# Optimization of Allium cepa L. cultivation in urban Sahelian areas amended with local mixed organic compost

Alexis Dzokom, Roger Darman Djouldé

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Alexis Dzokom, Roger Darman Djouldé. Optimization of Allium cepa L. cultivation in urban Sahelian areas amended with local mixed organic compost. Sahel Nature Consulting Revue, In press, Compost et Biochar, 11 (05), pp.1-11. hal-05032018

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# Optimization of *Allium cepa* L. cultivation in urban Sahelian areas amended with local mixed organic compost.

Alexis DZOKOM¹,², Roger Djouldé DARMAN³

Sahel Nature Consulting¹

¹Department of Environmental Sciences, National Advanced School of Engineering, University of Maroua, Cameroon

³Department of Agriculture Animal Husbandry and By-Products, National Advanced School of Engineering, University of Maroua, Cameroon

## Abstract

In the Sahelian zones of Cameroon, low soil fertility, increasing aridity, and abiotic stress factors compromise vegetable production, particularly that of *Allium cepa* L. This study aims to assess the effect of various organic composts made from dried *Pennisetum* sp., dead biomass of *Azadirachta indica*, and manure from *Gallus gallus domesticus* on the yield of two *Allium cepa* L. varieties cultivated in urban and peri-urban Sahelian environments. The experiment was conducted in Maroua and Koza, in the Far North of Cameroon, over two consecutive dry seasons. Three types of compost were applied to two *Allium cepa* L. varieties (V1: Violet de Galmi, V2: Goudami F1) grown on arid sandy soils and semi-arid sandy loam soils. Growth parameters (plant height, number of leaves), yield parameters (average bulb weight, marketable yield), and stress resistance indicators (survival rate, abortion percentage) were analyzed. The results show a marked improvement in the growth and yield of both varieties, with superior effectiveness of the combined compost (*Pennisetum* sp. + *Azadirachta indica* + poultry manure) on semi-arid soils. V2 (Goudami F1) demonstrated greater tolerance to abiotic stress. These findings suggest that targeted organic amendments represent an effective agroecological alternative for sustainably improving onion production in Sahelian contexts.

**Keywords:** onion, organic compost, *Azadirachta indica*, *Pennisetum* sp., environmental stress, Sahelian zone, Cameroon, urban agriculture.

## Introduction

Vegetable Production in the Sahelian Zone is increasingly challenged by agroclimatic constraints such as low soil fertility, high temperatures, water scarcity, and wind or water erosion, which significantly limit agricultural yields (FAO, 2019; Cissé, 2022; Osunde, 2016). Among strategic vegetable crops, onion (*Allium cepa* L.) plays an important role in the subsistence and commercial economy of urban and peri-urban households in northern Cameroon (Moustier et al., 2004; Dzokom et al., 2024; Djouldé, 2007; Darman et al., 2010). However, its yield remains low, especially in arid and semi-arid areas, due to inadequate management of organic amendments and increasing exposure to environmental stresses (Stéphane & Dabire, 2016; Dzokom et al., 2024; IRAD, 2022).

In this context, optimizing soil fertility through targeted organic amendments appears to be a promising strategy to enhance the resilience of onion cropping systems. Several studies have highlighted the role of compost in improving the physicochemical and biological properties of degraded soils (Ramel & Ghanem, 2024). In particular, the use of enriched composts made from dried *Pennisetum* sp., dead biomass of *Azadirachta indica* (neem), and poultry manure represents an effective agroecological alternative due to their richness in organic matter, macro-elements (NPK), and bioactive compounds with nematicidal and insect-repelling effects (Serpantié et al., 2024; Diagne et al., 2010; Oumarou et al., 2022; Konate et al., 2022). Moreover, certain onion varieties exhibit greater tolerance to abiotic stresses, particularly under saline, drought, or
nutrient-deficient conditions (Edbo, 2021; Ndour-Badiane et al., 2021). Identifying high-performing varieties and their interaction with different types of organic compost could help optimize yields while reducing reliance on costly and polluting chemical inputs.

Thus, this study aims to evaluate the impact of a composite organic compost made from dried *Pennisetum* sp., dead biomass of *Azadirachta indica*, and poultry manure on the yield of two onion varieties cultivated in urban and peri-urban Sahelian areas of Cameroon under environmental constraints. The objective is to formulate technical recommendations for sustainable, productive agriculture adapted to local ecological realities.

# Material and Methods

## 1. Study Area

The study was conducted in two representative localities of the urban and peri-urban Sahelian zones of Cameroon: Maroua (urban area) and Koza (peri-urban area), located in the Far North Region. These localities are characterized by a Sahelian climate, with average annual rainfall ranging from 400 to 700 mm, average temperatures between 30 and 42°C during the dry season, and predominantly sandy to sandy-loam soils, low in organic matter (IRAD, 2022; Hinimbio, 2019).

## 2. Plant Material

Two *Allium cepa* L. varieties were selected:

* V1: Violet de Galmi (a widely used local variety in the Sahel)

* V2: Goudami F1 (an improved, early-maturing, drought-tolerant variety)

These varieties were selected based on their local adaptability, growth cycle, and performance reported in previous studies (Sawadogo et al., 2022; Edbo, 2021;

Ndour-Badiane et al., 2021; Stéphane & Dabire, 2016; Dzokom et al., 2024).

## 3. Compost Preparation

The compost used was a local organic formulation prepared from:

* Dried *Pennisetum* sp. (forage harvested at the end of the rainy season)

* Dead biomass of *Azadirachta indica* (dried leaves and twigs)

* Poultry manure (locally collected and partially composted)

The components were mixed in the following weight ratios: 40% *Pennisetum*, 30% neem, 30% poultry manure, following the method described by Serpantié et al. (2024); Diagne et al., (2010); Oumarou et al., (2022) and Konate et al., (2022). The composting process lasted 45 days, with weekly turning, moisture control (60–70%), and monitoring of internal temperature (>55°C for 2 weeks) to ensure hygienization.

Samples of mature compost were analyzed to determine organic matter content, total nitrogen, available phosphorus, exchangeable potassium, and pH, following INRA standard methods (Cahurel et al., 2018; Naisse, 2014; Dzokom, 2025; Dzokom, 2024; Dzokom, 2023; Dzokom, 2019).

## 4. Experimental Design

A randomized complete block design (RCBD) was used with three replications. Each block contained six plots corresponding to the interaction between:

* Two varieties (V1, V2)

* Three types of amendments:

* T0: Control (no compost)

* T1: Full local compost (*Pennisetum* + neem + poultry manure)

* T2: Standard compost (poultry manure only)
Plots of 3 m² were manually tilled, and composts were incorporated two weeks before sowing at an equivalent rate of 5 tons/ha (Serpantié et al., 2024; Diagne et al., 2010). Regular irrigation was applied twice daily, taking into account high evapotranspiration.

## 5. Measured Parameters

The following agro-physiological parameters were recorded:

* Germination rate (%)

* Average plant height (cm)

* Bulb diameter (cm)

* Average bulb weight (g)

* Total yield at harvest (t/ha)

Additionally, observations on environmental stress tolerance were made: foliar wilting, early senescence, and soil parasite attacks.

## 6. Statistical Analyses

Data were analyzed using one-way and two-way analysis of variance (ANOVA) (compost and compost × variety), followed by Tukey HSD test to compare means at a 5% significance level (p<0.05), using R

software version 4.3.1. Significant interactions were interpreted to recommend the best soil/compost/variety combinations.

## Results and Discussion

### 1. Germination and Plant Establishment

Data analysis showed that organic amendments significantly improved germination speed, germination rates, and plant establishment for both onion varieties compared to the unamended control. Treatment T1 (mix of the three amendments) showed the best performance in terms of rapid and uniform germination (8.9 ± 0.3 days for *Violet de Galmi* and 8.7 ± 0.2 days for *Goudami*), as well as germination rates above 84%. This confirms the findings of Tchiagam et al. (2018), who demonstrated that balanced compost enhances the natural hormonal stimulation of seeds through phenolic compounds from woody plants and humic acids from poultry manure. The table below provides detailed results on germination and plant establishment.

<table><caption>Table 1. Germination and Plant Establishment</caption><thead><tr><th>Treatment</th><th>Onion Variety</th><th>Mean Germination Time (days)</th><th>Germination Rate (%)</th><th>Establishment Rate (%)</th></tr></thead><tbody><tr><td>T1: Unamended control</td><td rowspan="4">Violet de Galmi</td><td>12.3 ± 0.5</td><td>64.5 ± 2.4</td><td>55.3 ± 3.1</td></tr><tr><td>T2: <i>Pennisetum sp. compost only</i></td><td>10.1 ± 0.3</td><td>76.2 ± 1.8</td><td>68.4 ± 2.7</td></tr><tr><td>T3: <i>Azadirachta indica compost only</i></td><td>10.7 ± 0.4</td><td>72.5 ± 2.0</td><td>65.1 ± 2.3</td></tr><tr><td>T4: Chicken manure compost only</td><td>9.8 ± 0.2</td><td>79.3 ± 1.5</td><td>71.0 ± 2.5</td></tr><tr><td>T5: 1/3 mix (<i>Pennisetum sp. + Azadirachta indica + manure</i>)</td><td rowspan="4">Goudami</td><td>8.9 ± 0.3</td><td>86.7 ± 1.2</td><td>78.5 ± 1.8</td></tr><tr><td>T1: Unamended control</td><td>11.9 ± 0.6</td><td>62.4 ± 2.7</td><td>53.9 ± 2.8</td></tr><tr><td>T2: <i>Pennisetum sp. compost only</i></td><td>10.4 ± 0.4</td><td>75.3 ± 1.9</td><td>67.6 ± 2.6</td></tr><tr><td>T3: <i>Azadirachta indica compost only</i></td><td>10.8 ± 0.3</td><td>70.8 ± 2.2</td><td>63.5 ± 2.4</td></tr><tr><td>T4: Chicken manure compost only</td><td rowspan="2">Goudami</td><td>9.6 ± 0.2</td><td>77.9 ± 1.7</td><td>70.3 ± 2.1</td></tr><tr><td>T5: 1/3 mix (<i>Pennisetum sp. + Azadirachta indica + manure</i>)</td><td>8.7 ± 0.2</td><td>92.6 ± 1.3</td><td>76.9 ± 1.7</td></tr></tbody></table>

The presence of *Azadirachta indica*, rich in azadirachtin compounds, may also play a biostimulant and protective role against

early soil-borne pathogens (Kebede et al., 2020). Although the varieties responded differently to the organic treatments, both
benefitted from enriched substrates. *Violet de Galmi*, known for its sensitivity to early water stress, showed a significant improvement under the mixed compost treatment. These findings support the recommendations of FAO (2021) ; Palou(2011) ; Temple et al.(2024) and Moustier et al.(2004), which highlight the use of local and diverse organic materials in Sahelian vegetable cropping substrates to enhance resilience to climatic hazards.

Seedling emergence rates were significantly influenced (p<0.05) by the application of organic compost. The best emergence rates were observed with T5 (enriched compost: Pennisetum + neem + manure), reaching 92% for Goudami and 86.78% for Violet de Galmi, compared to 74% and 69% respectively under the unamended control (T1). This improvement is linked to the early availability of nutrients, especially nitrogen, promoting seed germination and initial seedling vigor (Ramel & Ghanem, 2024; Serpantié et al., 2024; Diagne et al., 2010).

## 2. Vegetative Growth

The results show a notable improvement in vegetative growth (height, number of leaves, collar diameter) of onion plants under organic amendments, with the best performance observed under treatment T5 (mixed compost). T5 generated an average plant height of 32.4 ± 1.0 cm for *Violet de Galmi*, with 6.4 leaves per plant, indicating optimal vegetative vigor. Chicken manure, rich in readily available nitrogen, stimulates photosynthesis and cell division, explaining the strong performance under T4. Although the release of nutrients from *Pennisetum* compost is slower, it improves water retention and soil aeration—beneficial features in semi-arid conditions. The dead biomass of *Azadirachta indica*, in addition to its fertilizing properties, offers natural antifungal and insecticidal activity, creating a favorable environment for initial plant growth (Mbaye et al., 2022; Touré et al., 2018 ; Ngom et al., 2017 ; Dzokom, 2024 ; Dzokom et al.,2025). Overall, *Goudami* showed slightly lower growth than *Violet de Galmi*, possibly due to its slower varietal response to water stress (FAO, 2021).

<figure><img src="image_2.png" /><figcaption>Photo 1: Vegetative Growth of *Violet de Galmi* Onion Plants at 45 Days after Emergence</figcaption></figure>

<caption>Table 2. Vegetative Growth of Onion Plants at 45 Days After Emergence</caption>
<table><thead><tr><th>Treatment</th><th>Onion Variety</th><th>Average Plant Height (cm)</th><th>Average No. of Leaves/Plant</th><th>Collar Diameter (mm)</th></tr></thead><tbody><tr><td>T1: Unamended control</td><td rowspan="4">Violet de Galmi</td><td>21.3 ± 1.4</td><td>4.1 ± 0.3</td><td>4.8 ± 0.4</td></tr><tr><td>T2: <i>Pennisetum sp.</i> compost only</td><td>27.5 ± 1.2</td><td>5.2 ± 0.4</td><td>6.0 ± 0.3</td></tr><tr><td>T3: <i>Azadirachta indica</i> compost only</td><td>25.8 ± 1.5</td><td>4.9 ± 0.3</td><td>5.5 ± 0.4</td></tr><tr><td>T4: Chicken manure compost only</td><td>29.6 ± 1.1</td><td>5.8 ± 0.2</td><td>6.7 ± 0.2</td></tr><tr><td>T5: 1/3 mix (<i>Pennisetum</i> + <i>Azadirachta</i> + manure)</td><td></td><td>32.4 ± 1.0</td><td>6.4 ± 0.3</td><td>7.4 ± 0.2</td></tr><tr><td>T1: Unamended control</td><td rowspan="4">Goudami</td><td>20.9 ± 1.6</td><td>4.0 ± 0.4</td><td>4.5 ± 0.5</td></tr><tr><td>T2: <i>Pennisetum sp.</i> compost only</td><td>26.7 ± 1.3</td><td>5.0 ± 0.3</td><td>5.9 ± 0.3</td></tr><tr><td>T3: <i>Azadirachta indica</i> compost only</td><td>24.6 ± 1.4</td><td>4.8 ± 0.2</td><td>5.3 ± 0.4</td></tr><tr><td>T4: Chicken manure compost only</td><td>28.9 ± 1.2</td><td>5.6 ± 0.2</td><td>6.6 ± 0.2</td></tr><tr><td>T5: 1/3 mix (<i>Pennisetum sp</i> + <i>Azadirachta indica</i> + manure)</td><td></td><td>31.6 ± 1.1</td><td>6.2 ± 0.3</td><td>7.2 ± 0.3</td></tr></tbody></table>

Average plant height and leaf vigor were significantly improved by the use of enriched organic compost. At 60 days after transplantation, T5 plants reached average heights of 43.2 cm (Goudami) and 40.7 cm (Violet de Galmi), compared to 29.5 cm and 26.8 cm for the unamended control. These findings suggest improved macronutrient (NPK) availability and enhanced soil structural properties (Cahurel et al., 2018; Naisse, 2014; Dzokom, 2025; Dzokom, 2024; Dzokom, 2023; Dzokom, 2019). The synergistic effects of *Pennisetum* as a structural agent, neem biomass for its bioactive compounds, and chicken manure for its nitrogen richness were pivotal (Oumarou et al., 2022; Konate et al., 2022). These observations are consistent with Palou (2011); Temple et al. (2024) and Moustier et al. (2004), who concluded that mixed composts significantly improve vegetative performance in Sahelian conditions by combining nutrient supply, soil structure enhancement, and abiotic stress resilience.

<figure><img src="image_3.png" /><figcaption>Photo 2: a) Violet de Galmi ; b) Goudami</figcaption></figure>

The nutritional synergy between poultry manure (rich in NPK), *Pennisetum* organic matter (structuring and humifying), and neem (*Azadirachta indica*) bioactives appears to play a key role in enhancing bulb metabolism (Sonko, 2021; Tchinde et al., 2020). Treatment T4 (poultry manure only) also stands out, supporting the findings of Amsallem & Tréboux (2014); Konate et al., (2022) regarding the direct effect of poultry droppings in forming large, well-developed bulbs through rapid nutrient release. Conversely, *Azadirachta* compost alone (T3) provides intermediate results, likely due to its slower nutrient release but protective effect against soil-borne diseases (Mbaye et al., 2022; Touré et al., 2018; Ngom et al., 2017; Dzokom, 2024;
Dzokom et al.,2025). The higher yield observed for Violet de Galmi under compost amendment aligns with Stéphane & Dabire (2016) and Gravel (2016), who

demonstrated this variety's strong response to balanced and rich compost inputs in semi-arid zones.

<table><caption>Table 3. Bulb development and yield</caption><thead><tr><th>Treatment</th><th>Onion variety</th><th>Average bulb diameter (cm)</th><th>Average bulb weight (g)</th><th>Yield (t/ha)</th></tr></thead><tbody><tr><td>T1: Unamended control</td><td rowspan="4">Violet de Galmi</td><td>3.8 ± 0.2</td><td>48.6 ± 3.5</td><td>8.3 ± 0.6</td></tr><tr><td>T2: Pennisetum sp. compost only</td><td>4.5 ± 0.3</td><td>62.1 ± 4.2</td><td>11.7 ± 0.7</td></tr><tr><td>T3: Azadirachta indica compost only</td><td>4.2 ± 0.3</td><td>58.4 ± 3.8</td><td>10.6 ± 0.6</td></tr><tr><td>T4: Poultry manure compost only</td><td>4.9 ± 0.2</td><td>68.9 ± 3.1</td><td>13.4 ± 0.5</td></tr><tr><td>T5: One-third mix (Pennisetum sp + Azadirachta indica+ poultry manure)</td><td></td><td>5.3 ± 0.2</td><td>74.2 ± 2.9</td><td>15.2 ± 0.4</td></tr><tr><td>T1: Unamended control</td><td rowspan="4">Goudami</td><td>3.6 ± 0.3</td><td>45.2 ± 3.9</td><td>7.8 ± 0.7</td></tr><tr><td>T2: Pennisetum sp. compost only</td><td>4.4 ± 0.3</td><td>60.5 ± 3.7</td><td>11.1 ± 0.6</td></tr><tr><td>T3: Azadirachta indica compost only</td><td>4.1 ± 0.2</td><td>56.7 ± 3.4</td><td>10.1 ± 0.5</td></tr><tr><td>T4: Poultry manure compost only</td><td>4.8 ± 0.3</td><td>67.2 ± 2.8</td><td>13.0 ± 0.4</td></tr><tr><td>T5: One-third mix (Pennisetum sp + Azadirachta indica+ poultry manure)</td><td></td><td>5.2 ± 0.2</td><td>72.8 ± 2.7</td><td>14.6 ± 0.3</td></tr></tbody></table>

Bulb diameter and average bulb weight showed highly significant differences across treatments (p < 0.01). The enriched compost (T1) yielded a mean bulb diameter of 6.1 cm and weight of 115 g for Goudami, versus 4.8 cm and 92 g for Violet de Galmi under the same treatment. Control plots produced bulbs weighing less than 75 g. Overall yield reached 23.4 t/ha for Goudami and 19.2 t/ha for Violet de Galmi under T1, representing over a 60% increase compared to controls. These findings confirm Stéphane & Dabire, (2016) and Dzokom et al., (2024), who emphasized the importance of nitrogen and potassium nutrition for bulb development, and Edbo (2021); Ndour-Badiane et al. (2021), who identified Goudami as more resilient to abiotic stress.

### 4. Resilience to Environmental Stresses

The results demonstrate that organic amendments significantly enhance onion

resilience to the harsh environmental conditions typical of the Sahelian climate. Treatment T5 (balanced mix of all three amendments) displayed the highest resilience scores, with a survival rate exceeding 87%, strong leaf turgor (>4.5), and a marked reduction in pest attacks (up to 79.5% healthy plants). Dead Azadirachta indica biomass (T3) plays a key role in pest protection (thrips, nematodes), thanks to its bioactive compounds (azadirachtin, nimbin) known for their repellent properties (Mbaye et al., 2022; Touré et al., 2018; Ngom et al., 2017; Dzokom, 2024; Dzokom et al., 2025). Poultry manure compost (T4), rich in nitrogen, supports rapid plant tissue growth, enhancing recovery capacity after water or heat stress. The superior performance of Violet de Galmi over Goudami suggests a better genetic adaptation of this variety to arid environments, corroborating the work of Stéphane & Dabire (2016); Gravel (2016);
Palou(2011) ; Temple et al.(2024) and Moustier et al.(2004).

<table><caption>Table 4. Onion plant resilience under environmental stress</caption><thead><tr><th>Treatment</th><th>Variety</th><th>Survival rate (%)</th><th>Turgor index</th><th>Pest-free plants (%)</th></tr></thead><tbody><tr><td>T1: Unamended control</td><td rowspan="5">Violet de Galmi</td><td>61.7 ± 3.5</td><td>2.4 ± 0.3</td><td>51.3 ± 4.2</td></tr><tr><td>T2: Pennisetum sp. compost only</td><td>74.2 ± 2.9</td><td>3.5 ± 0.4</td><td>63.6 ± 3.9</td></tr><tr><td>T3: Azadirachta indica compost only</td><td>76.8 ± 2.7</td><td>3.7 ± 0.3</td><td>70.4 ± 3.4</td></tr><tr><td>T4: Poultry manure compost only</td><td>81.3 ± 2.5</td><td>4.0 ± 0.2</td><td>66.8 ± 2.9</td></tr><tr><td>T5: One-third mix of all</td><td>89.6 ± 2.1</td><td>4.6 ± 0.2</td><td>79.5 ± 2.6</td></tr><tr><td>T1: Unamended control</td><td rowspan="4">Goudami</td><td>58.9 ± 3.7</td><td>2.2 ± 0.4</td><td>48.7 ± 4.0</td></tr><tr><td>T2: Pennisetum sp. compost only</td><td>71.4 ± 3.1</td><td>3.3 ± 0.4</td><td>61.2 ± 3.7</td></tr><tr><td>T3: Azadirachta indica compost only</td><td>74.9 ± 2.8</td><td>3.5 ± 0.3</td><td>68.3 ± 3.5</td></tr><tr><td>T4: Poultry manure compost only</td><td>80.1 ± 2.4</td><td>3.9 ± 0.2</td><td>65.5 ± 3.1</td></tr></tbody></table>

Field observations revealed increased tolerance to water and heat stress in amended plots, especially under T1. Plants exhibited better leaf turgor, reduced wilting, and delayed senescence, particularly during temperature peaks (>40°C). The structural effect of compost improved soil water retention, while neem bioactive compounds likely contributed to reducing underground pest pressure (Serpantié et al., 2024; Diagne et al., 2010 and IRAD, 2022).

In general, the use of organic composts enhances the agroecological resilience of vegetable crops by improving soil water retention capacity, root aeration, and microbial diversity, thereby mitigating the effects of climatic stress (Sonko, 2021; Tchinde et al., 2020).

## 5. Comparative Discussion and Agronomic Implications

These findings highlight the agronomic superiority of locally enriched organic compost in terms of both fertility and crop resilience. The combination of Pennisetum sp. (a lignin and stable organic matter source), Azadirachta indica biomass (a source of limonoids with biopesticide effects), and poultry manure (a direct

nutrient source) constitutes an ecological, economical, and easily replicable solution for small-scale farmers in Sahelian areas (Cissé, 2022; Osunde, 2016; Oumarou et al., 2022; Konate et al., 2022). Additionally, varietal selection is crucial to yield optimization: Goudami exhibits better adaptation to semi-arid conditions due to its shorter growth cycle and greater tolerance to heat stress, confirming the conclusions of Edbo, (2021); Ndour-Badiane et al., (2021). The integrated approach adopted here aligns with the principles of agroecology and sustainable agriculture, especially in urban and peri-urban areas facing land and climate constraints.

## Conclusion

The experiment conducted in urban and peri-urban Sahelian zones of Cameroon demonstrated the agronomic effectiveness of a locally formulated organic compost based on dried *Pennisetum* sp., dead *Azadirachta indica* biomass, and poultry manure in enhancing the productivity of two onion varieties (*Allium cepa* L.): improved Goudami and Violet de Galmi. The results revealed significant improvements in vegetative growth, bulb
development, and total yield in both varieties, especially under enriched compost (T1), which promoted better mineral nutrition, enhanced resilience to water and heat stress, and reduced pest constraints under Sahelian conditions. The improved Goudami variety outperformed, with yields exceeding Violet de Galmi by over 20%. These performances confirm that the rational and local use of organic resources can restore the fertility of degraded soils and strengthen food security in urban and peri-urban settings under climate change.

## Recommendations

### To urban/peri-urban producers and vegetable farmers:

* Adopt enriched compost (Pennisetum sp. + neem + poultry manure) as a base amendment for onion cultivation in arid zones.

* Prioritize the improved Goudami variety, better suited to extreme climate conditions, while preserving local varieties for genetic diversity.

* Produce compost locally by mastering the sanitation and maturation steps to ensure agronomic quality.

### To local authorities and NGOs:

* Support the dissemination of enriched composting technologies in urban agricultural centers through training and targeted subsidies.

* Encourage agroecological production systems integrating plant waste and animal manure to reduce reliance on chemical inputs.

* Promote local markets for sustainably produced onions, especially during the dry season, to increase urban and peri-urban household incomes.

### To researchers and technical institutes:

* Continue comparative studies on other vegetable species (tomato, pepper, okra) and compost formulations.

* Integrate socio-economic and environmental studies to assess the profitability and sustainability of this approach in Sahelian contexts.

* Document long-term effects on soil structure and edaphic biodiversity regeneration.

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