The experiment was carried out at Somali National University’s experimental farm, Gaheyr Campus, Wadajir district, Mogadishu (See Figure 1 ). The study area has a semi-arid to arid climate, marked by very low, highly variable, and often unpredictable rainfall. The Benadir region, like much of southeastern Somalia, experiences a hot, semi-arid climate (Köppen classification, BSh—mid-latitude steppe and desert) [14] . In Mogadishu, the average annual rainfall is about 474 mm, falling mainly during two rainy seasons. The first, called “Gu,” runs from April to June and accounts for roughly 52% of the annual total, while the second, “Deyr,” occurs from October to November and accounts for about 28% of the year’s rainfall. The region is generally dry, with potential evapotranspiration reaching around 1,782 mm per year. The initial dry season 20% of the year’s rainfall, known as “Xagaa” (July-September), is relatively mild with occasional showers along the coast. The second dry season, “Jilaal” (January-March), is hot and very dry, with almost no rainfall. Wind speeds in Mogadishu tend to be low, ranging from 3 to 5 m/s throughout the year, usually lowest in April and November, coinciding with the peaks of the rainy seasons [14] (see Figure 2 ).

The study examined the effect of different nitrogen fertilizer rates on the growth and yield of Panicum maximum (Mombasa Guinea Grass). The experiment was conducted on a 264 m² field (24 m × 11 m) using a Randomized Complete Block Design (RCBD) with three replications. Seven nitrogen fertilizer rates were tested (0 as control, 25, 50, 75, 100, 125, 150 kg∙N/ha). The experimental area consisted of 21 plots (3 m × 3 m each), separated by 0.5 m between plots and 1 m between replications. Land preparation involved hoeing and hand leveling to create a uniform seedbed. Seeds of Panicum maximum were sown on October 30, 2022, at a spacing of 50 cm × 50 cm.

Nitrogen fertilizer treatments were randomly assigned to plots according to the RCBD. Randomization was done manually using a lottery method, where each nitrogen rate was written on a separate piece of paper, folded, and randomly placed on the plots. The papers were then opened to reveal the nitrogen level assigned to each plot. This method ensured unbiased allocation of treatments within each replication. To address phosphorus deficiency, 108.7 kg/ha of DAP (46% P₂O₅) was applied during land preparation. Nitrogen was supplied as urea (46% N) and used in three equal splits at 20, 35, and 50 days after germination to coincide with critical growth phases. Organic compost was incorporated uniformly across all experimental plots at a rate of 27.8 t∙ha⁻¹, equivalent to 25 kg per 9 m² plot, to improve and standardize soil fertility before fertilizer treatments. The total treated area (189 m²) included only the cultivated plots, excluding paths and borders. The compost rate was calculated as:

$\begin{array}{c}\text{Rate}\left(\text{t}\cdot {\text{ha}}^{-1}\right)=\frac{\text{Total compost applied}\left(\text{kg}\right)}{\text{Treated area}\left({\text{m}}^2\right)}\times 10,000\\ =\frac{525}{189}\times 10,000\\ =27,778\text{kg}\cdot {\text{ha}}^{-1}\\ \approx 27.8\text{t}\cdot {\text{ha}}^{-1}\end{array}$

The experiment was conducted on loamy sand soils typical of the coastal lowlands of the Benadir region in southern Somalia, which are characterised by low fertility. The laboratory results confirmed extremely low OM (0.009%) and N (0.0015%), very low available phosphorus (P₂O₅—4 ppm; NaHCO₃ extract), low exchangeable potassium (K₂O—0.25 meq/100 g), and a measured pH of 7.6, indicating a slightly alkaline soil environment.

The net water requirement (NWR) for the Mombasa Guinea Grass was estimated using the monthly PET and rainfall data over the experimental period. The general formula applied was $\text{NWR}\left(\text{mm}\right)=\text{PET}-\text{Effective Rainfall}\left(\text{Pe}\right)$, where PET = potential evapotranspiration (mm/month), and Pe = effective rainfall (mm/month). For sandy loam soils, effective rainfall was assumed to be 100% of the monthly rainfall, given high infiltration and moderate runoff. Total NWR = 75 + 141 + 151.9 = 367.9 mm

We calculated total water requirement for the growing period, using the monthly values for November to January (See Table 1 )

$\text{Water Volume}\left(\text{L}\right)=\text{NWR}\left(\text{mm}\right)\times \text{Plot Area}\left({\text{m}}^2\right)$

$\text{V}=367.9\text{mm}\times 9{\text{m}}^2=3,311\text{L}\approx 3.31{\text{m}}^3$

1 mm of water over 1 m² corresponds to 1 L of water. The daily water requirement was calculated by dividing the total water requirement by the number of days in the growing period (2022 November-2023 January, 92 days):

$\text{Daily NWR}\left(\text{L/day}\right)=\frac{\text{Total Volume}\left(\text{L}\right)}{\text{Number of days}}$

$\text{Daily NWR}=\frac{3,311}{92}\approx 36\text{L/day}$

The irrigation duration for each 3 × 3 m plot was determined based on the computed daily water requirement using the following formula:

$\text{t}=\frac{\text{Water required}\left(\text{L}\right)}{\text{Flow rate}\left(\text{L/min}\right)}=\frac{36}{12}=3\text{minutes}$

Accordingly, each plot was irrigated for 3 minutes per day in a single session using a 5/8-inch garden hose delivering water at 12 L/min. This schedule ensured that the Mombasa Guinea Grass received sufficient moisture to meet its physiological needs while compensating for the high evaporation characteristic of the hot Benadir climate.

Data on growth parameters (plant height, tillers per plant, leaves per plant, and leaf area estimated using Sticker’s formula: LA = Length × Width × 0.75) [15] . were collected from 10 randomly selected plants per plot within a 4 m² sample area. Yield components included fresh and dry biomass yield. Using Statistix 8.0, data were subjected to analysis of variance (ANOVA) to ascertain how nitrogen fertilizer rates affected Panicum maximum growth and yield metrics. Plant height, the number of tillers per plant, the number of leaves per plant, and the area of the leaves were among the growth factors that were examined; fresh weight and dry weight were among the yield characteristics. The Least Significant Difference (LSD) test was used to differentiate treatment means at a 5% probability level (α = 0.05). The appropriateness of the model and the assumption of additivity were also evaluated using Tukey’s one degree of freedom test for no additivity.

A palatability/edibility test was conducted using four livestock species (Camel, Cattle, Sheep, and Goats) to evaluate the acceptability of both fresh and dry Panicum maximum forage. A total of 28 animals were used, comprising seven animals from each species. Each animal was offered 1 kg of either fresh or sun-dried grass, and the amount consumed was recorded after feeding. The animals used in the test were locally kept livestock whose owners regularly provided them with feed. To ensure uniformity and eliminate the effect of prior feeding, all animals were offered the test forage early in the morning before receiving any other feed. The edibility percentage was calculated using the formula. Edibility percentage was calculated as:

$\text{Edibility (\%)}=\frac{\text{Amount offered}-\text{Amount unconsumed}}{\text{Amount offered}}\times 100$

The economic analysis was conducted to evaluate the profitability of nitrogen application using the following formulas. The fixed cost (FC) was calculated as the sum of seed and DAP input costs: FC = (Seed quantity (kg/ha) × Seed price per kg) + (DAP quantity (kg/ha) × DAP price per kg). Substituting the actual values gives FC = (4 × 40) + (108.7 × 2) = 160 + 217 = 377 $/ha. The urea input per treatment, considered as the variable input, was determined using the formula Urea input (kg/ha) = (N rate/0.46) × 1.5, where 0.46 represents the nitrogen content in urea. The variable cost (VC) was then computed as VC = Urea input (kg/ha) × Urea price per kg. The total cost (TC) was obtained by adding fixed and variable costs, TC = FC + VC. The revenue (R) was calculated based on the dry yield multiplied by the market price per kilogram of dry matter: R = Dry yield (kg/ha) × 0.50 (Price per kg of dry yield). Finally, profit (π) was estimated as the difference between revenue and total cost: π = R − TC.

According to Table 2 , plant height increased significantly (P < 0.01) with increasing nitrogen rates compared to the control, but declined slightly beyond 125 kg∙N/ha. The lowest plant height (116.87 cm) was observed at 0 kg∙N/ha, while the highest (179.7 cm) was recorded with 125 kg∙N/ha. This increase can be attributed to nitrogen’s role in promoting vegetative growth and internodal elongation. Similar findings were reported by [16] , who observed a maximum plant height of 101 cm at 60 kg∙N/ha compared to 47 cm at 0 kg∙N/ha. The number of tillers per plant also increased significantly (P < 0.01) with nitrogen application. The maximum mean (30.9) was achieved at 150 kg∙N/ha, while the minimum (12.9) occurred under zero treatment. The increase is linked to nitrogen stimulating shoot development and tiller initiation. Comparable results were obtained by [17] , where tiller numbers of Panicum maximum increased progressively up to 250 kg∙N/ha, with values ranging from 181 to 424 tillers/m². Leaf production responded strongly to nitrogen, with significant differences (P < 0.01) among treatments.

P = 0.0000; CV = 2.65 - 7.24; SEM = 0.11 - 8.72.

The highest number of leaves per plant (169) was recorded at 150 kg∙N/ha, compared to 67.2 leaves at 0 kg∙N/ha. Nitrogen is essential for node formation, which directly contributes to increased leaf numbers. Leaf area also expanded markedly, rising from 173.04 cm² at 0 kg∙N/ha to 331 cm² at 150 kg∙N/ha. This result is consistent with [18] , who showed that nitrate-ammonium mixtures at 70:30 and 55:45 ratios ( ${\mathrm{NO}}_3^{-}$: ${\mathrm{NH}}_4^{+}$) enhanced leaf area and shoot growth by up to 30%. Similarly, the number of leaves per tiller increased significantly (P < 0.01) under nitrogen application, peaking at 5.73 leaves/tiller with 125 - 150 kg∙N/ha compared to 4.4 at 0 kg∙N/ha. According to [19] , they also reported a steady rise in leaves per tiller with higher nitrogen rates, from 3 at 0 mg/dm³ to 6 at 200 mg/dm³. Overall, nitrogen application consistently improved growth parameters of Mombasa Guinea Grass, with 125 - 150 kg∙N/ha emerging as the most effective range for promoting height, tillering, leaf number, and leaf area.

As shown in Table 3 , Nitrogen application had a marked influence on the fresh yield of Panicum maximum. The differences were highly significant (P < 0.01) across treatments compared to the control. Fresh yield increased progressively with nitrogen application from 0 up to 100 kg∙N/ha, after which the response became less pronounced. The maximum fresh yield (60,417 kg/ha) was obtained at 150 kg∙N/ha, while the lowest yield (20,333 kg/ha) occurred in the untreated plots. The yield improvement is closely associated with enhanced leaf and stem growth, reflecting the positive effect of nitrogen on photosynthetic activity and vegetative development. Similar results were reported by [19] [20] , who found that nitrogen sources significantly influenced fresh matter yields of tropical pastures, with urea treatments consistently outperforming control plots by 13% - 17%.

P = 0.0000 - 0.0001; CV = 9.57 - 15.66; SEM = 1076.5 - 4.22.

The effect of nitrogen on dry yield followed a similar trend, with highly significant (P < 0.01) differences observed among treatments compared to the control. Dry matter yield increased steadily up to 100 kg∙N/ha, beyond which the response plateaued. Although the highest dry yield (28,167 kg/ha) was achieved at 150 kg∙N/ha, the increase was statistically insignificant compared to 125 kg∙N/ha. In contrast, the lowest dry matter yield (5,917 kg/ha) was recorded under the zero treatment. This suggests that while nitrogen strongly promotes biomass accumulation, there may be diminishing returns beyond moderate application levels.

These findings are in line with [21] , who examined different nitrogen rates (0 - 300 kg∙N/ha) in Panicum maximum and observed a progressive rise in stem, leaf, and total dry matter production with increasing fertilizer. In their study, the highest dry yield (9,734 kg/ha) was obtained at 300 kg∙N/ha, while the lowest (3,636 kg/ha) occurred in unfertilized plots. Together, these results confirm that nitrogen fertilization enhances both fresh and dry matter production, though the economic efficiency of very high rates may not justify their application.

Overall, the results of this study highlight that nitrogen fertilizer significantly improves forage yield in Mombasa Guinea Grass. Moderate rates between 100 and 150 kg∙N/ha appear most effective in balancing productivity gains with input efficiency, ensuring both higher forage biomass and sustainable management for farmers.

A palatability/edibility test was conducted on the fresh and dry yield of Panicum maximum by selecting four different farm animals: camels, cattle, sheep, and goats. In terms of fresh yield, camels scored the greatest palatability rate, followed by cattle, sheep, and goats, with the latter having the lowest palatability rate. The grass’s palatability was high in fresh yield compared to dry yield because it was soft, had higher moisture content in the stem, and had more leaves, which enabled the animals to consume almost all parts of the grass, including both stem and leaves.

Fresh palatability tests of Panicum maximum (see Table 4 ) have shown that the grass is highly preferred by ruminants when offered at young regrowth stages. The forage is characterized by high succulence and digestibility, which enhances voluntary intake across cattle, sheep, and goats [22] . Studies further demonstrate that both yield and palatability are influenced by management factors such as variety, soil type, and fertilizer application. For instance, [23] reported significant variation in fresh biomass production and voluntary intake of different Panicum maximum varieties fed to sheep. Similarly, [24] observed that palatability decreases with advancing maturity, with younger stands producing higher fresh yield quality and better animal preference compared to older, stemmy growth. Overall, Panicum maximum is recognized as one of the most palatable tropical grasses for livestock feeding under fresh forage systems.

In terms of dry yield (see Table 5 ), camels scored the highest palatability rate, followed by cattle, then sheep, and lastly goats, which had the lowest palatability rate. When the grass was dried by using the sun drying method, it became less palatable due to the reduced moisture levels and increased toughness, resulting in animals consuming less of it, around 3/4 compared to fresh grass. Consequently, animals are divided into two groups. Large ruminants (camel, cattle), which can consume large amounts of dried grass, and small ruminants (Goat and Sheep), which consume less due to the change in the grass’s characteristics resulting in greater toughness, low water content, and reduced palatability.

Dry Panicum maximum (Guinea grass) is widely used as hay and remains moderately palatable to ruminants, although its nutritive value and intake decline with maturity. When cut at early flowering and properly cured, the hay retains acceptable levels of crude protein and digestibility for cattle, sheep, and goats [25] . Again [23] , reported that voluntary intake of Panicum maximum decreases significantly when the forage is fed in dried form compared to fresh, reflecting the reduction in moisture content and increased fiber concentration. Also, [24] found that hay prepared from younger stands was more palatable and supported higher intake in small ruminants than hay from older, stemmy plants. Despite this reduction, Panicum maximum hay remains an important feed resource in the dry season, providing bulk forage when fresh grasses are scarce and supporting maintenance or moderate production in ruminants.

According to the economic analysis data presented in Table 6 , the profit increases with higher rates of fertilizer application. The profit can potentially increase up to input level 5 (100 Kg∙N/ha), where it reaches $12,881/ha. Although applying 100 kg∙N∙ha⁻¹ required an additional $81 ha⁻¹ compared to the 75 kg∙N∙ha⁻¹ rate, it yielded an extra profit of $2,961 ha⁻¹. Increasing the fertilizer application beyond 100 Kg∙N/ha leads to a decrease in profit due to the rise in input cost and decline in output. It is important to note that the rate of 100 Kg∙N/ha, which is economically optimal for this study, also results in the highest statistically significant yield increase compared to the control treatment (27,167 Kg/ha).