Skip to content
BY 4.0 license Open Access Published by De Gruyter Open Access December 31, 2021

Influences of spacing on yield and root size of carrot (Daucus carota L.) under ridge-furrow production

  • Habtamu Tegen EMAIL logo and Mnuyelet Jembere
From the journal Open Agriculture

Abstract

Although there is adequate information on the influence of plant population on root yield and size of carrot on flat and raised bed for rain fed production system, information on ridge-furrow bed preparation method is limited for irrigation production system. Therefore, in this study, field experiments were conducted for 2 years to determine the appropriate spacing of carrot on ridge-furrow carrot production practice under irrigation. Root yield increased significantly as the population increased. On the contrary, root size significantly decreased as population increased. The result of combined analysis over season and locations indicated that the narrowest spacing of 10 cm × 4 cm rows on the ridge and between plants, respectively, which accommodates 1,250,000 plants ha−1 gave significantly highest marketable carrot root yield of 26 t ha−1 followed by 22.6 t ha−1 with spacing of 20 cm × 4 cm which accommodates 1,000,000 plants ha−1, but it produced the smallest individual root weight of 83 g which is mostly preferred for household consumption unlike jumbo roots. Therefore, in terms of root sizes and marketable yield, the current study identified that spacing of 10 cm × 4 cm is optimum on ridge-furrow carrot production practices.

1 Introduction

Carrot (Daucus carota L.) is a short duration crop and it is among the top ten most economically important vegetable crops in the world in terms of areas of production and market value [1,2]. The main reason for widespread production of carrot is because it is a cheap source of vitamin A in the diets of many cultures. It is also a good source of other vitamins, minerals, and fiber [3]. It contains high amount of carotene (10 mg per 100 g), thiamin (0.04 mg per 100 g), and riboflavin (0.05 mg per 100 g). It also serves as a source of carbohydrate, protein, fat, minerals, vitamin C, and calories [4]; thus, it can play a great role in preventing night blindness due to sever deficiency of vitamin A in children, which is a problem of public health in developing countries. Due to these multiple functions, the worldwide consumption of carrot has increased over the years [5,6].

Carrot yields can range from 30 to 100 t ha−1 in major carrot growing countries of the world [7]. In most developing countries, carrot yields per unit area still remain below the world average. For example, the average productivity of carrot was only 3.5 t ha−1 in Ethiopia as compared to 36.5 t ha−1 of world average [6]. Low productivity is associated with so many factors including lack of improved production practices, unavailability of technological inputs, pests, and postharvest losses [7].

Plant population density is one of the main factors which influence root yield and root size of carrot [8]. According to Kelley and Phatak [3], the ideal plant populations should be in the range of 450,000 per ha for fresh market carrots and 300,000 per ha for processing carrots. Many research reports revealed different population densities to enhance the yield of carrot in different production practices. For instance higher carrot root yield was produced with the narrow spacing [9,10,11]. On the contrary Kabir et al. [12] reported that maximum yield was obtained from the plants grown at widest spacing. The difference may arise from the objective of the intended use of carrot since each use has its own certain root size range [13]. Simões et al. [2] confirmed that the use of high population density cropping and early harvesting may lead to production of baby carrots that are more acceptable for commercialization. Although, some authors have reported some information on the optimum population density on different bed preparation methods (flat and raised) for carrot production, information on ridge-furrow bed preparation method is very limited. In the study areas, flat and raised bed preparation method is used for rain fed carrot production to facilitate drainage [14,15]. But this method of bed preparation is usually not suitable for carrot production under irrigation condition to manage the irrigation water applied through furrow irrigation method [15]. Adopting onion production system through ridge-furrow bed preparation method is vital for carrot production under irrigation condition. Therefore, the objective of the current study is to identify optimum population density by adjusting inter and intra row spacing for root yield and root size of carrot on ridge-furrow bed preparation method under irrigation condition in Western Amhara of Ethiopia.

2 Materials and methods

2.1 Description of the study areas

The experiment was conducted in Ethiopia at Woramit and Ribb research sites of Adet Agricultural Research Center in 2015 and 2016 under irrigation production system from January to April. Site description of each location is provided below. Environmental conditions in terms of maximum and minimum temperatures (oC) and relative humidity (RH; %) of the locations during the experimental period are described in Figure 1.

Figure 1 
                  Environmental conditions of the study areas during the experimental years.
Figure 1

Environmental conditions of the study areas during the experimental years.

2.1.1 Woramit

Woramit is located at 11°38′ N and 37°10′ E and at an altitude of 1,800 m above sea level. It has warm and humid climate with distinct dry and wet seasons. The mean daily maximum temperature is 29.5°C in April, while the mean daily minimum temperature is 6.2°C in January. The area receives a mean annual rainfall of 800–1,250 mm and is characterized as mild altitude agroecology. The soil is nitosol. The soil is moderately acidic (pH 6.4) and consists of sand (13%), silt (33%), and clay (54%). It has 3.9 and 0.16% organic matter content and total nitrogen content, respectively. Available phosphorus content is 6.3 mg kg−1 [16,17].

2.1.2 Ribb

Ribb is located in Fogera district of North-West part of Ethiopia. It is located at 11°44′ to 12°03′ N and 37°25′ to 37°58′ E at 1,774 m above sea level. It receives 1,400 mm mean annual rainfall. The mean daily maximum and minimum temperatures are 30 and 11.5°C, respectively. The area is characterized as mid altitude agroecology. The soil is fluvisol (an alluvial deposit). The soil has high available phosphorus (36.71 ppm) and very low to low total nitrogen contents (0.003%). The cation exchange capacity of the soil is high (33.00 cmol kg−1). The soil is strongly acidic with high exchangeable acidity and high exchangeable Al3+ content [18].

2.2 Experimental materials, treatments, and design

Carrot variety “Nantes” was used for the study. The experiment consisted of three inter row spacing on the ridge (10, 20, and 30 cm) and three intra row spacing (4, 7, and 10 cm) which were arranged in 3 × 3 factorial combination in randomized complete block design with three replications combined over locations and years.

2.3 Experimental procedure

Seeds were sown by hand drilling on ridge in double row manner on 12 m2 gross plot size (3 m × 4 m). 9, 7, and 5 double rows per plot were maintained for the row spacing on ridges of 10, 20, and 30 cm, respectively. For each treatment combination, 30 cm furrow width was also maintained for irrigation water application. Theoretically it accommodates 1,250,000; 1,000,000; 750,000; 716,666; 573,333; 500,000; 430,000; 375,000, and 300,000 plant population per hectare. Nitrogen (46 kg ha−1) and phosphorus (P2O5; 69 kg ha−1) in the form of urea and di-ammonium phosphate (DAP) fertilizers, respectively, were applied for each treatment. The entire DAP was applied at the time of planting, while urea was applied in two splits, first half (50%) at the time of planting and second half (50%) at 30 days after sowing [19]. Thinning was performed 30 days after sowing to maintain 125, 100, 75, 72, 57, 50, 43, 38, and 30 plants per m2 according to the treatments. Irrigation water was applied with the furrow irrigation method with 7 days interval by adopting onion production of the area [19]. First weeding, along with thinning, and ridge maintenance were applied at 30 days after sowing, while the second and third were done at 45 and 60 days after sowing, respectively [15].

2.4 Data collection

Days to physiological maturity: It was determined as the actual number of days from sowing to the time at which more than 90% of the plants in a plot were mature by using distractive sampling taken from border rows.

Root length (cm): It was measured by using caliper placed at the point of the leaf detached to tip of the matured root.

Root diameter (cm): It was measured by using caliper placed at the widest point in the middle portion of the matured root.

Average root weight (g): Randomly selected marketable roots were measured by using digital balance, which were produced from central rows of each plot.

Root (cortex) to core ratio: It was determined by cutting carrot roots at the widest (middle) point. Then, core was measured from center to beginning of flesh part of each carrot root, while root (cortex) was measured from the beginning of flesh part to skin of each carrot root. The value of root (cortex) divided by core gave root to core ratio.

Carrot root yield: Marketable root yield was determined as the total weight of roots free from soft rot, and free from damage caused by growth cracks, sunburn, pithiness, woodiness, oil spray, dry rot, other diseases, insects, or other means, and the length of each carrot is not less than 7.62 cm which accommodates both processing and fresh types of carrots per net plot area and converted to t ha−1 [20]. Unmarketable root yield was determined as total weight of roots with soft rot and damage-caused growth cracks, sunburn, pithiness, woodiness, oil spray, dry rot, other diseases, insects, or other means, and the length of each carrot is less than 7.62 cm which do not fulfill the requirements of both processing and fresh types of carrots per net plot area and converted to t ha−1 [20]. Total root yield was determined as sum of marketable and unmarketable roots in t ha−1.

2.5 Statistical analysis

The analysis of variance (ANOVA) was conducted for each location and season using PROC GLM procedure [21] version 9.0 to see the effect of inter and intra row spacing. After Bartlett’s homogeneity test, the combined ANOVA over location and season was conducted using PROC MIXED procedure. Inter and intra row spacing were considered as fixed effects, while location and season were considered as random effects. Whenever the ANOVA result was significant (P ≤ 0.05), the mean separation was performed using Fisher’s LSD for the main effects and Duncan’s multiple range test for the interaction effects.

3 Results and discussion

3.1 Days to maturity

The combined ANOVA over location and season showed that days of 90% maturity were significantly (P ≤ 0.05) influenced by inter and intra row spacing, season and location, two way interaction of intra row vs location and intra row vs season. Horticultural root maturity was also significantly (P ≤ 0.05) influenced by three and four way interaction of intra row vs location vs season and inter vs intra vs location vs season, respectively, as indicated in Table 1. Although the observed maturity date difference among treatments does not have a vital role in supply for early market to fetch premium price, plants grown with widest inter row spacing on the ridge (30 cm) and intra row spacing (10 cm) matured lately as presented in Table 2. Regarding the growing environment, plants grown in 10 cm intra row spacing on the ridge matured lately by 7 days and 5 days as compared to plants grown in 4 cm at Ribb and Woramit condition, respectively, as illustrated in Table 4. The observed early maturity on highest plant population might be due to the narrowest intra row spacing (4 cm) convincingly by the presence of high resource competition such as plant nutrient, water, and sunlight. Splittstoesser [22] stated that adequate space ensures less competition for sunlight, water, and fertilizers. In this regard, Manimurugan et al. [23] confirmed that earliness in days to 50% flowering was observed in high plant density.

Table 1

Combined ANOVA mean squares of treatments’ effects on yield, yield components, and days to maturity of carrot over years and locations

Source of variation df Mean squares
HRM (day) RL (cm) RD (cm) RW (g) R:C MRY (t ha−1) UMRY (t ha−1) TRY (t ha−1)
Inter 2 106.71** 9.02** 2.25** 762.28** 0.05** 154,366,150** 1,636,887** 175,640,503**
Intra 2 302.86** 23.90** 1.35* 3,511.64** 0.10** 163,562,709** 1,117,833** 182,900,144**
Location 1 29.03** 2.76ns 195.39** 201.47** 19.46** 221,179,812** 45,685,579** 65,820,840**
Season 1 37.92** 10.39** 242.18** 8,782.43** 19.46** 695,712,048** 146,344,116** 203,892,032**
Replication (location vs season) 8 6.27ns 0.43ns 0.13ns 100.17** 0.02ns 8,001,952ns 300,993** 5,585,498ns
Inter vs intra 4 4.61ns 0.67ns 0.13ns 141.97** 0.06** 9,286,784* 553,369** 10,750,268**
Inter vs location 2 1.64ns 0.20ns 0.44ns 18.55ns 0.01ns 38,836,607** 415,560** 34,314,320**
Inter vs year 2 6.01ns 0.38ns 0.63ns 100.68ns 0.01ns 43,221,660** 2,056,331** 31,851,298**
Intra vs location 2 38.01** 0.21ns 0.09ns 201.02** 0.035* 40,954,677** 332,167** 34,822,931**
Intra vs season 2 33.71** 0.21ns 0.06ns 225.93** 0.035* 1,266,299ns 1,257,137** 3,910,125ns
Location vs season 1 0.59ns 2.44ns 872.63** 11,644.33** 0.00ns 132,347,508** 28,496,019** 38,020,448**
Inter vs location vs season 2 1.53ns 0.58ns 2.14* 63.06ns 0.00ns 2,542,012ns 634,916** 802,735ns
Intra vs location vs season 2 26.01** 0.76ns 0.21ns 0.80ns 0.00ns 45,772,136** 315,542** 53,688,425**
Inter vs intra vs location 4 11.15** 0.76ns 0.07ns 58.92ns 0.01ns 4,278,443ns 128,966* 5,614,410*
Inter vs intra vs season 4 8.28* 0.76ns 0.08ns 172.64** 0.01ns 3,584,438ns 355,402** 4,300,345*
Inter vs intra vs location vs season 4 0.28ns 0.76ns 0.24ns 94.21* 0.00ns 5,147,670* 76,544ns 4,817,455*
Error 70 2.02 0.66 0.28 29.66 0.01 1,595,112 38,354 1,660,549

*, **, and ns – significant (P < 0.05), highly significant (P < 0.01), and non-significant, respectively. HRM – horticultural root maturity; RL – root length; RD – root diameter; RW – individual root weight; R:C – root to core ratio; MRY – marketable root yield; UMRY – unmarketable root yield; TRY – total root yield.

Table 2

Main effects of spacing, location, and year on yield, yield components, and days to maturity of carrot

RL (cm) RD (cm) RW (g) R:C HRM (day) MRY (t ha−1) UMRY (t ha−1) TRY (t ha−1)
Inter row spacing (cm)
 10 14.1b 5.5b 91.1c 1.3b 102c 22.5a 1.8a 24.3a
 20 14.7a 5.6b 96.4b 1.3b 104b 20.6b 1.4c 22.0b
 30 15.1a 6.0a 100.3a 1.4a 105a 18.4c 1.5b 19.9c
 SE(±) 0.47 0.30 3.10 0.05 0.80 0.70 0.10 0.80
 Sig ** ** ** ** ** ** ** **
Intra row spacing (cm)
 4 13.9c 5.5b 87.1c 1.2c 101c 22.9a 1.7a 24.6a
 7 14.6b 5.7ab 94.1b 1.3b 104b 19.7b 1.7a 21.4b
 10 15.5a 5.8a 106.6a 1.4a 106a 18.8c 1.4b 20.2c
 SE(±) 0.46 0.30 3.07a 0.05 0.80 0.7 0.1 0.8
 Sig ** * ** ** ** ** ** **
Location
 Ribb 14.8 7.0a 97.3a 1.7a 103b 21.9a 0.9b 22.8a
 Woramit 14.5 4.3b 94.6b 0.9b 104a 19.1b 2.2a 21.2b
 SE(±) 0.31 0.21 2.09 0.04 0.55 0.5 0.08 0.5
 Sig ns ** ** ** ** ** ** **
Season
 2015 14.3b 4.2b 86.9b 0.9b 104a 17.9b 2.7b 20.7b
 2016 15.0a 7.2a 105.0a 1.7a 103b 23.0a 4.2a 23.4a
 SE(±) 0.31 0.21 2.09 0.04 0.54 0.4 0.07 0.49
 Sig ** ** ** ** ** ** ** **
CV% 5.58 9.41 5.67 7.14 1.37 6.17 12.36 5.84

*, **, and ns – significant (P < 0.05), highly significant (P < 0.01), and non-significant, respectively. Means with common letter within the column do not differ significantly (P ≥ 0.05). HRM – horticultural root maturity; RL – root length; RD – root diameter; RW – individual root weight; R:C – root to core ratio; MRY – marketable root yield; UMRY – unmarketable root yield; TRY – total root yield.

3.2 Root (cortex) to core ratio

The combined ANOVA showed that root to core ratio of carrot was significantly (P ≤ 0.05) influenced by main effect of spacing, location and season, two way interaction of inter vs intra row spacing, intra row vs location, and intra row vs season as indicated in Table 1. Significantly highest root to core ratio (1.36) was obtained on carrot roots produced in combination of wider inter and intra row spacing of 30 cm × 10 cm followed by 20 cm × 10 cm as presented in Table 3. In line with the current findings, Pandey et al. [24] reported that carrot varieties cultivated with 30 cm × 10 cm spacing produced a root to core ratio value of 1.22. Significantly (P ≤ 0.05) highest root to core ratio was produced at Ribb in 2016 as shown in Table 2. As illustrated in Table 4, carrots produced with all possible intra row spacing at Ribb gave higher root to core ratio as compared to carrots produced with all possible intra row spacing at Woramit conditions. The reason behind is that carrot roots produced at Woramit condition had bigger root diameter. According to Northolt et al. [25], thicker carrot roots had a relatively smaller root (cortex) and larger core. In nitosol condition at Woramit, carrot plants subjected to develop shorter root length but large root diameter compared in alluvial deposit soil at Ribb. In alluvial deposit soil, roots can easily penetrate the soil to develop larger root length but relatively shorter diameter. According to Johansen et al. [26], with relatively compacted soil layers at nitosols, roots will be concentrated more in the upper layers of the soil with larger root diameters.

Table 3

Inter and intra row interaction effects on yield and yield component of carrot as combined over locations and years

Treatment inter × intra rows RW (g) R:C MRY (t ha−1) UMRY (t ha−1) TRY (t ha−1)
10 × 4 83.0e 1.3bc 26.0a 1.9ab 28.0a
10 × 7 90.9d 1.2c 21.4bc 2.1a 23.5b
10 × 10 99.5bc 1.3bc 20.0cd 1.4de 21.4c
20 × 4 87.8de 1.2c 22.6b 1.4de 24.0b
20 × 7 92.8cd 1.3bc 19.9cd 1.3e 21.2c
20 × 10 105.9b 1.4ab 19.3de 1.5cde 20.7cd
30 × 4 90.6d 1.3bc 20.0cd 1.7bc 21.7c
30 × 7 98.7c 1.3cb 17.8ef 1.7cd 19.5de
30 × 10 114.4a 1.4a 17.2f 1.2e 18.4e
SE(±) 7.11 0.12 1.65 0.26 1.68
Significance ** ** ** ** **
CV% 5.67 7.14 6.16 12.36 5.84

** – highly significant (P < 0.01). Means with common letter within the column do not differ significantly (P ≥ 0.05). RW – individual root weight; R:C – root to core ratio; MRY – marketable root yield; UMRY – unmarketable root yield; TRY – total root yield.

Table 4

Interaction effects of spacing by location on yield, yield components, and days to maturity of carrot as combined over years

Trait RW (g) R:C HRM (day) MRY (t ha−1) UMRY (t ha−1) TRY (t ha−1)
Ribb Wor. Ribb Wor. Ribb Wor. Ribb Wor. Ribb Wor. Ribb Wor.
Inter
 10 89.75 92.51 1.70 0.89 101 102 24.8a 20.2bc 1.0c 2.6a 25.9a 22.7bc
 20 94.36 98.51 1.71 0.87 103 105 22.3ab 18.9c 0.82c 2.0b 23.1b 20.9bcd
 30 99.66 100.94 1.80 0.92 105 106 18.7c 18.1c 0.93c 2.1b 19.6d 20.2cd
 SE(±) 10.88 0.11 3.23 2.65 0.36 2.77
 Sig ns ns ns ** ** **
 CV% 11.68 8.99 3.21 13.36 23.64 12.96
Intra
 4 84.00c 90.27bc 1.76ab 0.93c 99d 102c 25.2a 20.6bc 1.0c 2.4a 26.2a 22.9b
 7 91.83b 96.39b 1.65b 0.86c 105ab 104bc 21.5b 18.0c 0.96c 2.4a 22.4bc 20.4bc
 10 107.95a 105.32a 1.81a 0.89c 106a 107a 19.1b 18.6c 0.84c 1.9b 19.9c 20.5bc
 SE(±) 7.64 0.11 2.18 2.61 0.41 2.7
 Sig ** ** ** ** ** **
 CV% 8.21 8.29 2.16 13.12 26.55 12.39

** and ns – highly significant (P < 0.01) and non-significant, respectively. Means with common letter within the column do not differ significantly (P ≥ 0.05). RW – individual root weight; R:C – root to core ratio; HRM – horticultural root maturity; MRY – marketable root yield; UMRY – unmarketable root yield; TRY – total root yield.

3.3 Root length

The combined ANOVA showed that carrot root length was significantly (P ≤ 0.05) influenced by inter and intra row spacing and season as indicated in Table 1. Root length increased as the corresponding spacing increased in the current study as shown in Table 2. The widely spaced plants produced longer roots than the closely spaced plants [27]. According to Lana and Carvalho [13], root length should be as long as 6.0 cm for carrot processing. Similarly, Kabir et al. [12] reported that the largest root (11.02 cm) was recorded from the plants grown at the wider spacing of 30 cm × 20 cm inter and intra row spacing of carrot. The authors also explained that plants grown at the wider spacing received more nutrients and rate of photosynthesis for vegetative and root growth. Thompson [28] also concluded that plant density can influence carrot root shape.

3.4 Root diameter

The combined ANOVA showed that carrot root diameter was significantly (P ≤ 0.05) influenced by all the main effects of inter and intra row spacing, season, location, two way interaction of location vs season, and three way interaction of inter vs location vs season as indicated in Table 1. Root diameter values ranging from 4.0 to 6.0 cm were obtained in the current study. According to Szczepanek et al. [29], small roots (<1.9 cm in diameter), medium roots (1.9–3.8 cm in diameter) as well as large roots (3.8–5.0 cm in diameter) are the standard size distribution. Therefore, the root diameter values recorded in the current study falls in large root category. The highest root diameter value was obtained when plants were grown with widest inter row spacing of 30 cm on the ridge and intra row spacing of 10 cm at Woramit growing condition in 2016 as compared to Ribb growing condition in 2015 as presented in Table 2. Similarly, McCollum et al. [30] obtained maximum root diameter at the inter and intra row spacing of 30 cm × 20 cm. Generally, greater than Salter et al. [31] root size standard (2.0 to 3.0 cm diameter) for canning purpose, Sanders [1] root size standard (1.9 to 3.2 cm in diameter) for fresh market purpose, and Lana [8] carrot size standard (2.5 cm in diameter) for dual purpose were obtained in the current study with all sources of variations such as inter and intra row spacing, locations, and season (Table 2). According to Simões et al. [2], with the inter and intra row spacing of 20 cm × 4 cm for 64–78 days growing period produced carrot roots up to 2.3 cm in diameter on one meter width raised bed. As indicated in Table 2, the current study also identified that significantly higher root length was produced under Ribb growing condition, whereas significantly higher root diameter was produced under Woramit growing condition. The soil at the Ribb experimental site is fluvisol (an alluvial deposit) which is light to roots to easily penetrate as compared to nitosol at Woramit condition. With relatively compacted soil layers, roots will be concentrated more in the upper layers of the soil [26].

3.5 Average root weight

The combined ANOVA showed that average carrot root weight was significantly (P ≤ 0.05) influenced by all sources of variations except two way interaction of inter vs location and inter vs season as indicated in Table 1. As indicated in Table 3, the highest root weight value of 114 g followed by 106 g per plant were obtained from plants grown with the spacing combination of 30 cm × 10 cm and 20 cm × 10 cm, respectively, while the smallest root weight value (83 g) was obtained from plants grown with the combination of 10 cm × 4 cm inter and intra row spacing. Similar to the current result, maximum root weight of 312 g was obtained by the wider spacing of 30 cm × 15 cm in Ambo conditions of Ethiopia [9]. The present study also showed that root weight values increased as inter and intra row spacing increased. This trait is also influenced by growing location and season. Table 2 shows that significantly higher root weight value was obtained when plants were grown at Woramit condition compared to Ribb in terms of location as well as season of 2016 compared to 2015. This might be due to the prevailing growing condition in terms of temperature and RH condition observed at Woramit location and in 2016 growing season. As indicated in Figure 1, relatively higher temperature and lower RH condition were observed throughout the growing season. The current study confirmed that narrowest spacing of 10 cm × 4 cm gave larger proportion of small roots which is mostly the preference of household consumption (Table 3). The present result is in line with Lana [8] who reported that decreasing line spacing from 16.6 to 10.0 cm was important to assure larger proportion of superior quality thinner roots. Dawuda et al. [11] also reported that the wider spacing of 30 cm × 5 cm promoted vegetative growth and increased root length of carrot, but planting at closer spacing of 20 cm × 5 cm resulted in higher total and marketable yields and also increased income and profit.

3.6 Carrot root yield

The combined ANOVA showed that marketable root yield was significantly (P ≤ 0.05) influenced by all sources of variations except two way interaction of intra spacing vs season. Similarly unmarketable root yield was significantly (P ≤ 0.05) influenced by all sources of variations (Table 1). The combined mean in Table 3 shows that significantly (P < 0.05) highest marketable root yield of 26 t ha−1 was produced when plants were grown with the combination of the lowest inter and intra row spacing of 10 cm × 4 cm. While the lowest root yield of 17 t ha−1 was produced with plants grown with the combination of the largest inter and intra row spacing of 30 cm × 10 cm. Similarly, combined mean shows that significantly (P < 0.05) highest unmarketable root yield (1.9 t ha−1) was produced with plants grown with the combination of the lowest inter and intra row spacing of 10 cm × 4 cm followed by treatment combination of 10 cm × 7 cm. Similar to the current study, Shiberu and Tamiru [9] found higher carrot root yield of 55 t ha−1 with the lowest intra row spacing of 5 cm. Taivalmaa and Talvitie [10] also reported that the highest yields were recorded from carrots sown in double rows on a narrow ridge. Dawuda et al. [11] also reported that planting at closer spacing of 20 cm × 5 cm resulted in higher total and marketable yields and also increased income and profit. In contrast with the present findings, Kabir et al. [12] reported that maximum fresh root yield was obtained from the plants grown at widest spacing of 30 cm × 20 cm with hybrid (F1) variety. According to Mack [32], total root yields as well as roots less than 25 and 25–38 mm diameter were increased as row spacing were decreased from 60 to 15 cm. The lowest commercial yields were found with the widest spacing between plants, while the smallest spacing between plants (4 cm) had yields of 45.9 Mg ha−1 [33]. The total and marketable yields were larger in flat land and narrow ridge than in the broad and compacted broad ridges [34]. The Brasília Nina carrot cultivar showed high performance in root yield and quality, mainly in the 15 cm spacing between rows in an agroecological system [35].

Unlike unmarketable yield, the significantly higher marketable yield was obtained at Ribb as compared to Woramit and in 2016 as compared to 2015 in terms of two-way interaction of inter and intra row spacing by location (Table 4) and in terms of two-way interaction of inter and intra row spacing by season (Table 5). Generally, the overall higher marketable yield was obtained at Ribb in 2016 as compared to at Woramit in 2015 in terms of three-way interaction of inter and intra row spacing by location by season (Table 6). The observed yield difference might be due to the fluctuation of temperature and RH condition particularly minimum temperature and RH that occurred at locations and growing years. As indicated in Figure 1, there was a fluctuation of temperature and RH condition at Woramit compared to Ribb and in 2015 as compared to 2016 condition. Higher and lower temperatures reduce the rate of growth and adversely affect the physical quality of the roots [12]. Growth and yield pattern of carrots are affected by varietal performance and change in climatic conditions [36].

Table 5

Interaction effects of spacing and season on the root yield of carrot as combined over locations

Trait MRY (t ha−1) UMRY (t ha−1) TRY (t ha−1)
2015 2016 2015 2016 2015 2016
Inter
 10 18.8cd 26.2a 3.2a 0.39c 22.1bc 26.5a
 20 18.1cd 23.1b 2.4b 0.44c 20.5c 23.5b
 30 16.9d 19.8c 2.6c 0.43c 19.5c 20.3c
 SE(±) 2.65 0.36 2.77
 Sig ** ** **
 CV% 13.36 23.64 12.96
Intra
 4 20.2 25.5 3.0a 0.43c 23.2 26.0
 7 17.4 22.0 2.9a 0.40c 20.4 22.4
 10 16.2 21.5 2.3b 0.23c 18.5 21.9
 SE(±) 2.61 0.40 2.65
 Sig ns ** ns
 CV% 13.12 26.55 12.39

** and ns – highly significant (P < 0.01) and non-significant, respectively. Means with common letter within the column do not differ significantly (P ≥ 0.05). MRY – marketable root yield; UMRY – unmarketable root yield; TRY – total root yield.

Table 6

Interaction effects of spacing, locations, and season on the root yield of carrot

Traits MRY (t ha−1) UMRY (t ha−1) TRY (t ha−1)
Location 2015 2016 2015 2016 2015 2016
Inter row (cm)
 10 Ribb 22.5bcd 27.2a 1.816c 0.272d 24.3abc 27.4a
Woramit 15.2e 25.1ab 4.671a 0.506d 19.8cd 25.7ab
 20 Ribb 20.6cd 23.9abc 1.397c 0.259d 22.0bcd 24.1abc
Woramit 15.6e 22.2bcd 3.319b 0.614d 19.0d 22.8bcd
 30 Ribb 18.4de 18.9de 1.537c 0.317d 19.9cd 19.3d
Woramit 15.4e 20.7cd 3.745b 0.549d 19.2d 21.3bcd
 CV% 13.36 23.64 12.96
Intra row (cm)
 4 Ribb 22.9bcd 27.5a 1.687c 0.322d 24.6ab 27.8a
Woramit 17.6efg 23.6abc 4.208a 0.530d 21.8bcd 24.1abc
 7 Ribb 19.7b–e 23.2bc 1.684c 0.231d 21.4bcd 23.4bcd
Woramit 15.1fg 20.9b–e 4.250a 0.571d 19.3de 21.5bcd
 10 Ribb 18.8def 19.3cde 1.380c 0.295d 20.2cde 19.6de
Woramit 13.5g 23.6ab 3.277b 0.567d 16.8e 24.2abc
 Sig ** * **
 SE(±) 4.25 0.66 2.46
 CV% 13.12 26.55 12.39

* and ** – significant (P < 0.05) and highly significant (P < 0.01), respectively. Means with common letter within the column do not differ significantly (P ≥ 0.05).

MRY – marketable root yield; UMRY – unmarketable root yield; TRY – total root yield.

At both location and season, increased plant density due to inter and intra row spacing resulted in an increase in the production of marketable and total yield. On the other hand, increased plant density due to the incremental of inter and intra row spacing resulted in decrease in the production of unmarketable root yield as demonstrated in Tables 4 and 5. According to Kelley and Phatak [3], the only disadvantages of high density plantings include producing fewer jumbo carrots and lack of airflow through the field that can increase the incidence of foliar diseases. The author also confirmed that the incidence of disease may be managed by other integrated pest management practice. According to Salter et al. [31], the yield of canning-size root yield increased with plant density to a maximum and then declined, the maximum yield being achieved at a higher density.

4 Conclusion

The findings of the research indicated that the performance of carrot in terms of yield and root size was better at Ribb location as compared to Woramit. Although there was an interaction between spacing and location, the overall trend of the spacing was quite similar from location to location. Therefore, each location does not need a location-specific recommendation. The narrowest spacing of 10 cm × 4 cm which accommodates 1,250,000 plants ha−1 gave the significantly highest marketable carrot root yield of 26 t ha−1 followed by 22.6 t ha−1 with the spacing of 20 cm × 4 cm which accommodates the plant population of 1,000,000 plants ha−1. The widest spacing of 30 cm × 10 cm which accommodates 300,000 plants ha−1 produced the largest individual root weight per plant of 114 g with the yield penalty of 9 t ha−1. Although the narrowest inter and intra row spacing produced the smallest individual root weight of 83 g compared to other treatment combinations, it fell under the large size carrot category. This size category is mostly preferred for household consumption, unlike jumbo roots. Therefore, it is concluded that the spacing of 10 cm × 4 cm was identified as optimum inter and intra row spacing under the ridge-furrow practice of irrigated carrot production.

Acknowledgments

The authors acknowledge Amhara Regional Agricultural Research Institute (ARRI) for the financial support for successfully accomplishing this work. They are also indebted to Adet Agricultural Research Center staff and Horticulture research case team members for their assistance during field experiment.

  1. Funding information: The authors state no funding involved.

  2. Author contributions: H.T.: idea conceptualization, data analysis, the methodological design, original draft synthesizing and reviewing, and edition of the study; M.J.: field experiment superstations, investigation, and data collection.

  3. Conflict of interest: The authors state no conflict of interest.

  4. Data availability statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

References

[1] Sanders D. Commercial carrot production. Horticulture information leaflet. North Carolina, USA: University of California Extension; 1998.Search in Google Scholar

[2] Simões AdoN, Moreira SI, da Costa FB, de Almeida AR, Santos RHS, Puschmann R. Population density and harvest age of carrots for baby carrot manufacture. Hortic Bras. 2010;28(2):147–54.10.1590/S0102-05362010000200002Search in Google Scholar

[3] Kelley WT, Phatak SC. Commercial production and management of carrots. USA: University of Georgia Extension Office; 2012.Search in Google Scholar

[4] Simon PW, Freeman RE, Vieira JV, Boiteux LS, Briard M, Nothnagel T, et al. Carrot. In: Prohens J, Nuez F, editors. Vegetables II: Fabaceae, liliaceae and umbelliferae. Springer Street New York, USA: Springer; 2008.10.1007/978-0-387-74110-9_8Search in Google Scholar

[5] Chandy KT. Carrot. Vegetable production: VPS – 35. India: Agricultural and Environmental Education. Booklet No. 178; 2010.Search in Google Scholar

[6] FAO. FAOSTAT online. Rome: Food and Agricultural Organization of United Nations: Economic and Social Department: The Statistical division; 2016. Available from: www.http:faostat.fao.org/site/567/.Search in Google Scholar

[7] Muendo KM, Tschirley D, Weber MT. Improving Kenya’s domestic horticultural production and marketing system: current competitiveness, forces of change, and challenges for the future. Vol. 1. Tegemeo Institute of Agricultural Policy and Development; 2004.Search in Google Scholar

[8] Lana MM. The effects of line spacing and harvest time on processing yield and root size of carrot for Cenourete® production. Hortic Bras. 2012;30(2):304–11.10.1590/S0102-05362012000200020Search in Google Scholar

[9] Shiberu T, Tamiru S. Effect of intra spacing on yield and yield components carrot (Daucus carrota L. sub sp. sativus). Curr Res Agric Sci. 2016;3(1):1–6.10.18488/journal.68/2016.3.1/68.1.1.6Search in Google Scholar

[10] Taivalmaa S-L, Talvitie H. The effects of ridging, row-spacing and seeding rate on carrot yield. J Agric Food Sci. 1997;6(5–6):363–9.10.23986/afsci.72799Search in Google Scholar

[11] Dawuda MM, Boateng PY, Hemeng OB, Nyarko G. Growth and yield response of carrot (Daucus carota L.) to different rates of soil amendments and spacing. J Sci Technol. 2011;31(2):11–20.10.4314/just.v31i2.69389Search in Google Scholar

[12] Kabir A, Ali A, Waliullah MH. Effect of spacing and sowing time on growth and yield of carrot (Daucus carrota L.). Int J Sust Agri. 2013;5(1):29–36.Search in Google Scholar

[13] Lana MM, Carvalho ADF. Effect of plant density and genotype on root size and recovery of Cenourete® raw-material. Hortic Bras. 2013;31:266–72.10.1590/S0102-05362013000200015Search in Google Scholar

[14] Asfaw Z, Eshetu D. Production and management of major vegetable crops in Ethiopia. Addis Ababa, Ethiopia: Ethiopian Institute of Agricultural Research; 2015.Search in Google Scholar

[15] Tabor G, Yesuf M. Mapping the current knowledge of carrot cultivation in Ethiopia. Unpublished paper submitted to Carrot Aid Project. Denmark; 2012.Search in Google Scholar

[16] Berihun B. Effect of mulching and amount of water on the yield of tomato under drip irrigation. J Hort For. 2011;3(7):200–6.Search in Google Scholar

[17] Tegen H, Jembere M, Mihiretu E, Enyew A. Influences of inter and intra-row spacing on yield, yield component and morphological characteristics of onion (Allium cepa L.) at western Amhara region. Afr J Agric Res. 2016;11(20):1797–804.10.5897/AJAR2015.9960Search in Google Scholar

[18] Teshome A, Wale M, Mengistu F, Yitaferu B. Agricultural potentials, constraints and opportunities in the Megech and Ribb rivers irrigation project areas in the Lake Tana Basin of Ethiopia. Survey report. Bahir Dar, Ethiopia: 2009.Search in Google Scholar

[19] MOA (Ministry of Agriculture). Guideline on irrigated agronomy. Ministry of agriculture. Addis Ababa, Ethiopia: 2011.Search in Google Scholar

[20] USDA (United States Department of Agriculture). United States standards for grades of carrots for processing. USA: 1997.Search in Google Scholar

[21] SAS Institute Inc. SAS 9.0 version. SAS institute Inc.; 2002.Search in Google Scholar

[22] Splittstoesser WE. Vegetable growing handbook. Organic and traditional methods. 3rd edn. UK: Chapman and Hall; 1990. p. 215.Search in Google Scholar

[23] Manimurugan C, Pandita VK, Tomar BS, Gupta N, Singh PM. Effect of plant density and foliar nutrient application on seed yield and quality in Asiatic carrot (Daucus carota). Indian J Agric Sci. 2017;87(3):419–24.10.56093/ijas.v87i3.68791Search in Google Scholar

[24] Pandey A, Sharma MD, Shah SC. Quality parameters of Carrot as affected by varieties and nutrient sources. Azarian J Agric. 2017;4(6):200–5.Search in Google Scholar

[25] Northolt M, van der Burgt G-J, Buisman T, Vanden Bogaerde A. Parameters for carrot quality and the development of the inner quality concept. The Netherlands: Louis Bolk Institute; 2004.Search in Google Scholar

[26] Johansen TJ, Thomsen MG, Løes AK, Riley H. Root development in potato and carrot crops – influences of soil compaction. Acta Agr Scand Sect B – Soil Plant Sci. 2015;65(2):182–92. 10.1080/09064710.2014.977942.Search in Google Scholar

[27] Misganaw A, Yeshambel Y. Effect of row spacing on growth and yield components of carrot (Dacusa carrot L). J Hortic. 2021;8(2):1–6.Search in Google Scholar

[28] Thompson R. Some factors affecting carrot root shape and size. Euphytica. 1969;18:277–85. 10.1007/BF00035699.Search in Google Scholar

[29] Szczepanek M, Wilczewski E, Pobereżny J, Wszelaczyńska E, Ochmian I. Carrot root size distribution in response to bio stimulant application. Acta Agric Scand Sect B Soil Plant Sci. 2017;67(4):334–9. 10.1080/09064710.2017.1278783.Search in Google Scholar

[30] McCollum TG, Locacio SJ, White JM. Plant density and row arrangement effect on carrot yields. J Amer Soc Hort Sci. 1986;111(5):648–51.10.21273/JASHS.111.5.648Search in Google Scholar

[31] Salter PJ, Currah IB, Fellows JR. Further studies on the effects of plant density, spatial arrangement and time of harvest on yield and root size in carrots. J Agric Sci. 1980;94(2):465–78.10.1017/S0021859600029087Search in Google Scholar

[32] Mack HJ. Effect of row spacing on processing carrot root yields. Hortic Sci. 1980;15(2):144–5.Search in Google Scholar

[33] Resende GM, Yuri JE, Costa ND. Planting times and spacing of carrot crops in the São Francisco Valley, Pernambuco state, Brazil. Rev Caatinga Mossoró. 2016;29(3):587–93.10.1590/1983-21252016v29n308rcSearch in Google Scholar

[34] Evers AM, Tuuri H, Hagg M, Plaami S, Häkkinen U, Talvitie H. Soil forming and plant density effects on carrot yield and internal quality. Plant Foods Hum Nutr. 1997;51(4):283–94.10.1023/A:1007955818503Search in Google Scholar

[35] Basso NCF, Bianchi CAM, Lucchese OA, Schiavo J, Carvalho IR, da Silva JAG, et al. Performance of agro-ecological based carrot cultivars affected by plant arrangement. Genet Mol Res. 2021;20(4):GMR18941.10.4238/gmr18941Search in Google Scholar

[36] Ladumor RG, Nandre BM, Sharma MK, Wankhade VR, Joshi PC. Performance of different varieties of carrot (Daucus carota L.) with respect yield, quality and chemical compositions under varying sowing times. Int J Curr Microbiol Appl Sci. 2020;9(2):126–32.10.20546/ijcmas.2020.902.015Search in Google Scholar

Received: 2020-10-20
Revised: 2021-12-06
Accepted: 2021-12-06
Published Online: 2021-12-31

© 2021 Habtamu Tegen and Mnuyelet Jembere, published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

Downloaded on 28.2.2024 from https://www.degruyter.com/document/doi/10.1515/opag-2021-0062/html
Scroll to top button