soil testing question
I posted this in the tropical fruits forum but I'm double posting because I really need some good feedback on this one. So, Please excuse.
Just got a Kona Sharwil Avocado tree.
I've read that they like it around a ph of around 6 and I'm pretty sure I'm up there around 7 or more, so I'm going to get it tested professionally.
From the pic I drew with my fine artistic skills in MSPaint, here's a cross section of the plot. The DG and Clay is native and the top fill is 40 year old top fill that been amended many times off and on over those 40 years. Where should I take the samples from since the tree will be growing about half and half in the native and the fill? How deep should I take from? Should I take a bit of the native and a bit of the fill and mix together equally half by volume or weight prior to sending off for testing?