Results of the 2019-2021 organic farming unemployment test

Many farmers ask themselves the question of stopping plowing, but plowing plays an important role in weed management in organic farming… The Reine Mathilde program has taken up this topic and is reporting the results of its raised system trial in Calvados. for the first three years (2019-2021).

After 10 years of work infood autonomy of livestock systems in organic farmingThe Reine Mathilde program is changing course in 2019 to “focus more closely on the ground, and more specifically on the effects of not-until compared to plowing in Organic Agriculture “. Objectives: “to find planting systems that are less destructive to the soil and its biological life, while maintaining carbon “.

Comparison of 2 tillage systems

Before we present the lessons learned from these first three years of testing (2019-2021), let’s first review the established protocol. The teams follow two different rotations: “a ‘livestock type’ with forage crops and grains for self-consumption, and another ‘crop type’, which includes grains for sale. Each rotation is subject to two land strategies: plowing AND not-until “. Goal: to be able to compare them in a variety of cultures and measures effects IN pollution, soil structure, soil biodiversity, but also carbon balance, fuel consumption, etc. “For three years, the new rotation begins after the destruction of the pastures and the crops follow each other in the order of the selected rotations. »

The two test rotations started in 2019. (©Reine Mathilde programme)

More difficult weed management but variable impact on yield

Among the various lessons learned from this system trial, program teams confirmed “better structural stability of the soil using no-baking techniques”: “on the surface of the soil we notice less crust, more grains and more macropores”. of microbial biomass it is also more developed. The unexpected result, however: the presence of earthworms it is greater in plowed areas. As a clarification, the teams suspect the large number of passes of the working equipment to destroy the temporary meadow in the cleared area.

circle winter output nitrogen residues, they are stronger, in 5 situations out of 7, in techniques without work than in work. The program raises several hypotheses: “greater winter biological activity? Less washing? Reducing nitrogen uptake from fall planting using no-till techniques? »

Another lesson from the essay: “the weed management it is harder and grows over time. Their presence is systematically greater in no-tillage: from +15 to 20% in suffocating societies to 2 to 4 times more in certain corn or wheat… regrowth of cut grasses, chamomile, and quarter lambs in the corn, specify the teams . “.

Note: toimpact of weeds on yield is variable. Sometimes, it is marked as in 2020, simultaneously with a complex, but weak establishment or even zero in 2019 and 2021. It seems that “no-till” rhymes with more biological activity, so more weeds and of course culture less dense, but more powerful and that definitely compensate. »

“Drown crops are also a way to tame weeds: the triticale + bean mix, surprisingly, covers more than barley + peas or pure wheat. As for mechanical weeding, it is difficult to carry out the passage of cereals at the right stage in winter. When conditions permit (March 2021), one or even two aggressive passes improve weed efficiency and have little effect on wheat yield, despite temporary coverage by tool passes. »

It is the condition of the land and the pollution that will guide the decisions

Based on these results and various analyzes (see the table below), the Reine Mathilde program proposes an initial list of recommendation to be impatient in organic farming:

  • “Apply the tools to successfully destroy grassy land: in summer with drying conditions, with a surface-operated rotary tool, allow several days of drying before planting a catch crop. » ;
  • “To move the dates of sowing and tillage when the soil has not dried enough, or even to change the planned production. It is the condition of the land and the pollution that will guide the decisions. » ;
  • ABOUT manage pollution :

– “Limit the presence of plant residues to be able to clean mechanically”
– “In a livestock farm, in case of heavy pollution, it is possible, for example, to enil a crop intended for harvesting wheat, or to introduce a covering meslin for early harvesting”;
– “In the case of perennial plants, cover at least to work on the surface before and after this cover”;
– “Be more attentive to the contamination of the growing culture (for weeds)”;
– “Worst case: reverse a poorly started crop to limit weed development later”;
– “Compliance with the basics of rotation (two corns in a row favored the reinforcement of summer weed contamination)”;
– “Keep the plow in the toolbox if necessary, especially to catch a runaway mess. Don’t be manic: multiply the number of vehicle passes or think: which is worse? “.

Indicators for “crop type” rotation.

Find the main quantitative results collected for the “crop type” rotation in the first test campaigns:

(swipe right with the slider at the bottom to reveal the full results)

spring wheat
Intercropping of forage seed and then maize
Triticale + horse beans
Leave No plowing Leave No plowing Leave No plowing
Technical indicators
Description of tillage actisol x1
rotator x1 straw cultivator x1 plow x1 seeder/rotator/ pick x1
Actisol x1 rotary cultivator x2 straw x3

seed/rotator/ pick x1

Rape Cultivator x2 Weed + Planter x1 Corn Rotary x1 Rotary Plow x1 / Seeder x1 Rapeseed stubble cultivator x2 seed grasses + planter x1 corn rotator x1 stubble cultivator x1 rotator/seeder x1 straw cultivator x2 (second pass not recommended) plow x1 pick/rotator/planter x1 straw cultivator x2

pick/rotator/planter x1

planting date 04/06/2019 04/06/2019 26.05.2020 26.05.2020 12/11/2020 12/11/2020
Planting density (grains/m²) 400 400 110,000 seeds/ha 110,000 seeds/ha 190 + 32 190 + 32
Intercrop yield before maize 1.5 t DM/ha is calculated 1.3 t is calculated
Yield (q/ha) 25.1 31.1 6.7 t DM/ha with 29.7% DM 5.8 t DM/ha at 29.1% DM 18.7T+34F 21.4T+29.2F
Land indicators
Buried shortcuts test
date of funeral 21.04.2019 21.04.2019 06/12/2020 06/12/2020 19.04.2022 19.04.2022
Burial slide duration 4 months 4 months 4 months 4 months 2 months / 3 months 2 months / 3 months
Degradation shorts too strong too strong very strong: residue 7.7 g very strong: residue 6.6 g % degradation: 18% / 69% % degradation: 30% / 63%
Date of earthworm sampling 15.04.2019 15.04.2019 20.04.2020 20.04.2020 15.02.2021 15.02.2021
Number of earthworms (nb/m²) 88 75 158 152 88 119
Meadow count standard (nb/m²) 325 94 (beware dry conditions) 506
Remaining winter production (kg N/ha) No analysis 12
until 03/02/20 (for rapese)
until 03/02/20 (for rapese)
until 02/11/2021
until 02/11/2021
Random observation 50 to 150 weeds/m² 200 weeds/m² and many other perennials Lamb droppings contamination is moderate in plowing, significant in no-till. Lamb’s quarters less developed in tillage than in no-tillage: more efficient stocking in tillage, less efficient in no-tillage. Estimated 110 kg DM/ha weeds in early summer Estimated 470 kg DM/ha weeds in early summer
Economic indicators
Number of soil passes (including seedlings) 5 7 6 6 4 3
Total number of passes 7 9 14 14 7 7
time to work 4.7 hours 5.4 hours 5.7 hours 5.1 hours 4.0 hours 3.0 hours
Fuel 89 liters 111 liters 90 liters 86 liters 96 liters 81 liters
The cost of mechanization €363 €406 €440 €405 €370 €319
Product 1182 € 1430 € 1261 € €1091 1749 € 1683 €
Operating costs (seeds) €213 €213 €350 €350 €250 €250
Gross margin €969 1217 € €911 €741 €1499 €1433
Margin with mechanization €606 €811 €471 €336 €1129 1114 €

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