It takes so long to decompose because worms ,bugs ,insects cannot eat it ;natural occurring enzymes can't dissolve it easily ,it does weather over time making the structure breakdown it takes up to 100 yrs , acids will dissolve it and fire will too. These are harmful to the environment.
If the plastic is not specially designed to decompose in the soil it will last a very long time because the chemical bonds that hold the molecules together are often stronger than nature's power to take them apart
soil micro-organisms can attack and decompose wood and other formerly "living" materials but they cannot break down the various kinds or strong bonds that are common to most plastics
soil micro-organisms can attack and decompose wood and other formerly "living" materials but they cannot break down the various kinds or strong bonds that are common to most plastics