Efficient use of N in agricultural practice can increase yield, decrease production costs and reduce the risk of environmental pollution. Effects of N fertilizer application rates on grain yield and physiological N us...Efficient use of N in agricultural practice can increase yield, decrease production costs and reduce the risk of environmental pollution. Effects of N fertilizer application rates on grain yield and physiological N use efficiency (PE) in relation to the accumulation and redistribution of biomass and N in rice (Oryza sativa L.) cultivars were studied at two experimental farms of Nanjing Agricultural University, Nanjing, China in 2004. Three high N use efficiency (NUE) rice cultivars (Wuyunjing 7, Nanguang and 4007) and one low NUE rice cultivar (Elio) with similar growth patterns were studied under seven N rates (0, 60, 120, 180, 240, 300 and 360 kg ha -1 ). Grain yield increased with the N application rate and attained plateau at 180 kg N ha -1 for rice cultivars at each site. Increasing N rate decreased PE for biomass and grain yield. Grain yield and PE of Elio were about 20% and 18% lower than those of high NUE cultivars. Differences in biomass, N accumulation and N redistribution were observed at the post-heading stage among rice cultivars with differing NUEs. The less reproductive tillers of Elio resulted in less demand for C and N during grain filling, thus leading to lower PE of Elio compared with the high NUE rice cultivars.展开更多
Currently, in the course of serious environmental problems where the cause is anthropogenic, such as global wanning, not only the technology and policies but also the promotions of pro-environmental behavior are requi...Currently, in the course of serious environmental problems where the cause is anthropogenic, such as global wanning, not only the technology and policies but also the promotions of pro-environmental behavior are required. However, previous studies reported a gap between high environmental awareness and behavior. So to promote this practice, it is necessary to clarify the determinants that lead to practice. Because of the rapid economic growth in developing countries, including Vietnam, pollution problems and energy consumption are of major importance. This study aims to propose methods to promote pro-environmental practices based on a questionnaire and statistical analysis that investigated university students in Vietnam＇s Ho Chi Minh city. From the factor analysis, in actions to do with the power-saving behavior of standby power and home electronics, and the use of air conditioning, four evaluation criteria including effectiveness, cost feasibility, convenience, and social norms are extracted. The covariance structure analysis showed that the evaluation of convenience represented the strongest causal relation to a given power-saving action, and the action, in turn, can lead to improvements in most practical activities so as to enhance their convenience. Finally, several methods to save energy are proposed based on the results of the questionnaire.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 30771290 and 30671234)
文摘Efficient use of N in agricultural practice can increase yield, decrease production costs and reduce the risk of environmental pollution. Effects of N fertilizer application rates on grain yield and physiological N use efficiency (PE) in relation to the accumulation and redistribution of biomass and N in rice (Oryza sativa L.) cultivars were studied at two experimental farms of Nanjing Agricultural University, Nanjing, China in 2004. Three high N use efficiency (NUE) rice cultivars (Wuyunjing 7, Nanguang and 4007) and one low NUE rice cultivar (Elio) with similar growth patterns were studied under seven N rates (0, 60, 120, 180, 240, 300 and 360 kg ha -1 ). Grain yield increased with the N application rate and attained plateau at 180 kg N ha -1 for rice cultivars at each site. Increasing N rate decreased PE for biomass and grain yield. Grain yield and PE of Elio were about 20% and 18% lower than those of high NUE cultivars. Differences in biomass, N accumulation and N redistribution were observed at the post-heading stage among rice cultivars with differing NUEs. The less reproductive tillers of Elio resulted in less demand for C and N during grain filling, thus leading to lower PE of Elio compared with the high NUE rice cultivars.
文摘Currently, in the course of serious environmental problems where the cause is anthropogenic, such as global wanning, not only the technology and policies but also the promotions of pro-environmental behavior are required. However, previous studies reported a gap between high environmental awareness and behavior. So to promote this practice, it is necessary to clarify the determinants that lead to practice. Because of the rapid economic growth in developing countries, including Vietnam, pollution problems and energy consumption are of major importance. This study aims to propose methods to promote pro-environmental practices based on a questionnaire and statistical analysis that investigated university students in Vietnam＇s Ho Chi Minh city. From the factor analysis, in actions to do with the power-saving behavior of standby power and home electronics, and the use of air conditioning, four evaluation criteria including effectiveness, cost feasibility, convenience, and social norms are extracted. The covariance structure analysis showed that the evaluation of convenience represented the strongest causal relation to a given power-saving action, and the action, in turn, can lead to improvements in most practical activities so as to enhance their convenience. Finally, several methods to save energy are proposed based on the results of the questionnaire.
