Unlocking fertilization potential of anaerobically digested sewage sludge centrate for protein-rich rice cultivation with composted sludge amendment

Luc Duc Phung; Chiekh Adrame Ba; Putri Aditya Padma Pertiwi; Ayumi Ito; Toru Watanabe

doi:10.1016/j.envres.2023.116912

Unlocking fertilization potential of anaerobically digested sewage sludge centrate for protein-rich rice cultivation with composted sludge amendment

Environ Res. 2023 Nov 15;237(Pt 1):116912. doi: 10.1016/j.envres.2023.116912. Epub 2023 Aug 22.

Authors

Luc Duc Phung¹, Chiekh Adrame Ba², Putri Aditya Padma Pertiwi², Ayumi Ito³, Toru Watanabe⁴

Affiliations

¹ Faculty of Agriculture, Yamagata University, 1-23 Wakaba-machi, Tsuruoka, Yamagata, 997-8555, Japan; Center for Foreign Languages and International Education, Vietnam National University of Agriculture, Trau Quy, Gia Lam, Ha Noi, 12406, Viet Nam. Electronic address: phungducluc0305@gmail.com.
² Graduate School of Agricultural Science, Yamagata University, 1-23 Wakaba-machi, Tsuruoka, Yamagata, 997-8555, Japan.
³ Faculty of Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate, 020-8551, Japan.
⁴ Faculty of Agriculture, Yamagata University, 1-23 Wakaba-machi, Tsuruoka, Yamagata, 997-8555, Japan. Electronic address: to-ru@tds1.tr.yamagata-u.ac.jp.

PMID: 37619638
DOI: 10.1016/j.envres.2023.116912

Abstract

The use of composted sewage sludge (CSS) and centrate as alternatives to synthetic fertilizers in rice cultivation holds great promise. This study aims to determine the effects of varying doses and timings of centrate derived from anaerobically digested sewage sludge on rice yield, nutrient quality, and soil fertility when applied as a topdressing to rice fields fertilized with CSS. At the panicle initiation (PI) stage, 100, 300, and 500 kg N ha^-1 of centrate topdressing (CT100, CT300, and CT500, respectively) was applied. In addition, different topdressing timings at a total dose of 500 kg N ha^-1 were evaluated, including a two-split application (40% at active tillering (AT) and 60% at PI; CT500S2) and a three-split application (40% at AT + 40% at PI + 20% at heading; CT500S3). At a rate of 160 kg N ha^-1, CSS was used as a base fertilizer in all treatments. A control treatment received synthetic fertilizers at a rate of 160 kg N ha^-1 as a base application and 100 kg N ha^-1 as a topdressing. Results showed that CSS-treated rice plants exhibited a lower N status and leaf chlorophyll content during the vegetative growth stage; however, the split application of centrate topdressing improved plant N status, resulting in an increase in biomass and grain yield. Centrate and CSS tended to increase the mineral content of rice; nevertheless, a significant accumulation of As in grains raised concerns about food safety. Combining CSS and centrate has the potential to increase rice production, improve grain nutritional value, and decrease reliance on synthetic fertilizers. However, it is essential to optimize this fertilization, mitigate environmental risks, and ensure food safety by employing appropriate fertilization dosing and timing as well as appropriate field management strategies.

Keywords: Centrate; Composted sewage sludge; Protein-rich rice cultivation; Resource recycling.