关键词: 碳储量, 林龄, 喀斯特, 分配格局, 生物量

Abstract: To provide a theoretical basis of scientific division and layout of japonica rice Nanjing 9108 under ricewheat copping system in different ecological regions of Jiangsu, we studied the growth characteristics and utilization of temperature and illumination of high-quality rice Nanjing 9108 at different sowing dates with mechanical-transplanting in Xinghua (Suzhong, 33°05′ N) of Lixiahe ricegrowing region and Donghai (Subei, 34°34′ N) of Huaibei ricegrowing region. As the sowing date delayed, jointing, heading and maturity stages postponed accordingly and the yield of Nanjing 9108 reduced. As the sowing date delayed 1 d, the growth period shortened 0.5 d and the yield decreased by 59.6 kg·hm^-2. With the increase of latitude, jointing, heading and maturity stages at the same sowing date were delayed correspondingly, while the accumulated temperature and illumination hours decreased. The growth period in Donghai extended 13.4 d compared with that in Xinghua at the same sowing date. Furthermore, the average production in Donghai was 289.7 kg·hm^-2 less than in Xi〖JP2〗nghua. The accumulated temperature and illumination at different sowing dates reduced significantly or very significantly from jointing to mature stages, especially from heading to mature stages. Different ecological regions and sowing dates had great impacts on growth stage, accumulated temperature illumination, and yield production. Sowing on May 21st to June 6th is suitable for high yield of Nanjing 9108 in Lixiahe rice-growing region, and sowing on May 21st to May 26th is appropriate in Huaibei rice-growing region. If rape and barley are previous crops, appropriately early sowing is beneficial for high yield.

Key words: karst, biomass, carbon storage, allocation, stand age