求翻译：多次野外取样调查是什么意思？

Many times the field sampling survey

Many field sampling survey

Many times in the open country sample investigation, the room after blows the bromine to acidify the bittern to enter the salt field in the pH change influence factor inquisition and the room imitates the salt field pH change the influence which grows to the Du dunaliella and the Qingdao big platymo

Multiple sampling in the field investigation

many field sampling survey;