Other translations:
Rough/risky ground

https://www.collinsdictionary.com/dictionary/english/treache...
Certainly! Here's an improved adaptation of the translation to better fit its context:

It can be translated as "treacherous ground" or "unforgiving terrain" in English. In the context of the soldiers training in the rain, the sentence would convey that the once smooth track or path they were running on rapidly transformed into a treacherous and challenging landscape due to the mud brought about by the rain. There was no leeway for halting or even stumbling. The term "أرض وعرة" suggests a rough, uneven, and demanding surface that poses difficulties in navigating.