The Grande Ferme Neuve ('Big New Farm'), which was once part of the Marolles estate, was built in the 19th century by Jacques Philippe Dubreuil-Chambardel, doctor, academic and agronomist, who made it his first teaching farm in 1849. The teaching farm failed within a couple of years and the institution was moved to a farm near Chédigny, under the direction of the Registrar.
His technique for improving the land was to roughly clear the heath and apply fertilizer made from carbonised animal bones along with the seed for crops. Dubreuil-Chambardel did not invent the techique but copied it from a Monsieur de la Selle, who farmed just outside Preuilly sur Claise. The noir animal, as bone charcoal is called in French, was not made as a fertilizer. Its principal use was as a filter for refining sugar, thus it was a waste product from the sugar beet industry. In addition, blood was used to clarify the sugar syrup, and the refineries were left with a product that was a mixture of bone charcoal, blood, vegetable residue, lime (CaO) and beet juice. It was full of nitrogen and other nutrients, and didn't smell too bad. Once treated with the magic black powder the mediocre soil produced yields five times greater.
The cost of clearing the heath, which is a habitat dominated by heather, besom heath and gorse, was recuperated by selling the cut heather and besom heath for use as stable bedding. The remaining roots and plant material were burnt in the field in a technique known as écobuage which is still practiced in a few places. It was hard, slow work clearing the land and Dubreuil-Chambardel imported hardy workers from the Auvergne and oxen which had to be regularly rested in order to maintain their strength. Equipment had to be carefully and regularly maintained too.
Even in imperfectly cleared and ploughed land, Dubreuil-Chambardel was astonished to observe that his crops of wheat and rye were much better than in long cultivated land that had been spread with stable manure. Not only was the yield of grain better, but the quantity and quality of straw was exceptional, reaching more than two metres high. The soil was a mix of clay with flint, with topsoil only about 17cm deep, underlaid with an impervious claypan. Crops of vetch sown for hay performed equally impressively, but where the land was not fertilized with the bone charcoal the crops reached no more than 5cm and never produced grain. They were only good for grazing sheep.
This new fertilizer did not come cheap though -- it cost more than twice any of the other input costs, and more than the cost of ploughing and seeds put together. But because the quantity and quality of the grain was so exceptional there was still a profit in it. Initially his traditional neighbours thought he was crazy and told him he would be better feeding his seed grain to poultry.
His results were so extraordinary that after a couple of years, other progressive farmers began querying Dubreuil-Chambardel's costings for clearing and ploughing, and the quantities of fertilizer he was using. They agreed that good results could be had, but that the costs were far higher and the quantity of fertilizer needed to be greater. Reading the reports from the National Agriculture Society, it seems that Dubreuil-Chambardel was indeed getting the results he claimed, but that there was some misunderstanding about exactly how he was applying the fertilizer (it was more complicated than just distributing it over the land before sowing, and relied on careful timing and cultivation techniques).
During this period more research was done to understand exactly what was in the fertilizer and how it benefitted plant growth. As the use of bone charcoal increased so the price of the product increased and this affected profits too. Dubreuil-Chambardel was also regarded with some suspicion because he sold most of his straw rather than use it for animal bedding. Instead he used a marl (a type of lime rich clay) mixture, which he then spread on his land. Another thing that caused suspicion was the way the land was not cleared or ploughed to perfection, but just roughly, and seemed to produce better results that way. All around him, Dubreuil-Chambardel's neighbours were producing pitiful crops on what appeared to be much more carefully cultivated land. After about four years of this practice he increased the range of the crops tried to canola, oats and buckwheat.
Despite the agricultural successes, the school rapidly ran into financial difficulties. The first year there were 20 students, but the second year only nine. According to a report of 1850 the students left because they were badly fed. The frequent absences of the farm director didn't help either. The school was forced by the authorities to close in 1851, and the estate was sold.
The Marolles estate was greatly enlarged by subsequent owner Fernand Raoul-Duval who turned it into a vast agricultural enterprise. We stopped off to photograph what you can see from the road today at the Grande Ferme Neuve because they have not just one, but two, Eoliennes Bollées. These rather special wind turbines are a favourite of ours [link] and were installed on many chateaux estates in the Touraine Loire Valley in the 19th century.
Fernand Raoul-Duval, a Parisian engineer, moved to Genillé in 1863. He accumulated around the Chateau of Marolles a vast domain of 1400 ha, including the Grande Ferme Neuve. His farms were equipped with the latest technological innovations (tractors and steam harvesters, mills and fruit presses powered by wind turbines). The newfangled agricultural practices were important and impressive enough that the President of the Republic visited in 1877.
See also my post on the lime kiln at Marsin, which the Raoul-Duval family also owned and operated as part of the Marolles estate [link].
Update: According to John Walter and Régis Girard on Archiving Industry [link] the iron framed farm buildings of the Grande Ferme Neuve were designed by Gustave Eiffel, to pay off a gambling debt.