Abstract: A field experiment with four rice (Oryza sativa L.) cultivars and different nitrogen application rates was conducted, with the dry matter accumulation (DMA) in the cultivars aboveground part measured at their main growth stages. The dynamic model of relative dry matter accumulation (RDMA) was established with the normalized DMA and TEP (product of thermal effectiveness and PAR) from emergence to maturity, and the temporal characteristics of DMA changes was quantitatively analyzed based on the RDMA model. The dynamic changes of the RDMA could be well described with Richards equation, i.e., RDMA=1.0157/(1+e^{3.6329-7.5907×RTEP})^1/0.5574 (r=0.9938). The model was validated with independent field experiment datasets, involving different eco-sites, cultivars, and nitrogen application rates. The RMSE (root mean square error) between the simulated and observed values of DMA at varied RTEP was 0.86 t·hm^-2. According to the two inflexion points of dry matter accumulation rate equation, the whole process of dry matter accumulation could be divided into early, middle, and late phases. The maximum dry matter accumulation rate (AR_max), relative TEP at  AR_max, and relative dry matter accumulation at  AR_maxwere found to be 2.24, 0.56, and 0.46, respectively.

Key words: rice (Oryza sativa L.), dry matter accumulation, product of thermal effectiveness and PAR, growth analysis, Richards equation, maize plant type, soybean, dry matter accumulation, yield.