Global change pressures on soils from land use and management

Abstract

Soils are subject to varying degrees of direct or indirect human disturbance, constituting a major global change driver. Factoring out natural from direct and indirect human influence is not always straightforward, but some human activities have clear impacts. These include land-use change, land management and land degradation (erosion, compaction, sealing and salinization). The intensity of land use also exerts a great impact on soils, and soils are also subject to indirect impacts arising from human activity, such as acid deposition (sulphur and nitrogen) and heavy metal pollution. In this critical review, we report the state-of-the-art understanding of these global change pressures on soils, identify knowledge gaps and research challenges and highlight actions and policies to minimize adverse environmental impacts arising from these global change drivers. Soils are central to considerations of what constitutes sustainable intensification. Therefore, ensuring that vulnerable and high environmental value soils are considered when protecting important habitats and ecosystems, will help to reduce the pressure on land from global change drivers. To ensure that soils are protected as part of wider environmental efforts, a global soil resilience programme should be considered, to monitor, recover or sustain soil fertility and function, and to enhance the ecosystem services provided by soils. Soils cannot, and should not, be considered in isolation of the ecosystems that they underpin and vice versa. The role of soils in supporting ecosystems and natural capital needs greater recognition. The lasting legacy of the International Year of Soils in 2015 should be to put soils at the centre of policy supporting environmental protection and sustainable development.

Soil carbon debt of 12,000 years of human land use

“…Scaling these limited point measurements to calculate a cumulative SOC loss for the world's agricultural land has been difficult, with estimates ranging from 40 Pg C to over 500 Pg C (20). Recent estimates from dynamic global vegetation models run with actual land use versus with potential natural vegetation have put this figure at 30 Pg C to 62 Pg C for the industrial post-1850 period (21,22).A credible estimate of the global total and spatial distribution of SOC loss is a critical step in understanding the potential for soil carbon sequestration to be an effective climate abatement strategy. To quantify the cumulative impact of human land use on changes in SOC at the global scale, we have developed a machine learning-based data-driven statistical model, which is based on a global compilation (N = 158,147) of soil profile observations and samples collated at The International Soil Resource and Information Center (ISRIC) -World Soil Information over the last decade (23).…”

“…Scaling these limited point measurements to calculate a cumulative SOC loss for the world's agricultural land has been difficult, with estimates ranging from 40 Pg C to over 500 Pg C (20). Recent estimates from dynamic global vegetation models run with actual land use versus with potential natural vegetation have put this figure at 30 Pg C to 62 Pg C for the industrial post-1850 period (21,22).…”

Introductory Chapter: Land Use Change Ecosystem Services and Tropical Forests

“…Carbon emissions due to deforestation in the tropics were 810 Tg C year −1 between 2000 and 2005 [30], in which Brazil and Indonesia were the first two contributing countries with an emission rate of 340 and 105 Tg C year −1 , respectively. Soil carbon loss due to land use change in the tropical area was estimated to be 79 Pg CO 2 during the past 150 years (1860-2101, averaged from three different models) [31].…”

Soil carbon sequestration by three perennial legume pastures is greater in deeper soil layers than in the surface soil

“…Recent studies on the Loess Plateau have investigated and estimated the changes in SOC stocks in the top 1 m of soil as a result of revegetation of regional watersheds (Fu et al, 2010;Wang et al, 2011;Yan et al, 2007;Zhang et al, 2013). However, deep-rooted perennial legumes may penetrate deeper in the soil profile than 1 m, likely underestimating the SOCsequestration potential of these forage legumes in northwest China (Smith et al, 2015).…”