Great absorption and accumulation of N of RCUS happened mostly after jointing stage, while the rice crop in waterlogged soil absorbed N in large amounts from transplanting stage to filing stage.

• 水稻各部位的含氮量均大于水作。旱作水稻的氮素吸收、累积主要在拔节期以后，而水作水稻从移栽后就大量吸收氮素，灌浆期后很少吸收氮素；