Skip to Main content Skip to Navigation
New interface
Theses

L'alimentation des troupeaux peut-elle empêcher le boisement spontané des espaces ruraux dans les Alpes du Nord ? Organisation spatiale des pratiques fourragères et d'entretien mécanique des prairies permanentes dans la vallée d'Abondance (Haute-Savoie)

Abstract : In the Northern Alps, rural spaces have been transforming for the last fifty years. These changes can be linked with the deep economical, social and technical mutations that French agriculture has known. We chose to study an aspect of these transformations : the natural afforestation of semi-natural grasslands. The valley of Abondance symbolizes a frequent paradox in the Northern Alps : shrubs populations are progressing within a lot of grasslands while farmers still use them as pastures. Theoretically, such a use may prevent the phenomenon. How explain that it does not ? At the parcel scale, an agro-ecological model shows that a repeated low rate of grass consumption favours shrubs settlement and spread into grasslands. This low consumption is a consequence of grazing practices. At the farming system scale, grazing practices are linked in time and space by the necessity of feeding a herd. Given that the characteristics of space influence the way farmers use it, we have chosen to study the spatial management of herd food within a sample of 27 farms. Their territory are included in a 6000 ha continuous area. We first sliced up the continuous area into seven great zones having the same abilities to forage harvesting (by mowing or grazing) with a GIS. Then we studied the uses of parcels inside each zone in order to reveal great features of the spatial organization. We shown that farmers mow preferentially flat surfaces and make pastures in their steep or higher parcels. One cannot understand why some farmers mow steep grasslands without taking account of their hay stocks : they are looking for a fodder autonomy but they do not have enough flat parcels to harvest the whole hay. An estimation of grasslands production (dry matter) and herd needs for food shown that in each farm, an important part of grasslands were under-grazed. These important grass excesses must repeat each year because the spatial organization of grazing does not change : the animals always go in the same parcels at the same periods. These excesses can explain why shrubs progress into grasslands and we observed this afforestation process within a sample of pastures. Do farmers have an interest in creating such excesses ? The pasture season is highly planned and animals make their own diets without any control from farmers within huge parcels (free grazing). We have called this form of management "picking". This is a solution found to save time because labour is a real limiting factor for production in mountain farms. In such an organization, the advantage of low grazing is to make a security against grass growth fluctuations. Animals have always enough to eat. Nevertheless, the cost is a progressive loss of agronomic resources by afforestation. In this valley, grazing practices won`t restrict the afforestation processes. As a consequence, farmers have to maintain the vegetation with other means (mechanical for example). We studied the maintenance practices and shown that farmers rarely maintained their whole pastures. Their choices depend on determinants we studied at the farming system scale (age of farmers, ownership status of parcels, distances between parcels~). As a conclusion, we made an interpretation of the landscape aspect, knowing how farmers set the hey grasslands and pastures and how they manage their vegetation.
Keywords : thesis
Document type :
Theses
Complete list of metadata

https://hal.inrae.fr/tel-02583751
Contributor : Migration Irstea Publications Connect in order to contact the contributor
Submitted on : Thursday, May 14, 2020 - 10:37:26 PM
Last modification on : Friday, October 23, 2020 - 4:45:07 PM

File

pub00015612.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-02583751, version 1
  • IRSTEA : PUB00015612

Collections

Citation

O. Camacho. L'alimentation des troupeaux peut-elle empêcher le boisement spontané des espaces ruraux dans les Alpes du Nord ? Organisation spatiale des pratiques fourragères et d'entretien mécanique des prairies permanentes dans la vallée d'Abondance (Haute-Savoie). Sciences de l'environnement. Doctorat Agronomie, Institut National Agronomique Paris-Grignon, 2004. Français. ⟨NNT : ⟩. ⟨tel-02583751⟩

Share

Metrics

Record views

15

Files downloads

0