Iron supply to soybean plants through the foliar application of IDHA/Fe3+: effect of plant nutritional status and adjuvants.
BACKGROUND
Synthetic Fe chelates are commonly used to overcome Fe deficiencies in crops, but most of them are scarcely biodegradable. Iminodisuccinic acid (IDHA) is a biodegradable chelating agent that is currently being evaluated as an alternative to EDTA. In this work, the efficacy of the foliar application of IDHA/Fe(3+) to soybean chlorotic plants under controlled conditions was studied, testing the influence of the adjuvant used and of the plant nutritional status.


RESULTS
When IDHA/Fe(3+) was applied to soybean plants with severe Fe chlorosis and the foliar sprays were the sole source of Fe, this chelate behaved similarly to the EDTA/Fe(3+) and the recovery of the plants was slight in both cases. The same chelates were tested when foliar sprays were an additional source of Fe for mildly chlorotic plants, which were also being supplied with low concentrations of Fe applied to the nutrient solution. Then, plant recovery was appreciable in all cases, and the IDHA/Fe(3+) was as effective as EDTA/Fe(3+). Among the adjuvants studied, a urea-based product was the only one that did not damage the leaf surface and that could improve the efficiency of IDHA/Fe(3+) up tp the level of EDTA/Fe(3+).


CONCLUSIONS
Thus, it was concluded the foliar application of IDHA/Fe(3+) can be an environmentally friendly alternative to the non-biodegradable chelate EDTA/Fe(3+) when the appropriate adjuvant is used.
Rodríguez-Lucena
Patricia
P
Agricultural Chemistry Department, Universidad Autónoma de Madrid, Madrid, Spain.
Ropero
Edgar
E
Hernández-Apaolaza
Lourdes
L
Lucena
Juan J
JJ
D000596:Amino Acids / Q000494:pharmacology*; D003247:Conservation of Natural Resources; D004492:Edetic Acid / Q000494:pharmacology; D005290:Ferric Compounds / Q000494:pharmacology; D005308:Fertilizers; D007501:Iron / Q000378:metabolism / Q000494:pharmacology*; D007502:Iron Chelating Agents / Q000494:pharmacology*; D000090463:Iron Deficiencies; D010935:Plant Diseases; D018515:Plant Leaves / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013025:Glycine max / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013386:Succinates / Q000494:pharmacology*; D014508:Urea / Q000494:pharmacology
D000596:Amino Acids; D005290:Ferric Compounds; D005308:Fertilizers; D007502:Iron Chelating Agents; D013386:Succinates; C412825:iminodisuccinic acid; D014508:Urea; D004492:Edetic Acid; D007501:Iron