To compare the grain yield and growth behaviors of hybrid rice, field experiments were conducted in a subtropical environment in Changsha, Hunan Province, China, and in two tropical environments in Gazipur and Habigan...To compare the grain yield and growth behaviors of hybrid rice, field experiments were conducted in a subtropical environment in Changsha, Hunan Province, China, and in two tropical environments in Gazipur and Habiganj in Bangladesh during 2009 to 2011. Three hybrid rice cultivars were grown under three nitrogen (N) management treatments in each experiment. The results showed that grain yield was significantly affected by locations, N treatments and their interaction but not by cultivars. Changsha produced 8-58% higher grain yields than Bangladesh locations. Sink size (spikelet number per unit land area) was responsible for these yield differences. Larger panicle size (spikelet number per panicle) contributed to greater sink size in Changsha. Aboveground total biomass was greater in Changsha than in Bangladesh locations, whereas harvest index was higher in Bangladesh locations than in Changsha. Crop growth rate (CGR) was greater at Changsha than Bangladesh locations during vegetative phase, while the difference was relatively small and not consistent during the later growth phases. Higher leaf area index and leaf area duration were partly responsible for the greater CGR in Changsha. Real-time N management (RTNM) produced lower grain yields than fixed-time N management in more than half of the experiments. Our study suggested that further improvement in rice yield in the tropical environments similar to those of Bangladesh will depend mainly on the ability to increase panicle size as well as CGR during vegetative phase, and the chlorophyll meter threshold value used in RTNM needs to be modified according to environmental conditions and cultivar characteristics to achieve a desirable grain yield.展开更多
叶面积指数(Leaf area index)是描述叶片生长过程的重要参数之一。为探讨我国帽儿山地区落叶阔叶林长时间序列叶面积指数变化规律,利用LAI-2200对帽儿山林场老爷岭试验站12块样地生长季叶面积指数进行测量,使用生长方程对离散LAI值进行...叶面积指数(Leaf area index)是描述叶片生长过程的重要参数之一。为探讨我国帽儿山地区落叶阔叶林长时间序列叶面积指数变化规律,利用LAI-2200对帽儿山林场老爷岭试验站12块样地生长季叶面积指数进行测量,使用生长方程对离散LAI值进行拟合,计算不同时间的叶面积指数生长速率和生长季累积叶面积指数,分析不同立地条件下不同林分叶面积指数生长情况,对其动态变化规律进行研究。研究表明:生长季4月到8月,12块落叶阔叶林叶面积指数均随时间呈单峰变化。以杨树有优势树种的样地用Mitscherlich生长方程拟合其LAI效果最优,以色木和白桦为优势树种的样地采用logistic生长方程拟合效果最优,其它样地Gompertz生长方程拟合最优,各样地生长方程拟合R2均高于0.962。杨树林叶面积指数增速最快,胡桃楸林增速缓慢,6月初到8月中下旬为冠层LAI生长速度趋于平稳。空间位置相近的阴阳坡样地叶面积指数生长规律差别较大,最高累计叶面积指数相差17.6%。此研究结果为帽儿山地区阔叶林叶面积指数动态变化规律提供数据基础,为该地区林冠植被的空间异质性及其造成影响,以及提升日步长碳循环、水循环生态机理模型精度提供更为准确的数据支持。展开更多
基金supported by the National Basic Research Program of China (2009CB118603)the Green Super Rice (GSR) Project from the International Rice Research Institute (IRRI) for South Asia+1 种基金Project was completed through the generous cooperation of Hunan Agricultural University, Changsha, Hunan, Chinathe Bangladesh Rice Research Institute (BRRI)
文摘To compare the grain yield and growth behaviors of hybrid rice, field experiments were conducted in a subtropical environment in Changsha, Hunan Province, China, and in two tropical environments in Gazipur and Habiganj in Bangladesh during 2009 to 2011. Three hybrid rice cultivars were grown under three nitrogen (N) management treatments in each experiment. The results showed that grain yield was significantly affected by locations, N treatments and their interaction but not by cultivars. Changsha produced 8-58% higher grain yields than Bangladesh locations. Sink size (spikelet number per unit land area) was responsible for these yield differences. Larger panicle size (spikelet number per panicle) contributed to greater sink size in Changsha. Aboveground total biomass was greater in Changsha than in Bangladesh locations, whereas harvest index was higher in Bangladesh locations than in Changsha. Crop growth rate (CGR) was greater at Changsha than Bangladesh locations during vegetative phase, while the difference was relatively small and not consistent during the later growth phases. Higher leaf area index and leaf area duration were partly responsible for the greater CGR in Changsha. Real-time N management (RTNM) produced lower grain yields than fixed-time N management in more than half of the experiments. Our study suggested that further improvement in rice yield in the tropical environments similar to those of Bangladesh will depend mainly on the ability to increase panicle size as well as CGR during vegetative phase, and the chlorophyll meter threshold value used in RTNM needs to be modified according to environmental conditions and cultivar characteristics to achieve a desirable grain yield.
文摘叶面积指数(Leaf area index)是描述叶片生长过程的重要参数之一。为探讨我国帽儿山地区落叶阔叶林长时间序列叶面积指数变化规律,利用LAI-2200对帽儿山林场老爷岭试验站12块样地生长季叶面积指数进行测量,使用生长方程对离散LAI值进行拟合,计算不同时间的叶面积指数生长速率和生长季累积叶面积指数,分析不同立地条件下不同林分叶面积指数生长情况,对其动态变化规律进行研究。研究表明:生长季4月到8月,12块落叶阔叶林叶面积指数均随时间呈单峰变化。以杨树有优势树种的样地用Mitscherlich生长方程拟合其LAI效果最优,以色木和白桦为优势树种的样地采用logistic生长方程拟合效果最优,其它样地Gompertz生长方程拟合最优,各样地生长方程拟合R2均高于0.962。杨树林叶面积指数增速最快,胡桃楸林增速缓慢,6月初到8月中下旬为冠层LAI生长速度趋于平稳。空间位置相近的阴阳坡样地叶面积指数生长规律差别较大,最高累计叶面积指数相差17.6%。此研究结果为帽儿山地区阔叶林叶面积指数动态变化规律提供数据基础,为该地区林冠植被的空间异质性及其造成影响,以及提升日步长碳循环、水循环生态机理模型精度提供更为准确的数据支持。
