Many of these products tend to be high in pH and nutrients and probably should be considered organic fertilizers rather than soil amendments. Green manure . The so-called green manure crops, small grains and legumes, are actually cover crops that are grown to improve the soil. Upon maturity, green-manure crops are turned into the soil. This age-old practice produces a large amount of organic matter and releases nutrients into soil slowly as the crop decomposes.
Limestone is added to soil to increase the pH, but also supplies some plant nutrients.
Calcitic limestone is calcium carbonate and is an important source for calcium. Dolomitic limestone contains both calcium and magnesium carbonates, thus supplies two important plant nutrients. Use a soil test to determine the limestone requirement for your soil and crop. Most sphagnum peat moss is commercially harvested from huge peat bogs in the northern hemisphere. Sphagnum peat has a spongy, fibrous texture, a high water-holding capacity, and a low pH and nutrient content.