Published in PLOS One on 2026-07-28, this study is presented as an attributed evidence briefing. The excerpts below are the original researchers’ words, reproduced under their Creative Commons Attribution licence. Health Signal has selected the abstract and, where needed, opening background paragraphs; the complete methods, results, limitations and references remain in the linked paper.
Original authors: Girmaw Mulugeta, Ermias Alayu, Yitayal Addis Alemayehu, Muhammad Amjad Ali
Source: PLOS One • DOI 10.1371/journal.pone.0353951
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
Tomato (Solanum lycopersicum) is one of the most widely cultivated and economically important vegetable crops worldwide, contributing significantly to food security. However, its low productivity remains a substantial concern in Ethiopia due to mainly poor soil quality and limited use of inorganic fertilizers. On the contrary, improper disposal of recyclable charcoal and anaerobic cow dung bioslurry (ACDB) wastes poses environmental pollution challenges. Hence, this study aimed to evaluate the synergetic effects of ACDB and charcoal co-composted fertilizers (ACDBCFs) on tomato productivity and soil properties. A pot experiment consisting of eight treatments (T1 – T8) was arranged in a randomized complete block design with three replications. Characterization of the five formulated ACDBCFs revealed good physico-chemical properties of pH, organic carbon, ammonium, nitrate, and orthophosphate, fluctuated from 8.9 to 9.63, 26.8 to 65.6%, 2.5 to 4.6 mgL ⁻ 1, 11.9 to 18.2 mgL ⁻ 1, and 0.74 to 3.1 mgL ⁻ 1, respectively. Significant differences (p < 0.05) were observed in tomato fruit yield with relatively higher values of 2.87 and 2.73 kgpot ⁻ 1 for T6 and T8 under ACDB + charcoal (+10%) and inorganic fertilizers amendments, respectively. Principal component analysis (PCA) demonstrated strong associations between nutrient availability and tomato growth and yield component parameters. Heat map visualization further confirmed that ACDBCFs application improved soil background nutrient and carbon contents. Overall, the findings from this short-term study indicate that ACDBCFs can enhance tomato productivity while improving soil organic matter and nutrient availability. However, further long-term studies on field level validation in real soil conditions and nutrient dynamics are recommended to support large-scale adoption of this resource-recovery approach, contributing to sustainable agriculture, environmental protection, and socio-economic development.
1. Introduction
Tomato (Solanum lycopersicum) is an important nutritional crop in many parts of the country, including Ethiopia, contributing to smallholder livelihoods. However, its average national potential yield (12.5 t ha-1) remains low as compared with the neighboring Sub-Saharan African countries such as Kenya (16.4 t ha-1) [1]. This yield is mainly limited by factors like poor soil fertility and limited use of inorganic fertilizers [2]. Loss of agricultural soil fertility is one of the major constraints limiting vegetable production in Ethiopia, particularly in smallholder systems where access to inorganic fertilizers is restricted by high cost and inconsistent supply [3]. This implies that sustainable agricultural practices are increasingly needed in Ethiopia to ensure resilient agriculture. Organic amendments such as compost, anaerobic cow-dung bioslurry (ACDB), and other locally available wastes have gained attention for resilient agricultural practices through improving soil health [4], and through supporting essential plant nutrition, and mitigating plant stresses [5]. ACDB contains easily decomposable organic matter and essential nutrients that enhance soil structure, microbial activity, nutrient cycling, and plant growth [6,7]. It is also reported that the use of ACDB as fertilizer produces higher tomato yields than farmyard manure [8]. In the same argument, utilization of ACDB in Ethiopia also shows enhanced vegetable production through improving soil fertility [9,10]. Despite its importance, the direct use of ACDB alone often has a low organic carbon content, carbon to nitrogen ratio, and high pH, which hinder its potential uses [11,12]. Furthermore, ACDB easily loses its nitrogen content through ammonia volatilization and requires co-digestion with other eco-friendly substrates that have the potential to retain nutrients [13,14]. This highlights a need for selecting effective adsorbents that recover nutrients from ACDB while reducing environmental contamination.
Reading this evidence
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© 2026 Girmaw Mulugeta, Ermias Alayu, Yitayal Addis Alemayehu, Muhammad Amjad Ali. Excerpts reproduced under CC BY. Selection, formatting and contextual notes by Health Signal. The researchers are the authors of the source study, not members of Health Signal’s staff.
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