Optimal agricultural water allocation for enhanced productivity of hot pepper (Capsicum annum L) and economic gain: an experimental study from Southern Ethiopia

Abstract

The experiment was conducted to determine the irrigation scheduling effect on hot pepper green pods, yield attributes, and irrigation water productivity (WP) in the Arba Minch area. Field trials comprised five levels of treatments: 140 % MAD, 120% MAD, 100% MAD, 80% MAD and 60% MAD. The results revealed that different depletion levels had significantly affected hot pepper’s yield and related attributes. The maximum yield of hot pepper was observed under 100% MAD without significant variation of 120% MAD whereas the minimum was under 140% MAD in both years of experimentation. WP was also highly influenced by depletion, and the maximum water productivity of (24.67 kg/ha-mm, 24.72 kg/ha-mm was observed under 120% MAD and minimum (19.26 kg/ha-mm, 16.49 kg/ha-mm) under 60% MAD in the year 2019 and 2021, respectively. The results revealed that as the level of depletion increased, irrigation frequency (event) increased, yield and water productivity decreased of hot peppers. 120% MAD offered the highest economic return (11,795.96 US$) and saved water, wage, and irrigation events compared to more frequent applications. The current findings showed that applying 120% MAD is better for hot pepper production in the Arba Minch areas and similar ecology.

Keywords:

• Soil water balance
• depletion
• water demand
• water productivity
• irrigation event

Subjects:

• Agriculture & Environmental Sciences
• Agriculture and Food
• Agriculture

Reviewing Editor:

• Manuel Tejada
• University of Seville
• Spain

1. Introduction

Hot pepper (Capsicum annum L.) is produced for its multiple benefits as a vegetable, spice and processed product (Kulkarni & Phalke, 2009; Wale & Girmay, 2019). Reports indicate that pepper is very sensitive to water shortages and stress (Alvino et al., 1994; Kulkarni & Phalke, 2009). In Ethiopia, pepper is mainly produced in central, northern and southern regions and shares approximately 34% of total spice production (Food and Agriculture Organization of the United Nations [FAO], 2017; Roukens et al., 2005; Wale & Girmay, 2019) and reported that about 300,000 ha of land is predominantly covered by hot pepper.

The high demand for food and fiber, along with population growth and development, has led to an increase in water use for irrigation worldwide. For instance, in Ethiopia, irrigation accounts for above 70% of water use and expected to be to increase in the coming decades (Delfine et al., 2015; FAO, 2017). This is because irrigation is essential for increasing agricultural yields and reducing the risk of drought and has the potential to increase population density in sparsely occupied areas (Delfine et al., 2015; Wale & Girmay, 2019). The increased demand for water for irrigation places a strain on freshwater resources. This is a cause for concern, as freshwater is a limited resource (Wale & Girmay, 2019). They summarized that irrigation can be made more efficient, which would help to reduce the strain on water resources (Wale & Girmay, 2019). They summarized the mechanisms to enhance irrigation performance (drip irrigation or other methods that deliver water directly to the roots of plants, applying water only when needed and using water conservation practices, such as mulching and cover crops). By making irrigation more efficient, we can ensure that water resources are used sustainably and that everyone has access to the water they need. This is a challenge that we must all work together to address (Wale & Girmay, 2019).

Ethiopia faces several challenges, including a growing population, drought and lack of arable land. Irrigation is seen as a way to address these challenges, as it can help to increase agricultural yields (Wale & Girmay, 2019). However, water availability is a limiting factor in crop cultivation in some irrigation schemes in Ethiopia. In addition, the limitations of studies on major economic crops have made it challenging to improve the scheduling and irrigation water productivity.

A good irrigation calendar is crucial for ensuring high crop yields with minimal water use, knowing the water (Wale & Girmay, 2019) and applying water for crops based on water demand to ensure high gain and least (Tyagi et al., 2000; Wale & Girmay, 2019). By conducting crop water requirement studies and optimizing irrigation scheduling, Ethiopia can increase its agricultural productivity and reduce the risk of water scarcity. This will help ensure food security for the growing population and improve farmers’ livelihoods.

Effective irrigation water management is important for improving water productivity and yield, and it can be achieved by frequent soil water content level follow-ups and crop physiological performance in the field (Wale & Girmay, 2019). Applying too much or too little water that cannot satisfy crop water demand can lead to significant yield losses (timing of irrigation is a highly important mechanism to prevent water and yield loss). Valipour (2015) and Wale and Girmay (2019) found that proper irrigation water management can minimize the leaching potential of nitrates. This is important because nitrate leaching can contaminate groundwater and surface water. By following these best practices, farm managers can ensure that irrigation water is used efficiently and effectively. This will help protect water resources and ensure a sustainable food supply for the future.

In the Arba Minch Zuria District, small-scale irrigation schemes are typically applied without scheduling, which results in mismanagement of water and water shortage within schemes in the area of hot pepper grower farmers and decision makers have low awareness and evidence of how to manage water and develop a schedule to optimize water productivity and yield (Wale & Girmay, 2019). Kirda (2002) found that proper irrigation scheduling can help sustain irrigated agriculture permanently. Irrigation scheduling depends on different factors like climate, soil and crop varieties of hot pepper. In the case of Ethiopia, specifically the southern Rift Valley areas there are many hot pepper varieties across the region, but for the most high-yielding varieties, there is a limitation of scientific studies on agricultural water management and productivity maximization. This needs to maximize water productivity and economic returns of hot peppers in the study area.

Many other researchers remarked that despite the high contribution of hot pepper to economic and livelihood improvement there is limited analysis of the economics of irrigation water (Ma et al., 2022; Mohammed & Hussen, 2023). The determination of appropriated Irrigation events and water productivity of hot pepper in the specified areas is needed to enhance farmers’ income, decision-makers and policy direction. This study identified the optimal irrigation water demand, irrigation calendar for pepper (C. annum L.) and water productivity and economic returns of irrigation water applied.

2. Materials and methods

2.1. Site description

An experiment was conducted in the Arba Minch Zuria district, Gamo Administrative Zone of the Southern Region, Ethiopia, in 2019 and 2021 and the study site shown in Figure 1. Specifically, it was experimented at Chano Mille Kebele (located approximately 18 km northeast of Arba Minch town). The site is located at a latitude of 6°6′ N, 37°36′ E, altitude of 1198 m. The study area has two main cropping seasons due to a bimodal rainfall system: the study area receives an annual rainfall of 820.3 mm and temperature (minimum (17.2 °C) and maximum (30.5 °C (NMA: Southern Branch, Arba Minch, 2021/2022).

Figure 1. Map of the study site.

2.2. Treatment and design

6(six)levels of irrigation depletion were used: 140% of the maximum allowable depletion (MAD), 120% MAD, 100% MAD, or control, 80% MAD and 60% MAD. A randomized complete block design (RCBD) with three replications was used for the field experiments. For the experiment; 18 plots with a gross area of 3.7 × 3.6 m (10.08 m²) and blocks and plots of 15 0 cm and 75 cm, respectively. Each plot consisted of four rows spaced 70 cm apart, with 12 plants per row spaced 30 cm apart (EIAR, 2004). The outermost row on each side of the plot was considered the border. The net plot area was 1.4 × 3.3 m (4.62 m²), with two harvestable rows in each plot.

2.3. Experimental procedures and field management

The land was plowed before transplanting, and nursery seedbeds, 1 m wide and 5 m long, were prepared. Mareko Fana varieties of hot pepper seeds were hand-drilled into the nursery at a spacing of 15 cm. During sowing, 100 g of urea was applied to each seedbed (EIAR, 2004). The dry grass mulch was used and seedlings were watered, and less competent seedlings were thinned out to keep vigorous seedlings. Water application to seedlings was reduced when one week was left for transplanting, and uniform, healthy and vigorous seedlings were selected and transplanted after approximately 46 days in the nursery to the experimental field, and seedlings were planted with a spacing of 70 cm × 30 cm.

2.3.1. Fertilizer and crop management practices

200 kg ha⁻¹ NPS applied during transplanting and 100 kg ha⁻¹ Urea applied in split (50% during transplanting, the remaining 50% at half month after transplanting). These fertilizer applications were intended to meet crop nutrient requirements (EIAR, 2004). All crop management practices, except irrigation water amount, were by the recommendations for hot pepper production (EIAR, 2004).

2.3.2. Crop growth cycle and disease and weed management:

The Marko Fana variety of hot pepper was grown for 120 days with 20, 40, 50 and 20 days of initial, development and late stages, respectively. These crop growth stages were derived from the CROPWAT 8.0 software (Ethiopian Institute of Agricultural Research [EIAR], 2004; Wale & Girmay, 2019). Frequent monitoring of diseases and weeds was performed, and appropriate management actions were applied. Kosovate was applied to minimize the impact of trips during the vegetative period, and karate and mancozeb (3 kg ha⁻¹) were used to control the impact of disease, following the label instructions (EIAR,2004).

2.4. Climate data

For reference evapotranspiration determinationclimatic parameters were collected from the Arba Minch metereological station using the principle of Allen et al. (1998). Figure 2 shows the average daily climatic conditions during the experiment. The monthly climatic conditions of the study area during the trial period are shown in Figure 2.

Figure 2. Average daily climatic element over experimentation period.

2.5. Soil parameter determination

Samples were collected by the zigzag method and analyzed in the laboratory for chemical and physical properties. The soil composition analysis showed 13%, 21% and 66% sand and silt clay, respectively, and the texture class is clay soil, which has a low infiltration rate and requires extended irrigation scheduling because the soil can sustain soil moisture for a long time. The soil had a dry bulk density of 1.36 grams per cubic centimeter, which is suitable for crop root growth. The soil had a field capacity of 42%, a permanent wilting point of 29.8%, and available soil moisture of 12 cm per meter (Table 1).

Table 1. Soil physical and chemical properties of the study area.

S. no	Parameters	Value (amount)
1	Texture	Clay
3	Field capacity (%)	42%
4	Permanent wilting point (%)	29.8%
5	Available water (cm/m)	12

2.6. Irrigation water application and soil moisture monitoring

Soil moisture was continuously monitored, and irrigation events were carried out based on soil moisture depletion levels. The amount of water in the soil was measured in the laboratory using the gravimetric method. Irrigation water was delivered to the field through furrows that were 30 centimeters wide and 40 centimeters deep. Irrigation water was applied to the field based on available water, pepper depletion and treatment, and the parameters were determined using the following formula:

1. Total available water (mm) = $\frac{\left(\mathit{\text{Field}}\mathit{\text{capacity}}(\text{\%})-\mathit{\text{permanent}}\mathit{\text{wilting}}\mathit{\text{point}}(\text{\%})\right)}{100\text{*}\mathit{\text{Bulk}}\mathit{\text{density}}\text{*}\mathit{\text{Depth}}(\mathit{\text{cm}})}$(1)

2. Readily Available Water (mm) $=\mathit{\text{depletion}}\hspace{0.17em}\mathit{\text{factor}}\left(p\right)\text{*}\mathit{\text{Total}}\mathit{\text{avalibale}}\mathit{\text{water}}\hspace{0.17em}$(2)

3. Net irrigation(mm) = Evapotranspiration(mm)– effective rainfall(mm)(3)

4. Gross Irrigation requirement (mm) $=\frac{\text{Net irrigation}(\mathrm{\text{mm}})}{\text{application efficiency}(\mathrm{\%})}\mathrm{ }$(4)

5. Time required (minute) $=$ $\frac{\text{Gorss depth of water}(\mathrm{\text{cm}}(\times \mathrm{\text{Lengh}}\left(\mathrm{m}\right)\times \mathrm{\text{widt}}(\mathrm{m})}{6\times \text{dischage through parshall flume}\left(\frac{\mathrm{L}}{\mathrm{S}}\right)}$(5)

2.7. Agronomic data measurement

Plant height, pods, and branches per plant were recorded before harvest. Pods per plant and branches per plant were continuously measured. The yield of the hot peppers was measured using a spring balance after harvesting. The total yield was calculated by adding marketable and unmarketable yields. The unmarketable yield is hot pepper yield that is attacked by worms, or other vectors, or has a diameter below 5 mm.

$\begin{array}{l}\text{Water productivity of ho pepper}\left({\text{kg m}}^{-3}\right)\\ =\frac{\text{Hot pepper yield}\left(\text{kg}\right)}{\text{Evapotranspiration of hot pepper(mm})}\end{array}$(6)

2.8. Economic analysis

The economic analysis of treatments was determined to support the statistical analysis carried out. the following parameters were determined for net benefit and benefit-cost ratio analysis using the guidelines of the International Maize and Wheat Improvement Center (1988). The fixed costs involve the costs of fertilizers, pesticides, chemicals and seeds of hot pepper. The flexible costs include the costs of watering, weeding, and harvesting.

1. Net benefit (NB) =pod yield (kg/ha) * Current price in the market (US$) (7)

2. Total cost = $\sum (\sum \mathit{\text{all fixed costs}}(\mathit{\text{US}}\mathrm{\$})+\sum \mathit{\text{flexible costs}}(\mathit{\text{US}}\mathrm{\$}\mathrm{ })$(8)

3. Benefit cost ratio (BCR) = $\frac{\mathit{\text{Total costs}}}{\mathit{\text{Net Benefit}}}\mathrm{ }$(9)

2.9. Statistical analysis

The experiment was conducted using a randomized complete block design (RCBD). RCBD is a statistical method used to control for variability in the experimental results. Analysis of variance (ANOVA) was performed using the statistical software SAS version 9.1. ANOVA is a statistical test used to determine whether there were significant differences between the treatment means. The least significant differences (LSDs) were used to compare the treatment means. LSDs are statistical methods used to determine which treatment means are significantly different.

3. Results and discussions

3.1. Irrigation treatment effect on yield and attributes

Irrigation scheduling significantly affected pepper at the experimental site. Table 2 shows statistically significant differences in terms of plant height (only in 2019), number of pods per plant and yield, except for bunch number (only in the year 2021, as shown in Table 3). In 2019 there is significant plant height among treatments. Treatment 60% and 80% of MAD showed higher, while 100–140% showed lower plant height (there is no significant variation among treatments (100–140%). However, in 2021 among treatments, there is no significant variation in plant height.

Table 2. Irrigation treatments impact on yield and related components of hot pepper at A/Minch Zuria in 2019, dry cropping season.

Treatment	PH (cm)	BN (no)	PPP	Yld
140% MAD	56.01c	16.5	11.58b	11.25b
120% MAD	53.63c	16.25	16.57a	12.73a
100% MAD	58.13bc	18	15.32a	13.05a
80% MAD	62.45ab	17.15	11.69b	11.93ab
60% MAD	64.85a	16.33	11.62b	8.85c
Mean	59.01	16.85	13.4	11.56
CV	6.77	7.26	15.12	6.81
LSD	6.02	NS	2.76	1.19

Note: PH: plant height in cm; BN: bunch number (number); PPP: pods per plan in cm; Yld: yield in ton/hectare.

Table 3. Irrigation treatment impact on yield and related components of hot pepper at A/Minch Zuria in 2021, dry cropping season.

Treatment	PH	BN	PPP	Yld
140% MAD	63.04	16.5b	11.1b	11.15b
120% MAD	62.5	17.7ab	14.75a	12.97a
100% MAD	63.38	19a	16.57a	13.29a
80% MAD	61.7	17.65ab	9.75b	12.68ab
60% MAD	60.85	16.5b	8.6b	10.32c
Mean	62.29	17.48	12.2	12.08
CV	4.59	5.73	6.32	3.59
LSD (0.05)	NS	1.51	9.68	0.64

Note: PH: plant height in cm; BN: bunch number (number); PPP: pods per plan in cm; Yld: yield in ton/hectare.

In consecutive years (2019 and 2021), in terms of pepper green yield and pods per plant, the maximum mean was observed under 120% MAD without significant variation with 100% MAD, while the minimum was under 60% MAD and 80%. These results indicate hot pepper needs extended irrigation intervals rather than shorter intervals. The result is in line with other researchers’ findings that better diameter and pod length of hot peppers were observed by applying appropriate irrigation amounts (Delelegn, 2011; Wale & Girmay, 2019). The lower performance of hot pepper in the case of below 100% MAD (60% and 80%) was due to the influence of waterlogging, which could decrease the aeration of the root zone. The lack of sufficient aeration across pepper roots was due to increases in the ponding of water across the active root zone which reduced the metabolic processes of the crop. This shows that the hot pepper in the Arba Minch area needs water stress to some extent compared to frequent irrigation. Hot pepper growers in the study area can produce green pods by increasing the number of irrigation events rather than by frequent irrigation.

Peppers with higher pod lengths have good demand for fresh and dry pods, and larger pepper pods have a higher dry matter content, vitamin C content and pungency than smaller pepper pods (Beyene & David, 2007). They also found that larger pepper pods are more resistant to pests and diseases.

The results of this study showed that 120% MAD (maximum allowable depletion) gave the highest green pod yield and yield-related parameters at the Chano Mille experimental site. This suggests that the application of more water to pepper plants leads to higher yields. However, the amount of water that crops need varies depending on climate, soil type and other factors. It is also important to avoid overwatering plants as this can lead to root rot and other problems. The variation in water applied and irrigation events had a significant influence on yield and attributes, which indicates the need for appropriate management of water to increase pepper productivity.

Field experimentation indicated that reducing irrigation from one-third to two-thirds did not affect yield performance, especially during development and mid-stages (Yang et al., 2017). They also found that water deficit irrigation can even increase fruit yields because water deficit irrigation can allow water levels to reach about seventy percent of field capacity. On the other hand, irrigation with full water content (100% of field capacity) can reduce pepper yield. These results are consistent with the findings of Serna Perez and Zegbe (2012), who found that deficit irrigation can save water by 8 to 30% without compromising pepper yield. Many studies have shown that deficit irrigation is an effective way to save water during hot pepper production. For example, Dorji et al. (2005), Gençoğlan et al. (2006), González-Dugo et al. (2007), Yang et al. (2018), Al-Ghobari and Dewidar (2018) and Abayomi et al. (2012) found that deficit irrigation could lead to significant water savings without compromising yield or quality. Wale and Girmay (2019) also reported that extending irrigation scheduling to application depth above 100% MAD has increased the additional command area of 2.2 ha. They also remarked that it increased the yield performance of hot pepper by 25.2 tons/ha. Ichwan et al. (2022) also remarked that hot pepper could give optimal yield with a deficit level of 75% FC. He also pointed out that there is no significant yield and water productivity reduction at 75% FC between FC. Mohammed and Hussen (2023) also reported that Maximum number of fruits per plant (85.4) was recorded from 20% (−20% from 100% of MAD) level while minimum fruit number per plant (20.93) was observed from 60% (−40% from 100% of MAD) which was four times lower than 80% ET.

3.2. Water productivity of hot pepper

ANOVA analysis showed that the water productivity (WP) of hot pepper was significantly affected by the application of irrigation amount and frequency. In both years, 2019 and 20221, the highest water productivity offered from 120 % MAD, without significantly varying with 100% MAD, 80% MAD and 140 % MAD (Tables 4 and 5). However, the minimum WP was observed under 60% MAD in both experimental periods.

Table 4. Effects on hot pepper water productivity (WP) at Chano Mile in 2019.

Treatment	Yld	WP
140% MAD	11.25	20.77b
120% MAD	12.7	24.76a
100% MAD	13.05	23.63a
80% MAD	11.93	21.23ab
60% MAD	8.85	19.26b
CV	11.56	18.3
LSD	6.81	5.56

Note: Yld: yield (quantal/ha); WP: water productivity (kg/ha-mm).

Table 5. Hot pepper water productivity (WP) at Chano Mile in 2021.

Treatment	Yld	WP
140% MAD	11.15b	20.96ab
120% MAD	12.97	24.72a
100% MAD	13.29	24.32a
80% MAD	12.68	22.23ab
60% MAD	10.32	16.49b
CV	12.08	17.2
LSD	3.59	8.4

Note: Yld: yield (t/ha) WP: water productivity (kg/ha-mm); CV: coefficient of variance; LSD: least square difference.

The highest water productivity observed at 120% MAD showed that the hot pepper can withstand water stress to some extent. This stress did not affect the yield performance when compared with no stress or application of 100% of MAD (P = 30%). From Tables 4 and 5, it can be observed that as the irrigation frequency decreased, the green pod productivity of hot pepper decreased. However, extending irrigation frequency up to 20% above normal depletion is recommended for hot pepper production. The findings of the current study are consistent with those of Zegbe-Domínguez et al. (2004) which were cited by Wale and Girmay (2019). They concluded that optimal irrigation scheduling requires knowledge of the soil water status, crop water requirements, water stress status and the threshold reduction that occurs when crops remain under stressed conditions. Additionally, Yang et al. (2018) reported that full irrigation and less water deficit (80% of ET) resulted in the highest or higher water use efficiency which agrees with this study, that −20% (120%) of water stress has no more yield reduction in comparison with 100%.

3.3. Irrigation scheduling and irrigation water demand and soil water balance

Based on climatic, soil and crop parameters; water demand and irrigation scheduling were determined for hot pepper. Table 6 shows that under 100% MAD, 80% MAD and 60% MAD, the average NIR of hot pepper was 390 mm/season, whereas the minimum NIR was observed under 140% MAD. As the irrigation schedule was extended total irrigation water demand decreased, as Table 6; the maximum irrigation event (21) was observed under 60% MAD, whereas the minimum irrigation event was observed under 140% MAD. Table 6 also shows that, as the number of irrigation events increased, the depletion level of the soil increased. In terms of both 140% MAD and 120 % MAD, the hot pepper has suffered from moisture stress (below critical depletion level), whereas at 80% MAD and 60% MAD, the crop attained water without reaching field capacity during irrigation time (Figure 3(a–c)). The gross and net irrigation demand of 60% MAD exceeded the other treatments owing to a continuous supply of irrigation water to the crop root zone. Figure 4(a–e) shows that in the case of 120% MAD and 140%MAD, hot pepper did not receive sufficient water during growing period, but in case of 80% MAD and 60% MAD, crops irrigated early (before reaching to the optimum depletion level p = 30%).

Figure 3. (a) Gross and net irrigation requirement through growth irrigation event. (b) Net irrigation requirement across growth season of hot pepper. (c) Gross irrigation requirement.

Figure 4. Soil moisture depletion level status through growth season of 80, 60, 100%, 140 and 120 MAD, respectively.

Table 6. Irrigation demand and irrigation event per each treatment.

Treatment	Seasonal irrigation demand
	Net irrigation requirement (mm/season)	Gross irrigation requirement (mm/season)	Irrigation event
140 % MAD	145	263.64	5
120% MAD	190	3461.1	7
100% MAD	390	428.6	10
80% MAD	390	431.2	15
60% MAD	390	537.6	24

3.4. Economic analysis of irrigation treatments

In economic analysis, both costs are considered; fixed costs like water, fertilizer pesticides and flexible ones like weeding and watering. The total benefit is determined by multiplying farm gate yield with the current price of hot pepper in the market. Five different irrigation depletion levels for hot pepper the economic benefit and benefit-cost ratio were determined, separately in Table 7. The current study result showed that 120% MAD treatment emerges as the unquestionable high economic gain provider, offering the highest benefit-cost ratio (BCR) of 12.50. This implies for every dollar invested in this method 12.5 harvest value is obtained. Not far behind is the 100% MAD treatment, giving a BCR of 12.20. The 140% MAD treatment also puts up a good fight with a BCR of 11.80. The 120% MAD treatment again takes the higher position with a net benefit of $11,795.96 per hectare, while the 80% and 60% MAD treatments have lower BCRs and net benefits. The net benefit and BCR indicate that applying 120% is advisable for the hot pepper growers in the area. Since in this area, the competition for irrigation water is getting higher, so to save water and in turn, maximize water productivity and land productivity.

Table 7. Economic analysis of the treatments.

Treatments	Average yield (kg/ha)	Total cost (US$/ha)	Total benefit (US$/ha)	Net benefit (US$/ha)	Benefit-cost ratio
120% MAD	11,250	1029.3	12,825.2	11,795.96	12.5
100% MAD	12,700	998.7	12,147	11,148.05091	12.2
140 % MAD	12,050	954.8	11,318	10,363.14049	11.9
80% MAD	11,930	1039.7	11,975	10,935.22909	11.5
60% MAD	8850	1115.31	8539.34	7424.087273	7.7

Note: 1 kg of hot pepper =1US$.

4. Conclusion

The current study showed that the treatments highly influenced the yield, attributes and water productivity in the Arba Minch area. This suggests that irrigation is an important factor in achieving higher pepper yields in this region on top of other agronomic practices. Full irrigation (100%MAD) gave a higher yield, pod per plant bunch number, without significant variation over two consecutive years. The highest water productivity obtained under 120 % MAD, without significant variation with 100% MAD, 80% MAD and 140 % MAD. However, the minimum WP was observed under 60% MAD in both experimental periods.

The highest water productivity was observed at 120% MAD, which showed that hot peppers could withstand water stress to some extent (up to 20% above normal conditions). The average water requirement of hot pepper in the Arba Minch area was approximately 390 mm/season, which was obtained under a depletion level of 100% MAD (p = 30%), whereas the minimum net irrigation requirement was observed at 140% MAD. The study showed that the higher the number of irrigation events, the higher the soil moisture, which has a significant impact on yield and water productivity.

The maximum irrigation event (24) was recorded under treatment with 60% MAD, and the minimum (5) was under 140% MAD. The current study revealed that 100% MAD produced a higher yield, without significantly differing from 120% MAD. However, 120% can save some amount of irrigation water that can irrigate additional areas. 120% MAD has also shown fewer irrigation events than 100% MAD and other frequently irrigated treatments, which may save time and water to be applied. The economic analysis also revealed that 120% MAD gave maximum net benefit (11,795.96 US$) and benefit-cost ratio (12.5) in comparison with other treatments. As for the findings of this study, 120% MAD gave better yield and related components, water productivity and saved time and water. By applying 120% MAD, hot pepper growers can produce with no significant yield reduction and increase the command area, save wages and energy due to the application of frequent application of water. Therefore, it can be recommended that applying 120% MAD for green pod production in Arba Minch area and other similar agroecology is appropriate.

Author contributions

For this research, Gezimu Gelu contributed in stages (proposal development, experimental work, data analysis and draft preparation and final manuscript, Alemnesh Ayza contributed in filed work and data collection, Chanako Dane contributed in experimentation, data collection and organization, and Markos Habtewold contributed in data collection during first year of field experiment.

Acknowledgments

Authors highly recognize and appreciate the Southern Agricultural Research Institute for Budgetary support and the Arba Minch Agricultural Research Centre for logistic and other administrative support. And also appreciate Chano Mile Kebelle Agricultural agents and other administrative bodies for providing experimental land and allowing irrigation water.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data of this experimental work will be provided up on reasonable request for research purposes. The data will be shared via email address of corresponding author.

Additional information

Funding

The authors appreciate Southern Agricultural Research Institute for financing this research work with Grant code SARI/GOV-Irr-08/2021.