A drought is a normal occurrence in arid and semi-arid environments. It is caused by a prolonged shortage of water due to atmospheric, surface, or ground water conditions and it is one of many factors that can lead to land degradation. While a drought can affect crop yields, good management practices can reduce the impact of droughts by increasing water holding capacity of the soil, reducing evaporation, and creating shaded microclimates. However, in the absence of practices that create more resilient agronomic systems, more frequent and intense droughts can lead to desertification.
Desertification is an overall decrease in plant and biological productivity causing a shift from productive land to more baren, infertile land that cannot support plant growth. It can be the result of natural processes or it can be induced and accelerated by human activities, a key activity being agriculture land use. As natural processes like droughts become more common under climate change, there is an increased risk of desertification on croplands because the conventional way agriculture is practiced is not as resilient under drought conditions compared to other types of agriculture production systems, namely regenerative agriculture.
In Corsica, South of France, climate change, monoculture and higher temperatures have slowly induced drought and desertification in the summer. Those droughts are some of the reason behind intense wildfires.
You may have heard people refer to land being “broken” when natural areas are converted to agriculture use. When this conversion happens, the land and the soil undergo a change which, more often than not, is a decline in soil quality and fertility which we term soil degradation. So in a sense, this conversion marks the start of a breakdown of the land and the normal ecosystem functions it can provide.
Soil degradation is a result of physical, chemical and biological processes. Physical processes are set in motion by a decline in structure and the strength of soil aggregates to be held together, caused by excessive plowing and a reduction in soil organic matter which is the glue that holds soil aggregates together. Chemical degradation is caused by losses of essential nutrients for plant growth, which are leached out and lost. Changes in soil pH, salinity, and the breakdown of soil aggregates combined with excessive irrigation and drainage transports these nutrients from the land into water where they can cause problems for water quality and ecosystem health. Soil biological processes, which are fueled by soil organic matter, decline as this food source is lost from the soil from erosion, decreased organic inputs and the removal of crop residues.
At PUR Projet, we see regenerative agriculture as intrinsically linked to farmer livelihoods as it must also provide beneficial economic and social impacts for farmers and local communities if it is to be sustainable over the long term.
Globally, the total extent of soil degradation in 2003 was estimated to be 13,048 Mha (Lal, 2003). So, is this land lost or can we improve it so it’s productive again? If we discard it and break new land for agriculture production how long until it becomes degraded and we need to find new land? I like analogies so let me try to use one here.
Imagine your first bank account. Your parents open it for you and put in $100 which seems like a lot of money for your 10-year-old self. You go to the store and buy some candy and now you have $98 which still seems like a lot of money and the amount of new candy you can buy is more than you can even imagine eating so you’re feeling pretty good about your candy budget. A few months go by and suddenly you only have $13 left to buy candy. You run to your parents and tell them the horrible news that you’re nearly out of money and you need them to put another $100 in your account so you can continue your endless buying of candy. To your shock, they inform you they don’t have another $100 to give you and suggest you get a job!
We started off with a bank account full of free, productive, and high-quality soil. We’ve been making withdraws for more than a century by extracting the natural fertility of soil that has been built up over millennia to produce our food. Now, we’re down to $13 so it’s time to find a job and get to work. Back to the analogy.
You hear about a new company that is hiring (let’s call it Regenerative Agriculture INC.) and it seems like a good way to start banking some money. You get an entry-level position, start doing your duties (agroforestry, windbreaks, cover cropping) and begin making a steady paycheck and adding to your bank account. As you learn more, you’re promoted to a mid-level position with more responsibility (diverse crop rotations, mulching, conservation tillage, riparian restoration) and you start adding even more money to your account. You’re promoted once again to a senior level position with new duties (composting, alley-cropping, integrated crops and animals, no-till) and with your new income, you’re able to build back up a solid amount in your bank account. Of course, you still have your candy expenses but now you have a steady income to support your sweet tooth. So, let’s have a closer look at that job description called regenerative agriculture.
Regenerative agriculture encompasses holistic practices that create net beneficial impacts on ecosystem services. At PUR Projet, it’s a base upon which we build our projects to restore ecosystems, sequester atmospheric carbon into soils and aboveground biomass, improve watershed health, and promote biodiversity. We see regenerative agriculture as intrinsically linked to farmer livelihoods as it must also provide beneficial economic and social impacts for farmers and local communities if it is to be sustainable over the long term.
Regenerative practices can create more resilient agro-ecosystems under a changing climate. Let’s use a period of drought as an example and highlight a few regenerative practices that can mitigate its effects. Cover cropping and compost application can improve soil structure through the addition of organic matter which helps to bind soil aggregates together. This creates more micropores and macropores where water can be stored during rainfall events and released to plants during dry spells. Reducing tillage or adopting no-till avoids disturbing the soil which causes these aggregates to breakdown and these important pore spaces to be lost. Agroforestry, the integration of trees into cropland, can shade soil and reduce evaporation while minimizing the loss of organic matter from erosion by slowing down wind and reducing surface runoff. Organic matter is an incredibly important piece of overall soil health and is tied to many important soil functions so increasing organic matter often means a more resilient system.
On this day for Day for Desertification and Drought, let’s recognize the contribution our current agricultural system has to these issues and think about the investments that are needed to create more resilient production systems in the face of climate change. Let’s all get to work and start making deposits in our shared bank account called soil.
Lal, R. Soil degradation and global food security: A soil science perspective. In Land Quality, Agricultural Productivity, and Food Security: Biophysical Processes and Economic Choices at Local, Regional, and Global Levels; Wiebe, K.,Ed.; Edward Elgar Publis
Paul is an adaptive manager, problem solver, and soil expert with a strong understanding of carbon dynamics and sequestration potential under various agricultural management practices. After earning his MSc in Soil Science, Paul joined PUR Projet as Project Manager and lead on Regenerative Agriculture topics, where he develops, implements, manages and monitors ecosystem restoration projects in agricultural landscapes across North America.