Nutrient mobilization and nutrient contents of Zea mays in response to EDTA additions to heavy‐metal‐contaminated agricultural soil

Abstract

Enhanced phytoextraction of heavy metals (HMs) using chelating agents and agricultural crops is widely tested as remediation technique for agricultural soils contaminated with less mobile HMs. Nutrients are complexed by chelating agents simultaneously to HMs. In this study, the effect of EDTA (ethylenediaminetetraacetic acid) application on nutrient mobility in the soil and nutrient contents of Zea mays was tested on the laboratory and on the field scale. EDTA effectively increased the mobility of total water‐soluble macronutrients (Ca, K, Mg, P) and micronutrients (Fe, Mn) in the soil solution. Thereby nutrient co‐mobilization did cause competition to target HMs during the phytoextraction process. Mobilization was caused by complexation of nutrient cations by negatively charged EDTA and by dissolution of oxides and hydroxides. Increased concentrations of negatively charged P indicate the dissolution of metal phosphates by EDTA. Higher total water‐soluble nutrient concentrations enhanced bioavailability and plant contents of all determined nutrients especially that of Fe. Mobilization of nutrients may result in leaching and loss of soil fertility.

Phytoremediation of lead by jack beans on a Rhodic Hapludox amended with EDTA

“…Macro and micronutrients as well as toxic elements in soil may reduce EDTA efficiency. These effects agree with Neugschwandtner et al (2009) …”

Removal of Al, Fe and Mn by Pistia stratiotes L. and its stress response

“…The leaching of metal complexes through the soil profile could be prevented efficiently through the use of natural organic compounds such as low molecular weight organic acids (LMWOA) [4]. In addition to the leaching of metals, potentially toxic elements such as Al, Mn or Fe are also leached during mobilization of metals [5]. A factor that has not been sufficiently discussed in previous studies describing soil washing or soil leaching, but the pH changes due to leaching have a crucial role in toxic and potentially toxic element availability.…”

Biofortificação de feijão com zinco: efeitos de fontes, formas de aplicação, doses, e do fungo Pochonia chlamydosporia

“…Além disso, houve aumento no acúmulo de P, K, Ca, Mg, S, Fe e Mn nos grãos, com destaque para a resposta à aplicação do Zn-EDTA (Figura 4). No solo, o agente quelante EDTA remobiliza íons-metálico, formando complexos solúveis que aumentam a disponibilidade desses metais para as plantas (Nowack et al, 2006;Komárek et al 2007b;Neugschwandtner et al, 2009;Qureshia et al, 2020). A complexação de íons-metálicos no solo pode aumentar os fluxos difusivos dos mesmos em direção às raízes, elevando as concentrações de metais dissolvidos e aumentando a absorção desses elementos (Nowack et al, 2006).…”

“…O EDTA livre na planta tem alta afinidade pelos cátions divalentes essenciais (Vassil et al, 1998) O uso do EDTA na fitoextração de metais pesados em solos contaminados, é largamente pesquisado (Vassil et al, 1998;Hovsepya e Greipsson, 2005;Nowack et al, 2006;Chaturvedi et al, 2019). Porém, as pesquisas avaliando os efeitos da aplicação do EDTA no solo no crescimento e aumentos da absorção de nutrientes essenciais pelas culturas agrícolas são escassas (Neugschwandtner et al, 2009;Bloem et al, 2017).…”

“…O EDTA pode ter sido absorvido pelas raízes na forma de complexos metálicos,Greipsson, 2005). O aumento de P em plantas na presença de EDTA pode ocorrer pela dissolução de fosfatos metálicos pelo EDTA, que aumentam a concentração do nutriente no solo, favorecendo sua maior absorção pelas raízes(Neugschwandtner et al, 2009). Em…”