After a fire, the soil sparks interest

Jorge Mataix-Solera in a soil profile in fire-affected area in Guimaraes, Portugal. Photo: A. Cerdà

In 2015, thousands of wildfires burned across the world. Over 20,000 square kilometers have burned in Indonesia this year after annual, and perhaps some illegal, burning of peatland became unmanageable. In the United States, a combination of extended drought and high winds has led to over 37,000 square kilometers catching fire. And in Australia, a massive bushfire caused by lightning, dry conditions and a heatwave continues to burn.

Fire is a natural part of almost every ecosystem. It can clear away dead and decaying materials and make way for new growth. There are even some plants that exhibit pyriscence, releasing their seeds only in response to a fire. While the effect of fire on flora is well studied less is know about how fire effects the living material beneath vegetation, the soil.

Dr. Jorge Mataix-Solera has been studying fire’s effect on soil for more than two decades. In 1994, when Jorge was considering what subject to pursue for his PhD, thousands of hectares of land caught fire around his home-city of Alicante in eastern Spain. His father, a professional soil scientist, had ‘taught him to love the soil’ and now the circumstances in Alicante provided him the motivation (and grant money) to pursue his degree.

Jorge has traveled to Israel, Wales, United States, Australia, and Slovakia to investigate fire’s effect on soil. Fire only interacts with the top few centimeters of soil, but it can have enormous repercussions for the soil properties within those few centimeters. Depending on the severity of the fire, soil organic matter can be burned off, which in turn effects the quantity and quality of the soil microbial community. A fire can also alter soil structure, which can lead to less water infiltration and more erosion.

Another post-fire trend that has interested researchers is water repellency in soils. Water repellency can contribute to erosion and water runoff, the latter of which when paired with a lack of vegetation can lead to catastrophic flooding. Water repellency, as Jorge points out, doesn’t happen ‘in a uniform layer: it’s patchy.’ In the past, this inconsistency was primarily explained by the varying temperatures achieved by the soil during a fire, or ‘the type of vegetation which excretes different organic compounds’ that coat soil particles and repel water. But thanks in part to Jorge’s work, another explanation based on the materials that make up the soil can be included.

The soil has four basic ingredients, and certain ingredients repel water more than others. Soil is composed of minerals, organic matter, water and air. We have already mentioned that some organic compounds can repel water, and the same is true for organic matter. The minerals fraction – from biggest to smallest – is sand, silt and clay. Sand particles, which are coarse and have a low surface area, need very little organic compounds to coat them. Clay particles, on the other hand, are tiny and have over 1,000 times the surface area of sand. They need a lot of organic compounds to coat them in order to become water repellent. As Jorge states, ‘if there is a little bit more clay that may make the difference between if a drop stays on the soil surface or infiltrates.’

In the 21st century the number of large and uncontrollable fires – fires that can burn off organic matter and change the ability of water to infiltrate the soil – has increased on all vegetated continents. This surge in fire frequency and intensity is due to many factors. In some regions a higher proportion of climatic extremes such as drought has led to drier conditions and an abundance of parched vegetation that is ready to spark. Humans moving into previously uninhabited areas is also an issue as naturally occurring fires, which previously might have been allowed to burn, are extinguished to preserve the new inhabitants’ homes. When a fire does ignite, the glut of vegetative fuel that has accumulated over the years can lead to fires with greater intensity and higher potential to become uncontrollable.

After these destructive fires, it is extremely important to protect the soil. Post-fire management can be in some situations, says Jorge, ‘worse than the fire.’ ‘In many cases the land managers want to remove the dead trees. And if they do this when the soil is very fragile – in the first few months after a fire just when some vegetation is just starting to grow – it can degrade the soil.’

During the International Year of Soils, Jorge has been taking citizens and students from fire-affected areas in Spain to his study sites. They work together to set up plots with different types of management. One plot might have mulch applied while another is compacted as if heavy machinery had been used to remove the trees. Then they use a rainfall simulator to measure which plot has the highest amount of water runoff and erosion. ‘And really, the difference was amazing,’ says Jorge. The mulched plots had little water runoff, and what did runoff was crystal clear. Almost all the water ran off the compacted plot and the water was muddy with eroded soil.

Jorge hopes that experiences like this will encourage citizens to value the soil. He likes the term ‘geoderma’ to describe soil, from the Greek for ‘earth’ (geo) and ‘skin’ (derma). It helps people to understand ‘that the soil is not meters and meters and meters, we have only centimeters of soil. And we must take care of it.’

 

 

 

 

Gully developed after post-fire management of salvage logging (removing trees) and rainfall of 50 mm in a few hours. Pictured: researchers from the University Miguel Hernández. Photo: J. Mataix-Solera
An activity with children using a rain simulator in a fire–affected area. Sierra de Mariola, Alicante, Spain. Photo: J. Mataix-Solera
An activity with children using a rain simulator in a fire–affected area. Sierra de Mariola, Alicante, Spain. Photo: J. Mataix-Solera
An activity with children using a rain simulator in a fire-affected area. Plot with straw mulch treatment. Sierra de Mariola, Alicante, Spain. Photo: J. Mataix-Solera
Water over an extremely water repellent soil that was burned in Pinoso, Alicante, Spain. Photo: J. Mataix-Solera
Researcher Katka Chrenkova installing a plot in fire-affected area before the first soil sampling. Montgó Natural Park. Alicante, Spain. Photo: J. Mataix-Solera

The views expressed here belong to the speaker and do not necessarily represent FAO’s views, positions, strategies or opinions.

Submitted by Catherine DeLong

 

 

 


Comments:

Caption Aesthetic 22-06-23 07:42
Comfort Zone Mattress 07-06-23 09:45
King Size Bed in Dubai
While it's not always possible to find the best living room furniture, it is definitely possible to find an affordable piece of king size bed.

that is of excellent quality and will last for years. The following are some of the best brands to consider. Hopefully, you can find the perfect set to suit your needs. If you have no idea where to start, these tips will help you narrow down your options. Read on to discover the best furniture for your home. Let's begin!



First and foremost, determine the look and feel of the room. Consider the style of the room and what you want to achieve with the space. A rustic, country look will call for solid wood pieces, while a modern, minimalist look will require fuss-free furniture collections with clean lines. If you're planning on a family room or a relaxed living room, you can opt for plush sofa sets with comfortable cushions and a multi-functional coffee table.

Sofa Set in Dubai
To add character, choose a sofa and lounge chair with tufted upholstery. The combination of these two pieces will create a feast for the eyes and soul. Another option is carved wood furniture. This option offers both elegance and durability. This style is also upholstered in silk fabric. The leather can be easily maintained. A sofa with carved wood legs is an excellent option for a contemporary home. It's also possible to find leather furniture that matches your color scheme.

Collapse
Storage ottomans are another great option for the living room. They're versatile, providing both comfortable seating and storage space. They're perfect for a minimalist home, and can be paired with a sofa and other furniture. Depending on the size of the room, an ottoman can either double as a coffee table or serve as a footrest. Make sure to leave enough room for it to fit comfortably. You don't want to overcrowd the room with too many pieces. It's important to choose the right size ottoman for the room and to ensure that it complements the other items in the room.

Living room furniture
When selecting the best living room furniture, look for a blend of high-quality materials and an affordable price. Although many companies offer great living room furniture, there are some that stand out among the rest. Comfort Zone Mattress & Furniture stands out among these because it combines age-old manufacturing techniques with modern-day machinery and technology. This company offers a wide range of living room furniture. A combination of these factors allows you to create a room with a unique look and feel.



Consider durability. The best living room furniture is not cheap, and you don't want to replace it every year or two. Make sure you get a quality sofa with a stain-resistant fabric. Another important feature to consider is the cushion material. Foam cushions are more durable and comfortable, so make sure to look for these features before you purchase your furniture. You may also want to invest in media storage furniture. This will allow you to store and display your electronics and DVDs.
Tommy Wilson 29-05-23 08:39
With the Linksys extender properly set up, you can enjoy expanded Wi-Fi coverage and improved connectivity throughout your home or office.
https://www.linksys-extendersetup.com/
Fsh furniture 18-05-23 09:57
Welcome to FSH Furniture – [furniture stores](https://fshfurniture.ae/) in dubai. Shop for bed furniture, TV cabinets, dressing tables and more.
donky hote 12-05-23 13:56
There are many different types of https://car-games.io available for you to play, depending on your interests and preferences. Some popular types of car games include racing games, driving simulation games, and open-world driving games. Here are a few examples of popular car games.
Jordan jasy 09-05-23 12:47
https://www.anobii.com/en/019e2426d9b33a984b/profile/activity
🍉 Watermelon is a refreshing fruit that is enjoyed by many during hot summer days. It is sweet, juicy, and filled with essential nutrients that the body needs.
carrot Gudie 20-04-23 06:45
Thank you for sharing this information and your experience!

https://carrotguides.com/

<a href="https://carrotguides.com/
">carrotguides</a>
Loufing Loufing 19-04-23 11:49
Cataract Surgery Cost in Kolkata – A Comprehensive Guide
🤔Cataracts is a common eye problem that affects many people, 👀especially those who are over 60 years of age. It is a condition that causes the natural lens of the eye to become cloudy, leading to a loss of vision👓.

https://surgery-costs.com/cataract-surgery-cost-in-kolkata/
janni olsson 17-04-23 06:55
The following helpful article will provide every detail on Australian super Quicksuper login, registration, and retrieving your account. Read the article carefully and get the most out of the payment portal. https://employeebenefitnow.com/quicksuper-login/

> Not a member yet? click here to register
> Forgot password?

Share this page