What type of information are you looking for? A history of the Women's Land Army in England or elsewhere? There is a brief description of the British Land Army at http://www.spartacus.schoolnet.co.uk/Wland.htm . According to a booklet I have called Life on All Fronts: Women in the First World War by Gill Thomas, women could join one of three section: agriculture, forestry or forage (looking for food for animals).
Do you know when or where your grandmother was married? What year was she born? Where was she from? Is Parker her maiden name?