This article was reprinted with permission from the March/April issue of Irrigazette International.
Situated on the boundary of the Landes and Gironde departments, near Sanguinet [in France], Mr. Thierry Nérault’s farm covers an area of 1,460 ha. Mr. Nérault grows maize under a monoculture system, entirely irrigated by 45 pivots and linear move machines, which are fully automated.
We traveled to the site with Armel Morlet from the company Valmont® Irrigation. The pivot located in the middle is covered in rust: “The water in this part of the Landes has a high iron content, which gives the pivots a rusty colour, particularly when the sprinklers are located above the spans,” he explained.
We traveled to the site with Armel Morlet from the company Valmont® Irrigation. The pivot located in the middle is covered in rust: “The water in this part of the Landes has a high iron content, which gives the pivots a rusty colour, particularly when the sprinklers are located above the spans,” he explained.
The pivot is fitted with two control panels: one old panel, which is no longer operational, and a brand new Valley® GPS Ready control panel: “Since automating the installation the different makes of old panels have been replaced with Valley control panels,” he said. The position of the machines, in most cases, is pinpointed by a GPS device installed in each machine (pivots and linear move machines).
We returned to the car and drove on to a second site, to a smaller-sized field. At this location, the field is irrigated by one large single Otech pivot with 13 spans. We could see a Valley GPS Ready control panel and an antenna on the pivot, which sends information about the pivot to the farm, by radio. We returned once again to the car and this time we drove on to a circular 98-hectare field irrigated by a single Valley PolySpan® pivot of 10 spans. This pivot has a tank, which itself is supplied by six or seven small pumps. The building located near the tank acts as a control room for managing all the pumps used to fill the tank/reserve, as well as the supply pump.
This type of installation with a tank can be used with all the large pivots on the farm. As far as the small pivots are concerned, they are directly supplied by the borehole pumps. The choice of the Landes region for growing maize, which requires a lot of water, does not pose any great risk; in fact, there is an abundance of water resources. Below the sandy soils of the Landes region there is a plio-quaternary aquifer, with a high iron content, which allows the farmers to have permanent access to a plentiful supply of water.
45 pivots Linked to the Farm by Radio
We then went to the farmhouse where we were met by the owner’s son, Romain Nérault, as well as his assistant, Eric Gilbert. Originally, this was divided into two farms, the Lucate and Courlouze properties, which explains its present size of 1,460 hectares.
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| From left, Romain Nérault, Armel Morlet and Eric Gilbert |
Romain Nérault explained: “When my father bought the property three years ago, it was already a maize-only farm, equipped with poorly maintained pivots with the control boxes in a pitiful state.”
The person responsible for operating the irrigation system would have to arrive at 6 a.m. and he would have to go around the farm and check that the pivots were working properly, one by one. He had to go around the farm three times each day, the last visit being at 8 o’clock in the evening, knowing that he would have to travel 7 kilometres from one end of the farm to the other. The time spent going to and fro was considerable, but essential nonetheless because in the summer the maize simply had to be irrigated.
“One week without irrigation represented a loss of 10 or 15 quintals of maize," Romain Nérault lamented, “So when we took over the farm, we had the irrigation installation fully automated so that we could visually and constantly check the situation of all the pivots on the screen.”
The installation now has a total of 45 pivots, of which 10 or so are Valley machines, as well as pivots made by Otech and France Pivot. Every time that Mr. Nérault replaces a machine he chooses a Valley pivot with an inner polyethylene lining (PolySpan), to prevent the ferruginous water from corroding the spans (PolySpan is a polyethylene lining that is installed inside the span tubes, protecting them from the corrosive effects of this water with a high iron content). It is also preferable for the pivots to be fitted with sprinklers attached to downpipes to prevent the ferruginous water from wetting the spans, thus protecting them from outer corrosion.
Of the 45 pivots, six are actually linear move machines. Unlike the pivots, which irrigate in a circular form around a central pivot point, the linear moves irrigate in line, moving up and down the field; these being used on the ire-breaks. The installation also has two hose reels, which allow for the field to be irrigated crosswise.
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| The pivot can be set in motion from a standard computer or a mobile computer system, and it is possible take action remotely. |
Furthermore, 10 or so hectares are irrigated with full cover (sprinkler) systems. This technique allows for the irrigation of the zones that the pivots cannot manage to reach; in fact, with the pivots irrigating in a circle, there are often blind spots, which are not irrigated. Finally, a small “L-shaped” field is irrigated with subsurface drip irrigation. “This is a kind of test”, explained Romain. “In fact, certain complex fields are difficult to irrigate with pivots or linear moves. The aim is also to reduce the amount of water applied per hectare and the consumption of KW/h per hectare.”
Romain Nérault received us in his office with his technical assistant, Eric Gilbert, so that they could tell us about the technique of controlling the pivots by remote control. The whole installation is automated using the Valley GPS Ready technology. This technology allows the user to know the position of the pivots and linear move machines on the farm at any given time. In the office the irrigation operation can be monitored on a large screen with the use of a computer.
Thus it is possible to see the whole installation displayed on the screen. “The pivots are represented by circles or arcs of a circle, and the linear moves are represented by rectangles,” explained Romain Nérault. “When the zone is shaded in grey, this means that the machine is stopped; when the zone is green, this means that the machine is functioning without water and when the pivots are blue, this means that there is water and the pivot is operating correctly. Finally, when the zone is red, this means that there is a problem and we have to step in. Therefore, it is no longer necessary to make a trip to the farm and check the pivots one by one. We only have to take any action when the pivots are broken down.”
When we click on a pivot, the control box appears on the screen, giving the pressure, position in degrees and forward speed of the pivot. The pivot can be set in motion from a standard computer or from a mobile computer system and it is possible to take action remotely.
Thus, automation has allowed this farmer to make significant savings on labor, time and money.
Read the last section of the article, How the Irrigation Season Unfolds.
Read the last section of the article, How the Irrigation Season Unfolds.
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