Question - The tractor shown in “Field Trip 1.1” (which has been there for several decades) appears to be preventing plant growth

The tractor shown in “Field Trip 1.1” (which has been there for several decades) appears to be preventing plant growth in the immediate surroundings. Can you think of any reasons why this might be the case?

Answer: 

The breakdown of various components of the tractor has likely contributed to changes to the chemistry of the soil in the immediate area.  This might include acidification due to oxidation of metal parts, erosion of components of the painted surfaces, and dispersal of fuel and lubricants.