Simulation On Growth And Development In FACE Rice

Global atmospheric CO₂ concentration([CO₂]) was projected to reach levels of 650～780μmol.mol^-1 by the end of this century(IPCC, 2000). The increasing atmospheric [CO₂] and associated climate changes may greatly affect agricultural productivity worldwide. Rice was one of the most important crops in China, and stabilizing and increasing rice production are of great importance in assuring the security of Chinese food supply. However, little was known about the effects of free-air CO₂ enrichment(FACE) on growth and development of rice. In order to predict the changes of growth and development of rice under FACE condition, we conducted FACE experiments at Anzhen(31037'N,120028'E), Wuxi in 2001～2003 and Xiaoji(32°35'N,119°42'E), Jiangdu, Jiangsu province in 2005.The FACE facility consisted of three FACE rings(three replicates) and five ambient rings, and the ambient rings were 90m apart to avoid contamination of elevated CO₂. Rice were grown from transplanting to harvest under two levels of [CO₂] for three consecutive years(2001～2003), and the target [CO₂] of the FACE rings was 200μmol.mol^-1 above that in the ambient air. The Japonica cultivar Wuxiangjing 14 was used in 4-year experiment. Seeds were sowed on 18 May and seedlings were hand transplanted with 3 plants each hill on 13 June. Hills and rows were 16.7 cm and 30 cm apart, respectively(equivalent to 24 hills.m^-2). Three levels of N application were 150kg.hm^-2(LN), 250kg.hm^-2(MN) and 350 kg.hm^-2 (HN). The results were showed as follows.1.The mean days from sowing to heading, from heading to maturity and the whole growth duration of rice shortened 3～4.5d(mean value 3.4d), 2～3d(mean value 2.4d) and 5～7.5d(mean value 5.8d) respectively in FACE treatment compared with CK. Increasing nitrogen application rate could weaken the effect of FACE on growth...