How quickly is phosphorus (P) available in dairy manure?

Phosphorus in dairy manure is typically available for plant uptake relatively quickly after application. When dairy manure is applied to fields, much of the phosphorus is in a soluble form or associated with particulate matter that can be readily absorbed by plants. This rapid availability is due to the inherent chemical and physical characteristics of the phosphorus compounds present in the manure, which allow them to dissolve in soil moisture and be assimilated by plant roots shortly after application.

This quick release contrasts with the option that suggests phosphorus availability increases over several months, which could apply to some other fertilizers or nutrient sources where microbial breakdown is necessary for nutrient release. Additionally, the notion that phosphorus takes a year or more to become available doesn't align with the immediate accessibility of phosphorus from fresh manure, as this nutrient is often available for plant uptake within a few days to weeks after application. Lastly, the idea that phosphorus isn’t available until spring overlooks that the nutrient can be utilized by plants as soon as it is applied, regardless of the season, if conditions for plant growth and soil moisture are favorable.