Ploughing is a traditional farming practice used to cultivate the topsoil in preparation for sowing. By turning over the soil between 10 and 35cm deep, ploughing creates a seedbed that promotes proper root growth and facilitates the circulation of water and air. The preparation of the seedbed directly influences agricultural yields. Discover the key principles for working the soil and optimising its potential to support your crops.
Importance of the seedbed
The main goal of preparing the seedbed is to create a crumbly, uniform surface that promotes quick germination and allows for easy root exploration for uniform crop development. A well-prepared top layer of soil provides a solid foundation for achieving high yields.
The soil’s particle size must serve several purposes for the crop:
- Eliminate excess water caused by heavy rainfall
- Act as a barrier to prevent evaporation
- Capillary action draws essential water to support root development
- Facilitates proper gas exchange through the soil particles
Conditions for preparing and homogenising the soil
Before preparing the soil each year, it is essential to consider factors such as soil type, its history, yield potential, and, most importantly, the current weather conditions. It is recommended to carry out the soil preparation as close to sowing as possible to prevent the soil from drying out or compacting.
Choose a sowing period when the soil has had time to warm up. Heat is a crucial element to initiate quick germination. A fine soil structure promotes faster warming and ensures optimal contact between the seeds and the soil. The soil should not be worked in excessively wet conditions, as this can lead to compaction.
The seedbed preparation will vary depending on the type of seeds being sown:
- For smaller seeds, the soil needs to be finely prepared through shallow cultivation, as the seed will be sown at a shallow depth. This applies to forage legumes (such as alfalfa, lupine, vetch, clover), rapeseed, grasses, etc.
- Larger seeds are more tolerant of surface aggregates (maize, sunflower, soya, etc.). Additionally, aggregates help reduce soil crusting during rainfall. Their size should be adapted to the size of the seed being sown.
Incorporation of plant residues, weeds, and organic amendments
In agriculture, the plough is one of the most effective tools for uniformly incorporating organic materials such as cover crops, harvest residues, weeds, and their seed bank into the soil at the desired depth. By incorporating fertilisers (fertiliser, manure, etc.) into the soil, ploughing reduces losses due to run-off or evaporation.
Ploughing accelerates the decomposition and transformation of organic materials into essential nutrients for plants. This process enables plant roots to access these nutrients more easily, allowing them to reach their full physiological potential and achieve high yields.
The timely availability of nutrients is critical for crop development, especially in diversified rotations.
Simplified tillage systems (STS) or direct sowing techniques may not effectively incorporate surface residues into deeper soil layers. This is where the plough offers a comprehensive action: it turns the topsoil while burying vegetation and bringing fertile soil to the surface, creating an ideal environment for future crops.
Finally, ploughing helps correct an uneven distribution of straw or issues related to weed control.
Loosening and aerating the soil
To sow a cereal crop, the soil must be properly warmed and well-aerated and have good structure. The soil should be loose, fine, and free of obstacles, with the right moisture content, avoiding excess. Soil aeration through ploughing optimises the circulation of water and air, both essential for plant growth. However, it is important to avoid creating air pockets, as they can hinder seed-to-soil contact, reducing germination rates.
Therefore, attention must be paid to weather conditions and the plough adjustments to ensure quality ploughing and create an ideal seedbed that facilitates the passage of the seed drill. A ploughing depth of less than 20cm helps control weeds and prepares the soil for subsequent interventions.
The working depth of the soil directly affects the quality of the seedbed and the overall health of the soil. Excessive ploughing depth can damage soil structure, deplete organic matter, and bring infertile soil layers to the surface. Conversely, shallow ploughing may fail to eliminate weeds or incorporate crop residues properly.
Homogenising and levelling the seedbed
Homogenising and levelling the soil is essential for preparing it to provide optimal conditions for germination, crop growth, and high yields. A levelled seedbed ensures precision and uniformity during sowing, resulting in rapid and even emergence.
Insufficient tamping pressure reduces interactions between the soil and the seed, as well as between the roots and the soil, which hinders seed hydration and impedes effective rooting of the young seedlings. A strong root system is essential for ensuring good water and nutrient absorption for the crops. Additionally, soil discontinuities can interfere with crop growth.
Successful soil preparation supports post-ploughing tools and prevents the formation of compacted areas, positively impacting the precision and uniformity of sowing depth. To save time in seedbed preparation, the plough can be equipped with a built-in roller, such as the DUOLINER, to create a well-broken surface and ensure deep compaction of the soil. Additionally, under certain conditions, this allows for immediate direct sowing after ploughing. This technique saves time by eliminating the need for rotary harrow passes. The DUOLINER refines the soil and breaks up clods in the top layer, leaving a smooth and levelled surface.
Homogenising the seedbed is key to ensuring the success of sowing and, more broadly, the crop yield. Other factors such as sowing depth, density, uniformity, fertilisation, etc. are also important.
Among soil preparation tools, the plough remains the instrument capable of combining multiple advantages. It holds an important position alongside other equipment, to loosen, aerate, homogenise, and level the soil. The plough is an essential tool for improving productivity and correcting issues (severe compaction, poor weeding, etc.), while also playing a key role in the current issue of carbon storage in soils.
Sources:
- https://www.lebulletin.com/cultures/comment-bien-faire-son-lit-de-semence-111659
- https://www.terre-net.fr/mais-grain/article/167713/semis-de-mais-preparation-du-sol-plusieurs-strategies-possibles
- https://www.bayer-agri.fr/fileadmin/bayer/DOSSIER-SITE/Traitement_semences/Broch-Etape-Semis-208x297-pap_fab_02-BD.pdf