'political' definition: Relating to the government or public affairs of a country.
origin: (from Greek: πολιτικά, (Politiká), meaning "affairs of the cities") is the process of making decisions that apply to members of a group.

'landscape' definition: All the visible features of an area of land, often considered in terms of their aesthetic appeal.
origin: Late 16th century (denoting a picture of scenery): from Middle Dutch lantscap, from land ‘land’ + scap (equivalent of -ship).

'Political landscapes' can be explored in many ways through photography, it could be argued that every photograph that we take has an underlying political statement even if there was no intention for it - a photograph can either conform to ideologies and standards of a culture/society or it could break them. 
Your Photography Is Political

Effectively the product produced by the fusion of politics and landscape photography is documentary photography, which essentially highlights and tackles current issues, daily life, events or traditions that have been developed through political influences, then reinforced through the media and dominant ideologies in societies. 

Landscape photography can present issues like global warming and the impact of human activity or capitalism in modern cities or societies and its effects on the lower classes, or natural landscapes and the impact of infrastructure and urban development; focusing on the sublime in nature or perhaps what has replaced the feeling of sublimity with the changing landscape; escapism.
As well as landscape photography conveying issues through the land and scenery of an area it can become something more abstract like the human body or inanimate objects. This can relate to social issues like equality within race, gender, disabilities, mental health and breaking stereotypes and breaking ideologies.