flying saucer create blank page when set landscape?

I am using flying saucer to create pdf from html.

@page land { size: A4 landscape; }
.landscapePage {
    page:land;
    height: 14cm;
    width: 30cm;
    background-color: green;
}

    <div class="landscapePage">
    </div>

But i don't know why it created a blank page before landscape page. How do I avoid it?