Hi Syl, I'm in first year of resource economics, its basically a mixture of environmental science and economics however a lot of maths is involved throughout the degree. From what i've heard, agricultural economics is like resource economics except without any science components. For example, resource economics students would have to do first year science subjects like maths and one science (such as biology, chemistry or geography), agricultural economics students could pick accounting or marketing instead.
Its a great course and I highly recommend resource economics, having done no science and only two unit maths in Yr 12 I found it challenging but not impossible to do. Both degrees have had very successful graduates who mostly go into the banking sector, doing economic research for government agencies or environmental sustainability firms. And these degrees will give you an edge over normal commerce/economics graduates (or so our program co-ordinator says).