Fallow Reduces Soil Losses and Increases Carbon Stock in Caatinga

Abstract

This study aimed at evaluating whether 10 years of fallow was sufficient to restore a degraded hillslope in the semi-arid Caatinga biome, Brazil. For this purpose, runoff, erosion, loss of nutrients and organic carbon were measured on two comparable hillslopes: one was left fallow and the other degraded caused by overgrazing. Fallow management reduced runoff (36%), soil loss (65%) and organic carbon loss (81%) in comparison with the degraded hillslope. However, the fallow did not significantly reduce nutrient loss. Animal grazing has been shown to influence the nutrient cycle in the soil. The loss of organic carbon shows significant correlation with the loss of other nutrients, and may be used to estimate nutrient loss. Results show that a decade of fallow did not promote significant changes in the loss of nutrients, but was enough to reduce runoff, erosion and loss of organic carbon.

Erosion at hillslope and micro‐basin scales in the Gilbués desertification region, Northeastern Brazil

“…In Gilbués, we understand that the extensive soil exposure influences the high C factor more than the vegetation size (Bagarello et al, 2018; Cebecauer & Hofierka, 2008; Schönbrodt et al, 2010). Besides, soil exposure during the dry season facilitates heating, causing soil temperature to rise up to 83°C, which hinders vegetative restoration by fallow (Almeida et al, 2017) and makes restoration more unlikely to occur, in contrast to the successful Spanish experience reported by Navarro‐Hevia, de Araújo, and Mongil‐Manso (2014). Schönbrodt et al (2010) show the high temporal variability of the C factor in China.…”

“…The prevalence of the Maner Equation ), whose only parameter is the ratio between a reference basin height and a basin length, over other models in such different spatial scales (from 10 −4 to 10 +3 km 2 ) suggest that relief is the key element to interpret long‐term sediment deposition (directly related to delivery ratio). In fact, terrain steepness influences (and is influenced by) soil formation, runoff formation (De Figueiredo, de Araújo, Medeiros, & Costa, 2016) and velocity, vegetation pattern (Almeida et al, 2017), and, thus, sediment dynamics (Nadal‐Romero & Regüés, 2010).…”

“…Anthropogenic erosion affects hydro‐sedimentological processes and causes significant impacts on environment and society, among which is soil degradation (Mukundan, Radcliffe, Ritchie, Risse, & McKinley, 2010; Zhao, Kondolf, et al, 2017; Zhao, Mu, et al, 2017), particularly in arid and semiarid regions (Moghadam, Jabarifar, Bagheri, & Shahbazi, 2015; Vaezi, Abbasi, Bussi, & Keesstra, 2016; Vaezi, Abbasi, Bussi, & Keesstra, 2017; Vaezi, Zarrinabadi, & Auerswald, 2017). It also impairs agricultural and forest yield (Almeida, de Araújo, Costa, Almeida, & Andrade, 2017); harms transport infrastructure (Cerdá, 2007; Farias, Medeiros, Navarro‐Hevia, & de Araújo, 2019; MacDonald, Sampson, & Anderson, 2001; Navarro‐Hevia, Farias, de Araújo, Osorio‐Peláez, & Pando, 2016); pollutes (Chaves, Lopes, Maia, Meireles, & Andrade, 2019; Gilley, 2005), and reduces water availability due to reservoir siltation (de Araújo, Güntner, & Bronstert, 2006; Medeiros & de Araújo, 2014; Zhang et al, 2016).…”

Grazing exclusion regulates bacterial community in highly degraded semiarid soils from the Brazilian Caatinga biome

“…This biome presents high seasonality, encompassing a mosaic of scrub vegetation and patches of dry forest, adapted to poor soils, and stressed environmental conditions, such as high temperatures and severe droughts (Leal, da Silva, Tabarelli, & Lacher Jr., 2005; R. M. Santos et al, 2012). However, among the main anthropic threats, slash-and-burn practices for the collection of firewood and charcoal, along with overgrazing, have contributed to the desertification of the Caatinga biome (Almeida et al, 2017;Brazier, Turnbull, Wainwright, & Bol, 2014;Cerdà & Lavee, 1999;Kurz, Coxon, Tunney, & Ryan, 2005).…”

Fungal community structure and functional genes abundance in Brazilian drylands under desertification process

“…Importantly, it presents a high biodiversity of plants and animals (Albuquerque et al, 2012), including microorganisms (Pereira et al, 2020, which are essential to Caatinga biome maintenance. Although important, this biodiversity is threatened by deforestation, unsuitable soil management, and overgrazing of native vegetation Almeida et al, 2017;. Between 1985 and 2020, an estimated more than 6 million hectares of native Caatinga vegetation were lost, mainly to livestock activities (MapBiomas, 2022), and it has brought adverse effects on plant diversity in this biome (Schulz et al, 2019).…”