North Florida Rainfall

Temperatures are about 5 to 10 degrees hotter than normal this time of year combined with the fact that we haven't seen much rainfall (not since my last post) makes keeping the grass green a challenge.   A majority of our neighbors are struggling.  And although the land here used to be a vegetable farm, I am sure that they cleared all that good soil away and left us with stuff devoid of organic matter and nutrients.  Am thinking of ways we can amend the soil we have so next year is not such a great challenge.  Any thoughts?  I have an edger and am think of just cutting lines through the soil 1 or 2 feet apart and adding composted manure to the trench I dug...