With an average yield of 11t/ha in 2021, French maize production beat all its previous records, mainly thanks to sufficient rainfall that was well spread over the entire production period. Years that are less favourable, both climatically and economically, are unfortunately likely in the future. Cereal producers, livestock breeders, and now biogas producers, must adapt their practices to stay competitive. Let’s take a look at how precision agriculture, in particular site-specific seeding, contributes to this objective.
French maize in 3 figures
- 3 million hectares cultivated (crop No. 2 after wheat)
- 50%: Cropping area is divided between fodder maize and grain maize (2% of the area is seed corn or sweetcorn)
- 40% of French production is sold for export to the European Union (primary exporting country in the EU)
Breeding and maize, doing well together
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The productivity of current varieties is increasing by 1.2% each year, ie, a gain of 0.10 to 0.14t/ha in grain maize, and 0.13 to 0.18t/ha in silage maize, according to a study conducted by Arvalis – Institut du Végétal (Plant Institute). One of the maize plant’s characteristics is its very high productivity, despite a low seed rate per hectare. More than 13 tonnes of grain can be obtained with less than 100,000 plants/ha. Current early varieties require 5,000 to 10,000 plants/ha less, compared to the varieties from the early 1990s.
Faced with fluctuating weather conditions, increasing input costs, and fewer protective seed treatments, farmers remain in constant search of security. And given the variety within fields, it is not in their interest to reduce seed rates too far. “Reducing the seed rate tends to lower the yield: Even if beautiful ears develop and the plants look good, the number of kernels/m² harvested is lower,” warned Pierre Cougard, of the Agronomic Department of the Eureden Co-operative in an interview with the newspaper Le Paysan Breton (The Breton Farmer).
Precision maize production
In an ideal world, farmers need to use the right variety, seed rate and nutrition, at the right time and in the right place. The fundamentals remain: An adequate soil structure, a well-prepared seedbed, and a well-maintained drill. Precision maize cultivation is taking over, through knowledge of in-field variation, the establishment of variable rate seed maps, and geolocation with centimetre-precision equipment guidance.
Where water reserves are low, plants will suffer from stress. Lower seeding rates will relieve the suffering maize plants, offering them more water per plant, because the population per m² is lower. This does not prevent farmers from increasing seed rates where growing conditions are good.
Variable rate seeding with support from trained service providers
Co-operatives and agricultural merchants are now developing agri-environmental services to meet societal expectations of reducing agriculture’s impact on the environment and biodiversity. Precision agriculture is the mainstay to reach these goals. Seed companies have started using specific applications, such as Agrility® (LG Semences), FITservices® (Pioneer Semences), Climate Fieldview® (Dekalb/Bayer-Agri), Xarvio™ (BASF), etc. With agricultural contractors, they make up the trio of precision farming: Seed producers, agricultural merchants, and users of precision farming technologies.
In the Grand-Ouest (Western France), the Cléo Network, with more than 15 contractor members and 400 employees in total, is a pioneer in implementing precision agriculture. Training in digital tools, shared field trial plantings, and piloting the latest generation single-grain drills are part of Cléo’s roadmap. Contractor company Coulon, located at Bouère, shares some customer experiences – mostly livestock farmers – about variable rate maize seeding.
Contractor company Coulon in a nutshell
- 20 full-time emplyees
- 5 sets of Monosem planters
- 23 tractors, mainly John Deere brand (dealer: Ets Chesneau Agri-Ouest)
- 5 self-propelled forage harvesters
- 7 combine harvesters
- 2 Self-propelled sprayers
- 7 muck spreaders
- 2 large square and 4 round balers
Coulon’s first experience of precision farming was applying variable rate nitrogen to cereals, based on N-Sensor data. “For variable rate maize seeding, things are more technical; you need to have knowledge of the varying yield potential within a field,” admits partner Jean-Louis Mary. “We started by compiling yield maps, using the JDLink™ tool. We found that within the same field the yield fluctuated from -20% to +20% of the average yield. Then we built variable rate seeding maps using the Xarvio™ tool.”
To better fulfil the needs of its customers, Coulon has gradually acquired five Monosem precision drills. “These are electric-drive drills, designed for automated seed rate variation and switching off of row units,” confirms Anthony Hardou, partner in charge of the equipment fleet.
Site specific seed rate gives an optimum stand, and up to 10% in seed savings.
Savings on seed is understandably attractive for customers, when the cost of certain recent varieties is close to €110 (£91) per seed unit (50 000 kernels), at a rate of 1.5 to units/ha. “We managed to save 7-10% on seed usage, which covers the slight additional costs in using our service, particularly on the least advantageous plots,” recognises Mr Mary. The yield history was accumulated free of charge, and is now available to farmers for any other operation, aimed at correctly evaluating the soil capital of a plot.
Net gain through variable rate seeding: At least €20/ha (£16.60), in 80% of the trials
Over the past seven years, the seed company Dekalb has been working across Europe on variable rate seeding, and its adaptation to the soil’s potential, reports Entraid’ Magazine (March 2020). Dekalb has tested variable rate seeding with farmers in the field. Eight out of 10 trials led to an efficiency gain with variable rate seeding, with the additional margin amounting to several tens of euros per hectare. “This is the result of combining our knowledge about plant genetics and the farmer’s knowledge about the fields,” the Dekalb experts explain.
The Breton co-operative D’Aucy has also tested variable rate seeding. First point: Switching off seeding rows when not needed reduces seed usage by 1-6%, depending on the shape and size of the field. Based on 3.5% savings, the additional cost of the drill and the GPS pays for itself after sowing 180ha per year, according to D’Aucy. Second point: Variable rate seeding allows a gain of around €20/ha (£16.60) (service costs included), which makes the drill more profitable than a traditional machine in all situations. The co-operative uses variable rate seeding maps, produced in the form of separate service, invoiced at €14/ha (£11.60).
The year 2021, with its record yields, should not make us forget that the trend is towards declining rainfall, says Mr Mary. “We have always been surprised at obtaining so much maize with so little water available in certain fields, and this is thanks to the site-specific adjustment of seed rates.”