How Do You Get Lots of Participation on Your Site From Other Bloggers

Hi, I am fairly new to participating on Blogher and I wanted to know how many of you get participation from lost of mom bloggers on your blog or site?

I have a contest for mom bloggers going on and 2 moms will win cash for submitting a short blog post, we have some participation, but I thought we would be able to get quite a bit more.

I am just wondering if it is because we made it about blog post instead of just about comments or a blog tour or carnival?

My mom blog is at http://www.mommie911.com. 

I would love to know what strategieswork best to get other mom bloggers to post to your site.