I have bought an orchard recently which has 42 apples 26 walnuts and 27 and some other trees. I know that no fertilizer has been added to soil for at least 2 years. I have read that adding 10cm of manure would help soil improvement. But local farmers here told me that that much of manure will kill your trees And they say you should apply that manure in fall and not summer (now).
So what should I do?
1- Is it safe to add 10 cm of manure.
2- Can I add that much of manure right now or should I wait until fall.