Allocation Real Estate Taxes

I own 20 acres of woodland/pastureland and my personal residence is on this land.  On schedule E, can I claim the entire $6000 Real Estate tax bill as an expense on schedule E even though the pastureland rental is only $1,000 or am I required to allocate only a portion of RE taxes to schedule E?  If required to do an allocation, what do I base the allocation on? Is there an IRS publication that provides guidance on this?