No-till farming

Technical articles

Carbon cycle and GHG Climate resilience Soil cover Biodiversity Soil regeneration

Source: International Maize and Wheat Improvement Center; license: (CC BY-NC-SA 2.0)

No-till seeding is an agricultural method that consists of sowing without intensive soil tillage, avoiding plowing, loosening, and seedbed preparation. The goal is to preserve the fertility and the structure of the soil.

The principle

• No-till seeding (NT) is part of conservation agriculture, favoring the impact of climate and the biological activity of the soil (root exploration, macrofauna action, etc.) to improve its structure.
• The transition to no-till seeding results from a redesign of the agricultural system, with a multi-year transition to observe the long-term benefits.
• NT involves sowing without disturbing the soil, directly into the residues of the previous crop or into an already established cover.
• It is recommended before starting to see what is being done, to conduct trials, to borrow equipment, to get advice and support.

Advantages

• Reduction of erosion thanks to the redistribution of nutrients on the soil horizon.
• Improvement of soil biodiversity by promoting biological life (earthworms, accelerated decomposition of residues, etc.).
• Energy savings thanks to a reduction of mechanization costs.
• Long-term reduction of nitrogen inputs.

Disadvantages

• Agronomic impact: Initially, yield may be affected, but benefits appear in the long term.
• Weed control is the main difficulty encountered in no-till which may be accompanied by an increased use of herbicides but not always. Some solutions exist such as cover crops and crop rotation choices.
• Economic constraints: The acquisition of specific equipment.
• Climatic conditions: The success of NT depends on climatic conditions, with sometimes narrow intervention windows.

Special case of No-Till Seeding under Living Cover (NTLC)

This technique of NTLC consists of sowing a crop directly into an existing crop. This can be a cover before harvest (relay crop) or maintained after. The choice of cover influences results, with potential advantages in terms of weed management and soil structure. But one must be cautious because the permanent presence of a cover can serve as a refuge for certain pests, such as slugs or voles and if poorly managed, this plant cover can generate competition with the crop.

In Conservation Agriculture (CA), some tend towards a permanent soil cover and the commercial crop is then sown into a multi-year cover.

Necessary adaptations

Lengthening rotations

Lengthening rotations allows better weed control. This rotation is studied according to 3 elements:

• Include spring crops.
• Review crop positioning favoring complementarity between nitrogen-fixing plants (grain legumes) and nitrogen-demanding crops (oilseed rape).
• Alternate, depending on situations, winter and spring crops over periods of 1 to 2 years, taking into account residue management, pest control, and grass weed pressure.

Differentiated straw management

The quantity and distribution of straw are penalizing in NT. At harvest, the goal is to cut high to avoid being hindered by too many residues lying on the soil surface. When in doubt, it is better to harvest too high than too low because, if stubble can hinder emergence, a roller pass can always be done to flatten it.

Density adjustment

It is recommended to slightly increase densities in no-till seeding, but this is not mandatory. The upward adjustment should depend on the type of seeder, the previous residues and the soil condition:

• Winter cereals, oilseed rape: + 0 to 10%.
• Spring cereals, spring grain legumes: + 5 to 15%.

Adjustment of sowing dates

For winter crops, it is advised to advance slightly the sowing date because the crop takes longer to establish, especially when aiming to work more in drier periods.

For spring crops, it is the opposite because the soil drying state will dictate the sowing date and, generally, dates are slightly delayed.

Specific equipment

The choice of seeder is an integral part of the technical itinerary. It must be reasoned according to soil type and chosen system based on several criteria:

• Number of hoppers: This criterion allows combining different species (with varied seed sizes) with localized fertilizers and a companion plant or slug control (3 hoppers for example).
• Furrow closing: Ensure appropriate furrow closing for the soil type.
• Work comfort: Accessibility of different parts of the seeder, ease of filling or emptying, seeding density adjustment, possibilities of associations or sowing at different depths.

• Tine or disc seeder.

Tine seeders have good penetration capacity in the soil (they are generally lightweight), good ability to clear obstacles (clods, stones, residues) but are less suited to stony soils. Tine seeders are the safest because the tine's work recreates structure and allows stimulation of mineralization favorable to crop establishment. However, they have the disadvantage of promoting weed germination and are less suited for sowing in twining covers like vetches or forage pea (upright growth forms are preferred) due to clogging risk.

Straight disc seeders are better suited for sowing in covers and angled disc seeders are better for sowing in straw. They allow faster sowing without moving the soil. However, they require more weight to penetrate the soil. The disc angle on some machines helps limit this constraint. Beware of heavy and unevenly distributed residues. They work better if the cover is not flattened and if stems are tall (less clogging).

Contraindications

• Less suitable for crops sensitive to compaction, requiring a fine seedbed preparation (potatoes and vegetable crops).
• More difficult on loamy soils with low structural activity.
• More delicate in climatic contexts with narrow intervention windows (e.g., harvesting in difficult conditions, soil structure degradation cannot be compensated by tillage). In the long term, however, it improves soil bearing capacity, thus widening intervention windows.

Effects on soils

Advantages

• Strong improvement of bearing capacity.
• Improvement of drying out.
• No hollows in the profile and no buried straw plugs.
• Reduction of hindrance caused by stones.
• Increase in earthworm populations.

Disadvantages

• Slower warming in spring.
• Presence of crop residues on the surface.
• Risk of cumulative compaction effects.

Effects on the sustainability of the cropping system

Environmental criteria

• Air and water quality: Potential increase in ammonia emissions, a related reduction in greenhouse gases, and greater carbon retention in the soil.
• Biodiversity: Soil life favored, macrofauna and biological activity. This biological activity (earthworms, microbial carbon) is notably concentrated on the surface, where effects are most beneficial. Earthworms are very important. They are considered the architects of the soil due to their mechanical action and their role in soil chemistry and biology (incorporation of crop residues, circulation of water and air in the soil). Microbial carbon, these microorganisms constitute the largest part of living biomass and are largely responsible for the proper functioning of the soil (decomposition of plant residues, humification, mineralization, nitrification, biodegradation, soil aggregation, etc.).

Agronomic criteria

• Productivity: Variable initially, but tends to improve in the long term, after 5 to 7 years.
• Soil fertility: Crucial management of organic matter to maintain soil fertility. The lower porosity of the soil surface in no-till can cause delayed mineralization in spring, linked to slower soil warming, implying an advancement of input dates. On chalky soils, increased surface organic matter leads to soil coloration allowing faster mineralization start. Generally, mineral elements are more concentrated on the surface and thus more accessible for crops. Moreover, no-till prevents dilution of organic matter at depth and thus favors structural stability and soil bearing capacity.
• Water stress: Improvement of plant-available water and reduction of evaporation (by maintaining residues on the surface).

• Weed pressure: NT limits weed emergence but the seed bank depletes more slowly.

• Pest pressure: The absence of deep tillage and maintenance of residues on the surface can lead to an increase in pressure from certain pests: slugs, rodents... as well as some beneficials (ground beetles...), which can lead to a long-term pest/predator balance. Techniques exist to mitigate slug risk by sowing less palatable covers (mustard, forage radish) and sowing the crop under good conditions to promote rapid emergence and establishment (good closing of the seed line).

• Disease pressure: No-till can lead to an increase in pressure from certain pathogens due to non-burial of residues (take-all, fusarium…). However, the reduction in the number of passes reduces the risk of inoculum transfer from one plot to another via equipment.

Social criteria

• Adaptation time: Changing practices requires a learning period, more observation and more exchanges with other farmers.
• Motivations: Farmers' main motivations to switch to NT are first to protect the soil and increase biodiversity, and second, time savings.

Economic criteria

• Mechanization costs: Although specific equipment acquisition is sometimes necessary, NT allows significant reduction of equipment fleet and passes, thus reducing fuel consumption and working time.
• Financial margin: On one hand, savings on mechanization costs (implantation costs: sowing, tillage...) are reduced but on the other hand, there are potential yield losses and potential additional costs in herbicides.
  

Comparison of economic performance

Implantation

A simulation was conducted by Arvalis for a 200 ha area with a oilseed rape/wheat/spring barley rotation. Comparing different models, it shows that implantation costs display a gain of almost 100 euros/ha between plowing and NT, a time saving of 1.5 h/ha. In the table, the "new value" is overestimated but gives an idea of mechanization costs which will gradually fade with reduced maintenance (fleet is smaller and less used) and decreased depreciation.

Implantation costs with eight different equipment fleets. Source: Arvalis

	Number of tractors	Traction (hp/ha)	Equipment new value (€/ha)	Mechanization for sowing (€/ha)	Non-selective herbicides (€/ha)	Labor (€/ha)	Total implantation cost (€/ha)	Working time (h/ha)
Systematic plowing	3	2.25	1,589	187	0	30	217	1.98
Plowing 2 years out of 3	3	2.25	1,589	182	2	26	210	1.76
No-till with classic equipment + subsoiler	3	2.25	1,523	178	5	30	213	2.02
No-till with classic equipment	2	1.35	1,098	138	5	27	170	1.79
No-till with cultivator/seeder	2	1.35	985	103	5	13	121	0.86
No-till seeding	2	1.35	1,020	107	14	8	129	0.52

Yield

Yields may be impacted in the first years, but once the model is well established, it returns to an equilibrium level with even the possibility of higher yields, depending on crop type, soil, etc.

Evolution of yields and economic results between a plowing itinerary and TCS compared to no-till. (Source: F. Tebrügge, University of Giessen )

Margin

During 6 years of experimentation, a comparison was made between plowing and no-till (NT) at the experimental station "Saint-Ex Innov" in Pusignan (69). On both sites, the UAA is 140 ha with 1 FTE, the rotation is the same (wheat, corn, corn, sunflower/soybean). In these trials, the gross margin is lower due to profitability penalized by technical results in the first years and increased inputs (crop protection, seeds, etc.).

Techno-economic comparison of NT vs plowing system (BTH: Winter soft wheat). Source: CA01

This experimentation should be nuanced with other feedbacks, notably with the practice of NT under cover. Another comparison of average production costs was conducted in Eure-et-Loir for wheat and results are rather satisfactory.

In this experiment, for wheat, there are few differences between the TCS system and a plowing system, however, NT stands out clearly.

These data were obtained from 5 farms in NTLC, 11 in TCS and 7 in plowing. (Sources: )

Comparison of average production costs in Eure-et-Loir for a wheat crop
Items	NT	TCS	Plowing
Yields (q/ha)	61	76	77
Herbicides (€/ha)	56	69	73
Crop protection (excluding herbicides) (€/ha)	26	57	53
Fertilizers (€/ha)	83	106	103
Number of passes (sowing and treatments)	6.4	9.4	10
Operating costs (€/ha)	182	246	241
Gross margins (€/ha)	503	546	564
Implantation costs (equipment and labor, €/ha)	60	106	139
Cost in euros per quintal produced
Herbicides	0.92	0.9	0.95
Crop protection (excluding herbicides)	0.43	0.75	0.68
Total	1.35	1.65	1.63
Fertilizers	1.36	1.45	1.34

Conclusion

In summary, no-till seeding is a sustainable approach requiring a thoughtful transition, specific adaptations and careful management to maximize long-term benefits.

For further information

• How to start no-till seeding? - Robert P., Entraid - Press article (2019)
• Cover crops: developing high-performing soils, encouraging biological diversity, recycling and producing nitrogen -
• Thomas F., TCS - Press article (2005)
• Oilseed rape: CETIOM confirms NT orientation and association with legumes - Archambeaud M., TCS - Press article (2009)
• Maize implantation dossier, No-till: a technique to handle with care - AGRICULTURAL PERSPECTIVES - Article 2011
• For Denis Brajeul, no-till is about efficiently managing working time and soil fertility - Agroperspectives - Press article (2011)
• Undersowing wheat with different living mulches in a no-till system, I. Yield analysis - Matthieu Carof, Stéphane De Tourdonnet, Patrick Saulas, Dominique Le Floch, Jean Roger-Estrade. - Agronomy for Sustainable Development, Springer Verlag/EDP Sciences/INRA, 2007, 27 (4), pp.347-356
• Undersowing wheat with different living mulches in a no-till system, II. Competition for light and nitrogen - Matthieu Carof, Stéphane De Tourdonnet, Patrick Saulas, Dominique Le Floch, Jean Roger-Estrade. - Agronomy for Sustainable Development, Springer Verlag/EDP Sciences/INRA, 2007, 27 (4), pp.357-365
• Original article from Geco Practicing no-till seeding of crops

Sources

• Jean-François Dobrecourt, CA 89, jf.dobrecourt@yonne.chambagri.fr, Avallon (89)
• Adeline Michel, CERFRANCE Normandy, amichel@50.cerfrance.fr, Fleury sur Orne (14)
• Marc Moraine, INRA, marc.moraine@toulouse.inra.fr, Toulouse (31)
• Rémy Ballot, INRA, remy.ballot@grignon.inra.fr, Grignon (78)
• PRACTICING DIRECT SEEDING OF CROPS - GECO
• Direct seeding: a technique to develop in Oise? - CA 60
• Magellan Guide: Direct Seeding, from annual cover ... to permanent cover - GIEE Magellan
• Relay associating a winter cereal with a legume sown in spring - GECO

• Density and spacing in maize to reduce weed pressure - Regional Chamber of Agriculture of Occitanie

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