Garden soils need organic matter to hold moisture, slowly release nutrients, add to soil tilth so roots can be cozy and get at soil particles... There are lots of horse stables and pastures where I live in N. Central Florida, as well as high temperatures which lead to fast decomposition of organic matter in these sandy well-drained soils, so my garden needs a healthy - pow! - shot of nutritious organic matter every fall.
Horse farmers have huge piles of free horse manure, urine and straw that get cleaned out of stables that can get them in trouble with the department of environmental protection because of the nitrogen that can leach out and go to creeks and streams in heavy rains. USDA or state agents go on visits to farms to see how their poop piles are doing, and the smaller they are the better.
This instructable tells you how to
1. find free fresh horse manure
2. get it to your house
3. add it to your soil as a mulch, or as a soil amendment for future plants.
You will need:
1. station wagon OR pickup truck with some big tarps
2. a few shovels
3. a hearty friend who likes poop
4. recycle bins or wheelbarrow
Found this here about why organic matter in soil is great:
• Improves tilth, condition, and structure of soil, providing better aeration and temperatures.
• Supports living soil-organisms.
• Improves ability of soil to hold water and nutrients.
• Helps dissolve mineral form of nutrients.
• Buffers soil from chemical imbalances.
• Maintains a steady supply of plant nutrients.
• Helps recycle organic wastes, thus keeping them out of landfills and waterways.
• Replaces manufactured nitrogen which requires energy to create in a factory and ship around.