Hoeing
In agriculture and gardening, hoeing consists of loosening the superficial layer of soil around cultivated plants. Hoeing can be done using manual tools such as the hoe and hand hoe, or mechanically using specialized instruments like the hoe.
Hoeing and weeding
When hoeing is done to remove weeds, it is called weeding. True hoeing serves to loosen and aerate the superficial layer of soil between cultivated plants.
By breaking any crust of crusting that forms due to watering and rain, water penetration into the soil is facilitated. Evaporation of water from the soil is also limited. Indeed, hoeing creates conditions that prevent water from rising by capillarity to the surface and breaks the cracks that appear in the soil when it is very dry.
Soil work by hoeing leads to its aeration and warming, which temporarily accelerates the mineralization process of organic matter, allowing the release of nitrogen available to plants. This phenomenon often results in healthier plants that become greener and grow better. The observed effect resembles that of a "boost" fertilizer application.
Finally, thanks to hoeing, plant roots breathe better, which helps reduce the appearance of mold.
Agricultural hoes
In agriculture, hoes are either pulled by draft animals or tractors. Some models are mounted at the front of the tractor to facilitate guidance.
To accommodate the use of hoes, crops are grown in rows with more or less spacing. It is difficult to reduce the spacing below about twenty centimeters without risking damaging the crop in place. For example, 20 cm for wheat, 40 to 60 cm for beets or rapeseed, and finally 75 to 80 cm for corn.
The tools are equipped with teeth and shares allowing soil work at the desired depth. Wide shares allow shallow soil work that cuts weeds 2 or 3 cm below the soil surface, at their roots, which is enough to destroy them. Indeed, if the weather is dry, no longer supplied with water, they die within a few hours to a few days. If it rains again, some may re-anchor their roots in the soil and continue their development. A second hoeing will be necessary if they are too numerous.
Some tools are adjustable or equipped with parts allowing ridging of the crop row, which covers small weeds on or near the row. This helps limit the competition these weeds have with the crop.
To preserve the crop in place, it is necessary to keep the tool in the inter-row space under penalty of damaging the crop. For this, different systems have been implemented:
- On animal traction systems, the operator guides the tool; precision is low and it is not allowed to work more than 60% of the inter-row width.
- On tractor traction systems, the operator can also guide the tool with the tractor's movement, whether pushed or pulled. Other solutions improve the work done: precision allowing work on 80% of the inter-row and working speed.
- Manual lateral guidance of the hoe: a person guides the hoe laterally behind the tractor using a steering wheel or joystick if it is a hydraulic system.
- Automated guidance of the hoe following different markers:
- Following a furrow dug in the soil during sowing
- Row sensors: detect the rows of the cultivated plant by touching them
- Camera that detects the rows of the cultivated plant
- GPS following the path made during sowing previously recorded
Manual guidance requires two operators, one driving the tractor, the other the hoe; reaction time is slow and working speeds are limited. The furrow and GPS systems allow intervention at any time, including before crop emergence. The camera system allows following the rows as soon as the crop has emerged but is less effective if there are many weeds. Finally, the row sensor is effective if the crop is tall enough and weeds are not well developed. In the 2000s, small "autonomous" hoeing robots, such as the Oz robot from the start-up Naïo Technologies, appeared on the market, equipped with cameras and infrared vision for market gardening.
