In this Brassica carinata (Ethiopian mustard) research update, we highlight the symptoms of nitrogen deficiency. These images are part of a project by the Southeast Partnership for Advanced Renewables from Carinata (SPARC) to develop a diagnostic series for the identification of nutrient disorders of Carinata. Carinata is an exciting new crop in the Southeast used for a wide variety of primary and secondary agricultural products including cover crops, feedstock, high protein meal, and jet fuel. It is similar in management to canola given both canola and carinata are winter annual Brassica oilseed crops. However, carinata oil is not edible.

Nitrogen (N), being one of the macronutrients, is required in large amounts for proper growth and development. As such, nitrogen deficiency is a common problem in many crops including Carinata. To properly identify nutritional problems, it is helpful to know the location of the symptomology and to track its movement over time. Nitrogen is a mobile element which means it will be reallocated in the plant from older, lower foliage to the newer growing foliage. This results in symptoms appearing on the lower portions of the plant first.

Nitrogen deficiency will first manifest as a general stunting of the plant (Figure 1). The plants will then display a yellowing or paling of the lower leaves as the nitrogen is translocated from the lower foliage to the actively growing portions of the plant (Figure 2). The key is to look for the general stunting with the paling of the lower foliage.

If nitrogen deficient conditions persist, symptomology will progress rapidly and the plant’s overall vigor will continue to decrease. In intermediate stages, some cultivars of carinata will undergo an interveinal chlorosis where the veins of the leaf take on a pink to red coloration (Figure 2 & Figure 3). This unique symptom was observed on two of three cultivars evaluated.

In more advanced stages of nitrogen starvation, the lower foliage will pale and turn a bleached yellow to white (Figure 4). In addition to the lower foliage showing severe discoloration, the middle foliage will also begin to discolor. This results in a tri-level discoloration where the lower foliage is a bleached white, the mid foliage is yellowing or light green, and the upper foliage is a lush green (Figure 5). If nitrogen remains unavailable to the plant, the lower leaves will eventually turn necrotic, and senesce. To ensure proper diagnosis the above material should be used in conjunction with a leaf tissue sample and/or field test.

Figure 1. The plant on the left has received all its essential macro and micro nutrients, while the plant on the right has been given all nutrients except nitrogen. Note specifically the severely stunted nature of the N deficient plant.

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Figure 1. The plant on the left has received all its essential macro and micro nutrients, while the plant on the right has been given all nutrients except nitrogen. Note specifically the severely stunted nature of the N deficient plant.

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Figure 2. The lower leaf is exhibiting initial stages of nitrogen deprivation. Note the greenish yellow discoloration of the leaf. The veins are also starting to turn a purple coloration.

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Figure 2. The lower leaf is exhibiting initial stages of nitrogen deprivation. Note the greenish yellow discoloration of the leaf. The veins are also starting to turn a purple coloration.

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Figure 3. The leaves here exhibit intermediate nitrogen deficiency symptoms. As the nitrogen is translocated to the growing foliage above, the leaf will change from green-yellow to yellow to pale white and eventually tan necrosis.

Forensic Floriculture, 2018

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Figure 3. The leaves here exhibit intermediate nitrogen deficiency symptoms. As the nitrogen is translocated to the growing foliage above, the leaf will change from green-yellow to yellow to pale white and eventually tan necrosis.

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Figure 4. As the lower leaves transition into advanced N deprivation symptomology, the purple coloration of veins will minimize or disappear, and the leaf will take on a pale coloration. The leaves will eventually become completely necrotic and abscise.

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Figure 4. As the lower leaves transition into advanced N deprivation symptomology, the purple coloration of veins will minimize or disappear, and the leaf will take on a pale coloration. The leaves will eventually become completely necrotic and abscise.

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Figure 5. In this plant, the progression of nitrogen deficiency symptoms is evident. Note the color gradation from the pale colored lower leaf, to the yellow-green of the mid foliage, to the bright vibrant green of the newest foliage.

Forensic Floriculture, 2018

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Figure 5. In this plant, the progression of nitrogen deficiency symptoms is evident. Note the color gradation from the pale colored lower leaf, to the yellow-green of the mid foliage, to the bright vibrant green of the newest foliage.

Forensic Floriculture, 2018

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We would like to thank the following for financial support of this project:

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