We are all very aware of the importance of the soil in a kitchen garden. Without good quality soil, it is difficult to yield a good harvest without using chemical plant protection products. A soil that lacks nutrients is not a gardener’s only fear: a shrinking biodiversity (particularly when using pesticides, fungicides and other chemical products) can be catastrophic for crops.
That is because under our feet, a multitude of creatures go about making the soil, which is so dear to us, of a better quality. Without this biodiversity, the soil would die. As an inert material, soil needs this fauna to regenerate itself. So, you ask yourself, who are these soil builders?
What is soil?
In pedology (the science of studying soil), the soil is not only studied in terms of composition, but also life, as one cannot exist without the other. From the biodiversity present comes the chemical composition, the quality, and from this quality comes the biodiversity. Hence, soil works in a cycle, which results in its strength and its weakness at the same time.
In his “Guide to the experimental study of soil”, Albert Demolon, a pedologist, defines the soil as the following: “the natural formation of ground, with a moveable structure and varying weight, resulting from the transformation of the underlying bedrock due to various processes – physical, chemical and biological – in contact with the atmosphere and living creatures.”
Without going into detail on the soil’s composition, as here we are more interested in the soil’s biodiversity than its composition, we can nevertheless have a simple overview.
Biodiversity has an essential role in the soil’s fertility, the protection of species, the battle against soil erosion, good drainage of resources or nutrients by water, and can even play a role in decontamination.
But what is soil biodiversity made of?
Soil biodiversity can be divided into four families:
- Mega fauna found on the surface: toads, snakes, moles…
- Macro fauna, visible to the naked eye: earthworms, ants, larvae…
- Mesofauna, visible under a magnifying glass: mites, springtails…
- Micro fauna, visible under a microscope: protozoa, nematodes, fungi, bacteria, algae…
Each of these families has a specific role in the soil’s structure. The macro fauna that gardeners know well, such as earthworms or ants, are known as “physical engineers”, that’s to say that they are in charge of the soil’s renewal: they build habitats for other organisms in the soil, and are responsible for spreading organic matter and good water distribution.
Mesofauna play the role of “regulator” with regards to the population of microorganisms living in the soil, and so are predators that can save our crops from various diseases linked to having too many fungi or bacteria in the soil. These micro-organisms that make up the mesofauna are the “chemical engineers” of soil. They are in charge of decomposing organic matter, thereby supplying nutritional elements. They are also capable of attacking some pollutants.
How do you promote this biodiversity?
• Avoid ploughing the soil
How many gardeners use a tiller in their gardens? Far too many. We know that as gardeners grow older, working the soil becomes very difficult, but did you know that if you do it right, your soil will rediscover its balance and you won't have to work so hard to have loose soil? What's more, when you use the tiller too deep, you can dislodge species from their natural habitat, so everything will be upside down and nobody will be able to find where they are. That's without considering the death of many worms and other creatures. Remember, an earthworm cut in two inevitably dies.
• Balance the amount of organic materials
Gardeners like us know that it is important to watch the amount of organic materials (such as compost, for example). As well as bringing nutrients thanks to the biodiversity in them, it also allows us to protect our soil and thereby improve its ability to retain water.
• Don't use chemical products.
With us, it's all biological! We can never repeat it too often: stop using chemical plant protection products. The biodiversity that maintains and works your soil will never thank you enough for it, and your crops will never look better. These days there are many biological solutions to help you fight against potential invasions or infections.
• Use green manure to minimise erosion
Bare soil is sensitive to all kind of things, notably the weather, whether it is rain, wind, drought, etc. In the growing season, don't skimp on ground covers and mulching. As well as conserving the soil's heat, these covers will allow water to be conserved for longer. In periods of drought like last year where the rain gauge remains low, this will give the garden a helping hand.
If you decide to leave a flowerbed bare in a less prosperous period or in case of absence, don't hesitate to use green manure (e.g vetch, mustard, etc.) which will nourish and protect your soil and will ultimately act as ground cover for your other crops.
In winter, you can observe a drop off in animal activity, whether they be mammals, reptiles, insects or even fish. However, not all animals behave the same way in the face of winter’s harshness. So what do they do?
To confront the cold, animals adapt different behaviours depending on either they stay where they are and therefore have to find a way to fight the cold, or alternatively leave and find a warmer place (the latter is done by some birds, insects, butterflies and fish).
When animals stay where they are, they must prepare themselves to fight the cold. They do so in three different ways:
• Morphological adaptation;
• Physiological adaptation;
• Behavioural adaptation.
Whilst some only adapt morphologically, others adapt to winter in all three ways. Each species has its own trick.
Some animals continue to move around in winter, living almost normally. Almost, because in reality they do adapt to lower temperatures and a shortage of food.
Some animals opt for morphological adaptation, which means modifying their body, such as the fox, which develops a “winter coat”. You see this in some mammals but also in certain birds, who fluff up their plumage. Other animals, such as the hare and stoat, go even further in modifying their coat: they turn white in winter to camouflage them in the snowy landscape and not be seen by predators.
Other animals, such as the great tit, change their behaviour and feeding habits. In fact, for the majority of the year the great tit eats insects, but during the winter it struggles to find insects and therefore eats seeds instead. As for the red squirrel, it simply builds up reserves of food throughout the year in preparation for winter, then once winter is here it continues to live normally. Only in severe cold, which can be fatal, will it take shelter until the temperature is milder. In fact, January-February is one of the breeding seasons for red squirrels.
You will also see some animals change physiologically, meaning that they change how their body works: this is the case of animals that hibernate or spend winter sheltering.
When the winter cold arrives, some animals adopt a behaviour called torpor: they fall into a very deep sleep, in a shelter, and only rarely wake up to get something from their food reserves that they built up prior to hibernating. When an animal hibernates, there is a drop in:
• Oxygen consumption;
• Respiratory rate;
• Heart rate (from 350 to 3 beats per minute for the ground squirrel, and from 500 to 5 for the garden dormouse);
• Blood flow (there is a special flow for the brain, heart and fatty tissue);
• Growth hormones.
Here are just some of the animals that hibernate: hedgehogs, garden dormice, bats, frogs, lizards, grass snakes…
Beware that some animals do not hibernate but do spend winter sheltering. Famously the bear, that there is no risk of finding in our garden, spends winter sheltering, rather than hibernating.
Winter sheltering (semi-hibernation)
When you think of hibernation you think of bears. However, that is wrong. In no way is the bear in a state of torpor, as it does not sleep deeply, far from it. The bear simply slows its activity; so, do not hang around near a bear, thinking it is hibernating, stay far away. An animal that does semi-hibernate and that you have more chance of coming across than a bear is the badger! You also see this drop in activity in some insects, such as bees, who rest next to each other to maintain their temperature at 35°C and eat the honey that they have stored (which is why it is important to leave it there).
And where are the insects in all of this?
Unfortunately, the majority of insects die in winter. This is the case with the magnificent dragonflies and grasshoppers. But some of them can semi-hibernate, even if all those who do don’t survive. Alongside bees, this also includes firebugs, ladybirds, earwigs, crickets and lacewings.
The olive tree is widespread in the south of France but can acclimatize itself pretty much anywhere. Although it is not common in our gardens due to its large size, we all use olive oil. We often add it to our vegetables; whether it be on salad, in food preparation, cooking or even in cosmetics. But did you know that as well as tasting good, olive oil is also good for you? In this article you will discover the benefits of olive oil, but don't forget that – as with everything – you shouldn't go overboard with it.
Olive oil is good for our health
First of all, if you aren't sure which olive oil to pick, it is best to choose cold-pressed, bio, extra-virgin olive oil. Above all, avoid refined and heated oils which are cancerogenic and harmful to health.
Olive oil contains oleic acid (56-83%), an acid which can reduce the highest cause of death: cardio-vascular disease.
It also contains as much linoleic acid (Omega 6) as breast milk; so you could put a spoonful of olive oil in your children's soup. Omegas 3 and 6 are essential fatty acids that we can't produce ourselves and that we can only get from our food.
However, beware of taking too much, as Omega 6 must always be balanced with Omega 3, which we often get too little of. You can find Omega 3 in fatty fish and certain fibres (flax, walnut, rapeseed, soya etc.)
What's more, olive oil has anti-oxidant properties (vitamins E, C and polyphenols) that prevent cancer, as these properties prevent the ageing of cells.
If you heat the oil, beware that it becomes cancerogenic at temperatures of more than 210c; so if your oil smokes, you must discard it.
Olive oil vs cow's milk
When we are cooking and want to add fat, we generally use butter from cow's milk, or oil. Although they are not the same from a taste perspective, and their use varies by region and cooking habits, you should know that olive oil is better for your health than butter.
Olive oil only contains 14% saturated fat, which is a lot less than margarine, which is around 40%, and butter, which contains 55%. Olive oil is the most easily digested fat: you can even use it instead of butter on your toast in the morning, if you place it in the freezer the night before.
In addition to being the most digestible, it has as much calcium as cow's milk, at 120mg per 100g; however, vegetable calcium is 75% absorbed by the digestive tract, as opposed to only 30% for animal calcium.
Olive tree flowers
Only one flower in 20 becomes an olive. Olive tree flowers can also be used for their energy: dried and in herbal tea. They are anti-cancerogenic, nourish the skin, can be used as a gentle laxative, for rheumatisms and are good for the brain.
Jardin Familial de France no. 502/2017