I want to know the answer to the following question:
Why is the concentrate of uranium in farmland so high?
All the background I'm provided with is that "The concentration of uranium in soil ranges from 0.7 to 11 parts per million (up to 15 parts per million in farmland soil due to use of phosphate fertilizers), and its concentration in sea water is 3 parts per billion.". Is that enough to answer the question?