دانلود کتاب خاک های حاشیه ای آفریقا – بازاندیشی در کاربردها، مدیریت و احیا

With the world population expected to grow from 8 billion to a projected 10 billion by 2050, the signi_icance of natural arid and semiarid rangelands becomes increasingly crucial (Alkemade et al. 2013). Currently, these ecosystems cover approximately 25% of the Earth’s land surface, supporting over one billion people’s livelihoods through livestock grazing and agriculture (van Oudenhoven et al. 2015). In Africa alone, rangelands account for approximately 65% of the total land surface (Nalule 2010), and provide a variety of ecological, cultural, biological, and socio-economical goods and services (Mussa et al. 2016). However, rangeland degradation poses a serious threat globally, including in sub-Saharan Africa impeding the effective management of arid and semi-arid areas (Mureithi et al. 2014). Approximately 75% of the world’s grazing land has already lost its capacity to sustain livestock (Moyo et al. 2013) due to local and global drivers of degradation. South Africa has been particularly impacted, with approximately 70% of its land surface degraded caused by soil erosion resulting in poor soil fertility and productivity (Le Roux et al. 2007). Notably, the grasslands and savannas have experienced substantial loss of soil organic carbon (SOC) compared to croplands and areas with a mix of natural vegetation and crops within regions like Argentina, southern Africa, and Australia. The restoration and conservation of these rangelands are of utmost importance to ensure the continued provision of essential services and support for both ecosystems and the communities that depend on them in the face of future population growth. However, South Africa is a country of extreme contrasts, with 80% of the country de_ined as arid to semi-arid, with an average rainfall of 450 mm per annum, compared to a world average of 910 mm per annum (Alkemade et al. 2013). The South African National Report on Land Degradation (NRLD; Wessels et al. 2007) indicates that rangeland degradation is severe on communal lands and small patches of commercial lands. Although rangeland productivity and resilience to environmental variability are a function of soil health and microbial functional diversity (Plassart et al. 2008), the effects of rangeland management and land-use change on land degradation and agricultural productivity remain poorly understood (UN 2011). This is because most soil functions recover slower than the biotic attributes such as vegetation structure and diversity, and consequently, they are only rarely measured (Ruiz-Jaen and Aide 2005). However, agro ecosystems that include grazing are more productive, stable and resilient when the soil is fully functional biologically, and they provide greater earnings and more abundant ecosystem services (Teague et al. 2013). Monitoring the impacts of grazing management practices on soil quality (SQ) is essential to ensuring the sustainability of grazing systems (Amorim et al. 2020).