The farmers are furrowing the field with a tractor to prepare for planting.

furrowing 是动词 furrow 的现在分词形式。furrow 本意是"犁沟、沟槽"，作动词时表示"犁出沟槽"的动作。在农业中特指用犁或拖拉机在田地里开沟，为播种做准备。