The rototiller, the spade fork, and the broadfork

The rotary tiller and the spade fork

For several decades now, the rotary tiller has become the tool of choice for amateur gardeners, replacing the flat spade used by our grandparents. The rotary tiller is very effective for loosening and aerating soil to a depth of 15 to 25 cm. For individuals with areas larger than 500 m², there are also small rotary tillers with one or two removable bases so that other tools such as a milling cutter or crumbler can be attached.

There is often confusion between the work done by a rotary tiller (often mistakenly called a motor cultivator) and that done by a ploughshare. Because it mixes the soil, the rotary tiller is similar to one of the soil cultivation techniques known as “no-till farming” (TCSL). The ploughshare turns the soil. TCSL techniques have in common that they do not turn the soil. Depending on the depth of soil cultivation performed by the cutters, the rotary tiller produces a “pseudo-ploughing” (approximately 25 cm) or a superficial soil cultivation (approximately 15 cm).

While rotary tillers greatly facilitate soil preparation for amateur gardeners, they also have disadvantages:

• The rotation of the blades is merciless to earthworms, which are cut into several pieces. Only the end of the earthworm containing the head and vital organs has a chance of survival. The other pieces are doomed to die. However, the blades do not cut the microorganisms in the soil that are essential to the balance of ecosystems.
• The roots of weeds are cut into small pieces without being destroyed. Ultimately, this may result in more weeds. This problem can be partially avoided by using a rake with teeth long enough to try to collect the root pieces. You can also remove as many weeds as possible with a spade fork before using a rotary tiller.

It is certain that rotary tillers alter soil biodiversity. But this is not necessarily a bad thing. While some macroscopic populations are disadvantaged, the most useful microorganisms are boosted. Soil life depends mainly on these microorganisms and not on macro-organisms. It is microorganisms that completely recycle organic matter into mineral salts that can be assimilated by plants. Aerobic microorganisms also fix atmospheric nitrogen in the soil. By increasing soil aeration, rotary tillers enable aerobic microorganisms to colonise the soil more easily at greater depths, which has the advantage of increasing soil fertility.

Of course, as the soil is better aerated, the humus in the soil is mineralised more quickly, which means that more compost needs to be added each year to compensate for this loss. For small areas, such as those found in most private gardens today, adding organic compost is not a problem. Balanced organic fertilisers for maintaining cultivated soil can easily be found in specialist shops without breaking the bank.

For small areas of around 100 m², the fork spade is still the most suitable tool for pseudo-tilling when you want to preserve as much of the soil’s original biodiversity as possible. However, it requires more elbow grease to use. It is often necessary to spread the work over several days. Many people do not have the physical capacity to carry out pseudo-tilling properly with a fork spade. As the loss of biodiversity is not as catastrophic as some critics of the rotary tiller claim, the latter remains a very practical and effective tool for aerating cultivated soil

Using a fork spade with a handle makes it easy to remove the roots of certain tough weeds such as couch grass and eliminate wireworm larvae, which are known to be highly resistant to pesticides. This is probably the most effective way to get rid of this formidable pest without resorting to toxic products. The arrangement of the blades on the fork spade prevents damage to earthworms. This tool is suitable for mixing soil with amendments and compost without using a rotary tiller. The principle is to turn the soil over two or three times while breaking it up with the tines of the fork. A wolf-type crumbler can then be used.

However, a wolf-type crumbler has the disadvantage of cutting earthworms if they have not been removed during ploughing. Of course, using this tool requires strength and many passes. This work will be even more difficult if the soil is compact. In terms of both ease of use and results, a manual crumbler can never match the work of a rotary tiller.

For a small area, ideal soil preparation involves pseudo-tilling with the addition of inputs (compost, sandy or calcium-based soil amendments, complete base fertilisers, etc.). At the same time, weed roots, wireworm larvae and other predators living in the soil are removed.

Electric motorised cultivators are now available at very reasonable prices in some garden centres and online. Due to their reduced motor power, most of these tools are actually motorised hoes designed for shallow tilling of the top ten centimetres of soil after ploughing. These electric hoes are suitable for preparing a plot of previously ploughed land for sowing.

For deeper soil work, don’t hesitate to purchase a heavier, more powerful tool with a 2000 W electric motor, such as the Texas ELTEX2000 rotary tiller, which has an adjustable lever to control the depth of the soil work; more information here. Please note that, like all rotary tillers, this machine performs well on soil that is free of stones. Stones can block or damage the blades, or even damage the drive system. The finer the soil, the better the machine will perform.

There is still room for improvement on these new electric machines in terms of robustness and performance. For example, the use of reverse gear for the heaviest machines, or speed control for the cutters, as found on the most powerful combustion engine machines.

For amateur gardeners, there are petrol-powered rotary hoes that perform much better than electric rotary hoes. For example, the Meso rotary tiller from Pubert is ideal for a 100 m² vegetable garden. Equipped with a reverse gear, its four blades can till soil up to 29 cm deep and its handlebars are fully adjustable. This allows you to steer your machine without trampling on the tilled soil