In mediaeval Europe, farmers were already cultivating crops (including cereals and legumes) while domesticated animals (which grazed grasslands and other ecosystems by day) were confined at night specifically to deposit manure on areas in preparation for the next cropping cycle (Slicher van Bath
1963; Loomis
1978). Despite grain yields per unit area less than 15% of those of today (Connor
2013), such landscapes attracted the attentions of foraging wild geese to the degree that the miraculous ability to remove wild geese from crops was rewarded by sainthood (Kear
2001). Although goose depredation of human agriculture is therefore long established, it is evident that the small scale of cultivation, the far higher human population density associated with agriculture of the time and the pressure from hunting on geese would have precluded any major demographic benefit to goose populations of the time in exploiting mediaeval farmland. European agriculture went through a series of troughs in the late mediaeval, seventeenth and nineteenth centuries (Abel
2006), but it was mainly in the twentieth century that large areas of land were physically claimed from waterbodies, wetlands and the sea. The invention of the Haber–Bosch process in 1908 enabled humans to fix atmospheric nitrogen (Galloway et al.
2008), and inorganic fertiliser application suddenly enabled a vast improvement in plant performance and crop yields, and the cultivation of grass and arable crops on even the most peaty and sandy, infertile soils that were formerly heath, bog and moorland (and ironically the subject of current restoration ecology projects, e.g. Kooijmana et al.
2016). Application of nitrogen fertiliser increased sixfold in the Netherlands between 1939 and 1992 (van Eerden et al.
1996) and 4.2-fold between 1960 and 1980 in the USA (USDA ERA
2016), but with relatively little increase since. Although environmental legislation in the European Union has reduced its regional use since then, global nitrogen application per hectare of land has continued to increase, enhancing grass and crop yields (World Bank
2016). From the 1950s until the 1990s, the use of fertilisers, in combination with better tillage techniques, rapid mechanisation, applications of pesticides and the breeding of better cultivars all combined to dramatically increase production in the European arable sector, including more than a doubling in yield of important crops such as wheat, barley and potatoes (van Eerden et al.
1996). Reseeding of grass cultivar leys in combination with fertiliser application implemented since the 1970s has also advanced the production of grasslands, by extending the growing season in spring and autumn, as well as enhancing the quality and quantity of the biomass produced. As a result, heavily fertilised modern cultivars of the commonly cultivated Italian Rye Grass
Lolium perenne can be sequentially defoliated and still produce high-quality leaf tissue to grazers, including geese, for prolonged periods of the year (Davies
1988; Lestienne et al.
2006).