Articles
Development of a methodology to characterize the nitrogen nutritional status of open field processing tomato by means of fast indicators
Article number
1351_14
Pages
89 – 94
Language
English
Abstract
Efficient nitrogen fertilization is essential for the environmental sustainability of crop production and cost reduction.
A fertilization plan should be based on the needs of the crop throughout the crop cycle and an assessment of the possible inputs and outputs of nitrogen.
The dynamics of the nitrogen cycle make it difficult to have a precise quantification of the nitrogen available to the plant, so it is helpful to have a reliable indicator of the nutritional status of the crop to readjust fertilization plans to avoid situations of excess or deficiency.
Optical sensors and nitrate meters provide quick measurements related to the nitrogen nutritional status of the plant.
However, to be useful, it is essential to have a reliable criterion to interpret these measurements in terms of deficiency, normality or excess.
To establish these criteria, it has been proposed to use the nitrogen nutrition index (NNI), which is calculated as the ratio between the current N content in the plant in relation to the critical value, so that contents below the critical value are classified as deficiency. To achieve this objective, in 2021 a field experiment of processing tomato (variety H1015) was carried out, in Vegas Bajas del Guadiana (Extremadura), with transplanting and drip irrigation and fertigation, under different doses of nitrogen fertilization: 0 UFN (N0), 95 UFN (N1), 190 UFN (N2) and 285 UFN (N3). We measured the biomass production, plant nitrogen content and nutritional status periodically throughout the crop cycle.
The analysis of nitrate in sap has provided better results on the nutritional status of the crop than the measurement of chlorophyll content.
However, the chlorophyll meter has the advantages of being non-destructive, rapid and easy to use.
This work proposes reference levels for three different phenological stages.
A fertilization plan should be based on the needs of the crop throughout the crop cycle and an assessment of the possible inputs and outputs of nitrogen.
The dynamics of the nitrogen cycle make it difficult to have a precise quantification of the nitrogen available to the plant, so it is helpful to have a reliable indicator of the nutritional status of the crop to readjust fertilization plans to avoid situations of excess or deficiency.
Optical sensors and nitrate meters provide quick measurements related to the nitrogen nutritional status of the plant.
However, to be useful, it is essential to have a reliable criterion to interpret these measurements in terms of deficiency, normality or excess.
To establish these criteria, it has been proposed to use the nitrogen nutrition index (NNI), which is calculated as the ratio between the current N content in the plant in relation to the critical value, so that contents below the critical value are classified as deficiency. To achieve this objective, in 2021 a field experiment of processing tomato (variety H1015) was carried out, in Vegas Bajas del Guadiana (Extremadura), with transplanting and drip irrigation and fertigation, under different doses of nitrogen fertilization: 0 UFN (N0), 95 UFN (N1), 190 UFN (N2) and 285 UFN (N3). We measured the biomass production, plant nitrogen content and nutritional status periodically throughout the crop cycle.
The analysis of nitrate in sap has provided better results on the nutritional status of the crop than the measurement of chlorophyll content.
However, the chlorophyll meter has the advantages of being non-destructive, rapid and easy to use.
This work proposes reference levels for three different phenological stages.
Publication
Authors
J.M. Vadillo, M.C. Gimenez, C. Campillo, V. González, M.H. Prieto
Keywords
chlorophyll content, sap nitrogen content, nitrogen nutrition index (NNI)
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