Question on Osmosis? Need to know?

I had to read a story about a kid who instead of putting just 25 bags of fertilizer in the tractor to fertilize his crops, he also added 15 extra bags. The day after, it rained. The day after that, he went out and the crops were wilted and withering. What kind of environment (hypotonic, hypertonic, isotonic), did the extra fertilizer create? Why?