




































 

 

 
83 

© 2019 Conscientia Beam. All Rights Reserved. 

OPTIMAL RATE OF NITROGEN AND INTRA-ROW SPACING FOR ECONOMICAL 
PRODUCTION OF ONION UNDER IRRIGATED FARMING SYSTEM IN EASTERN 
AMHARA REGION, ETHIOPIA   

 

 Alebachew 
Merawie1+ 

 Melkamu 
Alemayehu2 

 Biruk Masrie3 

 

1North Wollo Zone Agriculture Department Office, Woldia, Ethiopia. 

 
2College of Agriculture and Environmental Sciences, Bahir Dar University, 
Bahir Dar, Ethiopia. 

 
3Woldia University, Colleges of Agriculture, Woldia, Ethiopia. 

 
 

 
(+ Corresponding author) 

 ABSTRACT 
 
Article History 
Received: 13 February 2019 
Revised: 18 March 2019 
Accepted: 23 April 2019 
Published: 10 July 2019 
 
 
 

Keywords 
Allium cepa L. 
Bombay red 
Bulb yield 
Spacing 
Vegetative growth. 

 
Onion is one of the most important cash crops produced by smallholder farmers mainly 
during the irrigation season. However, the productivity of onion in Amhara Region is 
very low which is mainly associated with improper agronomic practices. This research 
was therefore conducted to increase the productivity of onion by identifying the 
optimum rate of nitrogen and intra-row spacing for economical production of the crop 
in Alawuha Small-Scale Irrigation Scheme. Four rates of nitrogen (0, 41, 82, 123 kg ha-
1) and three intra-row spacing (6, 8, 10 cm) in factorial combination were laid out in 
Randomized Complete Block Design with three replications. Results indicated that 
nitrogen and intra-row spacing significantly influenced most of the growth and 
phenological parameters of onion where application of 123 kg ha-1 nitrogen increased 
leaf number by 67.3% and prolonged days to maturity of onion by about 7 days 
compared to the respective control plants. Similarly, nitrogen rate and intra-row 
spacing significantly affected bulb yield of onion where the highest marketable bulb 
yield (37.48 t ha-1) was recorded by application of 123 kg ha-1 on plants spaced at 6 cm 
intra-row spacing which was statistically similar with those yield (35.07 t ha-1) 
recorded with the combination of 82 kg ha -1 nitrogen and 6 cm intra-row spacing. 
Application of 123 kg ha-1 nitrogen on plants spaced at 6 cm intra-row spacing is 
recommended for production of onion in Alawuha Small-Scale Irrigation Scheme as it 
recorded the highest net benefit (Eth-Birr 429,569) with relatively high marginal rate 
of return.  
 

Contribution/Originality: This study is one of very few studies which have investigated the influence of 

nitrogen rate and intra-row spacing on the bulb yield of onion in Amhara Region. Therefore, the findings of the 

present study will contribute to the improvement of production and productivity of onion in Eastern Amhara, 

Ethiopia. 

 

1. INTRODUCTION 

Onion (Allium cepa L.) belongs to the genus Allium of the family Alliaceae [1]. It was probably originated in 

central Asia between Turkmenistan and Afghanistan where some of its relatives are still growing as wild plants 

[2]. The crop was introduced to South-East Asia, Mediterranean areas and Roman Empire [3].  

Onions contribute significant nutritional value to the human diet and have medicinal properties. They are 

primarily consumed for their unique flavor to enhance the flavors of foods [4]. In Ethiopia, the onion is one of the 

most important vegetables produced by smallholder farmers mainly as a source of cash income and for flavoring the 

local stew ‘wot’ [5]. In the country, the crop is believed to be more intensively consumed than any other vegetable 

Current Research in Agricultural Sciences 
2019 Vol. 6, No. 2, pp. 83-94 
ISSN(e): 2312-6418 
ISSN(p): 2313-3716 
DOI: 10.18488/journal.68.2019.62.83.94 
© 2019 Conscientia Beam. All Rights Reserved. 

 
 
 

 
 

 

 
 
 
 

https://orcid.org/0000-0002-5634-1168
https://orcid.org/0000-0003-1080-2245
https://orcid.org/0000-0002-5861-991X
https://www.doi.org/10.18488/journal.68.2019.62.83.94


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84 

© 2019 Conscientia Beam. All Rights Reserved. 

crops [6]. Moreover, the onion contributes to the commercialization of the rural economy and creates jobs 

opportunities for young people in the country [7].  

Onion is produced both under irrigation and rain fed conditions in Ethiopia as well as in Amhara Region [5] 

The bulk of onion produced in Amhara Region comes from this region where cultivation is mainly carried out using 

irrigation [8]. The productivity of onion in the region [9] as well as in Ethiopia is however very low (9.74 t ha-1) 

compared to the world’s average (19.3 t ha-1) as indicated by Central Statical Agency [10] and Food and 

Agriculture Organization [11]. Land degradation mainly due to the rapidly growing population and lack of soil 

fertility management and improper agronomic practices, diseases and insect pests and poor extension services are 

among other the main challenges that lead to low levels of vegetables including onion in Amhara Region as well as 

in the country [9].  

Implementing appropriate agronomic practices including application of fertilizer and proper spacing has an 

undoubted contribution for crop yield increment including onion where optimum fertilizer rates and plant spacing 

vary with the type of crops, environmental conditions and soil fertility of the area.  Nitrogen is one of the most 

important nutrients required for growth and development of plants as it is the  component of proteins, enzymes, 

and vitamins in plants and as well as central part of essential photosynthetic molecule and chlorophyll [12]. The 

requirement of plants for nitrogen is mostly satisfied either from soil and or application of nitrogen fertilizer. In this 

regard, Minister of Agriculture [13] recommended the application of 92 kg ha-1 P2O5 and 46 kg ha-1 N for 

production of onion in Ethiopia without considering the soil fertility and the environmental conditions. While 

nitrogen application is known to increase yield of onions, many researchers on the other hand, found that high 

levels of nitrogenous fertilizer reduced onion storage life [14] delayed bulb maturity and increased bolting, which 

are undesirable characteristic of onion [15].  

Spacing is an important aspect regarding onion production and quality. Researchers indicated that wider 

spacing helped the individual plant to utilize more water, nutrients, air and light for their growth and development 

than those closer spaced plants [16]. Optimization of plant population is therefore important to avoid competition 

between plants for growth factors as well as to utilize available cropland efficiently without wastage [17]. In this 

regard, Ethiopian Agricultural Research Organization [18] recommended the spacing of 40 cm x 20 cm x 10 cm 

between furrows, row and plants, respectively, for the production of onion in Ethiopia without considering the 

status of soil fertility and environmental conditions of the growing areas. However, onion bulbs produced using this 

intra-row spacing are mostly bigger in size (>160 g) which are not preferred by consumers for home consumption 

[19]. According to Tegen, et al. [19] the proportion of medium-sized bulbs which are preferred by consumers was 

low at this intra-row spacing. In this regard, Dessalegn and Aklilu [5] reported that availability of full information 

packages including optimum rate of nitrogen and intra-row spacing for each growing areas is paramount important 

to increase production and productivity of onion. In view of these, the present study was initiated to determine the 

optimum fertilizer rate and intra-row spacing for economical production of onion in Eastern Amhara Region. 

 

2. MATERIALS AND METHODS 

2.1. Description of the Study Area  

A field study was conducted during the 2017/2018 from October to January under irrigation in Alawuha 

Model Nursery Site at Doro Giber Kebele of Gubalafto district, Northeastern Ethiopia. Experimental site is located 

at 11°53'N latitude and 38°51'E longitude Figure 1 with the altitude of 1510 meter above sea level. Alawuha is 

characterized by bimodal and erratic rainfall that varies widely from 800-1050 mm in year where a short rainy 

season is occurred between February and April, and a long rainy season is occurred between June and 

September. Gubalafto district has vast plain land suitable for large scale irrigated agriculture and livestock 

production where the soil is mostly clay loam in texture. The mean monthly minimum and maximum 

temperatures are 20oC and 22.5oC, respectively.  



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2.2. Experimental Treatments, Design and Procedures  

The treatments consisted of four levels of nitrogen (0, 41, 82, and 123 kg ha-1) and three intra- row spacing (6, 

8, and 10 cm) which were factorial combined in Randomized Complete Block Design (RCBD) with three 

replications. The size of each plot was 3 m x 1.5 m which accommodated ten single rows with 250, 188, and 150 

plants per plot for the intra-row spacing of 6, 8 and10 cm, respectively. The distance between plots and blocks were 

1 m and 1.5 m, respectively.  

  

 
Figure-1. Map of the study area. 

                       Source:: Gubalafto District Agricultural Office (2017)  

 

Seedlings of Bombay Red variety of onion were grown on well prepared nursery beds using the recommended 

management practices. The variety is well adapted and widely cultivated in the study area. Before seedling 

transplanting, experimental field was ploughed, pulverized, and leveled and a total of 36 experimental plots were 

prepared where the size of each plot was 3 m x 1.5 m and accommodated ten single rows with 250, 188, and 150 

plants per plot for the intra-row spacing of 6, 8 and10 cm, respectively. The distance between plots and blocks were 

1 m and 1.5 m, respectively. 

After 45 days healthy, vigorous and uniform-sized seedlings were transplanted on the experimental field with 

double row planting system at the spacing of 40 x 20 cm between irrigation furrows (double row) and rows of 

plants, respectively, as well as 6, 8 and 10 cm between plants in the rows based on the treatments. 

Triple super phosphate was applied as sources of phosphorous at the rates of 92 kg ha-1 P2O5 for all plots 

uniformly during transplanting as recommended by Minister of Agriculture [13]. Based on the treatments, about 

50% of predetermined nitrogen rate was applied as side dressing at 20 days after transplanting, while the remaining 

half of nitrogen was applied four weeks after transplanting [20].  



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2.3. Soil Sampling 

Soil samples were taken from five representative points of the experimental site at the depth of 0-30 cm and 

composite soil sample was prepared. The composite sample was sub-divided into working samples, air dried, lightly 

crushed with wooden pestle and screened to determine the physicochemical properties of the soil.  Soil analysis was 

carried out at Sirinka Agricultural Research Center Soil laboratory based on the standard methods. The total 

nitrogen, available phosphorus and organic matter content, soil pH, organic carbon, cation exchange capacity 

(CEC), Electric Conductivity (EC) and soil texture were analyzed from the composite soil sample.  

 

3. DATA COLLECTION AND ANALYSIS 

3.1. Growth Parameters 

Plant height (cm): Plant height was measured using ruler from the soil surface to the tip of longest leaf of ten 

randomly selected plants grown in the net plot area at physiological maturity and the mean values were computed 

for further analysis. 

Number of leaves: The total number of leaves was counted from ten randomly selected plants grown in the 

net plot area during physiological maturity and mean values per plant were computed and used for further analysis.   

Days to maturity (Days): It was determined by counting the number of days elapsed from date of 

transplanting to the date when 75% of the plants in each plot showed yellowing of leaves and bent at the neck.. 

 

3.2. Yield Components 

Bulb weight (g): The fresh weights of ten randomly selected bulbs harvested from the net plot area were 

measured using sensitive balance and the mean values used for further analysis. 

Marketable yield (t/ha): Onion bulbs harvested from the net plot area that  were free of mechanical, disease 

and insect pest  damages, physiological disorders, discolorations and that ranges from  20 g to 160 g in weight  

were  considered as marketable as described by Lemma and Shimeles Dessalegn and Aklilu [5] and Morsy, et al. 

[21]. The weight of such bulbs was weighed using sensitive balance and expressed in ton per hectare.  

Unmarketable yield (t/ha): Bulbs which were under as well as over sized (<20g and >160g), misshaped, 

decayed, discolored, diseased and physiologically disordered were considered as unmarketable as described by 

Dessalegn and Aklilu [5]. The weights of such bulbs obtained from the net plot area were measured using sensitive 

balance and expressed in ton per hectare. 

Total bulb yield (t/ha): The total bulb yield was obtained as summation of marketable and unmarketable 

yields.  

The collected data were subjected to analysis of variance (ANOVA) as described by Gomez and Gomez [22] 

using Statistical Analysis Software (SAS, 2004, version 9.0). Treatment mean separation was done using Fisher’s 

Least Significant Differences (LSD) test at 1% or 5% levels of significance depending on the results of ANOVA.  

 

3.3. Economic Analysis 

To evaluate the economic feasibility of the treatments economic analysis in the form of partial budget analysis 

and marginal rate of return was done using the procedures described by CIMMYT [23]. The cost of urea, seed and 

the labor required for placement of fertilizer and transplanting of seedling was used as variable cost where the 

market prices of fertilizer, seed and cost of labor as well as farm gate price of marketable onion were taken from 

market assessment during the experimental period.  

 

 

 

 



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4. RESULTS AND DISCUSSION 

4.1. Selected Soil Physico-chemical Properties of the Study Area  

The results of laboratory analysis of the experimental soil are presented below Table 1. Accordingly, the soil of 

the experimental site was clay loam in texture with slightly acidic pH [24]. The soil had medium total nitrogen and 

high phosphorous content as indicated by Tadesse [25] and Hazelton and Murphy [26]. According to Donald, et 

al. [27] the organic matter content of the experimental soil was moderate while Cation exchange capacity and 

electrical conductivity were high and low, respectively [26].  Based on the laboratory results, the experimental soil 

was generally suitable for onion production. 

 
Table-1. Physico-chemical properties of the experimental soil. 

Soil properties Unit Value Rating Sources 

Total N % 0.16 Medium Tadesse [25] 
Total available P ppm 29.65 High Hazelton and Murphy [26] 

pH - 6.6 Slightly acidic Savva and Frenken [24] 
Cation exchange capacity Cmol(+)/kg 33.13 High Hazelton and Murphy [26] 

Electrical conductivity dS /m 0.18 Low Hazelton and Murphy [26] 
Organic carbon % 1`.32 Medium Tadesse [25] 
Organic matter % 2.28 Moderate Donald, et al. [27] 

Particle size distribution   
Sand % 46.66   
Silt % 26.66   
Clay % 26.66   

Textural class  Clay-loam  
                  Source: Sirinka Agricultural Research Center Soil Laboratory (2017) .  

 

4.2. Growth Parameters of Onion 

4.2.1. Plant Height 

The analysis of variance revealed that the interaction effect of nitrogen and intra-row spacing significantly (P≤ 

0.05) influenced the heights of onion plants. The tallest onion plant (58.08 cm) was recorded with the combination 

of 123 kg ha-1 N and 10 cm intra-row spacing which was by about 59% higher than those plants planted at closer 

intra-row spacing without nitrogen Table 2.  The increased plant height at the combination of higher rate of N and 

wider spacing might be due to the fact that nitrogen is the building blocks of amino acids and proteins that 

improves the growth and development of plants including onion. Moreover, it could be attributed to less 

competition of the plants for nutrients and other growth factor in widest intra-row spacing. The results of the 

present study are consistent with the findings of Al-Fraihat [28] and Abdissa, et al. [29] who reported that 

increasing rates of nitrogen up to certain level increased plant heights of onion which is associated with its 

vegetative growth promoting effect. Similar, Khan, et al. [30] observed an increase of onion plant heights with 

increased nitrogen rates at wider intra-row spacing. 

 
Table-2. Interaction effect of nitrogen and intra-row spacing on height of onion plants grown in Doro Gibir Kebele at Alawuha Small-Scale 
Irrigation. 

Nitrogen rate (kg ha-1) Intra-row spacing (cm) 

6 8 10 

0 36.55g 41.21f 45.30de 
41 42.96ef 44.44e 45.76cde 
82 48.98cd 52.88b 56.25a 

123 48.66c 56.66a 58.08a 
P-value * 
CV (%) 3.58 

SE± 1.72 
P-value = Probability value; CV = Coefficient of variance; SE = Standard error; * = significant; Means followed by the same letter (s) are not significantly different 
at P = 0.05. 

 



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4.2.2. Leaf Number per Plant 

The analysis of variance revealed that number of leaves per plant was very highly significantly (P≤ 0.001) 

influenced by the main effects of nitrogen and intra-row spacing. However, the interaction of these factors had not 

influenced leaf number per plant. Increasing the nitrogen rate from 0 to 123 kg ha-1 significantly increased the leaf 

number by about 67.3% while increasing the intra-row spacing from 6 to 10 cm increased the leaf number of onions 

by 24% as indicated in Table 3.  

The results of the study indicate that nitrogen plays a pivotal role in leaf production and thus in promotion of 

vegetative growth of onion plants. The increment of leaf numbers with increased nitrogen rates at wider intra-row 

spacing observed in the present study is clearly associated with less competition of plants for nitrogen where more 

auxiliary branches have been produced at wider intra-row spacing compared to closely spaced plants. In agreement 

with the results of the present study, Jilani, et al. [31] observed maximum number of onion leaves at 25 cm intra-

row spacing followed by 20 and 10 cm intra-row spacing. Similarly, Akoun [32] reported more onion leaves were 

produced at lower plant density than at higher plant population.  

 

4.2.3. Days to Maturity 

The analysis of variance showed that days to maturity was very highly significantly (P≤ 0.001) influenced by 

the main effects of nitrogen and intra-row spacing. Nevertheless, the interaction effect of intra-row spacing and 

nitrogen levels did not showed significant variation on this parameter. Application of highest rate of nitrogen (123 

kg ha-1) prolonged days of onion maturity by about seven days as compared to controlled plant. Similarly, the 

highest intra-row spacing (10 cm) prolonged onion maturity Table 3. The results of this study clearly showed that 

excess nitrogen delayed onion maturity by extending the vegetative growth period of plants which is in agreement 

with the findings of various researchers. Morsy, et al. [21]. Similarly, Abdissa, et al. [29] reported that application 

of nitrogen fertilizer significantly extended days of physiological maturity of onion by about 6 days over the 

unfertilized plants.  

The prolonged maturity days of onion at wider intra-row spacing is obviously associated with less competition 

of plants for growth factors including nitrogen. Less competition of plants for growth factors may prolong 

vegetative growth period and thus delayed bulb maturity of onion. On the other hand, the reduced intra-row 

spacing between plants may exert competition for nitrogen that forced the plants to mature earlier which in line 

with the findings of Brewster [33]. According to the authors, decreasing intra-row spacing between plants may 

reduce vegetative growth and reduce duration of onion bulb maturity.  

 
Table-3. Main effects of nitrogen and intra-row spacing on leaf number and maturity of onion plants grown in Doro Gibir Kebele at Alawuha 
Small-Scale Irrigation. 

Treatment Growth parameters 
Nitrogen fertilizer rate (kg ha-1) Leaf number plant-1 Day to maturity (days) 

0 7.77d 111.22d 
41 9.92c 113.11c 
82 11.48b 116.00b 

123 13.00a 118.00a 
Significance level *** *** 

Intra-row spacing (cm)   

6 9.57c 113.58c 
8 10.25b 114.58b 

10 11.82a 115.58a 
P-value *** *** 
CV (%) 7.56 0.23 

SE± 0.80 0.26 
CV = Coefficient of variance; SE = standard error; P-value = probability; *** = very highly significant; Means within a column followed by the same letter(s) are not 
significantly different at P≤0.001.  

 



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4.3. Yields of Onion   

4.3.1. Bulb Weight  

The analysis of variance showed that the main effects of nitrogen and intra-row spacing very highly 

significantly (P < 0.001) influenced the bulb weight of onion. However, the interaction effect of nitrogen and intra-

row spacing did not influence the average bulb weight significantly. Increasing the application rates of nitrogen 

from 0 to 82 kg ha-1has increased the bulb weight by 101.9%. However, further increasing the nitrogen rates beyond 

82 kg ha-1 N did not increased the bulb weights of onion Table 4. Similarly, widening the intra-row spacing from 6 

to 10 cm increased the bulb weight by about 13.7%. 

Application of nitrogen generally enhances the production of assimilate and dry matter accumulation in plants 

including onion which is in line with the results of the present study. Similar results were also recorded by 

Soleymani and Shahrajabian [34] and Aliyu, et al. [15] who reported an increase of onion bulb weight with 

increased nitrogen rate. 

The increased bulb weight at the widest intra-row spacing recorded in the present study is possibly due to less 

competition of plants for growth factors such as nutrients, light and water. These results are similar with Khan, et 

al. [35] who reported that wider spacing accommodated less number of onion plants and helps them to absorb 

adequate nutrients, moisture and light for increased bulb weight.  

 
Table-4. Main effects of nitrogen and intra-row spacing on onion bulb weight in Doro Gibr Kebele at Alawuha 
Small-Scale Irrigation. 

Treatment Bulb weight (g) 

Nitrogen fertilizer rate (kg N ha-1)  

0 42.48c 
41 57.94b 

82 85.76a 

123 86.62a 

P-value *** 
Intra-row spacing (cm)  

6 64.28b 
8 67.24b 

10 73.08a 

P-value *** 
CV (%) 5.94 

SE± 4.05 
CV = Coefficient of variance; SE = standard error; P-value = probability; *** = very highly significant; Means 
within a column followed by the same letter(s) are not significantly different at P≤0.001. 

 

4.3.2. Marketable Bulb Yield 

The analysis of variance revealed that the main and interaction effects of nitrogen and intra-row spacing very 

highly significantly influenced the marketable yield of onion. The maximum marketable bulb yield (37.48 t ha-1) of 

onion was recorded by application of 123 kg ha-1 nitrogen on narrow spaced plants (6 cm) which increased the 

marketable yield by about 126.9% compared to the yield obtained from treatment combination of 10 cm intra-row 

without nitrogen Table 5.  

Generally, marketable bulb yield of onion was increased when the increased nitrogen rates were combined with 

increasing plant population. This might be due to the fact that higher plant population per unit area coupled with 

optimum supply of nitrogen results maximum number of bulbs that leads to higher marketable onion yield. These 

results are consistent with findings of various researchers where maximum bulb yield of onion was recorded in 

general with treatment combinations of narrow intra-row spacing and optimum nitrogen fertilizer levels Islam, et 

al. [36]. Soleymani and Shahrajabian [34] also reported higher marketable onion yield by application of high level 

(120 kg ha-1) of nitrogen. According to Kahsay, et al. [37] the marketable onion yield was decreased from 34.49 to 

28.1 t ha-1 when the intra-row spacing increased from 5 to 10 cm. 



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4.3.3. Unmarketable Bulb Yield  

The lowest unmarketable onion yield (0.28 t ha-1) was recorded by application of 123 kg ha-1 nitrogen to widest 

spaced (10 cm) plants which was statically similar with the combined effect of 123 kg ha-1 nitrogen and 8 cm intra-

row spacing. On the other hand, the highest unmarketable yield (1.05 t ha-1) was obtained by the combination of 

null nitrogen with 6 cm intra-row spacing which increased unmarketable bulb yield by about 275% compared with 

the treatment combination of 123 kg ha-1 N with 10 cm intra-row as indicated in Table 5.  

High unmarketable bulb yield of onion observed in the treatment combination of 6 cm intra-row spacing with 

null nitrogen could be obviously associated with higher plant competition for nitrogen that reduced vegetative 

growth and assimilate production that in turn resulting production of very small-sized bulbs which are not 

preferable by the consumers. The findings of the present study are in agreement with those of Seck and Baldeh 

[38] and Kahsay, et al. [37] where closer intra-row spacing increased unmarketable bulb yields of onion and 

shallot, respectively. Likewise, Aregay, et al. [39] reported that onion plants without nitrogen fertilizer produced 

small-sized onion bulbs which were unmarketable. 

 

4.4. Total Bulb Yield 

Similar to marketable yield, the highest total bulb of onion (37.97 t ha-1) was recorded by the treatment 

combination of 123 kg ha-1 nitrogen with 6 cm intra-row spacing which increased total bulb yield by about 181% 

when compared to the treatment combination of null nitrogen with 10 cm intra-row spacing Table 5.   

The increased total onion bulb yield by the combination of increased nitrogen level with increased plant density 

observed in the present study is associated with the supply of enough nitrogen that is necessary to improve the 

vegetative growth of plants that in turn boost the production of photosynthetic products. The present results are 

line with Eifediyi, et al. [40] who reported that total bulb yield was higher in narrow spaced plants than in wider 

spaced plants if enough plant nutrients are available in soil. This might be ascribed to the enhanced number of bulbs 

per unit area. Aliyu, et al. [15] also found that increase the rate of nitrogen dose up to 100 kg ha-1 resulted higher 

onion bulb yield but further increase of nitrogen to 150 kg ha-1 did not significantly increase the yield. 

 
Table-5. Interaction effects of nitrogen and intra-row spacing on bulb yield of onion grown in Doro Gibir Kebele at Alawuha Small-Scale 
Irrigation.  

Treatments Onion yields 

Rate of nitrogen (kg 
ha-1) 

Intra-row 
spacing (cm) 

Marketable bulb 
yield (t ha-1) 

Unmarketable bulb 
yield (t ha-1) 

Total bulb 
yield (t ha-1) 

0 6 16.52g 1.05a 17.58g 
8 15.95g 0.64bc 16.59g 
10 12.88h 0.59cd 13.48h 

41 6 27.84d 0.72b 28.56d 
8 21.24ef 0.53de 21.76ef 
10 18.96fg 0.42fg 19.38fg 

82 6 35.07ab 0.57cde 35.64ab 
8 29.73cd 0.48ef 30.22cd 

10 22.63e 0.35gh 22.98e 
123 6 37.48a 0.49ef 37.97a 

8 32.43bc 0.32h 32.76bc 
10 23.69e 0.28h 23.97e 

P-value  *** *** *** 
CV (%)  7.29 9.59 7.18 

SE±  1.78 0.05 1.8 
CV = Coefficient of variance; SE = standard error; P-value = probability; *** = very highly significant; Means within a column followed by the same letter(s) are not 
significantly different at P≤0.001. 

 

 

 



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4.5. Economic Analysis of Onion as Affected by Nitrogen and Intra-Row Spacing 

Costs of fertilizer, seed and labor were considered as variable costs as they vary with the treatments. Variable 

costs were calculated by considering the local prices which were existed during the experimental period. Moreover, 

gross income obtained from each treatment was calculated using the farm gate price of onion where the marketable 

yield was down scaled by 10%. Accordingly, application of 123 kg ha-1nitrogen on narrow spaced plants (6 cm) 

recorded the highest net benefit of onion (Eth-Birr 429,569.0) followed by the treatment combination of  82 kg ha-1 

nitrogen with 6 cm intra-row spacing Table 6. On the other hand, the lowest net benefit was obtained from plants 

spaced at 10 cm combined with null nitrogen.  

Moreover, marginal rate of return was calculated based on the procedures described by CIMMYT [23]. 

Accordingly, treatments were arranged in ascending order based on variable costs where treatments which had net 

benefits less or equal to the previous treatments were eliminated Table 7. Consequently, the treatment 82 kg ha-1 

nitrogen combined with 6 cm intra-row spacing recorded the highest marginal rate of return followed by the 

combination of 123 kg ha-1 nitrogen with 6 cm intra-row spacing. However, since the marginal rate of return is 

much higher than 50%, the treatment combination of 123 kg ha-1 nitrogen with 6 cm intra-row spacing with the 

highest net benefit was selected for economical production of onion in the study area. 

 

Table-6. Partial budget analysis of onion as affected by nitrogen and intra-row spacing in Doro Gibir Kebele at Alawuha Small-Scale Irrigation. 

Treatment 
combination 

MY 
(t ha-1) 

AMY 
(t ha-1) 

GI 
(Eth Birr) 

CS 
(Eth Birr) 

CF 
(Eth Birr) 

LCT 
(Eth Birr) 

LCFA 
(Eth 
Birr) 

TVC 
(Eth 
Birr) 

NB 
(Eth 
Birr) 

Rank 

6×0 16.52 14.86 193,180 2,664 0 3,500 0 6,164 187,016 11 
6×41 27.84 25.06 325,780 2,664 719 3,500 400 7,283 318,497 5 
6×82 35.07 31.57 410,410 2,664 1,438 3,500 500 8,102 402,308 2 
6×123 37.48 33.73 438,490 2,664 2,157 3,500 600 8,921 429,569 1 
8×0 15.5 13.95 181,350 2,000 0 3,000 0 5,000 176,350 12 

8×41 21.24 19.12 248,560 2,000 719 3,000 400 6,119 242,441 8 

8×82 29.73 26.76 347,880 2,000 1,438 3,000 500 6,938 340,942 4 
8×123 32.43 29.19 379,470 2,000 2,157 3,000 600 7,757 371,713 3 
10×0 18.06 16.25 211,250 1,600 0 2,500 0 4,100 207,150 10 
10×41 18.96 17.06 221,780 1,600 7,19 2,500 400 5,,219 216,561 9 
10×82 22.63 20.37 264,810 1,600 1,438 2,500 500 6,038 258,772 7 

10×123 23.69 21.32 277,160 1,600 2,157 2,500 600 6,857 270,303 6 
MY= Marketable yield, AMY = Adjusted marketable yield, CS =, Cost of seed, CF = Cost of fertilizer, LCT = Labor cost for transplanting, LCFA = Labor cost for 
fertilizer application, TVC = Total variable cost, NB = Net benefit. 

 
Table-7. Marginal rate of return of onion as affected by nitrogen and intra-row spacing in Doro Gibir Kebele at Alawuha Small-Scale Irrigation. 

Intra-row spacing x Nitrogen rate TVC (Birr ha-1) NB (Birr ha-1) DA MR (%) Rank 

10×0 4100 207150  -  
8×0 5000 176350 dominated   

10×41 5219 216561  841 7 
10×82 6038 258772  5153 3 
8×41 6119 242441 dominated   
6×0 6164 187016 dominated   

10×123 6857 270303  1407 6 

8×82 6938 340942  8708 2 
6×41 7283 318497 dominated   

8×123 7757 371713  3757 4 
6×82 8102 402308  8868 1 

6×123 8921 429569  3328 5 
TVC = total variable cost, NB = net benefit, DA = dominance analysis, MRR = marginal rate of return 
 

5. CONCLUSION  

The rate of nitrogen and intra-row spacing influenced both growth and yield of onion grown in the study area. 

While the tested growth parameters of onion including plant height, leaf number and days to maturity were 



Current Research in Agricultural Sciences, 2019, 6(2): 83-94 

 

 
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influenced only by the main effects, yield components of onion were also influenced by the interaction effects of 

nitrogen and intra-row spacing. Accordingly, all the tested growth parameters of onion were increased with 

increasing rate of nitrogen and widening of intra-row spacing where plants supplied by 123 kg ha-1 as well as those 

planted at 10 cm intra-row spacing recorded were best in all growth parameters.  On the other hand, the highest 

marketable (37.48 t ha-1) and total (37.97 t ha-1) bulb yields of onion with the highest net benefit were obtained by 

the treatment combination of 123 kg ha-1 nitrogen with 6 cm intra-row spacing. Since the combination of 123 kg ha-

1 nitrogen with and 6 cm intra-row spacing recorded acceptable high marginal rate of return, it can be 

recommended for economical production of onion at Alawuha Small Scale Irrigation Scheme, Northeastern Amhara 

Region.      

 

Funding: This study received no specific financial support.    
Competing Interests: The authors declare that they have no competing interests.  
Contributors/Acknowledgement: The authors would like to extend their sincere gratitude to Gubalafto 
District Agricultural Office for providing us experimental land and labor support as well as for their follow 
up of the experimental activities. 

 

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