But the low yields of organic agriculture in real-world settings – typically 20-50% below yields from conventional agriculture – impose various stresses on farmland and increase water consumption substantially. According to a recent British meta-analysis, ammonia emissions, nitrogen leaching, and nitrous-oxide emissions per unit of output were higher in organic systems than in conventional agriculture, as were land use and the potential for eutrophication – adverse ecosystem responses to the addition of fertilizers and wastes – and acidification.