Application of High-Cu Compost to Dill and Peppermint

• Published in: Journal of agricultural and food chemistry 2004-05, Vol.52 (9), p.2615-2622
• Main Authors: Zheljazkov, Valtcho D, Warman, Philip R
• Format: Article
• Language: English
• Subjects: Anethum graveolens; Anethum graveolens - growth & development; application rate; Aroma and flavouring agent industries; Biological and medical sciences; composted manure; contamination; copper; Copper - analysis; crop yield; dill; electrical conductivity; essential oil crops; essential oils; Food industries; Fundamental and applied biological sciences. Psychology; Germination; horticultural crops; Mentha piperita; Mentha piperita - growth & development; mineral content; mint; nutrient content; Oils, Volatile - chemistry; risk assessment; sandy loam soils; Soil - analysis; soil fertility; soil nutrients; soil pH; soil pollution; trace elements; Trace Elements - analysis; yard waste composts; zinc; Zinc - analysis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf035137y

A controlled environment experiment was conducted to determine the effect of amending soil with various rates of high-Cu compost (0, 20, 40, and 60% compost/soil by volume) on dill (Anethum graveolens L.) and peppermint (Mentha X piperita L.) yields, on fractionation of Cu and Zn in soils, on elemental composition of soil and tissue, and on the essential oils. The compost contained about 2000 mg kg-1 of Cu. Dill yields were greatest in the 20 or 40% treatments, but peppermint yields were greatest in the 20% treatment. Compost additions increased soil pH and electrical conductivity (EC), HNO3 extractable soil B, Ca, K, Mg, Mn, P, S, Na, and Pb. Additions of high-Cu compost to soil increased tissue P, S, and Na in both crops and Mn, Mo, and Zn in dill but decreased tissue Ca, Cd, and Fe in both crops and Mn, Mo, and Zn in peppermint, increased Cu in all soil fractions including exchangeable, and increased tissue Cu of dill and peppermint as compared to unamended soil. Addition of 60% of high-Cu compost to soil resulted in 760−780 mg kg-1 Cu in the growth medium. Nevertheless, Cu content in both crops reached only 12 mg kg-1 DW in the 60% compost treatment, which is below the toxicity levels for plants and below the upper chronic dietary exposure for animals. The application of high-Cu compost altered chemical composition of dill and peppermint essential oils, but oils were free of Cu, Zn, Cd, Ni, Cr, and Pb. Results from this study suggest that mature composts with concentrations of Cu and Zn of 2008 and 321 mg/kg, respectively, can be used as a soil conditioner without risk for phytotoxicity or risk of increasing the normal range of Cu and Zn in crop tissue. However, the long-term effect of the accumulation of heavy metals in soils following repeated compost applications needs to be carefully considered. Keywords: Dill; peppermint; compost; copper; zinc; sequential extraction; nutrients; trace elements; essential oils