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Imaggeo on Mondays: Life between the arid mountains of Gansu, China

Imaggeo on Mondays: Life between the arid mountains of Gansu, China

Even within Earth’s more arid environments, you can find life!

This featured photo was taken near the Lanzhou Zhongchuan Airport, about 50 km away from Lanzhou city, the capital of Gansu province in Western China. The area lies in a region between the Qinghai-Tibet Plateau and the Loess Plateau, with an elevation ranging from 1,500 m to 2,200 m. The landscape is dominated by a network of ridges and valleys; the Loess Plateau in particular is known for its highly erodible soil.

The region is a typical temperate or semi-arid area receiving just 260-290 mm of precipitation annually with a potential evapotranspiration of about 1660 mm each year, according to the Gaolan and Yongdeng National Meteorological Stations. However, even in these dry conditions, you can still find pockets of agricultural plots nestled between the winding mountain ridges. Farmers in this region commonly rely on an agricultural method called terrace farming, where crops are grown on graduated platforms, resembling wide steps. Often used in dry mountainous environments, the practice not only creates a flat surface for farming, but also reduces soil erosion and efficiently conserves water. The terraced farms in this area are mainly distributed in the valley where lands are irrigated for wheat and maize production.

By Olivia Trani, Communications Officer, and Xiaoming Wang, State Key Laboratory of Cryospheric Science, Chinese Academy of Science, Lanzhou, China

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Geosciences Column: The World’s soils are under threat

Geosciences Column: The World’s soils are under threat

An increasing global population means that we are more dependant than ever on soils.

Soils are crucial to securing our future supplies of water, food, as well as aiding adaptation to climate change and sustaining the planet’s biosphere; yet with the decrease in human labour dedicated to working the land, never have we been more out of touch with the vital importance of this natural resource.

Now, the first-ever comprehensive State of the World’s Soil Resources Report (SWRS), compiled by the Intergovernmental Technical Panel on Soils (ITPS), aims to shine a light on this essential non-renewable resource. The report outlines the current state of soils, globally, and what the major threats facing it are. These and other key findings of the report are summarised in a recent paper of the EGU’s open access Soil Journal.

The current outlook

Overall, the report deemed that the world’s soils are in fair to very poor condition, with regional variations.  The future doesn’t look bright: current projections indicate that the present situation will worsen unless governments, organisations and individuals come together to take concerted action.

Many of the drivers which contribute to soil changes are associated with population growth and the need to provide resources for the industrialisation and food security of growing societies. Climate change presents a significant challenge too, with factors such as increasing temperatures resulting in higher evaporation rates from soils and therefore affecting groundwater recharge rates, coming into play.

The three main threats to soils

Soil condition is threatened by a number of factors including compaction (which reduces large pore spaces between soil grains and restricts the flow of air and water into and through the soil), acidification, contamination, sealing (which results from the covering of soil through building of houses, roads and other urban development), waterlogging, salinization and losses of soil organic carbon (SOC).

Global assessment of the four main threats to soil by FAO regions. Taken from Montanarella, L., et al. 2016.

Global assessment of the four main threats to soil by FAO regions. Taken from Montanarella, L., et al. 2016.

Chief among the threats to soils is erosion, where topsoil is removed from the land surface by wind, water and tillage. Increasing rates of soil erosion affect water quality, particularly in developed regions, while crop yields suffer the most in developing regions. Estimating the rates of soil erosion is difficult (especially when it comes to wind driven erosion), but scientists do know that topsoil is being lost much faster than it is being generate. This means soil should be considered a non-renewable resource. When it comes to agricultural practices in particular, soils should be managed in such a way that soil erosion rates are reduced to near zero-values, ensuring long-term sustainability.

Eutrophication in lake Slotsø, Kolding, Denmark. Credit: Alevtina Evgrafova (distributed via imaggeo.egu.eu)

Eutrophication in lake Slotsø, Kolding, Denmark. Credit: Alevtina Evgrafova (distributed via imaggeo.egu.eu)

Soils contain nutrients, such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S), crucial for growing crops and pastures for raising cattle. While nutrient balance in soils has a natural variability, farming practices accelerate changes in soil nutrient content. Over-use of soils rapidly depletes the land-cover of nutrients and result in lower food production yields. This imbalance is often remedied by the addition of nutrients; in particular N and P. Excessive use of these practices, however, can lead to negative environmental effects, such as eutrophication (which increases the frequency and severity of algal blooms) and contamination of water resources. The findings of the report advocate for the overall reduction of use of fertilisers, with the exception of tropical and semi-tropical soils in regions where food security is a problem.

Carbon (C) is a fundamental building block of life on Earth and the carbon cycle balances the amount of C which ultimately enters the atmosphere, helping to stabilise the planets temperature. Soils play a significant role in helping to preserve this balance. Soil organic carbon (SOC) acts as a sink for atmospheric C, but converting forest land to crop land saw a decrease of 25-30% in SOC stocks for temperate regions, with higher losses recorded for the tropics. Future climate change will further affect SOC stocks through increased temperatures and fluctuating rainfall, ultimately contributing to risks of soil erosion and desertification and reducing their ability to regulate carbon dioxide emissions. It is vitally important that governments work towards stabilising, or better still, improving existing SOC stocks as a means of combating global warming.

Preserving a valuable resource

The case is clear: soils are a vital part of life on Earth. It is estimated that worsening soil condition will affect those already most vulnerable, in areas affected by water scarcity, civil strife and food insecurity.

Bed planting in northern Ethiopia. Credit: Elise Monsieurs (distributed via imaggeo.egu.eu)

Bed planting in northern Ethiopia. Credit: Elise Monsieurs (distributed via imaggeo.egu.eu)

Initiatives such as the 2015 International Year of Soil and the production of the SWRS report are fundamental to raise awareness of the challenges facing soil resources, but more needs to be done:

      1. Sustainable soil management practices, which minimise soil degradation and replenish soil productivity in regions where it has been lost, must be adopted to ensure a healthy, global, supply of food.
      2. Individual nations should make a dedicated effort to establish appropriate SOC-improving strategies, thus aiding adaptation to climate change.
      3. Manging the use of fertilisers, in particular N and P, should be improved.
      4. There is a dearth of current data, with many of the studies referenced in the SWRS report dating from the 1980s and 1990s. For accurate future projections and the development and evaluation of tools to tackle the major threats facing soils, more up-to-date knowledge about the state of soil condition is required.

Soils, globally, are under threat and their future is uncertain. The authors of report argue that “the global community is presently ill-prepared and ill-equipped to mount an appropriate response” to the problem. However, adoption and implementation of the report findings might (by policy-makers and individuals alike) just turn the tide and ensure soils remain “humanity’s silent ally”.

By Laura Roberts Artal, EGU Communications Officer

References

Montanarella, L., Pennock, D. J., McKenzie, N., Badraoui, M., Chude, V., Baptista, I., Mamo, T., Yemefack, M., Singh Aulakh, M., Yagi, K., Young Hong, S., Vijarnsorn, P., Zhang, G.-L., Arrouays, D., Black, H., Krasilnikov, P., Sobocká, J., Alegre, J., Henriquez, C. R., de Lourdes Mendonça-Santos, M., Taboada, M., Espinosa-Victoria, D., AlShankiti, A., AlaviPanah, S. K., Elsheikh, E. A. E. M., Hempel, J., Camps Arbestain, M., Nachtergaele, F., and Vargas, R.: World’s soils are under threat, SOIL, 2, 79-82, doi:10.5194/soil-2-79-2016, 2016.

Status of the World’s Soil Resources, 2015, Food and Agricultire Organization (FAO) of the United Nations.

Soils are endangered, but degradation can be rolled back, 2015, FAO News Article.

Imaggeo on Mondays: The soil in your veg patch

Imaggeo on Mondays: The soil in your veg patch

Do a search for images of dirt in Google and you might be surprised to find that the vast majority of returned images are of a substance that we ought to be protecting and treasuring, rather than dismissing as something unclean and without value: soil. It’s not the first time we’ve featured this precious resource on GeoLog recently, remember that post about soil in art? It’s not without reason either, soils play a key role in the Earth System.

“The hydrological cycle is determined by soil infiltration, the carbon cycle by soil behaviour as sink or source of CO2, rocks are weathered and form soils, fauna and flora live from and in the soil, and so on,” explains Artemi Cerdá, former president of the Soil System Sciences Division and Lecturer at the University of Valencia.

Soils also have a central role in human societies, as they are the source of services, goods and resources. Food is the most important resource we have from soils. Not only that, there is a cultural heritage for human societies related to soils: complex human organisations developed thanks to agriculture. After 12000 BP, humans developed a new strategy to exploit the land by farming, and since then our entire world was modified: welcome to the Neolithic revolution!

Modern day gardens are the best example of agriculture (in its true form, that is); they transform natural soils into man-made ones which produce vegetables and generate cultural landscapes all over the world. Take Mediterranean gardens, for instance, they hold the key to a millennia old tradition of irrigation, soil management and plants which arrived from all over the world. They are a great example of the interaction of humankind and the Earth System.

“There, in the gardens, a mixture of minerals, water, air, and biota, with the wise management of farmers, results in beautiful landscapes. And they produce food! Mediterranean gardens are one of the most productive due to the wisdom of farmers, the warm climate and the water supplied during drought periods by the flood irrigation,” says Artemi, who is passionate that this heritage must be preserved.

Artemi took today’s Imaggeo on Mondays picture, which shows the Gardens of the Celler del Roure in Les Alcusses valley in Eastern Spain. They produce high quality wine through the sustainable management of their soils, and they also produce their own vegetables. At the same time, they are a creating a modern landscape and perpetuating the heritage of Mediterranean vegetable production.

“One of our options, if we wish to have a sustainable society, is to use the knowledge in our gardens in vacant sites in the cities, in urban sprawl, in our balconies, in city gardens, and especially in our schools and colleagues because if the knowledge is lost we lose the most precious commodity we have. Gardens are more than a source of food; they are a source of culture, inspiration and millennia old knowledge,” concludes Artemi.

By Artemio Cerdá, Lecturer at the University of Valencia and Laura Roberts, EGU Communications Officer.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

 

Imaggeo on Mondays: A fly by some fantastic farming

This week’s Imaggeo on Mondays is brought to you by Kristof Van Oost, a scientist from the Georges Lemaître Centre for Earth and Climate Research (UCL) in Belgium. He tells us how local organic farms are being managed to ensure a lot of carbon stays in the soil…

An aerial photo of an organic farm, taken from a kite! (Credit: Kristof Van Oost, distributed via imaggeo.egu.eu)

An aerial photo of an organic farm, taken from a kite! (Credit: Kristof Van Oost, distributed via imaggeo.egu.eu)

This is a picture of the organic farm Het Open Veld in Leuven, Belgium. The farm is built around an alternative agriculture model in which food is grown and distributed locally – a concept known as Community Supported Agriculture (CSA). This means that about 200 people subscribe to CSA at the beginning of the year and pay a fixed sum of money to the farmer. The farmer does most of the work and when the fruit and vegetables are ready his clients come to the farm to harvest the produce themselves. Over 60 types of  fruit and vegetable are grown on this farm, not to mention the cherry trees, sheep, chicken and bees! The farm is conveniently located at the border of the city of Leuven, so production takes place very close to the people who eat the food – and it’s organic, seasonal and ethically sound.

The farmer is interested in improving the quality of his soil, mainly through adding carbon. The organic farm is very patchy and several different types of vegetables are grown on small plots. The kite pictures provide detailed information on the type and location of vegetables. Later, this information will be linked to measurements of carbon on the ground to understand the effect of soil management on carbon storage (SOGLO Project, funded by BELSPO).

By Kristof Van Oost, Georges Lemaître Centre for Earth and Climate Research, UCL

The EGU’s open access geoscience image repository has a new and improved home at imaggeo.egu.eu! We’ve redesigned the website to give the database a more modern, image-based layout and have implemented a fully responsive page design. This means the new website adapts to the visitor’s screen size and looks good whether you’re using a smartphone, tablet or laptop.

Photos uploaded to Imaggeo are licensed under Creative Commons, meaning they can be used by scientists, the public, and even the press, provided the original author is credited. Further, you can now choose how you would like to licence your work. Users can also connect to Imaggeo through their social media accounts too! Find out more about the relaunch on the EGU website.