수능완성 실전편 5회 31번
the problem of sharing machinery is always a rostering one.

few farm machines (except possibly tractors) are multipurpose: they are designated to do specific tasks at specific points in the agricultural cycle.

given their limited period of usefulness, every farmer wants his own, so that he is not inconvenienced, nor his yields jeopardised, by having to queue for shared equipment.

every farmer wants his lands prepared before the rains begin; his planting started immediately after the rains; his herbicides applied immediately after germination; his crops sprayed as soon as pests are detected, and harvested at optimum moisture contents.

he does not wish to forgo output by late ploughing, late planting, untimely pesticide applications, or herbicides applied too late to prevent weeds from using nutrients intended for the crops.
*roster: 순번을 정하다

붉은색 문장 보면 뒤쪽에 by ing구문 나오는데 앞 내용이랑 상반되지 않나요?
그래서 그런지 저는 자연스럽게 해석이 안되네요.
도와주세요.