Journal of Taiwan Agricultural Research

Author:Chwen-Ming Yang

Abstract:

    Field experiments were conducted at Taiwan Agricultural Research Institute Experimental Farm, Wufeng to investigate changes of leaf total chlorophyll and nitrogen content as well as values of chlorophyll meter for rice plants (Oryza sativa L. cv. TNG 67) grown from the 2^nd crop of 2000 to the 1st crop of 2002. The relationships between chlorophyll and nitrogen were analyzed, the responses of chlorophyll meter value to their variations were also studied, and the comparison between the first and the second crops were made. Results showed that leaf total chlorophyll and nitrogen content were decreased after transplanting in both cropping seasons, and values of chlorophyll meter followed the trend with these two components. The patterns were similar among different amounts of nitrogen fertilizer treatments. Relationship between leaf total chlorophyll and nitrogen was significant linearly. As no significant difference was found between data of two crops with dummy variable test, data were pooled and were shown to also have a linear correlation (R²=0.615, P<0.000l). The values of chlorophyll meter and leaf total chlorophyll were linearly correlated with the determination coefficients (R²) of 0.758 & 0.862 for the first and the second crops, respectively. Again, data from different crops can be pooled and showed a linear relationship between leaf total chlorophyll and chlorophyll meter readings (R²=0.784, P<0.000l). With the above results, leaf nitrogen content and chlorophyll meter readings were analyzed to indicate a significant linear relationship in both cropping seasons. The pooled data from two crops were fitted to a linear regression model (R²=0.411, P<0.0001). Results suggest that leaf chlorophyll and nitrogen content can be estimated by chlorophyll meter in rice cultivar TNG 67.

Key words:Rice, Chlorophyll meter, Total chlorophyll, Nitrogen content, Nitrogen fertilizer management

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