Loss of topsoil – part of chapter 1 of research study

A thin layer of organic matter produced over thousands of years by the natural life-cycles, topsoil is “comprised of countless species that create a dynamic and complex ecosystem”1. It is home “to billions of beneficial microorganisms per handful, in addition to nutrients, fungi and worms that are critical to healthy plant life”2 Topsoil is “among the most precious resources to humans.”3 In the informative documentary named ‘Dirt’ (2009), which takes its name from the common and often pejorative use of the mostly American word that denotes soil in general, topsoil is indeed shown to be the ‘precious resource’; as stated in the synopsis of the documentary4, ‘dirt’ has has “given us food, shelter, fuel, medicine, ceramics, flowers, cosmetics and color [sic] – everything needed for our survival.”

As forests are cut because of human activity5, the soil that was previously covered by the trees is left unprotected. The exposed topsoil is then exposed to all sorts of weathering (direct sunlight, extremes of hot and/or cold, water flows, etc.) which gradually kills the myriad of life present in healthy topsoil – the soil literally withers and dies shortly after its protecting canopy of trees is removed, and the resulting lifeless substance is easily eroded under different weather conditions. In wet climates, topsoils simply erode as water washes freely over tree-felled landscapes. As David Montgomery, a geologist at the University of Washington and the author of the book “Dirt” (2007), points out, the “estimate is that we are now losing about 1 percent of our topsoil every year to erosion”6. Montgomery adds that it is mostly due to human agriculture that such a worrying rate of topsoil-loss is occurring.

The World Wildlife Foundation corroborates the concerning rate of topsoil-loss: it states that “half of the topsoil on the planet has been lost in the last 150 years”7. The WWF draws attention to accompanying impacts of topsoil loss; for example, once forests are cleared and topsoils eroded into a water supply, it can eventually clog the supply and thereby adversely affect fish and other species. Land lacking a healthy layer of topsoil is also prone to flooding, which increases the level at which erosion occurs. The WWF is unambiguous when it comes to the causes of the topsoil-loss phenomenon: “transition to agriculture from natural vegetation often cannot hold onto the soil and many of these plants, such as coffee, cotton, palm oil, soybean and wheat, can actually increase soil erosion beyond the soil’s ability to maintain itself”8.

The result of topsoil loss is, of course, highly problematic considering the above information alone, but there is one last point that needs to added here: the global loss of topsoil is the loss of the fragile layer of ‘substance’ in which the bulk of human food is grown. Restated, we are losing that which is required to grow the food needed for human survival. According to University of Sydney professor John Crawford9, “we have just about 60 years of good soil left at current erosion rates due to farming methods that strip the soil of nutrients, which could lead to a serious food crisis in the mid-21st century”.

The above statement, however, could mislead readers – there is already a food crisis, one in which topsoil loss has played a central role. Take Haiti for example: a 2013 report says the following10: “An estimated 1.5 million Haitians face hunger because of poor harvests and rising food prices, … says the U.N. World Food Programme”. There is a long history behind Haiti’s food crisis; the following from National Geographic11 is offered to summarise Haiti’s situation in particular, and to put information about topsoil loss (and deforestation) into more perspective:

Virtually since 1492, when Columbus first set foot on the heavily forested island of Hispaniola, the mountainous nation has shed both topsoil and blood – first to the Spanish, who planted sugar, then to the French, who cut down the forests to make room for lucrative coffee, indigo, and tobacco. Even after Haitian slaves revolted in 1804 and threw off the yoke of colonialism, France collected 93 million francs in restitution from its former colony—much of it in timber. Soon after independence, upper-class speculators and planters pushed the peasant classes out of the few fertile valleys and into the steep, forested rural areas, where their shrinking, intensively cultivated plots of maize, beans, and cassava have combined with a growing fuelwood-charcoal industry to exacerbate deforestation and soil loss. Today less than 4 percent of Haiti’s forests remain, and in many places the soil has eroded right down to the bedrock. From 1991 to 2002, food production per capita actually fell 30 percent.

1http://worldwildlife.org/threats/soil-erosion-and-degradation accessed 19 May 2014

5“Increased demand for agriculture commodities generates incentives to convert forests and grasslands to farm fields and pastures”. From http://worldwildlife.org/threats/soil-erosion-and-degradation accessed 19 May 2014; “Forests are cleared all around the world for a number of reasons, including: Harvesting of timber to produce wood and paper products; Clearing land for farms, cash-crop plantations, and cattle ranching; Clearing land for urban development, including homes and roads.” From http://www.ecokids.ca/pub/eco_info/topics/forests/threats.cfm accessed 19 May 2014

8Same source as above footnote