To become muddy or broken up from being trampled. Used of land.

变泥泞，破裂：因被践踏而变得满是稀泥的或破损不堪的，用来指地面。

youdao

In the height of the rains from March through May, the trails become unpleasantly muddy.

BBC: Search the

During the long rains from March to May, many areas of the country become extremely muddy, and hiking during this time is not recommended.

BBC: Hiking in Tanzania

Hit by a series of scandals and highly-publicized attacks by opportunistic short-sellers like Citron Research and Muddy Waters, investor sentiment has weakened and doubt has become the default position.

FORBES: Short-Seller Attacks Highlight Chinese Companies Social Media Shortcomings