SPAD Values and Nitrogen Nutrition Index for the Evaluation of Rice Nitrogen Status
| Autor: | Jingping Yang, Hu Yang, Yaming Lv, Junjun He |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Plant Production Science, Vol 17, Iss 1, Pp 81-92 (2014) |
| ISSN: | 1349-1008 1343-943X |
| DOI: | 10.1626/pps.17.81 |
| Popis: | Plant-based diagnosis is one of the most important methods to determine nitrogen (N) content of crops. Our objective was to establish the relationship between soil-plant analysis development (SPAD) values and N nutrition index (NNI) during the three developmental stages of rice and apply the SPAD meter as diagnostic tools for predicting grain yield response to N fertilization. We determined the SPAD values of four uppermost fully expanded leaves of two rice cultivars at six N fertilization levels at three growth stages and examined the relationship between SPAD values and NNI. The critical N concentration (Nc) was 5.31 W–0.5 in Xiushui63, and 5.38 W–0.49 in Hang43, where W is the total shoot biomass. The correlation between SPAD value and NNI varied with the leaf position, developmental stage, and variety. The lower leaf appeared to be more sensitive to the N level than the upper leaf in the response of biomass, and could be more suitable as a test sample for N status diagnosis, especially in the booting and heading stage. The dependence of grain yield on SPAD values of the fourth fully expanded leaf (L4) was significant at booting stage (R2L4 = 0.82** in 2011, R2L4 = 0.72** in 2012). Ratio of SPAD values of L4 to that in the N-saturated plot (RSPAD) (R2L4 = 0.92** in 2011, R2L4 = 0.77** in 2012) and NNI (R2 = 0.96** in 2011, R2 = 0.86** in 2012) at booting stage demonstrated a closer relationship with grain yield. |
| Databáze: | OpenAIRE |
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