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Subtle Agroecologies
during the endives’ forcing phase, inside a thermo-regulated room with ambient humidity saturation. For each batch of endives, placed in containers, the cultivation period (forcing) lasted about
20 days, during which time the roots were permanently bathed in a nutrient solution. On maturity,
the containers were removed from the forcing room and the endives harvested. New containers were
immediately put in place for the next crop. During the 25 weeks of the season, acoustic diffusions
were made for periods of 21 days, followed by 21 days without diffusion, alternating. Thus, depending on their date of entry into the forcing room, the endives in each container received between
1 and 20 days of these sound broadcasts, during which the sequences were broadcast daily for 24
minutes at the beginning of season and 34 minutes at the end of season.
In this way, a diffusion gradient over time was realised in order to compare the batches, with
some receiving 500+ minutes at the beginning of the season and others 700+ minutes at the end.
The loudspeakers of the diffusion system were installed inside the thermo-regulated room, while
the amplifer and programmer were placed outside the room. For each batch, in addition to its exit
date from the forcing room (i.e. the date of harvest), the following characteristics were recorded:
• Quantity of endive produced, in kilograms;
• Duration of the broadcast on the batch, from 0 to the total number of days spent in the room
(up to 21 days);
• Percentage of ‘second-grade’ endive (based on the exterior appearance such as shape, size
and quality) in relation to the total produced;
• Production yield, in number of endives and in kilograms per container (based on kg per
container × no. containers per batch).
A total of 541 tonnes of endives produced under these conditions, grouped by batch, were analysed.
Case 4: Reduction of the impact of Mosaic Virus on courgettes.
This experiment was carried out on the market garden of l’Oustalet, Bouches-du-Rhône, in
2009, in 7 polytunnels on a sample of 100 courgette plants per tunnel (over 400 ft of plants in
total, of the Satellite variety). The tunnels were 7 m wide, 80 m long and 3 m apart. The tunnel
closest to the diffusion device was 20 m from the device, and the furthest tunnel was between 87
and 94 m from the device. The tunnels were installed perpendicular to the direction of the Mistral
wind, and the sound was emitted in the opposite direction to the Mistral. The sequences, aimed
at reducing the proliferation of viruses and stimulating the resistance of the courgettes, were
broadcast once a day for 6 minutes throughout the production phase from 30 July (planted on 6
July, frst harvest on 6 August). For each selected courgette plant in each tunnel, the following
criteria were recorded:
• healthy plants;
• plants showing virus-related symptoms (fliform or mottled leaves);
• dead plants.
In this way, the degree of impact of the virus could be assessed in a gradient from the loudspeaker
to the furthest tunnels.
RESULTS
Case 1a: Prevention and reduction of the effects of Esca on the vine, with historical data.
The historical values of the Esca mortality rate are plotted in Figure 10.1a and b, together with
mortality rates collected year by year from the start of the genodic process (year 1). Prior to year 1,
the mortality rate averaged between 1.8% and 5.5%. From year 1 onwards, there is a progressive decrease in the mortality rate, around 1.5% in year 1 (start of the diffusion process) and then
between 1% and 2% mortality in the following years. The difference between before and after
Subtle Agroecologies
during the endives’ forcing phase, inside a thermo-regulated room with ambient humidity saturation. For each batch of endives, placed in containers, the cultivation period (forcing) lasted about
20 days, during which time the roots were permanently bathed in a nutrient solution. On maturity,
the containers were removed from the forcing room and the endives harvested. New containers were
immediately put in place for the next crop. During the 25 weeks of the season, acoustic diffusions
were made for periods of 21 days, followed by 21 days without diffusion, alternating. Thus, depending on their date of entry into the forcing room, the endives in each container received between
1 and 20 days of these sound broadcasts, during which the sequences were broadcast daily for 24
minutes at the beginning of season and 34 minutes at the end of season.
In this way, a diffusion gradient over time was realised in order to compare the batches, with
some receiving 500+ minutes at the beginning of the season and others 700+ minutes at the end.
The loudspeakers of the diffusion system were installed inside the thermo-regulated room, while
the amplifer and programmer were placed outside the room. For each batch, in addition to its exit
date from the forcing room (i.e. the date of harvest), the following characteristics were recorded:
• Quantity of endive produced, in kilograms;
• Duration of the broadcast on the batch, from 0 to the total number of days spent in the room
(up to 21 days);
• Percentage of ‘second-grade’ endive (based on the exterior appearance such as shape, size
and quality) in relation to the total produced;
• Production yield, in number of endives and in kilograms per container (based on kg per
container × no. containers per batch).
A total of 541 tonnes of endives produced under these conditions, grouped by batch, were analysed.
Case 4: Reduction of the impact of Mosaic Virus on courgettes.
This experiment was carried out on the market garden of l’Oustalet, Bouches-du-Rhône, in
2009, in 7 polytunnels on a sample of 100 courgette plants per tunnel (over 400 ft of plants in
total, of the Satellite variety). The tunnels were 7 m wide, 80 m long and 3 m apart. The tunnel
closest to the diffusion device was 20 m from the device, and the furthest tunnel was between 87
and 94 m from the device. The tunnels were installed perpendicular to the direction of the Mistral
wind, and the sound was emitted in the opposite direction to the Mistral. The sequences, aimed
at reducing the proliferation of viruses and stimulating the resistance of the courgettes, were
broadcast once a day for 6 minutes throughout the production phase from 30 July (planted on 6
July, frst harvest on 6 August). For each selected courgette plant in each tunnel, the following
criteria were recorded:
• healthy plants;
• plants showing virus-related symptoms (fliform or mottled leaves);
• dead plants.
In this way, the degree of impact of the virus could be assessed in a gradient from the loudspeaker
to the furthest tunnels.
RESULTS
Case 1a: Prevention and reduction of the effects of Esca on the vine, with historical data.
The historical values of the Esca mortality rate are plotted in Figure 10.1a and b, together with
mortality rates collected year by year from the start of the genodic process (year 1). Prior to year 1,
the mortality rate averaged between 1.8% and 5.5%. From year 1 onwards, there is a progressive decrease in the mortality rate, around 1.5% in year 1 (start of the diffusion process) and then
between 1% and 2% mortality in the following years. The difference between before and after