Why do you come up with the idea of the object according to your fancy?
Panini has laid some descriptions of karma and adhikarana and some other parts of speech or kaaraka vibhakti-s according to which the usages could be justified.
What made you think bhumi is the object? According to Panini, it is adhikarana, or the location where she places the Krishna, and hence it takes saptami even for the common English sentence she places Krishna on the ground.
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