Evaluations of drip and furrow irrigation method under deficit irrigation for pepper productivity in Northwest Ethiopia

doi:10.21203/rs.3.rs-4176426/v1

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Evaluations of drip and furrow irrigation method under deficit irrigation for pepper productivity in Northwest Ethiopia

https://doi.org/10.21203/rs.3.rs-4176426/v1

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The combination of reduced food production and growing water scarcity posed significant difficulties for agriculture and economic development in Ethiopia. To minimize water loss, an experiment was carried out that was both economically viable and technically feasible. Thus, the purpose of this study was to evaluate the irrigation methods (Drip vs furrow) in terms of crop and water productivity, as well as technical implications in the Ethiopian context. A split plot in a randomized complete blocks design with three replications was used to experiment over two consecutive years, 2018 and 2019. Two irrigation systems, furrow irrigation and drip irrigation, were the focus of the plots. The sub-plots, on the other hand, examined four levels of deficit irrigation: 55%, 70%, 85%, and 100%. Drip irrigation resulted in a marketable fresh fruit yield of 6226.1 kg/ha, while furrow irrigation produced 5284.5 kg/ha. Water use efficiency is 20.678 kg/m3 for drip irrigation and 12.827 kg/m3 for furrow irrigation. Under full irrigation, the highest yield of marketable fresh fruit was 9560.2 kg/ha, while the lowest commercial fruit production was 4199.7 kg/ha at 55% of ETc. The results of the analysis suggest that drip irrigation may not be technically feasible for large-scale agricultural operations, as indicated by the substantial evidence from irrigating with 85% ETC using furrow irrigation. Hence, employing 85% ETC for irrigation in water-scarce regions has the potential to improve yield and water productivity.

Drip irrigation

furrow irrigation

deficit irrigation

pepper productivity and Northwest Ethiopia

Water scarcity is a persistent issue in sub-Saharan Africa due to several factors, including climate change and environmental degradation (Descheemaeker et al., 2010). In Ethiopia, declining food production and increasing water scarcity pose significant challenges to agriculture and economic development (Berhanu and Paden, 2004). To address this issue, efficient utilization of water and the development of new water supply sources are necessary. However, increasing food production with less water is a daunting task, particularly in countries with limited water, land resources, and inefficient water use (Wallace and Gregory, 2002).

Irrigated agriculture is a significant consumer of water, and its water demand will increase over time with a growing population (De Fraiture and Wichelns, 2010). Unfortunately, this practice is still not sustainable, as basic principles of soil and water resource conservation are often ignored (Fereres and Soriano, 2006). Therefore, adopting more efficient irrigation practices is necessary, especially in areas with water scarcity (Mebrahtu et al., 2018; Kuşçu et al., 2014). Several studies have shown that the use of deficit irrigation, which is an optimization strategy by reducing the amount of irrigation water, can improve crop water productivity and sustainability of crop production (Alebachew et al., 2017; Biswas et al., 2017). Deficit irrigation is a technique that reduces irrigation rates at predetermined crop stages with minimal impact on crop yield and quality(Geerts and Raes, 2009; Karrou et al., 2012). By exposing crops to a certain level of water stress, water use efficiency can be maximized (Kirda, 2002). Deficit irrigation strategy is designed to save irrigation water by reducing irrigation rate at predetermined crop stages with a minimum impact on yield and quality of crops (Iniesta et al., 2009; Geerts and Raes, 2009). It is one way of maximizing water use efficiency (WUE) (Kirda, 2002). The reduction of irrigation water in irrigated agriculture to the threshold level increases water productivity (Molden et al., 2010).

Under conditions of scarce water supply, application of deficit irrigation deficit irrigation could provide greater economic returns than maximizing yields per unit of water. The deficit irrigation has been considered worldwide as a way of maximizing water use efficiency (WUE) by eliminating irrigation that has little impact on yield (English, 1990). With deficit irrigation, the crop is exposed to a certain level of water stress either during a particular period or throughout the whole growing season (Kirda, 2000).

Deficit irrigation can increase the productivity of water in agriculture, minimize environmental degradation, and provide food security while reducing competition for scarce water resources. However, the amount of irrigation water reduction is based on crop characteristics, and the method used for irrigation plays a significant role in determining the efficiency of irrigation. Two different irrigation systems, drip, and furrow, are prevalent methods used to irrigate crops. While the drip system is more efficient, the furrow system can increase crop yields and water productivity under a deficit level of irrigation water. Therefore, comparing different irrigation methods for water saving, crop productivity, water productivity, and economic feasibility is necessary. Nevertheless, under deficit irrigation evaluations of different irrigation methods for water saving, crop productivity, water productivity, and economic feasibility has yet to be discovered. So, this study had comparable effects on drip and furrow irrigation systems under deficit irrigation levels. Those two different irrigation methods are ways used to irrigate crops. The drip system may have field-level application efficiencies of 70–90% as surface runoff, deep percolation losses and evaporation are minimized (Postel, 2000; Maisiri et al., 2005; Selim et al., 2013). Where as, furrow irrigation system from the total applied water 40–60% is effectively used by the crop, the remaining is lost in the system, in the farm, in the field, either through evaporation, through runoff or by deep percolation into the ground water (Criddle, 1956; Whittlesey, 2003; Kilemo, 2022). Reports showed that furrow irrigation system under deficit level of irrigation water is the option that can be increases crop yields and water productivity (Kifle and Gebretsadikan, 2016; Singh et al., 2010)

Limited water usage can lead to significant irrigation water savings and improved water productivity for various crops, including hot pepper (Enciso et al., 2009). However, hot pepper is particularly vulnerable to drought stress due to its wide range of transpiring leaf surfaces and high stomatal conductance, as well as its shallow root system (Zayzay Jr, 2015; Agliassa et al., 2021). To ensure high yields and sufficient water supply, moist soil is required throughout the growing season (Ismail and Ozawa, 2009; Agliassa et al., 2021). Hot pepper cultivation is prevalent in warm and semi-arid countries, including Ethiopia, where it is a high-value cash crop used in many ways (Dorji et al., 2005; Adametie and Mitku, 2021). In the Duanzebaguna irrigation scheme in Northwest Ethiopia, our study aimed to evaluate the furrow and drip irrigation systems under a deficit level of water for hot pepper fresh yield and water productivity. We also aimed to compare the effects of drip and furrow irrigation under a deficit level of water for potential water saving, optimum yield improvements and technical applicability.

Study Area description

This research study was conducted in Metekel zone, Benishangul-gumuz regional state. Metekel zone is the largest zone of the region, covering an area of 3,387,817 hectares, consisting of seven districts: Wombera, Bullen, Manbuk, Dibate, Mandura, Guba, and Pawe Woreda. The research activity took place in Mandura district, on Duanzebaguna irrigation scheme (Fig. 1). According to long term agroclimatic condition maximum and minimum temperature of the study area is 32.62 0^C and 16.4 0^C, respectively. The average annual rainfall and humidity also 1586.36 mm and 54.65%, respectively. The scheme is surrounded by scenic landscapes and rolling hills, making it an ideal location for farming. To conduct the experiment, the researchers selected a specific area within the irrigation scheme that met the criteria for the study. The area was chosen based on its accessibility, suitability for the crop being tested, and availability of resources.

Experimental design and treatment combinations

From the content provided, it appears that an experiment was conducted over two consecutive years to study the evaluations of different irrigation systems under deficit irrigation levels on the Duanzebaguna irrigation scheme. The experiment was designed using a split plot in a randomized complete blocks design with three replications. The main plots were devoted to two irrigation systems, furrow irrigation and drip irrigation, while the sub-plots were devoted to four levels of deficit irrigation, ranging from 55%, 70%, 85% and 100% ETc (Table 1).

It would be helpful to know more about the results of the experiment. Did the irrigation system or irrigation level have a significant effect on crop yield or water use efficiency? Further analysis and interpretation of the data would be necessary to draw any conclusions or make recommendations for optimal irrigation practices at the Duanzebaguna irrigation scheme.

In addition, it would be interesting to know if there were any challenges or difficulties encountered during the experiment, and how they were addressed. Sharing such information could help others who are planning similar experiments or facing similar challenges in their own agricultural practices.

Table 1

combinations of main plot, sub plot and treatments of experiment
Main plots (Irrigation methods)	Sub plots (Deficit irrigation levels)	Treatments
Drip Irrigation (DI))	100% Etc	T1
	85% Etc	T2
	70% Etc	T3
	55% Etc	T4
Furrow Irrigation (FI)	100% Etc	T5
	85% Etc	T6
	70% Etc	T7
	55% Etc	T8

Experimental Field Preparation and Irrigation

To ensure optimal crop growth, the field underwent meticulous preparation, including pre-irrigation to the maximum root depth of each individual plot. The field was organized into blocks and ridge lines that ran across the slope, with a total area of 882 m². The area was divided into 24 plots, each measuring 3m by 3m, accommodating five ridges with a 3m length each. To maintain consistency, the plots and blocks were separated by buffer zones of 2m and 3m in length, respectively. These buffer zones were intended to prevent lateral water movements between plots and blocks. The furrows were blocked at the end of the field to prevent surface runoff.

Two irrigations were provided to all plots to ensure adequate crop establishment. The first irrigation was given on the transplanting date, and the second irrigation was given after transplanting. Differential irrigation was then implemented based on the treatment. In furrow irrigation, the crop was allowed to utilize the allowable soil moisture depletion of the total available soil moisture in the root zone before the next irrigation. Similarly, in drip irrigation, the laterals were placed at the center of each row, with a 5cm distance from the plant. Each emitter had a flow rate of 2 L/hr.

Crop water requirements of hot pepper

Determining crop water requirements is a complex process that involves the consideration of multiple factors. It requires a thorough analysis of both the impact of climate on crop water requirements, such as the reference crop evapotranspiration (ETo), as well as the effect of crop characteristics (Kc) (Doorenbos and Kassam, 1979). To calculate crop water requirements using the CROPWAT model, it is necessary to collect long-term and daily climate data, such as maximum and minimum air temperature, relative humidity, wind speed, sunshine hours, and rainfall data of the study area. Additionally, crop data, such as crop coefficient, the growing season and development stage, effective root depth, critical depletion factor of pepper, maximum infiltration rate, and total available water in the soil must be determined.

The following formula is used to calculate crop evapotranspiration (ETc), crop coefficient (Kc), and reference evapotranspiration (ETo):

ETc = ETo x Kc (2.1)

By taking into account all of these factors, it is possible to accurately determine the water requirements for a given crop.

Determining Pepper's Water Requirements furrow vs drip

Determining the optimal water requirements for pepper crops is essential in achieving maximum yield and profitability. We utilized the CROPWAT 8.0 model to analyze climate data from the regional meteorological station. The results were used to estimate gross irrigation depth, which was determined to be 60% and 90% for furrow and drip, respectively, considering field irrigation application efficiency. We evaluated net irrigation depths, gross irrigation depth and time of watering based on a four-day average irrigation interval in the field.

Our team determined the total available water (TAW) stored in a unit volume of soil using a specific expression. We calculated the depth of irrigation supplied at any time using the IRn(mm) equation, which subtracts the effective precipitation (Peff) from the crop evapotranspiration (ETc). The gross irrigation requirement was obtained using the IRg expression, which factors in the application efficiency of the furrows (60%) and the drip (90%).

$$TAW=\frac{\left(\text{F}\text{C}-\text{P}\text{W}\text{P}\right)\text{*}\text{B}\text{D}\text{*}\text{D}\text{r}}{100}$$

2.2

The depth of irrigation supplied at any time can be obtained from the equation

IR_n(mm) = ETc(mm) – P_eff (mm) (2.3)

The gross irrigation requirement was obtained from the expression

IRg = $\frac{NI}{Ea}$ (2.4)

Ea = application efficiency of the furrows (60%) and drip (90%)

We calculated the time required to deliver the desired depth of water into each furrow using the equation, which considers gross depth of water applied (dg), application time (T), furrow length (L), furrow spacing (W), and flow rate (Q). We measured the amount of irrigation water applied at each irrigation event using the calibrated Parshall flume.

T = $\frac{LWdg}{6Q}$ (2.5)

Water Use Efficiency

We also calculated the water use efficiency (WUE), which is the yield harvested in kg per ha-mm of the total water used. The crop water use efficiency (WUE) was determined using the WUE equation, which considers the fresh pepper yield in kg ha^− 1 and crop evapotranspiration (ETc).

WUE = $\frac{Y\left(\frac{kg}{ha}\right)}{ETc\left(mm\right)}$ ( 2.6)

Where: WUE = crop water uses efficiency (kg/ha-mm) Y = fresh pepper yield in kg ha^− 1 and

ETc = Crop evapotranspiration (mm)

Crop Water Production Function for irrigation system on deficit irrigated water to pepper productivity parameters :

According to Vaux Jr and Pruitt (1983) and Bennett and Harms (2011)), agronomist develop on the crop water production function. Who aim to determine the optimal level of water inputs needed to achieve maximum yield per unit of land. In this study the functions of applied water to obtained crop parameters of pepper under drip and furrow irrigation system respectively were developed.

Agronomic Practices

During the crop growth period, we employed several agronomic practices, including fertilizers (Dap and Urea) applied at sowing, hand weeding, and cultivation. We collected daily climate data like maximum and minimum air temperature, relative humidity, wind speed, sunshine hours, and rainfall data to calculate crop water requirements. We determined soil moisture gravimetrically, and the amount of applied water per each irrigation event was measured using calibrated Parshall flume.

Data Collection

Daily climate like maximum and minimum air temperature, relative humidity, wind speed, sunshine hours and rainfall data were collected to calculate crop water requirement. Soil moisture was determined gravimetrically. Amount of applied water per each irrigation event was measured using calibrated Parshall flume. During harvesting Stand count, weight of marketable fresh fruit yield, fruit number of marketable yield, unmarketable fruit weight and unmarketable fruit number were measured from the net harvested area of each plot.

Statistical Analysis

We statistically analyzed the collected data using Statistical Agricultural Software (SAS 9.4), Microsoft excel and least significance difference (LSD) was employed to see a mean difference between treatments.

In Table 2, the usual composition of sand, silt and clay percentages in order to effective root depths 0 to 30, 30 to 60 and 60 to 90 respectively were recorded. Thus, obtained result deliberating to the USDA soil textural classification the experimental site soil in depth was classified as clay loam. The average soil bulk density and water holding capacity were 1.4g/cm³ and 0.12cm/cm respectively.

Table 2

physical properties of soil for experimental site
Depth (cm)	Result/parameter tested Texture
Depth (cm)	Clay (%)	Silt (%)	Sand (%)	Texture class	Bd g/cm3	PWp (%)	FC (%)	Available water cm/cm
0–30	38	20	42	Clay loam	1.44	23.6	35.9	0.12
30–60	38	24	38	clay loam	1.44	23.6	35.9	0.12
60–90	44	24	32	clay loam	1.41	26.8	39	0.12
Note: Bd, Fc and Pwp are bulk density field capacity and permanent wilting point respectively

Determining Pepper's Water Requirements furrow vs drip

The simulation results from CROPWAT confidently provide the net irrigation depths and gross irrigation depth required for pepper crops. Taking into account the climate and crop characteristics data, we estimated the gross irrigation depth to be 60% and 90% for furrow and drip irrigation systems, respectively, considering the field irrigation application efficiency. In this study area, the seasonal pepper crop water requirements were determined to be 454.1mm and 681.2mm for drip and furrow irrigation systems, respectively, representing 100% of the ETC. Moreover, in (Table 3) the deficit irrigation values for drip were confidently calculated to be 386.0mm, 317.9mm, and 249.8mm for 85%ETC, 70%ETC, and 55%ETC, respectively. Similarly, for furrow irrigation, the deficit irrigation values were determined to be 579.0mm, 476.8mm, and 374.7mm for 85%ETC, 70%ETC, and 55%ETC, respectively.

Table 3

Pepper net irrigation water requirement (Net.Irr) and gross depth water requirements under application efficiency (A.E) of 90% and 60% for drip and furrow irrigation system respectively
	Net. Irr	Drip 90% A.E (ETC mm)				Furrow system 60% A.E (ETC mm)
Stage	Mm	100%	85%	70%	55%	100%	85%	70%	55%
Init	9.6	10.7	9.1	7.5	5.9	16.0	13.6	11.2	8.8
Init	11.5	12.8	10.9	9.0	7.0	19.2	16.3	13.4	10.6
Init	13.5	15.0	12.8	10.5	8.3	22.5	19.1	15.8	12.4
Init	16.1	17.9	15.2	12.6	9.9	26.9	22.9	18.8	14.8
Dev	17.6	19.5	16.6	13.7	10.7	29.3	24.9	20.5	16.1
Dev	23.3	25.9	22.0	18.1	14.2	38.8	33.0	27.2	21.3
Dev	28.1	31.2	26.5	21.8	17.2	46.8	39.8	32.8	25.7
Dev	38.2	42.5	36.1	29.7	23.4	63.7	54.1	44.6	35.0
Mid	38.6	42.9	36.4	30.0	23.6	64.3	54.7	45.0	35.4
Mid	40.5	45.0	38.3	31.5	24.8	67.5	57.4	47.3	37.1
Mid	41.5	46.1	39.2	32.2	25.3	69.1	58.7	48.4	38.0
Mid	37.7	41.9	35.6	29.3	23.0	62.8	53.4	44.0	34.5
Mid	38.1	42.3	36.0	29.6	23.3	63.5	54.0	44.5	34.9
end	54.5	60.5	51.5	42.4	33.3	90.8	77.2	63.6	49.9
Total	408.7	454.1	386.0	317.9	249.8	681.2	579.0	476.8	374.7

Evaluations of irrigation system (Drip Vs Furrow) for Pepper productivity

A study was conducted to evaluate the impact of two irrigation systems, drip and furrow, on the growth and yield of pepper plants. The outcome of the combined analysis conducted over a span of two years, regarding the impact of different irrigation systems on plant height, total fresh fruit yield, and unmarketable fresh fruit yield were not significantly different between the two systems, there were some notable exceptions (Table 4). The result of the combined analysis for plant height after two years of observation did not show any significant difference in relation to the irrigation system. The plant height outcomes for the drip and furrow irrigation systems were 50.09 cm and 50.01 cm, respectively (as shown in Table 3). Whereas, the marketable fresh fruit yield and water use efficiency were significantly higher in the drip irrigation system compared to the furrow irrigation system. The obtained marketable fresh fruit yield showed that 6226.1 and 5284.5 kg/ha for drip and furrow irrigation respectively. Similarly for water use efficiency 20.678 and 12.827 kg/m³ for drip and furrow irrigation respectively. In fact, the drip irrigation system increased plant height, total fresh fruit output, marketable fresh fruit yield, and water usage efficiency in comparison to the furrow irrigation system. The only area where the furrow irrigation system outperformed the drip irrigation system was in the production of unmarketable fresh fruit yield.

These findings indicate that the drip irrigation system is a more efficient and effective method for growing peppers, providing higher yields of marketable fruit while using water more efficiently. This is particularly important in areas where water is scarce or expensive. The study results could be valuable for farmers and gardeners seeking to optimize their pepper crop yields.

Table 4

Comparative effects of irrigation method (MI) for Plant height, Fruit yield, Marketable fruit yield, Unmarketable fruit yield, and water use efficiency
MI	PH (Cm)	FY (kg/ha)	MFY (kg/ha)	UMFY (kg/ha)	WUE (kg/ha/mm)	WP (kg/m³)
DI	50.09a	7440.8a	6226.1a	1214.7a	20.678a	2.06
FR	50.01a	6789a	5284.5b	1504.5a	12.827b	1.28
Mean	50.1	7114.9	5755.3	1359.6	16.75	1.67
CV	0.98	13.17	5.88	67.1	6.53	6.46
SE±	0.2	382.63	138.2	372.45	0.44	0.04
LSD_0.05	NS	NS	*	NS	**	*
Note, MI, PH, FY, MFY, UMFY, WUE, DI and FI, were, Method of irrigation, Plant height, Fruit yield, Marketable fruit yield, Unmarketable fruit yield, water use efficiency, Drip irrigation and furrow irrigation respectively

Evaluations of deficit irrigation for pepper production

The influence of deficit irrigation levels during the cropping seasons on plant height was found to be substantial. The tallest plants, measuring 55.4 cm, were produced under full irrigation conditions, while the shortest plants, measuring 42.5 cm, resulted from a 55% shortfall in irrigation (as shown in Table 4). Further analysis revealed highly linear correlations between the amount of water applied and plant height for both the drip and furrow irrigation systems (as depicted in Fig. 4 (A) and (B)). The correlation coefficient (R2) for the relationship between applied water and plant height was found to be 0.9768 and 0.9785 for the drip and furrow systems, respectively. This indicates that the level of irrigation water applied directly affects plant height.

In the same way, the findings showed that the deficit irrigation significantly affected the production of marketable fresh fruit. The highest yield of marketable fresh fruit was obtained under full irrigation, while the lowest production occurred at 55% of ETc. The study also revealed that deficit irrigation had a significant impact on the production of unsalable fresh fruit. However, there was no noticeable difference in the production of unsalable fresh fruit between 70% and 55% ETc. Additionally, the study observed a negative impact of the overall fresh fruit production of hot pepper under deficit irrigation. It emphasized the importance of maintaining adequate irrigation levels to achieve a higher yield of marketable fresh fruit in pepper cultivation. The study further demonstrated that the deficiency of irrigation had a significant impact on the production of marketable fresh fruit. The highest yield of marketable fresh fruit, measuring 9560.2 kg/ha, was obtained under full irrigation, while the lowest commercial fruit production, measuring 4199.7 kg/ha, was obtained at 55% of ETc. The deficit irrigation level had a substantial impact on the production of unsalable fresh fruit, but there was no discernible difference between 70% and 55% ETc. The amount of irrigation had a considerable negative impact on the overall fresh fruit output of hot pepper. On the other hand, WUE and water productivity were not significant difference as deficit irrigation except 55% ETc. Thus, showed that 15% and 30% water amount reduced statistically not influenced water use efficiency and water productivity. While, the water reduced by 45% water use efficiency was minimum. The results of this finding were in agreement with Sezen et al. (2015) who reported that deficit irrigation is affected yield quality of red pepper, WUE and other yield and yield parameters.

Table 5

Effects of deficit irrigation (ETC %) for plant height, fresh fruit yield, marketable fresh fruit yield, unmarketable fresh fruit yield, water use efficiency and water productivity of pepper production
LI (%)	PH (cm)	FY (kg/ha)	MFY (kg/ha)	UMFY (kg/ha)	WUE (kg/ha/mm)	WP (kg/m³)
100	55.417a	9560.2a	8543a	1017.2a	17.911a	1.8a
85	51.867ab	7691.2b	6693.9b	997.2a	16.68a	1.65a
70	50.433b	7008.5b	5013.1c	1995.5a	18.547a	1.85a
55	42.5c	4199.7c	2771.3d	1428.4a	13.872b	1.38b
Mean	50.05425	7114.9	5755.325	1359.575	16.7525	1.67
SE±	1.8	509.15	652.52	724.26	1.13	0.11
LSD	**	**	**	NS	**	*
Note, LI, PH, FY, MFY, UMFY and WUE, were, Level of irrigation, Plant height, Fruit yield, Marketable fruit yield, Unmarketable fruit yield and water use efficiency respectively

Evaluations of crop water production function (drip vs furrow) to deficit irrigation for pepper productivity parameters

The relationship between crop production and water received is called as crop water production function. According to Vaux Jr and Pruitt (1983) and Bennett and Harms (2011), agronomists and other production-oriented scientists is frequently directed at the goal of establishing the level of water inputs necessary to achieve maximum yield per unit land. The findings of this study were presented in Fig. 5, it is evident that there is a strong positive correlation between the amount of water applied and plant height, total fresh fruit yield, and marketable fresh fruit yield. This correlation holds true for both drip and furrow irrigation systems. However, the correlation between applied water and unmarketable fresh fruit yield is weak. The results suggest that reducing water application through deficit irrigation techniques can be an effective strategy to minimize yield loss and maintain the quality of peppers. However, it is important to note that excessive water deficit can negatively impact yield and quality for both irrigation systems. Therefore, it is crucial to carefully manage water use in agriculture to optimize crop yield and quality.

.

Interaction Effects of Irrigation method with irrigation Level for Pepper production

The study discovered that the interaction of irrigation method and level has a significant influence on plant height, fresh fruit yield, marketable fresh fruit yield, water use efficiency, and water productivity of pepper production. However, there was no significant difference in the unmarketable fresh fruit yield among treatments.

Furthermore, the research found that the drip irrigation system with 100% ETc (T1) had the highest plant height, while the furrow irrigation system with 55% ETc (T8) had the shortest. Interestingly, the (DI*100% ETC) and (FR*100% ETc) treatments had a similar impact on pepper plant height. However, the other treatments had varying outcomes due to the effects of deficit irrigation level orderly.

The interaction effects of total fresh fruit yield, marketable fresh fruit yield, water use efficiency, and water productivity showed that the treatment with drip irrigation system and 100% ETc (T1) had a significant difference compared to the other treatments. Thus, treatment drip irrigation system with 100% ETc (T1) resulted in a total fresh fruit yield of 10562 kg/ha followed the treatment furrow irrigation system with 100% ETc (T5) observed resulted was 8558 kg/ha. On the other hand, the smallest fresh fruit yield was (DI*55 (T4)) 3990kg/ha followed by (FR*55 (T9)) 4409 kg/ha statically similar impacts. The rest treatment also observed statically similar ranks on obtained fresh fruit yield of pepper.

The highest yield of marketable fresh fruit for pepper, statically among treatments (DI*100 (T1)), was obtained at 9494.4 kg/ha. Besides, the results obtained from T5 (FR*100) and T6 (FR*85) indicate a yield of 7591.6 kg/ha and 6034.6 kg/ha respectively, thereby providing substantial evidence for the lack of technical feasibility of drip irrigation in large-scale agricultural operations and the resulting economic consequences in the study area optional result. There were no significant differences among treatments in terms of unmarketable fresh fruit yield. However, the highest unmarketable fruit yield for pepper was achieved at DI*55 (T4) with 1804.7 kg/ha, followed by FR*70 (T7) with 1479.2 kg/ha. The total fresh fruit yield within each treatment was affected by the irrigation system and the interactions of irrigation level, resulting in a loss of 10.1%, 6.6%, 20.0%, 45.2%, 11.3%, 19.7%, 22.8%, and 23.9% for DI*100 (T1), DI*85 (T2), DI*70 (T3), DI*55 (T4), FR*100 (T5), FR*85 (T6), FR*70 (T7), and FR*55 (T9) respectively, confidently emphasizing the impact of the irrigation system and level of irrigation. Similar finding to support this research (Sezen et al., 2015) who was reported deficit irrigation level affected yield quality of red pepper in both irrigation system.

Table 6

Interaction effects of irrigation level with irrigation method for plant height, fresh fruit yield, marketable fresh fruit yield, unmarketable fresh fruit yield, water use efficiency and water productivity of pepper production
MI*LI	PH (cm)	FY (kg/ha)	MFY (kg/ha)	UMFY (kg/ha)	WUE (kg/ha/mm)	WP (kg/m³)
DI*100 (T1)	55.567a	10562a	9494.4a	1067.9a	23.258a	2.33a
DI*85 (T2)	52.53ab	7869bc	7353.3b	515.2a	20.384a	2.03a
DI*70 (T3)	49b	7342bc	5871.2bc	1470.8a	23.096a	2.3a
DI*55 (T4)	43.27c	3990d	2185.6e	1804.7a	15.976b	1.6b
FR*100 (T5)	55.27a	8558ab	7591.6b	966.5a	12.563bc	1.26bc
FR*85 (T6)	51.2ab	7514bc	6034.6bc	1479.2a	12.977bc	1.26bc
FR*70 (T7)	51.87ab	6675c	5154.9c	1520.2a	13.999bc	1.4bc
FR*55 (T9)	41.73c	4409d	3357de	1052.1a	11.768c	1.16c
Mean	50.05425	7114.875	5755.325	1359.4625	16.752625	1.67
CV	12.39	12.39	19.64	92.67	11.68	11.8
LSD(0.05)	*	**	**	NS	**	**
Note, MI*LI, PH, FY, MFY, UMFY, WUE, DI and FI, were, Method of irrigation with level of irrigation, Plant height, Fruit yield, Marketable fruit yield, Unmarketable fruit yield, water use efficiency, Drip irrigation and furrow irrigation respectively

Evaluations of Irrigation method (drip vs furrow) under irrigation Level for Peper water usage

The combined result (Table 7) shows that among treatments the highest and lowest WUE were drip irrigation (DI*100% ETc) and furrow irrigation (FR*55% ETc) respectively not only water use efficiency but also water productivity of pepper. The results of this finding were in agreement with Conde et al. (2023); (Sezen et al., 2015) who reports drip irrigation has been found to be more efficient than furrow irrigation in terms of water usage. So as to do similar irrigation system this finding result was similar with who reported that WUE values decreased with increasing irrigation water.

In other words, considering avail water resource, technical skill and cost of material drip irrigation system water reduced to 30% shows obtaining high water use efficiency, without significant yield reduction. However, technically unskilled farmers for install drip irrigation this study set out options for furrow irrigation with deficit irrigation amount up to 15% can obtain good water efficiency without maximum fresh yield reductions of pepper.

Table 7

Interaction effects of irrigation level with irrigation method for total fruit yield, crop water requirement, applied water, water use efficiency, water productivity, yield reduction and water saving
MI*LI	Total fruit Yield (kg/ha)	CWR (mm)	Applied water(m³/ha)	WUE (kg/ha/mm)	WP (kg/m³)	Yield reduction (%)	Water saving (%)
DI*100	10562	454.13	4541.3	23.3	2.33	0	0.0
DI*85	7869	386.01	3860.1	20.4	2.03	34	17.6
DI*70	7342	317.89	3178.9	23.1	2.3	44	42.9
DI*55	3990	249.77	2497.7	16.0	1.6	165	81.8
FR*100	8558	681.2	6812	12.6	1.26	23	-33.3
FR*85	7514	579.02	5790.2	13.0	1.26	41	-21.6
FR*70	6675	476.84	4768.4	14.0	1.4	58	-4.8
FR*55	4409	374.66	3746.6	11.8	1.16	140	21.2
Note, MI*LI, WUE, DI and FI, were, Method of irrigation with level of irrigation, water use efficiency, Drip irrigation and furrow irrigation respectively

Effects of irrigation system, deficit irrigation and interaction of the two on Plant height of pepper

Plant height is a significant growth parameter for crops, which is affected by multiple factors such as genetic makeup, nutrient availability, climate, and soil (Terefa, 2017; AbdelRahman et al., 2016). The experiment studied the effects of irrigation systems and deficit irrigation on the plant height of pepper. The combined analysis of two years showed that there was no significant difference in plant height between drip and furrow irrigation systems, but a significant difference was observed in plant height due to deficit irrigation and the interaction effects of the two systems.

The average plant height for the drip and furrow irrigation systems was 50.09 cm and 50.01 cm, respectively. The full irrigation level produced the tallest plants, whereas a 55% shortfall produced the shortest plants. These findings were consistent with previous studies that indicated a reduction in plant height of pepper with lower irrigation levels (Sezen et al., 2014) and (Sezen et al., 2015).

The interaction effects of the irrigation system with deficit irrigation showed that the highest and shortest plant heights were observed for drip irrigation with 100% ETc and furrow irrigation with 55% ETc, respectively. Both drip and furrow irrigation systems had a highly linear correlation between applied water and plant height. The relationship between applied water and plant height was 97.68% and 97.85% for drip and furrow irrigation systems, respectively. This result indicates that plant height decreases with a decrease in the irrigation level.

Effects of irrigation system, deficit irrigation and interaction of the two on fresh fruit yield of pepper

The main aim of this experiment was to increase fresh fruit yield of pepper for deficit water area by simple utilized technology. Those trial technology was comparative effects of drip and furrow irrigation system both under on deficit irrigation. The interaction effects of total fresh fruit yield, marketable fresh fruit yield, water use efficiency, and water productivity revealed that the utilization of a drip irrigation system and 100% ETc (T1) led to a statistically significant difference compared to the remaining treatments. As a result, the implementation of a drip irrigation system with 100% ETc (T1) demonstrated a substantial difference in total fresh fruit output compared to the other treatments. Conversely, the minimal fresh fruit yield was recorded as 3990 kg/ha for (DI*55 (T4)), followed by (FR*55 (T9)) at 4409 kg/ha, showcasing similar impacts. The highest marketable fresh fruit yield for pepper, observed to be 9494.4 kg/ha, was attained under treatment (DI*100 (T1)), exhibiting statistical significance among the treatments. Additionally, the outcomes from T5 (FR*100) and T6 (FR*85) indicated yields of 7591.6 kg/ha and 6034.6 kg/ha respectively, highlighting compelling evidence regarding the impracticality of implementing drip irrigation in extensive agricultural practices and the subsequent economic implications within the research area as an alternative outcome.

The study evaluates drip and furrow irrigation methods under deficit irrigation on pepper productivity in Northwest Ethiopia. The obtained Plant height, total fresh fruit yield, and unmarketable fresh fruit yield did not significantly differ between drip and furrow irrigation systems. However, the drip irrigation system showed significant improvements in marketable fresh fruit yield and water use efficiency compared to the furrow irrigation system. Reducing water application through deficit irrigation techniques was found to be effective in minimizing yield loss and maintaining pepper quality. However, excessive water deficit can negatively impact yield and quality for both irrigation systems. The correlation between applied water and plant height, total fresh fruit yield, and marketable fresh fruit yield was strong for both irrigation systems.

The study concluded that the drip irrigation system is more efficient and effective for growing peppers, providing higher yields of marketable fruit while using water more efficiently. The interaction effects of total fresh fruit yield, marketable fresh fruit yield, water use efficiency, and water productivity showed that the treatment with drip irrigation system and 100% ETc (T1) had a significant difference compared to the other treatments. Thus, treatment drip irrigation system with 100% ETc (T1) resulted in a total fresh fruit yield of 10562 kg/ha followed the treatment furrow irrigation system with 100% ETc (T5) observed resulting was 8558 kg/ha. On the other hand, the smallest fresh fruit yield was (DI*55 (T4)) 3990kg/ha followed by (FR*55 (T9)) 4409 kg/ha statically similar impacts. The highest yield of marketable fresh fruit for pepper, statically among treatments (DI*100 (T1)), was obtained at 9494.4 kg/ha. Besides, the results obtained from T5 (FR*100) and T6 (FR*85) indicate a yield of 7591.6 kg/ha and 6034.6 kg/ha respectively, thereby providing substantial evidence for the lack of technical feasibility of drip irrigation in large-scale agricultural operations and the resulting economic consequences in the study area optional result.

Acknowledgment

Firstly, we would like to thank the almighty GOD for keeping us brave and inspired for the compilation of this work. We thank Ethiopian Meteorological Service Agency (EMSA) and Pawe Agricultural Research Center (PARC) soil laboratory for providing meteorological data and soil parameter data respectively.

Author Contributions:

Temesgen F. Adamtie was responsible for data collection, methodology, software, interpretation, investigation, and original manuscript preparation. Abeba H. Selie managed the data and drafted the manuscript. Demeke T. Mitku, reviewed and edited the manuscript, provided discussions, and visualizations, and wrote the final draft.

Availability of data and materials

The data used to support the findings of this study can be accessed from the corresponding author upon request.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare there is no competing interest.

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Evaluations of drip and furrow irrigation method under deficit irrigation for pepper productivity in Northwest Ethiopia

Status:

Version 1

Abstract

Figures

Introduction

Materials and Methods

Study Area description

Experimental design and treatment combinations

Experimental Field Preparation and Irrigation

Crop water requirements of hot pepper

Determining Pepper's Water Requirements furrow vs drip

T = \(\frac{LWdg}{6Q}\) (2.5)

Water Use Efficiency

WUE = \(\frac{Y\left(\frac{kg}{ha}\right)}{ETc\left(mm\right)}\) ( 2.6)

Agronomic Practices

Data Collection

Statistical Analysis

Results And Discussion

Determining Pepper's Water Requirements furrow vs drip

Evaluations of irrigation system (Drip Vs Furrow) for Pepper productivity

Evaluations of deficit irrigation for pepper production

.

Interaction Effects of Irrigation method with irrigation Level for Pepper production

Evaluations of Irrigation method (drip vs furrow) under irrigation Level for Peper water usage

Conclusions

Declarations

References

Additional Declarations

Status:

Version 1

Evaluations of drip and furrow irrigation method under deficit irrigation for pepper productivity in Northwest Ethiopia

Status:

Version 1

Abstract

Figures

Introduction

Materials and Methods

Study Area description

Experimental design and treatment combinations

Experimental Field Preparation and Irrigation

Crop water requirements of hot pepper

Determining Pepper's Water Requirements furrow vs drip

T = \(\frac{L*W*dg}{6Q}\) (2.5)

Water Use Efficiency

WUE = \(\frac{Y\left(\frac{kg}{ha}\right)}{ETc\left(mm\right)}\) ( 2.6)

Agronomic Practices

Data Collection

Statistical Analysis

Results And Discussion

Determining Pepper's Water Requirements furrow vs drip

Evaluations of irrigation system (Drip Vs Furrow) for Pepper productivity

Evaluations of deficit irrigation for pepper production

.

Interaction Effects of Irrigation method with irrigation Level for Pepper production

Evaluations of Irrigation method (drip vs furrow) under irrigation Level for Peper water usage

Conclusions

Declarations

References

Additional Declarations

Status:

Version 1

T = \(\frac{LWdg}{6Q}\) (2.5)