Evaluation of canola chlorophyll index and leaf nitrogen under wide range of soil moisture
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Department of Soil Science, University of Zanjan, post code 38791-45371, Zanjan, Iran
Department of Soil Science, University of Tabriz, post code 5166616471, Tabriz, Iran
Department of Agronomy and Plant Breeding, University of Zanjan, Zanjan, Iran
Publication date: 2015-01-15
Int. Agrophys. 2015, 29(1): 83–90
The paper presents a study on the effect of soil matric suction on the variation of leaf chlorophyll index and nitrogen concentration of canola. Results showed that chlorophyll index increases exponentially with soil matric suction, especially at the late season of canola growing time. At moderate matric suction (200 and 300 kPa soil suction heads), chlorophyll index remains nearly constant, but in drier soil (matric suction >300 kPa),chlorophyll index increases gradually with time. Despite the variation of the total leaf nitrogen with the soil matric suction, it is simi­lar to the variation of the chlorophyll index, but the results showed that the chlorophyll index – nitrogen concentration curve has a demarcated bi-modal shape. We suggest that 2.7% of nitrogen and 69.8 of the chlorophyll index value represent the upper limit of the chlorophyll meter reliability for estimation of canola nitrogen under a wide range of soil moisture levels. These results confirm that the chlorophyll meter can be used as an effective tool for rap­id and non-destructive estimation of the relative chlorophyll and nitrogen content in canola leaves at a wide range of soil moisture content, except for nearly wilting coefficient or extremely high drought stress.