Farmers’ fears and agro-economic evaluation of sown grass strips in France

Abstract

Since 2005, French farmers must set up sown grass strips along rivers in order to decrease pesticide levels and soil erosion. Farmers have thus parcelled out their fields, set aside 3% of their farm size and managed grass without herbicide. Consequently, this environmental policy may cause farmers' fears due to economic losses and weed infestations of their field margins. Here, we studied farmers' perception of sown grass strips. First, we interviewed 29 farmers in two French regions. Second, we evaluated the economic loss of gross margin when replacing crop by grass. Third, we evaluated the weed risk using flora surveys in sown grass strips. Our results showed that two thirds of interviewed farmers thought that sown grass strips affected their farm revenue and represented a weed risk. Concerning economy, we found that farmers loose from 358 to 853€/ha the year of installation and from 126 to 641€/ha next years. This economic loss is mainly due to the loss of crop production, with a minor impact of grass management cost. At the farm level, 3% of sown grass strips decreased the farm revenue by 7%. Concerning the weed risk, the farmers' perception was linked with the presence of some competitive perennial weeds, e.g. Cirsium arvense, and wind-dispersing weeds, e.g. Asteraceae. Sown grass strips with high weed species richness of 26 species on average, or with dominance of non-sown species (16.7% of sown grass strips) did not affect the farmers' perception.In our study, the economic loss was weak and acceptable at the farm level.

Weed dispersal by farming at various spatial scales. A review

“…Weed exchanges between the field and its boundary seem to occur in both directions (Marshall 1989) with some species located in the field that are able to exploit disturbed zones within the boundary and other species mainly occurring in the boundary and spreading into the field (Marshall 1989;Rew et al 1996;West et al 1997). Short distance seed dispersal from the margin to the field may explain why boundaries are often perceived by farmers as a source for crop infestation (Marshall and Smith 1987;Cordeau et al 2011a) but also clearly contributes to enhanced weed diversity levels within generally impoverished cultivated fields (Roschewitz et al 2005;Gabriel et al 2006). Indeed, diversity within a field depends not only on the conditions within the crop, but also to connectivity at short distances between neighbouring habitats.…”

Bioenergy production and Skylark (Alauda arvensis) population abundance – a modelling approach for the analysis of land‐use change impacts and conservation options

“…We defined IBA as near‐nature area adapted to the regional environment without pesticide treatment and closely linked to extensive land use, hence with high plant and invertebrate diversity. This includes meadows, nonmanaged grassland habitats, open verges and flower strips without cutting operations between May and July (Siebert et al ., ; Vepsäläinen et al ., ; Cordeau et al ., ; Deri et al ., ). A crop‐type subsumes both the characteristics of the crop species and the production regime that may affect habitat suitability of farmland birds during the breeding season (see section Crop‐type parameter estimation, sensitivity analysis and model validation).…”

“…operations between May and July (Siebert et al, 2010;Vepsäläinen et al, 2010;Cordeau et al, 2011;Deri et al, 2011). A croptype subsumes both the characteristics of the crop species and the production regime that may affect habitat suitability of farmland birds during the breeding season (see section Croptype parameter estimation, sensitivity analysis and model validation).…”

Which Traits Allow Weed Species to Persist in Grass Margin Strips?

“…Floral surveys were carried out on 75 sown-grass margin strips in two study regions in France in May 2008, 2009, and 2010 (Table 1) before mowing operations occurred in the given years. The study regions were situated in western France (Region 1: 46°11′N, 0°28′W, Plaine & Val de Sèvres study region) and eastern France (Region 2: 47°13′N, 5°03′W, Fénay study region), in landscapes with similar characteristics (Cordeau et al 2011). Summer rainfall patterns were similar in both regions (monthly total precipitation: 96 mm in June, 71 mm in July, 70 mm in August, and 49 mm in September), except that 169 mm fell in July 2009 in eastern France (Region 2).…”