Short-term grazing and its impacts on soil and pasture degradation

Abstract

The objective was to verify possible modifications of the soil structure and the pattern of the spectral response of pasture vegetation cover to animal trampling. The study was carried out on a farm in the Agreste region of Pernambuco, Brazil in an area with continuous grazing by heifers. Soil samples were collected at 36 regular points, before and after the grazing period, where the physical properties of the soil were determined at a 0.00—0.10 m depth. Before and after grazing, images of the Sentinel-2A satellite were also obtained to observe the pasture vegetation response pattern over time through Vegetation Indexes. The soil attribute data were submitted to multivariate factorial analysis. The vegetation index maps were evaluated for spatial variability. The results showed that after the grazing, there was a significant change in soil attributes and pasture, which can indicate possible degradation processes.

Sensing and Mapping the Effects of Cow Trampling on the Soil Compaction of the Montado Mediterranean Ecosystem

“…The economic and environmental sustainability of extensive livestock production systems requires the optimisation of soil management, pasture production and animal grazing [ 5 ], which justifies the actual research interest in animal/soil interactions [ 1 ] or in tree/soil interactions [ 6 ]. Livestock production is, however, associated with some negative environmental impacts on pasture quality or on soil attributes, becoming a precursor to degradation processes [ 7 ]. About 20% of the world’s pasture areas are degraded as a consequence of overgrazing and its associated erosion and compaction [ 8 ], where the main impact mentioned is the soil compaction by animal trampling [ 2 ].…”

“…Grazing animals can exert downward pressures on the soil surface similar or greater than those of heavy mechanical equipment [ 1 , 8 , 12 , 13 ]; therefore, this concern is understandable [ 1 ]. Soil compaction is considered, in general, a determinant factor of crop productivity [ 14 ], known and accepted as the factor that most negatively alters soil structure [ 7 , 15 ]. The hoof impact of livestock tends to cause the collapse of the larger soil pores, thus forming more small pores, increasing soil bulk density and soil penetration resistance, favouring soil compaction and, consequently, hindering the regrowth and renewal of the pasture and reducing productivity [ 7 ].…”

“…Soil compaction is considered, in general, a determinant factor of crop productivity [ 14 ], known and accepted as the factor that most negatively alters soil structure [ 7 , 15 ]. The hoof impact of livestock tends to cause the collapse of the larger soil pores, thus forming more small pores, increasing soil bulk density and soil penetration resistance, favouring soil compaction and, consequently, hindering the regrowth and renewal of the pasture and reducing productivity [ 7 ]. For these reasons, soil compaction is associated with serious soil degradation processes which culminate in a decrease in the soil aeration and water infiltration rate, and cause waterlogging, leading to runoff [ 1 , 14 , 15 , 16 ].…”

“…This process has a negative impact on the soil’s productive potential [ 17 ]. Soil type, soil moisture content and grazing management (e.g., stocking rate, stocking density or timing) are some of the factors that can accentuate the compaction resulting from animal trampling [ 2 , 7 ]. It is known that this risk is highest when the soil moisture content tends to increase [ 12 , 13 ].…”

Application of an improved vegetation index based on the visible spectrum in the diagnosis of degraded pastures: Implications for development

“…The normalized difference vegetation index (NDVI) was the most widely used indicator (de Torres et al, 2019;Imukova et al, 2015;Li, Gao, et al, 2012;Li, Verburg, et al, 2012;Valle Júnior et al, 2019;Wiesmair et al, 2016). Other frequently used indexes include the enhanced vegetation index (EVI) (Junges et al, 2016;Karnieli et al, 2013); the soiladjusted vegetation index (SAVI) (Batista et al, 2020); the leaf area index (LAI) (Batista et al, 2020;Chen et al, 2019;Wang et al, 2019); the water use efficiency (WUE) (Fernandes et al, 2018); the net primary productivity (NPP) (Fernandes et al, 2018;Jiang et al, 2019;Sun et al, 2019); among others. Many authors have also applied visible spectrum sensors (RGB) to quantify and map indicators of plant's biophysical state, such as aboveground biomass, plant vigor, productivity, and the LAI (C orcoles et al, 2013;Jang et al, 2020;Kim et al, 2019;Liu & Pattey, 2010).…”