Certified Crop Advisor Practice Exam

Potassium fixed by soil minerals is _________ available to crops?

1. Immediately

2. Slowly

3. Not

4. Freely

The correct answer is: Slowly

Potassium fixed by soil minerals is slowly available to crops. This form of potassium is typically bound within the structure of certain clay minerals, making it unavailable for immediate uptake by plants. While some potassium in the soil solution is readily accessible to crops, the potassium that is tightly held by mineral structures must first undergo a process of weathering or mineral breakdown before it can be released and become available. This gradual release process is important for ensuring a steady supply of potassium over time, which is crucial for plant health and growth. It underscores the significance of soil management practices that maintain a balanced supply of potassium, taking into consideration not only the immediately available potassium but also that which is fixed within the soil matrix.