaluated the relationships between channel density, root density, and vegetation cover in forested hillslopes of southwestern China. Methods Twelve locations (four slopes and three positions) of forested hillslopes with a wide range of understory degradation due to litterfall extraction and livestock grazing were selected for the study. Channel density as a measure of rill and (small) gully erosion, root density of different diameter classes, and vegetation cover of all types were determined using field measuring, soil coring and the line transect method, respectively. Soil loss rates were estimated using the caesium-137 ( 137 Cs) technique. Results Rills (depth<0.3 m) with a width of 0.05-0.1 m were the dominate channel erosion in all hillslopes with understory-degradation, and small gullies (depth>0.3 m) with a width 0.5-1.0 m were found at the locations of hillslopes with high understory-degradation. Channel density and soil loss rate increased with the increase in understory-degradation in the forested hillslopes. Simple correlation analysis indicated that channel density was negatively correlated with fine root density (diameter< 1 mm and 1-2 mm) and grass and shrub covers, but not with coarse roots (diam. 2-5 mm and 5-10 mm) and mulch and tree covers. The principal component regression revealed fine root density (diam. <1 mm), shrub and grass covers were the most important predictors for channel density in the forested hillslopes. Tree cover, mulch cover and coarse root density were found to have much less influence on channel density. For the model established from this study using principle component regression, vegetation variables could explain 82 % variance of channel density.

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“…Sustainable management of rangeland soils is especially challenging because of high variability, harsh environments, and the temptation for over-grazing. A reduction in the proportion of palatable perennials, increases in densification (compaction), and declines in SOC are some of the constraints that need to be alleviated [90][91][92]. An important strategy to reduce the risks of degrading rangeland soils is to conserve and efficiently manage soil water through an improved understanding of the hydrological attributes [93,94].…”

Section: Soil Restorative Farming/cropping Systemsmentioning

confidence: 99%

Restoring Soil Quality to Mitigate Soil Degradation

2015

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Abstract:Feeding the world population, 7.3 billion in 2015 and projected to increase to 9.5 billion by 2050, necessitates an increase in agricultural production of ~70% between 2005 and 2050. Soil degradation, characterized by decline in quality and decrease in ecosystem goods and services, is a major constraint to achieving the required increase in agricultural production. Soil is a non-renewable resource on human time scales with its vulnerability to degradation depending on complex interactions between processes, factors and causes occurring at a range of spatial and temporal scales. Among the major soil degradation processes are accelerated erosion, depletion of the soil organic carbon (SOC) pool and loss in biodiversity, loss of soil fertility and elemental imbalance, acidification and salinization. Soil degradation trends can be reversed by conversion to a restorative land use and adoption of recommended management practices. The strategy is to minimize soil erosion, create positive SOC and N budgets, enhance activity and species diversity of soil biota (micro, meso, and macro), and improve structural stability and pore geometry. Improving soil quality (i.e., increasing SOC pool, improving soil structure, enhancing soil fertility) can reduce risks of soil degradation (physical, chemical, biological and ecological) while improving the environment. Increasing the SOC pool to above the critical level (10 to 15 g/kg) is essential to set-in-motion the restorative trends. Site-specific techniques of restoring soil quality include conservation agriculture, integrated nutrient management, continuous vegetative cover such as residue mulch and cover cropping, and controlled grazing at appropriate stocking rates. The strategy is to produce "more from less" by reducing losses and increasing soil, water, and nutrient use efficiency.

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Rangeland degradation in a semi-arid South Africa—II: influence on soil quality

Cited by 102 publications

References 91 publications

Grazing depresses soil carbon storage through changing plant biomass and composition in a Tibetan alpine meadow

Grazing depresses soil carbon storage through changing plant biomass and composition in a Tibetan alpine meadow

Linking fine root and understory vegetation to channel erosion in forested hillslopes of southwestern China

Restoring Soil Quality to Mitigate Soil Degradation

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