Not sure I understand your question.

My assumptions: You use well water now with a pump that pushes water through a soaker hose system in your garden. You would like to replace the soaker hoses with drip-line. You would like to automate something using solar power.

My questions: Do you want to use solar power to run a timer? If so, why? Batteries or 110v would be cheaper. You surely are not talking about solar to run a pump? I would guess you would have to cover the back 40 acres with solar collectors to be able to pump water.

My off-the-cuff response without benefit of knowing exactly what you want: The system you have now pushes water through a soaker hose. That system should also be able to supply water to drip-lines. If you want more than one zone, I would think you would need a control for each zone, consisting of a filter and pressure regulator. To really "automate", you just need a timer to switch the zones on and off.

If I am answering questions you did not ask, you might clarify your questions for me.

Tom