For which plant is maintaining pH close to 7.0 most important for molybdenum availability?

Maintaining soil pH close to 7.0 is particularly important for alfalfa because molybdenum availability is heavily influenced by soil pH conditions. Alfalfa, being a legume, relies on molybdenum for its nitrogen-fixing capabilities, which are essential for the plant's growth and the overall health of the soil ecosystem.

In neutral pH conditions, molybdenum is more soluble and thus more readily available to plants. When the pH is significantly lower (acidic conditions), molybdenum can form insoluble complexes, making it less accessible to alfalfa roots. This is critical because if molybdenum is deficient, it can lead to nitrogen fixation issues, ultimately affecting the plant’s ability to thrive and produce effectively.

Other plants like tobacco, corn, and tall fescue have different nutrient requirements and tolerances to pH variations, making them less susceptible to molybdenum availability issues associated with pH levels outside of neutrality. Therefore, alfalfa stands out for its specific need for a near-neutral pH to optimize molybdenum availability and promote healthy growth.