Why is soil pH important for nutrient availability?

• A. It changes soil color.
• B. It affects nutrient solubility and uptake.
• C. It affects only microbial activity.
• D. It has no impact on nutrients.

Answer: (B)

Soil pH controls how readily nutrients dissolve and are taken up by plant roots. The hydrogen ion activity in the soil determines the chemical form a nutrient takes and how strongly it binds to soil particles. When pH is outside a plant’s optimal range, many nutrients become either too soluble and wash away or too bound up to soil particles to be absorbed, even if they’re present in the soil. For example, in acidic soils some nutrients can be more available, but elements like aluminum can reach toxic levels, while in alkaline soils iron, manganese, and phosphorus often become insoluble and unavailable. This makes pH the key factor that governs nutrient solubility and uptake, which is why adjusting soil pH to the crop’s preferred range improves nutrient availability. Manage pH by liming to raise it or adding sulfur to lower it, and then observe plant responses to fine-tune as needed.