Fertilising the Vineyards, Past and Present

Vines thrive in poor soil, but it is normal to judiciously fertilise them. Today, especially in organic vineyards, the rows of vines will be separated by a grassy sward. Close to the vines will be ploughed with a special vineyard two tined plough, and the paths between will be mowed. The ploughing is to reduce competition around the vines, and to cut through shallow roots. The vines are forced to rely on roots that go deep and are protected against drought. The 'grassy' paths are in fact mostly not grass, but in the case of the Chateau du Petit-Thouars vineyard, mostly clover. This is low growing and unlike grasses, does not compete with the vines for nutrients. Rather, it supplies nitrogen. In turn this increases soil health, including bacterial activity, carbon sequestration and the cycle of minerals such as iron. At Petit-Thouars they will also use a mixture of other cover crops such as Phacelia, but clover is established as the primary species. As a side benefit the vineyard aisles are protected against erosion because of their plant coverage.

 

Clover rich sward between the rows of 40 year old cabernet franc at the Chateau du Petit-Thouars.

Petit-Thouars retains a remnant of the old method of supplying nitrogen to the vineyards, used for centuries until 20th century agronomy ideas rendered it hopelessly old fashioned. Not far from the Chateau there is a domed cylindrical building which once housed a thousand pairs of pigeons. Royal assent had to be sought to build a dovecote, and the number of nest holes (Fr. boulins) was dictated by how much land you had. If you could prove that your peasants wouldn't starve if you fed a portion of your cereals to the pigeons. You wanted the pigeons to produce guano, which was the fertiliser equivalent of gold dust. As a bonus you also got squab (young pigeon) for the table. Dovecotes finally went out of use when huge guano deposits were discovered on islands along the South American coast in the 19th century. The mining and transporting of guano made a few businessmen rich beyond their wildest dreams. The use of guano in the vineyards also ceased because it was realised the pigeon poo was too acidic.

 

 Looking into the Chateau du Petit-Thouars dovecote from the doorway.

Chateau du Petit-Thouars is a family run estate in the Chinon AOC. For further details of how to visit for a tour and tasting, consult their website. https://www.chateaudptwines.com/