In-text citations for research papers?

I'm writing a research paper for my Cultural Geography cl, though I'm a little stuck on the citation part. I use the MLA citation style for my English papers, but since I've hardly ever written a research-oriented paper, I'm not too familiar with the citing of sources (or at least in-text). Do I provide an MLA in-text citation per sentence of information used? If so, my paper is littered with them.