Published in PLOS One on 2026-05-14, 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: Abrham Shumbulo, Mihret Jemal, Abraham Bosha
Source: PLOS One • DOI 10.1371/journal.pone.0312222
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
Production and productivity of garlic was constrained by many factors, among which soil fertility gradation and lack area specific fertilizer recommendation are the most important in Ethiopia. Thus, on site trial was executed at Wachemo University Lembuda demonstration field during 2021/2022 with the aims to identify the effects of NPS fertilizer and chicken manure levels on growth, bulb yield and quality and to determine the economically feasible combination of NPS and chicken manure rate for garlic productivity in the area. The treatments included four levels of chicken manure (0, 5, 10 and 15 t/ha) and five levels of NPS fertilizer (0, 50,100, 150 and 200 kg/ha) arranged factorially using a randomized complete block design (RCBD) and replicated three times. Growth, bulb yield and quality data were collected and subjected to analysis using SAS version 9.4. With the exception of days to maturity, leaf number and non-marketable bulb yield in the case of chicken manure, the majority of the investigated parameters were significantly (P < 0.05) affected by the main effects of chicken manure and NPS fertilizer. The interaction impact was not significant for nearly all of the examined variables except marketable and total bulb yield. As a result, combined application of 15 t/ha chicken manure with 150 kg/ha NPS fertilizer produced the maximum marketable bulb (19.52 t/ha) and total bulb yield (20.27 t/ha), with a 927% yield advantage over plants receiving no fertilizer. Plots with 15 t/ha chicken manure had the highest bulb dry matter (35.31%) and TSS (22.47° Brix). In terms of economic analysis, the plot treated with plants 15 t/ha of chicken manure and 150 kg/ha of NPS fertilizer had the highest net benefit (524224.8 ETB/ha) with an MRR of 10,159.1%. Hence, this combination was found to be the best and cost-effective one for smallholder farmers in the study area that could be recommended to boost garlic production and productivity.
Introduction
After onions, garlic (Allium sativum L.) is the second most popular bulb crop in the Amaryllidaceae family [1]. Ethiopia is among the many countries in the globe where it is extensively grown. Garlic was estimated to be grown on 1.5 million hectares worldwide, with a total annual production of 28.5 million tons [2]. In Ethiopia, 32,080.40 ha of land was under garlic cultivation with a production of about 196,416.15 tonnes resulting in an average productivity of 6.12 t/ha, which is far lower than the global average yield of 18.4 t/ha [3].
Reading this evidence
Use the full paper to check the study design, participant selection, comparator and outcome definitions before drawing a practical conclusion. An association does not by itself show cause and effect. A reported performance measure needs its denominator and uncertainty. A finding from a particular facility, sample or time period should retain that scope when it is discussed elsewhere.
This briefing makes the source accessible within the wider financing & policy desk. It does not assess an individual patient or certify a product. When considering relevance to another health system, examine the original authors’ account of context and limitations, then seek local implementation evidence. The related reporting below provides other studies to read alongside this one; it is a topic connection, rather than a claim that their results are directly comparable.
© 2026 Abrham Shumbulo, Mihret Jemal, Abraham Bosha. 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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