Growth and metal uptake of spinach with application of co-compost of cat manure and spent coffee ground

• Published in: Heliyon 2020-09, Vol.6 (9), p.e05086-e05086, Article e05086
• Main Authors: Mohd Noor Keeflee, Siti Nurathirah Kamaliah, Wan Mohd Zain, Wan Nur Azra, Mohd Nor, Muhammad Nuruddin, Jamion, Nurul’ Ain, Yong, Soon Kong
• Format: Article
• Language: English
• Subjects: Agricultural science; Cat manure; Chemistry; Co-compost; Environmental science; Fertilizer; Food science; Heavy metal; Materials science; Spent coffee ground; Spinacia oleracea
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2020.e05086

Cat manure (CM) possesses high level of nutrients for growing food crop. However, animal manure may contain toxic elements that may contaminate food crop. Spent coffee ground (SCG) may be used to reduce mobility of heavy metals and reduce crop uptake. In this study, SCG was composted with CM for 31 days to produce a co-compost (SCG-CM) for growing spinach (Spinacia oleracea). The growth rate of spinach was assessed until its maturity, and the metal uptake of spinach shoot was determined thereafter using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The effect of soil treatment with SCG-CM on the height and elemental composition of spinach were compared with that of chicken manure compost (CMC). The prepared composts were primarily organic matter (72.9–81.4 % w/w) with the rest are ash (13.3–23.4 % w/w) and moisture (1.2–2.6 % w/w). Zinc content in SCG-CM (1261 ± 0.1 mg/kg) is significantly higher than that of soil and CMC (p < 0.05) and has exceeded the maximum permissible limit set by European Union Standard (2002) and the Malaysian Compost Quality Standard and Guidelines (2000). Matured spinach reached maximum plant height after 33 days. The amendment of SCG-CM significantly increased the height of spinach (32 ± 6 cm) compared to that of CMC (13 ± 1 cm) (p < 0.05). However, contents of Zn, Cu, Pb and Cd were not increased for spinach grown in the SCG-CM-amended soil, and the level of those elements are below permissible limit set by the Malaysian Food Act 1983 and Food Regulations 1985. This study shows that SCG-CM is effective in improving yield without causing accumulation of toxic trace elements in spinach. Co-compost; Spinacia oleracea; Cat manure; Heavy metal; Spent coffee ground; Fertilizer; Materials science; Chemistry; Food science; Agricultural science; Environmental science.