Can livestock and fires convert the sub-tropical mountain rangelands of central Argentina into a rocky desert?

2013 ◽  
Vol 35 (3) ◽  
pp. 285 ◽  
Author(s):  
A. M. Cingolani ◽  
M. V. Vaieretti ◽  
M. A. Giorgis ◽  
N. La Torre ◽  
J. I. Whitworth-Hulse ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Surface Soil ◽  
Soil Surface ◽  
Rangeland Management ◽  
Livestock Grazing ◽  
Rock Surface ◽  
High Mountain ◽  
Rocky Desert ◽  
Stocking Rates ◽  
Bare Surface

Soil erosion, as a result of livestock grazing, has been widely reported for arid and semiarid ecosystems, but information is lacking in more mesic ecosystems where erosion is generally studied in relation to agriculture. To test the hypothesis that, in the high-mountain rangelands of Córdoba (Argentina), grazing by livestock can drive the system into a rocky desert, 200 4 × 4 m plots under different livestock stocking rates and timings of grazing were monitored for 5 years. Four indicators of soil erosion: change rate of rock surface and of total bare surface, advance rate of erosion edges, and their activity persistence were estimated for each plot. Erosion edges are steps with a vertical bare soil surface, whose advance usually leaves behind an exposed rock area. For each plot, the average annual stocking rate for the 5-year period, and an index of seasonality, were calculated. Multiple regressions were used to analyse the data. Under high stocking rates, rock and bare surface increased, edges advanced faster and persisted more actively, while under low or nil stocking rates, rock and bare surface decreased and edges tended to stabilise. From these results, it was estimated that under high stocking rates, 18% of the whole area could be transformed into rocky surface in 400 years. As fire is a usual tool for this rangeland management, surface soil loss during 1 year in 77 burned and unburned plots, with and without post-fire livestock grazing, were compared. Burned plots lost 0.6 cm of surface soil when grazed, and 0.4 cm when ungrazed, while unburned plots lost less than 0.05 cm when grazed, and gained 0.07 cm when ungrazed. It was concluded that the present-day combination of livestock and fire management has the potential to convert this rangeland into a rocky desert. It is suggested that commercial livestock production, as it is carried on at present, is not sustainable, and some suggestions on changes necessary for a future sustainable grazing industry are made.

scholarly journals Effects of Domestic and Wild Ungulate Management on Young Oak Size and Architecture

2021 ◽  
Vol 13 (14) ◽  
pp. 7930
Author(s):  
Aida López-Sánchez ◽  
Sonia Roig ◽  
Rodolfo Dirzo ◽  
Ramón Perea
Keyword(s):  
Plant Height ◽  
Plant Architecture ◽  
Management Practice ◽  
Rangeland Management ◽  
Livestock Grazing ◽  
Sheep Grazing ◽  
Management Schemes ◽  
System Sustainability ◽  
Stocking Rates ◽  
Deer Grazing

Scattered oaks in traditional silvopastoral systems (i.e., “dehesas”) provide important ecological services. However, livestock intensification applied to these systems over the last century has affected the architecture of young oak plants. This unsuitable rangeland management practice jeopardizes the long-term system sustainability. Here we examine the alterations in architecture of regenerating oak plants in Mediterranean dehesas under three representative management regimes: (1) traditional management with extensive sheep grazing; (2) commercially driven management with extensive cattle grazing, and (3) native deer grazing at moderate stocking rates (<0.11 livestock units × ha-1). Plant architecture was considerably altered in cattle-grazed “dehesas”, finding a 50% reduction in plant height–diameter ratios, compared to sheep-grazed dehesas where plants with higher height–diameter ratios predominated. Young oak plants, however, showed less altered architecture and less probability of damage on shoot apex (0.20-fold difference) in areas with deer grazing at moderate stocking rates. In addition, those young oak plants with multi-stemmed individual architecture were more stunted (lower values of crown height–diameter ratio) in areas with livestock grazing than wildlife areas (0.78-fold difference). Shrub presence, under all management schemes, helped to increase in plant height, except when shrubs were located under tree canopies. Conversely, plants without shrub protection showed stunted architecture with well-developed basal diameters but short stature. Appropriate sustainable practices should include cattle stocking rate reduction, traditional sheep grazing promotion, nurse shrub preservation and fencing stunted individuals along with pruning basal sprouts. Our study indicates that management may have important consequences on dehesa regeneration via alterations of plant architecture and therefore on system sustainability.

scholarly journals Impact of Weed Control by Hand Tools on Soil Erosion under a No-Tillage System Cultivation

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 974
Author(s):  
Rafael Blanco-Sepúlveda ◽  
Amilcar Aguilar-Carrillo ◽  
Francisco Lima
Keyword(s):  
Soil Erosion ◽  
Weed Control ◽  
Soil Cover ◽  
Soil Surface ◽  
Conservation Agriculture ◽  
Soil Disturbance ◽  
No Tillage ◽  
Tropical Mountains ◽  
Litter Cover ◽  
Vegetal Cover

In conservation agriculture, the no-tillage cultivation system and the retention of permanent vegetal cover are crucial to the control of soil erosion by water. This paper analyses the cultivation of maize under no-tillage, with particular reference to the effect produced on soil erosion when weed control is performed by a hand tool (machete), which disturbs the surface of the soil, and to the behavior of the soil cover in these circumstances. The study area is located in the humid tropical mountains of northern Nicaragua (Peñas Blancas Massif Nature Reserve). The results obtained show that 59.2% of the soil surface was affected by appreciable levels of sheet and splash erosion, although the vegetal cover of the soil was relatively high (with average weed and litter cover of 33.9% and 33.8%, respectively). The use of machetes for weed control provoked considerable soil disturbance, which explained the high rates of erosion observed. Moreover, this form of soil management disturbs the litter layer, making it less effective in preventing erosion. The litter remains loose on the soil surface, and so an increase in soil cover does not achieve a proportionate reduction in the area affected by erosion; thus, even with 80–100% weed and litter cover, 42% of the cultivated area continued to present soil erosion.

Influence of climate change on soil erosion in high mountain area: a case study of upper Heihe river basin

2021 ◽  
Author(s):  
Li Wang ◽  
Fan Zhang ◽  
Guanxing Wang
Keyword(s):  
Climate Change ◽  
Soil Erosion ◽  
River Basin ◽  
Effect Of Temperature ◽  
Heihe River ◽  
High Mountain ◽  
Mountain Area ◽  
Impact Of Climate Change ◽  
High Mountain Area ◽  
The Impact

&lt;p&gt;The impact of climate change on soil erosion is pronounced in high mountain area. In this study, the revised universal soil loss equation (RUSLE) model was improved for better calculation of soil erosion during snowmelt period by integrating a distributed hydrological model in upper Heihe river basin (UHRB). The results showed that the annual average soil erosion rate from 1982 to 2015 in the study area was 8.1 t ha&lt;sup&gt;-1 &lt;/sup&gt;yr&lt;sup&gt;-1&lt;/sup&gt;, belonging to the light grade. To evaluate the influence of climate change on soil erosion, detrended analysis of precipitation, temperature and NDVI was conducted. It was found that in detrended analysis of precipitation and temperature, the soil erosion of UHRB would decrease 26.5% and 3.0%, respectively. While in detrended analysis of NDVI, soil erosion would increase 9.9%. Compared with precipitation, the effect of temperature on total soil erosion was not significant, but the detrended analysis of temperature showed that the effect of temperature on soil erosion during snowmelt period can reach 70%. These finding were helpful for better understanding of the impact of climate change on soil erosion and provide a scientific basis for soil management in high mountain area under climate change in the future.&lt;/p&gt;

COMPUTER ASSISTED MAPPING OF SOIL EROSION POTENTIAL

1985 ◽  
Vol 65 (3) ◽  
pp. 411-418 ◽  
Author(s):  
T. VOLD ◽  
M. W. SONDHEIM ◽  
N. K. NAGPAL
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Surface Soil ◽  
Mineral Soil ◽  
Weighted Average ◽  
Bare Soil ◽  
Computer Assisted ◽  
Additional Information ◽  
Potential Map ◽  
Fraser Valley

Soil erosion potential maps and summary statistics can be produced from existing information with relative ease with the aid of computers. Soil maps are digitized and survey information is stored as attributes for each soil. Algorithms are then prepared which evaluate the appropriate data base attributes (e.g. texture, slope) for each interpretation. Forty surface soil erosion potential maps were produced for the Lower Fraser Valley which identify the most erosion-prone areas and indicate average potential soil losses to be expected under assumed conditions. The algorithm developed follows the universal soil loss equation. Differences across the landscape in the R, K, and S factors are taken into account whereas the L factor is considered as a constant equal to 1.0. Worst conditions of bare soil (no crop cover, i.e. C = 1.0) and no erosion control practices (i.e. P = 1.0) are assumed. The five surface soil erosion potential classes are determined by a weighted average annual soil loss value based both on the upper 20 cm of mineral soil and on the proportion of the various soils in the polygon. A unique polygon number shown on the erosion potential map provides a link to computer tables which give additional information for each individual soil within that polygon. Key words: Erosion, computer mapping, USLE

Using soil surface gray level to determine surface soil water content

2010 ◽  
Vol 53 (10) ◽  
pp. 1527-1532 ◽  
Author(s):  
YuanJun Zhu ◽  
YunQiang Wang ◽  
MingAn Shao
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Surface Soil ◽  
Soil Surface ◽  
Gray Level

scholarly journals Gestión activa frente a matorralización: buscando el equilibrio entre conservación y explotación en montaña

2019 ◽  
Vol 45 (2) ◽  
pp. 423
Author(s):  
T. Lasanta
Keyword(s):  
Soil Erosion ◽  
Cultural Landscapes ◽  
Fire Risk ◽  
Livestock Grazing ◽  
Prescribed Fires ◽  
Negative Effects ◽  
Subsequent Increase ◽  
Positive Effects ◽  
Shrub Clearing ◽  
In Fire

The mountains of Europe, especially in the Mediterranean, have undergone a significant process of revegetation since the mid-20th century with the spread of shrublands and forests in succession stages. This leads to negative effects (degradation of pasture, accumulation of biomass with the subsequent increase in fire risk, loss or trivialized of cultural landscapes, etc.) and other positive ones (greater rewilding of landscapes, recovery of forest life, more CO2 fixation, less soil erosion, etc.). Thus, two alternatives must be put forward: either allow the rewilding process to continue, or intervene in the region to reduce the negative effects of revegetation.In this paper, the literature forms the base for a discussion on the main interventions in the territory: extensive livestock grazing, combined with prescribed fires and shrub clearing. Prescribed fires are found to be insufficient to control the spread of shrublands, and in some cases promotes its regrowth (Echinospartum horridum), as well as degrading the pasture land and increasing soil erosion. On the other hand, clearing shrubland has positive effects: a reduction in wildfires, increased livestock numbers, and improved indicators of heterogeneity and fragmentation of the landscape.

Mapping of tank silt application using Sentinel-2 images over the Berambadi catchment (India).

2021 ◽  
Author(s):  
Cécile Gomez ◽  
Dharumarajan Subramanian ◽  
Philippe Lagacherie ◽  
Jean Riotte ◽  
Sylvain Ferrant ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Properties ◽  
South India ◽  
Surface Soil ◽  
Soil Surface ◽  
Calibration Data ◽  
Surface Soil Moisture ◽  
Soil Color ◽  
Color Changes ◽  
Sentinel 2

&lt;p&gt;Mapping soil properties is becoming more and more challenging due to the increase in anthropogenic modification of the landscape, calling for new methods to identify these changes. A striking example of anthropogenic modifications of soil properties is the widespread practice in South India of applying large quantities of silt from dry river dams (or &amp;#8220;tanks&amp;#8221;) to agricultural fields. Whereas several studies have demonstrated the interest of tank silt for soil fertility, no assessment of the actual extent of this age-old traditional practice exists. Over pedological contexts characterized by Vertisol, Ferralsols and Chromic Luvisols in sub-humid and semi-arid Tropical climate, this practice is characterized by an application of black-colored tank silt providing from Vertisol, to red-colored soils such as Ferralsols. The objective of this work was to evaluate the usefulness of Sentinel-2 images for mapping tank silt applications, hypothesizing that observed changes in soil surface color can be a proxy for tank silt application.&lt;/p&gt;&lt;p&gt;We used data collected in a cultivated watershed (Berambadi, Karnataka state, South India) including 217 soil surface samples characterized in terms of Munsell color. We used two Sentinel-2 images acquired on February 2017 and April 2017. The surface soil color over each Sentinel-2 image was classified into two-class (&amp;#8220;Black&amp;#8221; and &amp;#8220;Red&amp;#8221; soils). A change of soil color from &amp;#8220;Red&amp;#8221; in February 2017 to &amp;#8220;Black&amp;#8221; in April 2017 was attributed to tank silt application. Soil color changes were analyzed accounting for possible surface soil moisture changes. The proposed methodology was based on a well-balanced Calibration data created from the initial imbalanced Calibration dataset thanks to the Synthetic Minority Over-sampling Technique (SMOTE) methodology, coupled to the Cost-Sensitive Classification And Regression Trees (Cost-Sensitive CART) algorithm. To estimate the uncertainties of i) the two-class classification at each date and ii) the change of soil color from &amp;#8220;Red&amp;#8221; to &amp;#8220;Black&amp;#8221;, a bootstrap procedure was used providing fifty two-class classifications for each Sentinel-2 image.&lt;/p&gt;&lt;p&gt;The results showed that 1) the CART method allowed to classify the &amp;#8220;Red&amp;#8221; and &amp;#8220;Black&amp;#8221; soil with overall accuracy around 0.81 and 0.76 from the Sentinel-2 image acquired on February and April 2017, respectively, 2) a tank silt application was identified over 97 fields with high confidence and over 107 fields with medium confidence, based on the bootstrap results and 3) the identified soil color changes are not related to a surface soil moisture change between both dates. With the actual availability of the Sentinel-2 and the past availability of the LANDSAT satellite imageries, this study may open a way toward a simple and accurate method for delivering tank silt application mapping and so to study and possibly quantify retroactively this farmer practice.&lt;/p&gt;

A synecological account of the Suikerbosrand Nature Reserve. II. The phytosociology of the Ventersdorp Geological System

Bothalia ◽  
1980 ◽  
Vol 13 (1/2) ◽  
pp. 199-216 ◽  
Author(s):  
G. J. Bredenkamp ◽  
G. K. Theron
Keyword(s):  
Plant Communities ◽  
Soil Texture ◽  
Nature Reserve ◽  
Surface Soil ◽  
Soil Depth ◽  
Soil Surface ◽  
Habitat Features ◽  
Species Groups

The vegetation of the Ventersdorp Geological System of the Suikerbosrand Nature Reserve is analysed and classified according to the Braun-Blanquet method. Descriptions of the plant communities include description of habitat features, the identification of differentiating species groups as well as the listing of prominent and less conspicuous species for the tree, shrub and herbaceous layers. The habitat features that are associated with differences in vegetation include altitude, aspect, slope, rockiness of soil surface, soil depth and soil texture.

scholarly journals Erosion Control in the Sustainable Cultivation of Maize (Zea mays L.) and Beans (Phaseolus vulgaris L.) at Two Stages of the Agricultural Cycle in Southern Guatemala

2018 ◽  
Vol 10 (12) ◽  
pp. 4654
Author(s):  
Rafael Blanco Sepúlveda ◽  
Francisco Enríquez Narváez
Keyword(s):  
Soil Erosion ◽  
Ground Cover ◽  
Erosion Control ◽  
Soil Surface ◽  
Plant Litter ◽  
Mean Values ◽  
Tillage Practices ◽  
Erosion Threshold ◽  
Two Stages ◽  
Vegetal Cover

Agricultural intensification in the mountains of Central America has increased soil vulnerability to erosion by water. This study was undertaken to analyse the erosion that affects the mixed cultivation of maize and beans at two stages of the crop development cycle (at 3 and 6 months after sowing) in southern Guatemala, together with the influence of the ground and crop canopy vegetal cover on soil erosion. The main aim of this analysis is to establish the soil erosion threshold enabling sustainable agriculture. The results obtained show that the soil surface was severely eroded, with mean values of area affected of 88.4% and 73.5% at 3 and 6 months, respectively. In the 3-month plots, the erosion bore scant relation to the factors analysed. Conversely, the area affected by soil erosion in the 6-month plots was significantly related to the degree of ground cover by weeds and litter, and the erosion threshold was located at 80% of vegetal cover. However, plots with this level of cover did not achieve effective erosion control, due to the low level of plant litter cover (15.7%) compared to that of weeds (75.5%). We conclude that this low content of vegetal residue in the soil, together with the tillage practices employed, explains the large surface area affected by erosion and the impossibility of establishing an erosion threshold.

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