| In order to explore the characteristics of rice yield formation, the characteristics of dry matter accumulation and trans location, the regulation and its difference of nitrogen absorption and accumulation under different ecological conditions. Field experiments with super hybrid rice (Wuyou308 and Luoyou9348) and inbred rice (Huanghuazhan and Yuxiangyouzhan) conducted under different N application conditions ((N0)0, (N1)120～225, (N2)225 kg hm-2) in three locations from 2011 to 2013, in which was Xingyi city of Guizhou Province, Changsha city of Hunan Province and Huaiji county of Guangdong Province. The main results were summarized as follows:1. A significant difference in grain yield was observed among the experimental conditions. Xingyi produced the highest grain yield (two year average 11.86 t hm-2), which was 22.68% and 39.29% higher than that produced in Changsha and Huaiji, respectively. A significant difference in grain yield was observed among the three N rates. The yield of rice was the highest in N1 fertilization treatment (average 10.02t hm-2), significantly higher than NO and N2 fertilization treatment. Rice varieties showed significant genotypic differences in yield at different ecological conditions, grain yield Wuyou308 and Luoyou9348 higher than that of Huanghuazhan and Yuxiangyouzhanl.2. The yield components of rice in different ecological conditions were significantly different. A significant difference in panicles per m2, grains per panicles and grain fillings, except for 1000-grain weight. Panicles per m2, spikelet number and grain fillings were the highest in Xingyi; however, spikelets per m2 were the highest and grain fillings were the lowest in Changsha, whereas grains per panicles and spikelet number were the lowest in Huaiji. At maturity, the rice grain yield was positively correlated to the spikelet number. The panicle number per unit area showed the greatest contribution to the grain yield, and next the grain fillings, of which their path coefficients were 0.7054 and 0.2547.3. A significant difference in biomass of rice was observed among the experimental conditions. Dry matter production at heading, heading-maturity and maturity were relatively highest in Xingyi, respectively as 1291.Og m-2、346.3 g m-2、2068.0 g m-2 remarkable higher than that produced in Changsha and Huaiji 22.24%～36.47%、11.50%～19.69%、 23.78%～31.67%. The harvest index of cultivars was relatively higher in Wuyou 308. The grain yield was positively correlated to the dry matter accumulation under different ecological conditions.4. The transfer rate and contribution rate of dry matter production at the heading stage of ecological conditions were significantly different. The transport rate and contribution rate of dry matter production at heading stage were highest in Huaiji, respectively as 36.69% and 35.80%, remarkable higher than that produced in Changsha and Xingyi 0.74%～4.63% and 0.35%～5.39%.The rate of transport of dry matter at heading stage in different ecological conditions were NO>N1>N2, except for Changsha, but did not show the significant difference. There was a significant difference in the transport rate of dry matter production between cultivars at heading stage; the characteristics of hybrid rice were higher than that of conventional rice.5. The amount of nitrogen uptake by rice plants was significantly different between different ecological conditions, mainly in the grain and rice straw. The highest N uptake amount was observed in Xingyi (22.02 g m-2), which was 27.57% and 40.42% higher than Changsha and Huaiji, respectively. The N uptake amount was ordered as:N2>N1>N0 under different ecological conditions, and the difference was significant. N2 absorption amount for 22.76 g m-2, was the highest compared with N1, NO average higher than 8.45%～38.24%. The grain yield was positively correlated to the nitrogen uptake under different ecological conditions (R2=0.4555**).The nitrogen harvest index was the largest in Huaiji (65.45%) and the smaller in Changsha (62.92%). The nitrogen harvest index decreased with the increase of the nitrogen application rate. The nutrient requirement for N per 1000 kg filled grains was ordered as:N2>N1>N0, and genotypic differences among cultivars. The nitrogen requirement of different conditions showed a significant decreasing trend with the increase of rice yield, Xingyi, Changsha and Huaiji point of the correlation coefficient R2 respectively were 0.4378、0.7606 and 0.2932.6. There were significant differences in nitrogen agronomy efficiency, nitrogen recovery efficiency and partial factor productivity. The partial factor productivity was the highest in Xingyi (63.27 kg kg-1), which was 14.76 kg kg-1～22.11 kg kg-1 higher than Changsha and Huaiji. The nitrogen agronomy efficiency and nitrogen recovery efficiency were the highest in Changsha, which were 10.47kg kg-1 and 38.74%, and significantly higher than 26.46%～50.43%,3.14%～11.64% in Xingyi and Huaiji location. The nitrogen agronomy efficiency partial factor productivity were ordered as:N1>N2, which of average 19.69 kg kg-1 and 58.91 kg kg-1 under N1 conditions, compared with N2 average higher than 70.14% and 26.92%, respectively.7. The soil nitrogen dependent rate in rice showed the difference among the conditions, fertilizers and cultivars. The soil nitrogen dependency rate of different location was the highest in Xingyi(71.87%), which was 7.27% and 14.17% higher than in Changsha and Huaiji. The soil nitrogen dependent rate was ordered as:N1> N2, which of average 68.24% under N1 conditions, compared with N2 average higher than 7.04%. Among cultivars with the highest were Wuyou308, followed by Luoyou 9348, Huang huazhan and Yuxiangyouzhan, the value were 70.66%,63.71% ,63.61% and 60.92%, respectively. |
