Availability of Nickel in Soil Evaluated by Various Chemical Extractants and Plant Accumulation

Monika Jakubus,Małgorzata Graczyk

doi:10.3390/agronomy10111805

Monika Jakubus, Małgorzata Graczyk

Open Access

https://doi.org/10.3390/agronomy10111805

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Abstract

This work presents quantitative changes of nickel in soil and plants under the influence of compost and fly ash. The research was carried out in a 3-year experiment on medium soil fertilised with compost or fly ash. The plants: narrow leaf lupine (Lupinus angustifolius L.), camelina (Camelina sativa L.), and oat (Avena sativa L.) were planted in consecutive years. The soil from the experiment was subjected to extraction by sequential analysis with the Community Bureau of Reference (BCR) method, and single extractions using 1 mol·dm−3 HCl and DTPA solutions, obtaining the amount of nickel in various combinations with the soil solid phase. Total contents of the metal in soil and cultivated plants were determined. On the basis of Ni contents in the soil and cultivated plants, the bioconcentration factors and the risk assessment code were calculated. The type of amendments had a significant impact on the nickel content in lupine, for camelina and oat was the greatest in the control conditions. The differences between the amounts of Ni determined for bioconcentration factors were significant and depended on the amendments and nickel obtained by different methods. Regardless of the experimental conditions, the amount of Ni in the exchangeable bonds (Fr. I) had the greatest impact on the content of Ni in lupine and oat, whereas NiDTPA in the case of camelina.

Highlights

Nickel is an interesting element because it acts both as a toxic heavy metal and an essential microelement for plants
Nickel enters into the soil mainly through anthropogenic activities, such as mining, smelting, application of some organic amendments, e.g., sewage sludge or compost based on sewage sludge
In relation to the above, the effect of both substances on changes in nickel mobility in the aspect of its bioavailability for plants should be interpreted in two terms, i.e., sharing and limiting as evidenced by the results obtained in this study. Both compost and fly ash added to the soil caused an increase in the amounts of total, available, and sequentially separated fractions of Ni compared to the control

Summary

Introduction

Nickel is an interesting element because it acts both as a toxic heavy metal and an essential microelement for plants. Nickel enters into the soil mainly through anthropogenic activities, such as mining, smelting, application of some organic amendments, e.g., sewage sludge or compost based on sewage sludge. Other sources of this element include solid fuel combustion, burning of diesel, and fuel oil, as well as ceramic, glass, metal, and chemical industries [1,2]. Both nickel toxicity and its requirement in plants are well-documented in literature, more often studies focus on the negative effect of nickel on plants in the case of its excess amounts in soil. At low concentrations Ni has a positive effect on seed germination, growth of shoots, and roots, while it improves fruit yield and Agronomy 2020, 10, 1805; doi:10.3390/agronomy10111805 www.mdpi.com/journal/agronomy

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