agriculture has also exerted pressure on aquatic environments rivers lakes wetlands and coastal zones from increasing levels of livestock effluents and diffuse pollution through the use of chemicals in arable farming other issues include the genetic erosion of maize varieties which show a loss of of local varieties compared to the s and more recently possible contamination of domesticated landraces and wild relatives from transgenic maize oecd while agrienvironmental payments are possible under procampo for soil and water conservation for instance farmers uptake of these payments has been limited