At which pH level is phosphorus most available to plants?

Phosphorus availability to plants is influenced significantly by soil pH. The pH level where phosphorus is most available to plants typically ranges between 6.0 and 7.0. At these levels, phosphorus is less likely to react with soil particles and form insoluble compounds, making it more accessible for plant uptake.

When the pH is around 6.5, which is the middle of the optimal range, soil chemistry allows phosphorus to remain in forms that plants can absorb effectively. At pH levels lower than this, such as in more acidic soils, phosphorus can bind with iron and aluminum, leading to reduced availability. Conversely, in more alkaline conditions above 7.0, phosphorus may react with calcium and also become less available.

Thus, the choice of 6.5 represents the sweet spot for optimal phosphorus availability, ensuring that plants have sufficient access to this essential nutrient for their growth and development.