Benefits

• Phosphorous aids in root and flower development and increases the rate of growth. Phosphorous is used by plants to store and transfer energy.
  
  

Availability

• Most of the phosphorus in soil is in the insoluble form, especially in soil with a pH greater than 7.5. Optimum availability occurs when the soil pH is between 6.0 and 7.0.
  
  

Testing

• To determine the phosphorus level in your soil, take soil samples at a depth of 0 to 6 inches in no-till fields and 0 to 12 inches in tilled fields. Have the samples tested for phosphorus at an analytical laboratory.
  
  

Sources

• There are several types of phosphorus fertilizers including beef manure, dairy compost, verimicompost, rock phosphate and bone meal.
  
  

Considerations

• The amount of soluble phosphorus in fertilizers is small. Beef manure contains one percent of soluble phosphorus and bone meal contains 22 percent, by weight.