Application of proline-2′-deoxymugineic acid as potential fertilizer to alleviate zinc deficiency in paddy soils

Zinc (Zn) deficiency affects around 50% of rice paddy soils worldwide. This leads to reduced production and poor nutritional composition of food with detrimental consequences to human health. In this work we show that proline-2′-deoxymugineic acid (PDMA), a new synthetic organic ligand, forms strong and stable complexes with zinc(II) in paddy soil conditions and therefore can be used as a novel zinc(II)-fertiliser. To demonstrate this, we determined ZnII-binding properties of PDMA and potential competition with other metal ions, identifying the paddy soil conditions where PDMA application is more effective to increase ZnII-complexation. Our results indicate that PDMA is a strong ZnII-chelator in paddy soil and the most favorable conditions for the effective application of PDMA as ZnII-fertilizer is providing PDMA in flooded soil at pH from 7 to 9. In this condition 50% of ZnII-complexation is ensured even when ZnII soil concentration is ten times less than competitor metals.