What is strip tillage?
Strip tillage (strip till) involves loosening and cultivating the soil only where the seeds will be placed โ in narrow strips covering about 30% of the field surface. The cultivated bands are usually several centimeters wide and loosened to depths of several to even a few dozen centimeters, while the soil between them remains untouched. As a result, most of the field (around 70%) stays undisturbed and covered with crop residues or cover crops, forming a natural mulch that protects the soil. What does this mean in practice? The soil in the rows is well loosened and warmed, which promotes fast emergence, while between the rows moisture and structure are preserved because the soil is left โat restโ.
Important! Strip tillage combines the benefits of deeper cultivation in the sowing zone with the advantages of direct drilling, thanks to the protective cover left on the rest of the field. It is worth noting that the soil in the strips is not inverted like in conventional ploughing, but loosened to a greater depth โ which is why strip-till is considered a form of no till farming.
Strip till equipment: cultivation, fertilization and sowing in one pass
Strip tillage requires specialized implements that perform several operations in a single pass. During one run, a strip-till machine loosens the soil in strips (often down to 30โ35 cm), compacts it appropriately, applies fertilizer (e.g. phosphorus and potassium) directly under the future seed row, places the seed at the desired depth, and covers it evenly with soil.
Such a strip-till seedbed unit consists of many working elements: at the front it often features discs or spiked residue cleaners that sweep away residues; next come tines (chisels) that deeply loosen the soil in narrow strips; behind them are leveling discs that limit soil throw; and at the rear press wheels and the seeder. All components are synchronized to prepare the loosened strip, place seeds together with fertilizer, and lightly reconsolidate the soil above them โ all in a single pass of the machine. As a result, the operation is simplified and the number of field passes is reduced, which lowers soil compaction caused by heavy machinery.
Strip till in practice: when does it work best?
Strip tillage performs best for crops that require well-warmed soil and precise sowing, such as maize or winter oilseed rape. In cooler spring conditions, the dark, loosened strips warm up faster, providing seeds with better starting conditions than in full-mulch systems. At the same time, the residue mulch preserved between the rows retains soil moisture โ during spring droughts, strip-tilled fields hold more water, which translates into better seed emergence. Strip tillage is also recommended in erosion-prone areas, as leaving most of the soil covered with residues protects it against washing and wind erosion.
Example: in one maize season it was observed that on fields left since autumn with stubble or cover crops (and only strip-loosened before sowing), the soil beneath a thin layer of residues was clearly moist, which significantly improved maize germination and emergence compared with traditionally cultivated, dried-out soil.
The most important advantages of strip-till include:
- a clear improvement in soil structure and organic matter content in the topsoil, as well as stabilization of crumb structure,
- increased activity of microorganisms (e.g. earthworms),c),
- better water retention in the soil and reduced evaporation,
- reduced wind and water erosion,
- no formation of a plough pan (thanks to abandoning ploughing and fewer passes),
- higher work efficiency (time and fuel savings, and even the possibility of reducing mineral fertilizer rates).
Example: farmers using strip till often observe uniform emergence and good yields with lower inputs, especially in maize, oilseed rape, sugar beet, or sunflower cultivation.
Zero tillage โ direct drilling
Direct drilling โ also known as zero tillage (zero-till, no-till) โ is the most radical form of no till farming. According to some specialists (following the classification proposed by the Jaskulski family), it is even considered a separate farming system.
Zero-till involves completely abandoning soil cultivation: seeds are sown into untilled soil using a special drill capable of cutting through crop residues and placing the seed into a narrow slot. During this operation the soil is neither inverted nor mixed โ disturbance is limited solely to creating the slot and placing the seed. Crop residues from the previous crop remain on the surface as mulch.
Important! Does this mean that in zero-tillage the field is not prepared for sowing at all? Not entirely โ non-selective total herbicides (mainly glyphosate) are applied to stubble, which is a frequent criticism of this cultivation technology.
Direct drilling requires special disc or tine seeders capable of working in stubble and heavy soil, often equipped with reinforced openers, residue cutters, and press wheels. Only certain machine designs can cope with the challenge of sowing into untilled stubble. The result is a field fully covered with mulch โ the soil remains covered with plant residues at all times, resembling the conditions of natural forest litter.
Advantages of zero-till
Completely abandoning any tillage brings a number of potential benefits. Above all, fuel consumption and machine working time drop dramatically โ the lack of ploughing and cultivation means even several dozen percent fewer passes. It is estimated that switching to a zero-till system can reduce fuel inputs by several tens of percent and similarly cut labor hours compared with conventional cultivation. This clearly translates into lower production costs.
In addition, direct drilling delivers the same benefits as other reduced tillage systems:
- improved soil structure and fertility,
- better water retention,
- reduced erosion,
- increased biodiversity and soil life.
Challenges of zero-till
Direct drilling is very rarely used in Poland due to serious challenges:
- greater pressure from weeds, diseases, and pests (the most difficult to control are slugs),
- delayed soil warming in spring,
- high soil quality requirements.
Example: in Poland many soils are acidic and poor, which in a no-tillage system makes crop establishment even more difficult. Studies show that on weaker sites yields under direct drilling can be significantly lower โ in long-term trials on class IVbโV soils, cereal and oilseed rape yields under zero tillage amounted to just over half of those obtained with traditional ploughing.
Full no-till is considered a risky system that requires extensive knowledge and suitable conditions. In Polish agriculture it is practiced by only a handful of innovators on selected fields โ far more often, compromise techniques such as strip-till or reduced tillage without the plough are chosen.
