Is it a katar dagger ?

[Robert]

For the last few days I have been trying with no luck to locate an old gardening tool owned by my Great Grandmother called a dibble. Though not quite as large as the one being discussed here it too has a shovel style handle and a diamond profiled blade. These were used for planting and while some have only a round blade for punching holes into the soil others had blades like this that were used not only for planting seeds but for cutting sod and roots. Below is a photo of a newer example with a round blade. If this is a dibble (as I suspect it to be) it could have been pushed into the soil forgotten and lost for years which would explain the overall heavily rusted condition.

Best,
Robert