As already outlined in an earlier section, tillage is one of the main field operations on a farm and demands significant amounts of labour and time, regardless of the farm size. Organic farmers strive to take care of their soils and the surrounding environment in order to reduce the negative impacts of farming on the ecosystem. In this section, the learners will discuss the key pros and cons of the major approaches to farm tillage, namely: deep/conventional tillage, minimum/conservation tillage, and no tillage. The learners will learn about the relationship between these tillage types and mechanisation in later sections.

Inversion tillage with a mouldboard plough (either animal-powered or motorised, e. g. by a tractor) is often the basis of deep/conventional tillage. In this method, soils are disturbed up to 25 cm, and weeds and crop residue from the previous crop are incorporated into the soil to encourage their decomposition and create a ‘clean table’ at the soil surface. Because of the ridges and furrows left by this type of tillage, a secondary tillage operation is often used to create a level seedbed. An example is ploughing followed by disking or harrowing.

Pros:

• Aerates the soil providing favourable conditions for crop growth and water retention.
• Good weed control because weeds are buried by soil inversion. In the process, some pests and diseases can be controlled, too.
• Equipment widely used and understood, and often favoured in cultural traditions.

Cons:

• Degrades and compacts soil when used consistently over time leading to decreased yields.
• Most soils managed with conventional tillage have lost at least half of the original organic matter from the topsoil due to wind and water erosion.
• Excessive power requirement from either draught animals or a tractor.

1. Slash or knock down the vegetation or the plant residues from the previous crop in the field and leave it as a mulch.
2. Dig planting holes or basins with a hand hoe, or open narrow planting furrows, while retaining the mulch or residues on the soil.
3. Plant either directly into the planting basins with a daba or jab planter.
4. Fertilise with compost or well-rotted livestock manure or other types of farmyard manures.
5. Retain mulch to suppress weeds and hand weed as necessary.
6. Harvest the crops.
7. When practical, seed a cover crop into the mulch, or leave the field fallow covered by mulch between crops.

Pros:

• Allows for the least soil disturbance of all tillage methods, thus retaining the good soil structure, topsoil (protected from wind and water erosion), and organic matter.
• Generally, requires the lowest power or energy from either hand tools, draught animals, or a tractor.
• Can also increase timeliness of operations when less work is required than for deep or minimum tillage operations.

Cons:

• Does not aerate the soil as much as deep tillage, but similar to minimum tillage. Requires a healthy, well aerated soil as a baseline.
• Controls weeds less than deep and minimum tillage – requires a well-designed weed management system adapted specifically to no-till.
• Similar to minimum tillage, some equipment is not commonly used and therefore not widely available, and may not be well accepted by local cultural traditions hence the need for sensitisation.