It must have some source of phosphorous in it because the middle number is not 0. I just gave potassium phosphate as an example, I'm not specifically looking for phosphate. I would need more info for the comparison pictures, like are they growing in plain sand which is what is often the case for such tests. In which case it's not surprising the water only one would be small. I don't know if it says whether they applied all the other three fertilizers to supply the same rate of nitrogen, or whether there were enough microorganisms to convert the organic part of the N in blood meal to a form the plants can use in sufficient time for the test. Or what was in the "common fertilizer". To look at it critically one would need more information. I think there might be a study mentioned at the bottom? The analysis seems fine, though, so there's no reason I can see not to use it.
