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Soil versus foliar iodine fertilization as a biofortification strategy for field-grown vegetables.

Lawson PG, Daum D, Czauderna R, Meuser H, Härtling JW - Front Plant Sci (2015)

Bottom Line: Consequently, long-term effects of a one-time iodine soil fertilization could not be observed.The results indicate that a sufficient spreading of iodine applied on the edible plant parts is crucial for the efficiency of the foliar approach and leafy vegetables are the more suitable target crops.The low iodine doses needed as well as the easy and inexpensive application may favor the implementation of foliar sprays as the preferred iodine biofortification strategy in practice.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Nutrition, Faculty of Agricultural Sciences and Landscape Architecture, University of Applied Sciences of Osnabrück Osnabrück, Germany.

ABSTRACT
Iodine (I) biofortification of vegetables by means of soil and foliar applications was investigated in field experiments on a sandy loam soil. Supply of iodine to the soil in trial plots fertilized with potassium iodide (KI) and potassium iodate directly before planting (0, 1.0, 2.5, 7.5, and 15 kg I ha(-1)) increased the iodine concentration in the edible plant parts. The highest iodine accumulation levels were observed in the first growing season: In butterhead lettuce and kohlrabi the desired iodine content [50-100 μg I (100 g FM)(-1)] was obtained or exceeded at a fertilizer rate of 7.5 kg IO3 (-)-I ha(-1) without a significant yield reduction or impairment of the marketable quality. In contrast, supplying KI at the same rate resulted in a much lower iodine enrichment and clearly visible growth impairment. Soil applied iodine was phytoavailable only for a short period of time as indicated by a rapid decline of CaCl2-extractable iodine in the top soil. Consequently, long-term effects of a one-time iodine soil fertilization could not be observed. A comparison between the soil and the foliar fertilization revealed a better performance of iodine applied aerially to butterhead lettuce, which reached the desired iodine accumulation in edible plant parts at a fertilizer rate of 0.5 kg I(-)-I ha(-1). In contrast, the iodine content in the tuber of sprayed kohlrabi remained far below the targeted range. The results indicate that a sufficient spreading of iodine applied on the edible plant parts is crucial for the efficiency of the foliar approach and leafy vegetables are the more suitable target crops. The low iodine doses needed as well as the easy and inexpensive application may favor the implementation of foliar sprays as the preferred iodine biofortification strategy in practice.

No MeSH data available.


The iodine accumulation behavior of (A) kohlrabi and (B) butterhead lettuce cultivated in season 2010 after a one-time iodine soil fertilization applied 2010. Means with same letters do not differ according to Bonferroni MCP at a = 0.05 [One-way analysis of variance (A): probability level = 0.00, power = 1.00; One-way analysis of variance (B): probability level = 0.00, power = 1.00]. n = 3.
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Figure 3: The iodine accumulation behavior of (A) kohlrabi and (B) butterhead lettuce cultivated in season 2010 after a one-time iodine soil fertilization applied 2010. Means with same letters do not differ according to Bonferroni MCP at a = 0.05 [One-way analysis of variance (A): probability level = 0.00, power = 1.00; One-way analysis of variance (B): probability level = 0.00, power = 1.00]. n = 3.

Mentions: Figure 3A shows the iodine accumulation behavior of kohlrabi cultivated in the first season after a single iodine soil fertilization applied just before planting in 2010. An increasing iodine content in edible plant parts was observed with a rising iodine supply, particularly when using KIO3 as the iodine fertilizer. The desirable iodine amount in edible plant parts was achieved at ≥7.5 kg IO3--I ha-1. KI treatments were less effective and did not reach the target range [50–100 μg I (100 g FM)-1] in any variant using kohlrabi as a model crop.


Soil versus foliar iodine fertilization as a biofortification strategy for field-grown vegetables.

Lawson PG, Daum D, Czauderna R, Meuser H, Härtling JW - Front Plant Sci (2015)

The iodine accumulation behavior of (A) kohlrabi and (B) butterhead lettuce cultivated in season 2010 after a one-time iodine soil fertilization applied 2010. Means with same letters do not differ according to Bonferroni MCP at a = 0.05 [One-way analysis of variance (A): probability level = 0.00, power = 1.00; One-way analysis of variance (B): probability level = 0.00, power = 1.00]. n = 3.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477264&req=5

Figure 3: The iodine accumulation behavior of (A) kohlrabi and (B) butterhead lettuce cultivated in season 2010 after a one-time iodine soil fertilization applied 2010. Means with same letters do not differ according to Bonferroni MCP at a = 0.05 [One-way analysis of variance (A): probability level = 0.00, power = 1.00; One-way analysis of variance (B): probability level = 0.00, power = 1.00]. n = 3.
Mentions: Figure 3A shows the iodine accumulation behavior of kohlrabi cultivated in the first season after a single iodine soil fertilization applied just before planting in 2010. An increasing iodine content in edible plant parts was observed with a rising iodine supply, particularly when using KIO3 as the iodine fertilizer. The desirable iodine amount in edible plant parts was achieved at ≥7.5 kg IO3--I ha-1. KI treatments were less effective and did not reach the target range [50–100 μg I (100 g FM)-1] in any variant using kohlrabi as a model crop.

Bottom Line: Consequently, long-term effects of a one-time iodine soil fertilization could not be observed.The results indicate that a sufficient spreading of iodine applied on the edible plant parts is crucial for the efficiency of the foliar approach and leafy vegetables are the more suitable target crops.The low iodine doses needed as well as the easy and inexpensive application may favor the implementation of foliar sprays as the preferred iodine biofortification strategy in practice.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Nutrition, Faculty of Agricultural Sciences and Landscape Architecture, University of Applied Sciences of Osnabrück Osnabrück, Germany.

ABSTRACT
Iodine (I) biofortification of vegetables by means of soil and foliar applications was investigated in field experiments on a sandy loam soil. Supply of iodine to the soil in trial plots fertilized with potassium iodide (KI) and potassium iodate directly before planting (0, 1.0, 2.5, 7.5, and 15 kg I ha(-1)) increased the iodine concentration in the edible plant parts. The highest iodine accumulation levels were observed in the first growing season: In butterhead lettuce and kohlrabi the desired iodine content [50-100 μg I (100 g FM)(-1)] was obtained or exceeded at a fertilizer rate of 7.5 kg IO3 (-)-I ha(-1) without a significant yield reduction or impairment of the marketable quality. In contrast, supplying KI at the same rate resulted in a much lower iodine enrichment and clearly visible growth impairment. Soil applied iodine was phytoavailable only for a short period of time as indicated by a rapid decline of CaCl2-extractable iodine in the top soil. Consequently, long-term effects of a one-time iodine soil fertilization could not be observed. A comparison between the soil and the foliar fertilization revealed a better performance of iodine applied aerially to butterhead lettuce, which reached the desired iodine accumulation in edible plant parts at a fertilizer rate of 0.5 kg I(-)-I ha(-1). In contrast, the iodine content in the tuber of sprayed kohlrabi remained far below the targeted range. The results indicate that a sufficient spreading of iodine applied on the edible plant parts is crucial for the efficiency of the foliar approach and leafy vegetables are the more suitable target crops. The low iodine doses needed as well as the easy and inexpensive application may favor the implementation of foliar sprays as the preferred iodine biofortification strategy in practice.

No MeSH data available.