Phosphorus availability from rock phosphate: Combined effect of green waste composting and sulfur addition
Journal of Environmental Management
Phosphorus is extremely important for plant growth, yet it's use in agriculture is extremely inefficient. A conservative estimate is that 50% of applied phosphorus becomes unavailable as it binds with other elements in the soil. To help alleviate this, we can thank microbes.
To address this problem, a team of scientists from Italy and Spain added rock phosphate to greenwaste-compost piles at several levels, let the compost go through its thermophilic cycle, and then determined soluble phosphate levels.
The scientists found that soluble phosphorus levels increased with the addition of compost. The increase was most drastic in the treatments that had the lowest amount of rock phosphate added. Furthermore, the addition of rock phosphate made for more efficient use of nitrogen in the compost, retaining it so that it was not lost to the environment. Adding elemental sulfur was also shown to help increase phosphorus solubility. Take home message: add a little soft rock phosphate to your compost pile to create a phosphorus rich biofertilizer.