GOV.WALES uses cookies which are essential for the site to work. Non-essential cookies are also used to tailor and improve services. By continuing to use this site, you agree to our use of cookies.
Perth neu glawdd uchel neu lain o goed sy’n gallu helpu i rwystro paill rhag cael eu chwythu o un cae i’r llall. Yn ddefnyddiol os nad yw ffermwr am i baill o gnwd GM fynd a pheillio cnwd di-GM mewn cae cyffiniol.