Davin Stewart wrote:Here's what I did in my Chapel Hill, NC red clay garden.
1. Check google maps for the nearest horse stables, dairy farm, etc. Manure from any herbivorous animal should be good. Maybe not goats though, I've heard they have lots of worms.
2. Call them up and ask if they're selling or giving away their manure, stable cleanings, etc. Any organic matter is good.
3. Get a truck or trailer and go pick up as much as you can. Some farmers will even load the manure for you. Make sure the give the farmer something for his trouble.
4. Till the manure and maybe some lime amendment into your soil as deep as you can. I try to double-dig and usually shoot for 2 feet deep. This is the only time I'll be tilling the soil so I try to over do it.
5. Level the soil higher than the surrounding grade (maybe as high as 6") since the soil will compact over time. Remember, it's always easier to take away than add more so shoot for a little too much.
5. Plant immediately. I've put plants into horse manure fresh from the animal and it was fine.
The results for me were outstanding. I had to water some in the first year but after that no irrigation was necessary to get great results. It was a game changer for gardening in clay soil.
I have been amending my soil for a few years now with kitchen scraps, worm castings, and local horse manure. I've dumped in significant amounts of organic matter but my humic matter content is largely unchanged at 0.3 - 0.5% according to my most recent soil analysis.
I'm honestly at a loss as to why this would be. The soil is visibly darker, fluffier, and easily dug by hand ... not like the native heavy clay soil that I started with.
The issue that I'm now facing is that my potassium and phosphorous levels are so high that they're off the charts! So adding additional nutrient rich organic matter is not an option. The county extension agent said that I honestly only need to fertilize with pure nitrogen for about 2 years to get the potassium and phosphorous levels back to normal ranges.
So after doing some research, I discovered that aged pine bark fines will provide significant organic matter without locking up nitrogen or providing significant additional nutrients.
Fresh wood chips would do the same but I've heard that they lock up nitrogen in the soil and harm plant life for a couple years unless supplemental nitrogen is applied.
Problem is that aged pine bark fines aren't easy to find and aren't that cheap. ~ $2 / cubic foot ... also the quality is highly variable
Does anyone have any other options for adding organic matter to the soil without adding nutrients?