Soil System Sciences

Wikipedia is evil

Yesterday, I had to write the exam questions for my students of Soil Science in the Faculty of Biology. As there are many more than 300, because of the facilities that my government gives to the fulfilment of the Bologna Process and the European Higher Education Area (ironic mode activated), I usually make multiple choice tests (if you do the same, have a look at this). However, I like to put some questions to see if students are able to solve problems, rather than selecting the correct answer from a number of possibilities.

To achieve this, one of the things I do is to display a picture and ask the student to give me all the information that can be extracted. For example, if I show a soil profile, I ask the student to say, only from the soil profile in the image, the geographical location, the type of climate, land use, geomorphological description of the area, etc.

Look at the soil in this hillslope. Can you tell me something about the exact location? Credit: Flickr user raindog808. Click to see the original image at Flickr.

So, for this case, I decided not to use a picture from my collection, but go into Wikipedia and search for any image useful for my purpose. I typed “suelo” (soil, in Spanish) in the Spanish edition of Wikipedia and this is how one of the most funny times I’ve spent reading since I read “Lazarillo de Tormes” started. I hope someone has corrected the Spanish Wikipedia Suelo entry after December 11th 2013 (not me).

The Life of Lazarillo de Tormes and of His Fortunes and Adversities, anonymous (1554). Click to see the original picture at Wikimedia Commons.

I found statements such as the following:

  • In a simple way, it can be said that the steps involved in the formation of soil are: “mechanical disintegration of rocks and chemical weathering of regolitic materials, (comma) releasedAnd that’s all, folks. No more stages in soil evolution.
  • On colluvium materials, that thing commonly referred to as soil may develop. That’s it, just on colluvium. And this is that thing commonly referred to as scientific language.
  • According to its function (?), soils can be “sandy, calcareous, humiferous, clayey, rocky and mixed. In the case of clayey soils, these: “are formed by fine yellowish grains and retain water in ponds. This guy has managed to see the color of clay particles!
  • Calcareous soils are white. What about terra rossa?

Calcareous soil. So white that can blind you. Credit: A. Jordán. Click to see the original picture at Imaggeo.

  • According to their physical characteristics, soil groups are: Litosols, Cambisols, Luvisols, Acrisols,  Gleysols, Fluvisols, Rendzinas and Vertisols. No more soil types according to their physical characteristics. My students are infinitely grateful.
  • There are detailed reviews of each case. Rendzinas, for example, are soils with “a horizon of about 50 cm deep. Are you sure? More: Fluvisols are rich in calcium and Lithosols are soils that appear on rocky outcrops.

A Lithosol appearing? Credit: F. Cossu. Click to see the original picture at Imaggeo.

After this, a chapter is devoted to the classification of soils. According to Spanish Wikipedia:

  • Soils can be classified according to their texture: fine or coarse. Have you heard about “silty clay loam soils”? Not me, the Super-Wikipedist.
  • Poorly developed soils are: “polar soils, deserts (rock and sand) and beaches, and there are three types: Rankers, Rendzinas and steppe soils. Please, tell me: assuming that a beach is a soil, where are beaches included?

One of the three types of poorly developed soils in the world. Credit: E. Klimenko. Click to see the original picture at Imaggeo.

  • Among the wide variety of “developed soils, there are soils of temperate forests, rainy regions, temperate climates (I guess these do not include temperate forests) and the Mediterranean red soil. Hey, hey, hey… they were not white? But do not worry, because “if the weather is suitable and the place is accessible, most of these areas are now occupied by farms.
  • One of the most important soil problems is “soil destruction. According to Spanish Wikipedia, “very serious data claim that trees will be extinguished in twelve or thirteen years, and we will need to import all the wood. This is frightening. Where will we import wood from? From Endor?

Sequoia forest in Redwood National Park (USA). Here the forest moon of Endor scenes were filmed for Star Wars Episode VI – Return of the Jedi. Click to see the original picture at the RNSP Photo Gallery.

  • More. Due to excessive sedimentation, we will end up with… navigable rivers! That’s the key issue, world!

After this, and discovering that the O horizon is the surface layer of A, the A horizon is a washed horizon and the C horizon is the subsoil “fragmented by mechanical and chemical action (but the chemical weathering does not exist), the reader finds a chapter about Soil Classification (yes, again, this is the third one in the same page). Here, you can read things like:

  • There are three main soil models, namely: the Podzol, the Chernozem and the latosol.

Dear students: I hope this will serve to understand the difference between internet and books. Next time we will talk about Google Translator.


This post was also published simultaneously in G-Soil.

Antonio Jordán is a Senior Lecturer at the University of Seville and coordinator of the MED Soil Research Group. Antonio’s research focusses on rainfall-induced soil erosion processes, the effects of wildfires on soil properties and soil degradation in Mediterranean areas. He is an active members of the Soil System Sciences (SSS) Division of the European Geosciences Union (EGU), which coordinates the scientific programme on soil sciences.