Broccoli (Brassica oleracea L. var. italica) comes from the Latin word ‘brachium’. Brachium means ‘branched tree branches’, and it got this name because the shape of broccoli resembles the shape of tree branches (Doğru et al., 2016). Broccoli is a cruciferous vegetable renowned for its rich nutritional profile, including high levels of vitamins K, C and A, as well as essential minerals like potassium, calcium and iron. Its cultivation is influenced by various factors, notably fertilisation practices and geographical location. It contains several antioxidants, including vitamins C and E, β-carotene and various flavonoids (Syed et al., 2023). It is a well-known fact that the yield, chemical composition, nutritional value and quality of growing crops are influenced by factors such as genetic variation, climatic conditions and management practices, mainly mineral fertilisation (Serri et al., 2021; Hossaın and Islam, 2024). In Turkey, on a regional basis, as of 2023, the Aegean region (63218 tons) ranks first in production, followed by the Mediterranean region (21193 tons) and the Eastern Marmara region (14142 tons), which rank second and third, respectively (TUIK, 2024). According to broccoli production data in Turkey, there has been a consistent increase from 2019 to 2023. Turkish Statistical Institute (TUIK) data indicates that broccoli production will reach 131762 tonnes by 2024. It is clear that despite its health benefits, broccoli is not in a competitive position compared to other products. Broccoli grows best in clay-loam soils but is also tolerant to different soil types. The optimal soil pH should be between 5.5 and 6.5. The study comparing the effects of bio-fertilizers and inorganic fertilizers on the abundance of soil microorganisms, microbial activity, functional gene diversity and yield found that bio-fertilizers positively impact yield by enhancing soil biodiversity (Ollıo et al., 2023). Geographical location plays a crucial role in determining the environmental conditions to which broccoli plants are exposed, including climate, soil characteristics and altitude. These environmental factors can influence plant growth, development and biochemical composition, ultimately impacting the yield and quality of broccoli produced (Marschner, 2012).
Furthermore, fertilizer application is a fundamental aspect of modern agricultural practices aimed at enhancing crop productivity and quality and minimising the negative effects of excessive fertilisation (Kavıyarasan et al., 2024). Different types of fertilizers, such as organic and synthetic fertilizers, contain varying concentrations of essential nutrients that can affect plant growth and nutrient accumulation. Studies have shown that fertilizer management practices can significantly influence the yield of broccoli and other vegetables and their nutritional content. It was stated that sheep manure, bio-fertilizer and inorganic fertilizer applications are better in terms of yield and quality under greenhouse conditions (Saeed, 2022). In a study on the effect of leaf spray of zinc and boron elements on the growth, yield and nutritional values of broccoli heads, it was stated that in broccoli, leaf spray (mixed zinc + boron at 200 ppm each) increased the vegetative growth, physical quality and nutritional value of the heads (Mahmoud et al., 2019). In a study on broccoli yield and chemical components, the highest plant height, leaf area, leaf/plant fresh and dry weight, head weight and diameter values, as well as spike yield, were recorded with monoammonium phosphate (MAP) fertilizer and inoculation. Phosphoric acid (PA) fertilisation with mycorrhiza resulted in the highest head length, total carbohydrate and total soluble solid content (Mohamed et al., 2021). Research on 15 different applications of nano-zeolite, nano-micronutrients and biocapsules found that foliar application of T15 (NPK + nanozeolite 50 ppm [soil wetting] + biocapsule 500 ppm + ZnO and FeO nanoparticles) and T13 (NPK + biocapsule 500 ppm [soil wetting] + ZnO and FeO nanoparticles) yielded the best results in plant height, leaf area and number of leaves. The best head diameter and marketable head yield were achieved with T15 (Prıyanka et al., 2022). Additionally, bio-fertilizers, particularly those containing Bacillus megaterium, Pseudomonas fluorescens and Pantoea agglomerans, significantly increased broccoli yield and reduced the need for chemical fertilizers by 50% when used together (Demir et al., 2023). Fertilisation significantly impacts broccoli’s growth, yield and quality. Traditional inorganic fertilizers have been widely used to enhance crop productivity; however, concerns about environmental sustainability and soil health have led to increased interest in organic alternatives like vermicompost. Vermicompost, produced by the decomposition of organic matter by earthworms, is rich in essential nutrients and beneficial microorganisms, promoting plant growth and improving soil structure.
Studies comparing vermicompost with conventional fertilizers have demonstrated its effectiveness in enhancing broccoli production. For instance, research indicates that vermicompost application results in superior plant height, leaf area and head diameter in broccoli compared to traditional farmyard manure. Moreover, integrating vermicompost with inorganic fertilizers has been shown to improve growth, yield and quality in broccoli (Sharma et al., 2024). Similarly, Ghosh et al. (2020) and Patra et al. (2022) reported that vermicompost application led to increased yields in other crops such as maize and ginger. These findings suggest that the combination of vermicompost and bio-fertilizers is an effective approach for improving both the yield and quality of broccoli production. Geographical location significantly affects broccoli cultivation, as climatic conditions, soil characteristics and elevation influence plant growth, nutrient uptake and overall productivity (Mujahed et al., 2021). Therefore, understanding the interaction between fertilisation strategies and site-specific environmental variables is critical for improving broccoli yield and quality across diverse agroecological zones (Garbach et al., 2017; Basak et al., 2022). Understanding how different fertilisation methods interact with regional environmental conditions is essential for optimising broccoli production.
This study aims to evaluate the effects of conventional (urea, P-smart and K-smart) and vermicompost fertilizers on broccoli’s growth, yield and quality across various locations. By analysing these interactions, the research seeks to provide insights into sustainable fertilisation practices tailored to specific regional conditions, thereby enhancing broccoli production efficiency and contributing to environmental conservation.
The study was conducted in two locations in Turkey: Pozantı-Adana (N 37.447730, E 34.868925) and Hasancık-Adıyaman (N 37.776194, E 38.430364), each representing distinct climatic and geographical conditions. Pozantı experiences a transitional climate between Central Anatolia and the Mediterranean (Anonymous, 2021), while Adıyaman has a warmer climate with annual precipitation levels significantly higher (Anonymous, 2020). Experimental site coordinates and map images are shown in Figure 1 for both locations, and Table 1 provides the average climate data collected during the cultivation period. Soil characteristics for the Adıyaman and Pozantı sites are summarized in Table 2.
Coordinates of experimental sites and map images of Adiyaman and Pozantı locations, respectively.
Climate data for Adıyaman and Pozantı during broccoli cultivation in 2022–2023.
| Year | Location | Average temperature (°C) | Average humidity (%) | Total rainfall (mm)* |
|---|---|---|---|---|
| 2022 | Pozantı | 11.78 | 55.92 | 186 |
| Adıyaman | 18.07 | 46.22 | 456 | |
| 2023 | Pozantı | 12.32 | 58.60 | 155 |
| Adıyaman | 18.90 | 45.62 | 609 |
The variation in rainfall across different locations can be primarily attributed to seasonal differences.
Soil analysis of Adıyaman and Pozantı locations.
| Parameters | Adıyaman | Pozantı |
|---|---|---|
| Texture | Clay | Clay-loam |
| CaCO3 (%) | 2.05 | 6.85 |
| pH | 7.60 | 7.43 |
| EC (μS · cm−1) | 1158.0 | 0.045 |
| Organic matter (%) | 1.42 | 1.07 |
| P (kg · ha−1) | 14.01 | 18.5 |
| K2O (kg · ha−1) | 51.26 | 42.42 |
| Fe (mg · kg−1) | 5.5 | 4.9 |
| Zn (mg · kg−1) | 8.0 | 5.8 |
| Cu (mg · kg−1) | 5.2 | 3.6 |
| Mn (mg · kg−1) | 10.3 | 1.5 |
EC, electrical conductivity.
Two cultivars of broccoli (Brassica oleracea var. italica), ‘Orantes’ F1 and ‘Robredo’ F1 (from the company Rijk Zwaan), were grown under open-field conditions. Seedlings were obtained from the Çukurova Fide Ltd. ‘Orantes’ F1’s average maturity period is 70-75 days, which is suitable for cultivation in late summer and autumn, featuring a fruit weight of 0.5 kg, above-average plant height, long-standing in the field and easy to clean, and it has a very uniform fruit structure. ‘Robredo’ F1’s average maturity period is 110-120 days, which has very uniform curds, and the plant is vigorous and fast-growing. It is resistant to fungal diseases.
The experiment was conducted according to the randomised block trial design, with three replications in two locations. Although Adıyaman-Hasancık and Pozantı-Adana are located in different geographical regions—Southeastern Anatolia and the Mediterranean Region of Turkey, respectively, they exhibit several similar agroclimatic characteristics. Both locations experience long, hot and dry summers, along with mild spring and autumn seasons. The relatively low incidence of frost, combined with high annual sunshine duration (approximately 2800–3000 hr), supports vigorous vegetative.
According to preliminary trial results, it was determined that the autumn season is more suitable for planting in the Adıyaman location, while the spring season is preferable for the Pozantı location. Based on this finding, plantings were conducted during autumn (at the beginning of September) in Adıyaman (from 15 September 2022 to 5 September 2023) and during spring in Pozantı (from 15 April 2022 to 10 March 2023) for a period of 2 years.
Before transplanting the seedlings, land preparations were conducted in both locations according to the trial plan, and planting spots were measured and marked. Hoeing was performed to fill the collars, and irrigation was applied using the drip irrigation method at both locations. For pest control during the trial, spraying was conducted thrice every 2 years in Pozantı and twice in the second year in Adıyaman. Pest management was carried out using Matador, an insecticide formulated with 250 g · L−1 cypermethrin as the active ingredient. Weeds were manually removed and hoed away from the field.
According to the soil analysis, it is recommended to apply half of the nitrogen and all of the phosphorus and potassium as base fertilizers during soil preparation, while the remaining nitrogen is applied after the first harvest. P-smart (137.5 mL), K-smart (375 mL), and urea (157.5 g) were applied per planting area. Additionally, 150 g of vermicompost was added to the seedling pits during transplanting. The contents and amounts of vermicompost used in the study were as follows: CaCO3—8.46%, organic matter—57.43%, N—2.18%, P—8038 mg · kg−1, Na—3704 mg · kg−1, K2O—22.460 mg · kg−1, Ca—55.520 mg · kg−1, Mg— 21.050 mg · kg−1, Fe—18.290 mg · kg−1, Cu—47.04 mg · kg−1, Mn—361.60 mg · kg−1, Zn—461.30 mg · kg−1 and B—128.4 mg · kg−1.
The average main head weight (g), main head diameter (cm), main head height (cm), main head yield (kg · m−2) and total yield (kg · ha−1) were determined. The average main head weight and yield parameters were measured using a digital scale, while the primary head diameter and height were measured using a ruler.
The vitamin C (
Soil and plant analyses were conducted at the Central Research Laboratory of Adıyaman University’s Application and Research Center. The pH of soil samples was determined in 1:2.5 soil:water mixture (Thomas, 1996); CaCO3 content was determined using Scheibler calcimeter (Evliya, 1964); electrical conductivity (EC) was determined in saturation mud (Rhoades, 1996) and organic matter was measured using the Bouyoucos hydrometer method (Bouyoucos, 1962) and determined according to the modified Walkey-Black method (Nelson and Sommers, 1996).
From a final sample volume of 30 mL, 0.1 mL was taken for potassium (K) analysis, which was diluted in 15 mL of ultrapure water. For phosphorus (P), zinc (Zn) and copper (Cu) analyses, 0.2 mL was taken and diluted in 15 mL of ultrapure water. Additionally, 0.025 mL was taken for iron (Fe) analysis, diluted to 10 mL with ultrapure water and analysed using a Perkin Elmer NexION 350X model ICP-MS device (PerkinElmer Inc., Waltham, Massachusetts, USA) (Becker et al., 2007). To determine the nitrogen (N) levels, broccoli florets were dried and ground in an oven, and the dried samples were analysed for elemental composition using an elemental analyser (Vario MICRO cube, Elementar, Langenselbold, Germany).
The experiment was set up according to the randomised complete block design (RCBD) with three replications. In each replication, 16 plants of each cultivar and fertilizer type were grown. The data obtained were processed into an Excel file. Statistical analyses were performed using the JMP 8 package program (SAS Institute Inc., Cary, North Carolina, USA). The data were subjected to variance analysis, and the statistical differences between the averages were grouped at a 5% significance level using the LSD (Least Significant Difference) test.
According to statistical analysis, head width and head height did not show statistically significant differences (p > 0.05) in either the first or the second year. However, average head weight and SPAD values exhibited significant differences between treatments (p < 0.05), indicating a measurable response to the applied fertilizer types.
The effects of vermicompost and conventional fertilizer applications on ‘Orantes’ F1 and ‘Robredo’ F1 broccoli cultivars were investigated in the Adıyaman and Pozantı locations. The data obtained for plant growth parameters and yield parameters were analysed, and the results are presented in Table 3. The results of head width and head height parameters were found to be statistically significant. In the Pozantı location, the head width of the ‘Orantes’ F1 generally showed higher values in conventional fertilizer applications. The highest values were recorded as 12.16 cm and 12.72 cm in conventional fertilizer application in the first and second years, respectively. In the Adıyaman location, head width was recorded as 12.10 cm and 12.96 cm in conventional fertilizer application in the first and second years, respectively. In the Pozantı location, the ‘Robredo’ F1 head width generally showed higher values in vermicompost and conventional fertilizer applications. The highest values were recorded as 13.74 cm in the first year and 13.05 cm in the second year in conventional fertilizer application. In the Adıyaman location, head width was recorded as 11.63 cm in the first year and 12.53 cm in the second year in conventional fertilizer application.
Effects of vermicompost and conventional fertilizer applications on head width-height (cm) and SPAD reading in the cultivation of ‘Orantes’ F1 and ‘Robredo’ F1 broccoli cultivars in different locations.
| Plant growth parameters | Fertilizers | Cultivars/locations/applications | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Adiyaman | Pozanti | ||||||||
| Orantes | Robredo | Orantes | Robredo | ||||||
| First year | Second year | First year | Second year | First year | Second year | First year | Second year | ||
| Head width (cm) | Vermicompost | 8.96 e | 12.06 ab | 9.90 d | 11.66 b | 10.95 c | 12.66 ab | 13.01 a | 13.05 a |
| LSD0.05 = NS for first year; LSD0.05 = NS for second year | |||||||||
| Head height (cm) | Vermicompost | 12.10 e | 14.26 a | 11.83 e | 13.86 a | 14.01 bcd | 14.42 a | 14.76 ab | 14.47 a |
| LSD0.05 = NS for first year; LSD0.05 = NS for second year | |||||||||
| SPAD reading | Vermicompost | 55.20 e | 82.96 a | 73.33 c | 74.10 c | 79.48 b | 77.22 bc | 71.86 cd | 69.76 d |
| LSD0.05 = 0.79 for first year***; LSD0.05 = 1.15 for second year** | |||||||||
p ≤ 0.001;
p ≤ 0.01;
p ≤ 0.05. Different lowercase letters within the same column (or row) indicate statistically significant differences at the p< 0.05 level. Groups sharing the same letter are not significantly different.
NS, not significant; soil and plant analyzer development (chlorophyll meter).
In Pozantı, vermicompost application provided the highest head height in ‘Orantes’ F1. It was measured as 14.01 cm and 14.42 cm in the first and second years, respectively. In Adıyaman, the conventional fertilizer application gave the best result with 14.26 cm and 14.83 cm head heights in the first and second years. In ‘Robredo’ F1, similar values were measured from conventional fertilizer and vermicompost applications. Measurements were taken from the vermicompost and conventional fertilizer applications in the first and second years. It was measured as 14.76 cm and 14.87 cm in the first year, while it was measured as 14.47 cm and 14.74 cm in the second year. In the Adıyaman location, better results were obtained than conventional fertilizer application in both years (13.23 cm and 14.50 cm) (Table 3).
For the SPAD reading parameter in the Pozantı location, conventional fertilizer application reached the highest SPAD reading values in ‘Orantes’ F1. It was measured as 85.72 and 81.76 in the first and second years, respectively. In Adıyaman, the vermicompost application gave the best result with an 82.96 SPAD reading in the second year. In the Pozantı location, conventional fertilizer application reached the highest SPAD reading values in ‘Robredo’ F1. It was measured as 78.92 and 80.85 in the first and second years, respectively. In Adıyaman, the vermicompost application gave the best result with a 74.10 SPAD reading in the first year.
‘Orantes’ F1 generally performed better in the Pozantı location and conventional fertilizer applications. ‘Robredo’ F1 provided a higher yield than conventional fertilizer in the Adıyaman location. Conventional fertilizer applications gave better results in yield parameters such as head width, head height and average head weight in both the ‘Orantes’ F1 and ‘Robredo’ F1 cultivars. However, conventional fertilizer applications generally obtained higher results in SPAD reading values. In the Pozantı location, generally higher growth and yield parameters were observed in both broccoli cultivars. This situation shows that Pozantı may have more favourable environmental conditions for broccoli cultivation.
According to the statistical analyses made separately for both years, average head weight (g · plot−1) was not significant in the first year, while it was significant at p < 0.01 level in the second year (Table 4). Total yield (kg · plot−1) was found significant at p < 0.05 level, while it was insignificant in the second year. Total yield (kg · da−1) was significant in both years (first year, p < 0.001 and second year, p < 0.05).
Yield parameters of vermicompost and conventional fertilizer applications in the cultivation of ‘Orantes’ F1 and ‘Robredo’ F1 broccoli cultivars in different locations.
| Plant yield parameters | Fertilizers | Cultivars/locations/applications | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Adiyaman | Pozanti | ||||||||
| Orantes | Robredo | Orantes | Robredo | ||||||
| First year | Second year | First year | Second year | First year | Second year | First year | Second year | ||
| Average head weight (g · plot−1) | Vermicompost | 110.70 c | 190.63 de | 185.71 b | 238.09 bc | 202.50 b | 232.61 bcd | 195.66 b | 187.00 e |
| LSD0.05 = NS for first year; LSD0.05 = 42.91 for second year** | |||||||||
| Total yield (kg · plot−1) | Vermicompost | 1.69 cd | 1.96 ab | 2.54 ab | 2.14 ab | 1.21 cd | 0.90 c | 1.73 cd | 1.38 bc |
| LSD0.05 = 0.63 for first year*; LSD0.05 = NS for second year | |||||||||
| Yieldt (kg · da−1) | Vermicompostt | 753.88 de | 873.92 b | 1130.17 b | 953.31 b | 683.97 e | 1327.65 a | 948.43 c | 788.61 bc |
| LSD0.05 = 149.43 for first year***; LSD0.05 = 334.33 for second year* | |||||||||
p ≤ 0.001;
p ≤ 0.01;
p ≤ 0.05. Different lowercase letters within the same column (or row) indicate statistically significant differences at the p < 0.05 level. Groups sharing the same letter are not significantly different.
NS, not significant.
In Adıyaman, the average head weight (g · plot−1) for the ‘Orantes’ F1 cultivar with vermicompost application was 110.70 g in the first year and 190.63 g in the second year, while conventional fertilizer application resulted in 133.79 g and 216.58 g, respectively. In Pozantı, vermicompost application yielded 202.50 g in the first year and 232.61 g in the second year, whereas conventional fertilizer application produced 303.66 g in the first year and 336.50 g in the second year. Regarding total yield (kg · plot−1), vermicompost application in Adıyaman resulted in 1.69 kg in the first year and 1.96 kg in the second year, while conventional fertilizer produced 2.01 kg in the first year and 1.87 kg in the second year. In Pozantı, vermicompost resulted in 1.21 kg in the first year and 0.90 kg in the second year, and conventional fertilizer produced 2.59 kg in the first year and 2.60 kg in the second year. Yield (kg · da−1) measurements showed that vermicompost in Adıyaman yielded 753.88 kg in the first year and 873.92 kg in the second year, while conventional fertilizer produced 893.55 kg and 831.71 kg in the first and second years, respectively. In Pozantı, vermicompost application resulted in 683.97 kg in the first year and 1327.65 kg in the second year, while conventional fertilizer produced 1403.74 kg in the first year and 531.68 kg in the second year.
In Adıyaman, for the ‘Robredo’ F1 cultivar, the average head weight (g · plot−1) with vermicompost application was 110.70 g in the first year and 190.63 g in the second year, while conventional fertilizer yielded 133.79 g and 216.58 g in the first and second years, respectively. In Pozantı, vermicompost application resulted in 202.50 g in the first year and 232.61 g in the second year, while conventional fertilizer produced 303.66 g and 336.50 g in the first and second years, respectively. For total yield (kg · plot−1), vermicompost in Adıyaman resulted in 1.69 kg in the first year and 1.96 kg in the second year, while conventional fertilizer produced 2.01 kg and 1.87 kg in the first and second years, respectively. In Pozantı, vermicompost yielded 1.21 kg in the first year and 0.90 kg in the second year, and conventional fertilizer produced 2.59 kg and 2.60 kg in the first and second years, respectively. Yield (kg · da−1) measurements showed that vermicompost in Adıyaman resulted in 753.88 kg in the first year and 873.92 kg in the second year, whereas conventional fertilizer yielded 893.55 kg and 831.71 kg in the first and second years, respectively. In Pozantı, vermicompost produced 683.97 kg in the first year and 1327.65 kg in the second year, while conventional fertilizer yielded 1403.74 kg in the first year and 531.68 kg in the second year. As a general evaluation, in the Adıyaman location, conventional fertilizer applications generally resulted in higher yield and average head weight for both ‘Orantes’ F1 and ‘Robredo’ F1, indicating that conventional fertilizer is better suited for Adıyaman’s soil and climate conditions. In the Pozantı location, conventional fertilizer application generally yielded higher results in ‘Orantes’ F1. However, no significant difference was observed between vermicompost and conventional fertilizer in terms of yield parameters for ‘Robredo’ F1. ‘Orantes’ F1 produced the highest yield with conventional fertilizer, especially in Pozantı, where it also exhibited higher head weight and yield. In Adıyaman, ‘Robredo’ F1 showed the highest yield with conventional fertilizer. Overall, higher yield and head weight were obtained at both locations for both cultivars, suggesting that conventional fertilizer may be more effective for broccoli cultivation. Vermicompost applications also provided satisfactory results under certain conditions, but generally, lower yield and head weight values were observed compared to conventional fertilizer. These results highlight that location, cultivar and fertilizer type are crucial factors that significantly influence broccoli yield and plant growth parameters and should be carefully considered for optimal production.
The effects of vermicompost and conventional manure on vitamin C, total phenolic content, and color parameters in ‘Orantes’ F1 and ‘Robredo’ F1 cultivars across different locations are presented in Table 5. In Adıyaman, conventional fertilizer application in ‘Orantes’ F1 provided higher vitamin C content compared to vermicompost in both years. Vitamin C content of 1392.13 mg · 100 g−1 was measured in the first year and 1128.93 mg · 100 g−1 in the second year. Similarly, in ‘Robredo’ F1, conventional fertilizer application provided higher vitamin C content (1418.53 mg · 100 g−1) in the second year. In Pozantı, no significant differences were observed in vitamin C content between vermicompost and conventional fertilizer applications. However, low vitamin C values were generally obtained in both fertilizer types. In Adıyaman, conventional fertilizer application provided higher total phenolic content than vermicompost for both broccoli cultivars. In ‘Orantes’ F1, the phenolic content of 434.11 mg · 100 g−1 was measured in the first year with conventional fertilizer and 358.48 mg · 100 g−1 in the second year. In Pozantı, no significant difference was observed in terms of total phenolic content between the two fertilizer types. However, low total phenolic contents were generally obtained in both fertilizer applications (Table 5). In Adıyaman, conventional fertilizer applications typically provided higher chroma values from colour parameters.
Effect of vermicompost and conventional manure applications on vitamin C, total phenolic and colour parameters in the cultivation of ‘Orantes’ F1 and ‘Robredo’ F1 cultivars in different locations
| Quality parameters | Fertilizers | Cultivars/locations/applications | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Adiyaman | Pozanti | ||||||||
| Orantes | Robredo | Orantes | Robredo | ||||||
| First year | Second year | First year | Second year | First year | Second year | First year | Second year | ||
| Vitamin C (mg · 100 g−1) | Vermicompost | 1044.93 c | 974.46 c | 1249.06 b | 1257.83 ab | 115.00 f | 212.33 d | 113.66 f | 145.00 d |
| Conventional fertilizer | 1392.13 a | 1128.93 bc | 951.60 d | 1418.53 a | 172.33 e | 195.00 d | 112.66 f | 188.66 d | |
| LSD0.05 = 18.62 for first year***; NS for second year | |||||||||
| Total phenolic (mg · 100 g−1) | Vermicompost | 364.46 b | 315.82 a | 323.67 b | 347.72 a | 155.61 c | 116.64 bc | 136.64 c | 108.45 c |
| Conventional fertilizer | 434.11 a | 358.48 a | 331.81 b | 311.51 a | 163.05 c | 165.61 b | 136.64 c | 156.38 bc | |
| LSD0.05 = NS for first year; LSD0.05 = NS for second year | |||||||||
| Colour parameter chroma |(C) | Vermicompost | 125.96 ab | 127.23 b | 126.37 ab | 130.62 b | 92.37 d | 100.99 d | 95.98 d | 100.23 d |
| Conventional fertilizer | 129.85 a | 128.71 b | 120.71 b | 145.84 a | 99.51 cd | 106.35 c | 106.35 c | 110.31 c | |
| LSD0.05 = NS for first year; LSD0.05 = NS for second year | |||||||||
| Colour parameter (h°) | Vermicompost | 8.84 cd | 10.93 b | 7.40 de | 8.96 c | 9.71 bc | 10.32 bc | 12.51 a | 10.37 bc |
| Conventional fertilizer | 4.52 f | 9.41 c | 6.65 ef | 3.79 d | 5.54 ef | 9.08 c | 11.50 ab | 12.77 a | |
| LSD0.05 = NS for first year; LSD0.05 = NS for second year | |||||||||
p ≤ 0.001;
p ≤ 0.01;
p ≤ 0.05. Different lowercase letters within the same column (or row) indicate statistically significant differences at the p < 0.05 level. Groups sharing the same letter are not significantly different.
NS, not significant.
In ‘Orantes’ F1, a 99.51 chroma value was obtained in the first year and 106.35 in the second year with conventional fertilizer. In Pozantı, vermicomposting applications gave acceptable chroma results. In ‘Robredo’ F1, a 95.98 chroma value was obtained in the first year and 100.23 in the second year with vermicomposting. Regarding other colour parameter (h°) values in Adıyaman, conventional fertilizer applications generally gave lower h° values. In ‘Robredo’ F1, 6.65 h° value was obtained with conventional fertilizer in the first year and 3.79 h° value in the second year. In Pozantı, both vermicompost and conventional fertilizer applications showed similar h° values. In ‘Orantes’ F1, 9.71 h° values were obtained with vermicompost in the first year and 10.32 in the second year (Table 5).
In the evaluation of quality parameters of vitamin C content, conventional fertilizer provided higher vitamin C content for ‘Orantes’ F1 in Adıyaman both in the first and second years. Conventional fertilizer provided the highest vitamin C content for ‘Robredo’ F1 in the second year. No significant differences were observed between vermicompost and conventional fertilizer for both broccoli cultivars in Pozantı. In total phenolic content, conventional fertilizer application provided higher total phenolic content than vermicompost application for both broccoli cultivars in Adıyaman. No significant difference was observed between both fertilizer types in Pozantı. According to colour parameters, conventional fertilizer application in Adıyaman provided generally higher chroma values. In Pozantı, vermicompost applications gave acceptable results. While conventional fertilizer applications gave lower h° values in Adıyaman, both vermicompost and conventional fertilizer applications showed similar results in Pozantı. These results show that location, cultivar and fertilizer type selection in broccoli cultivation significantly affect yield plant growth parameters and quality parameters. These factors should be carefully evaluated to obtain optimum quality and yield.
The results obtained are shown in Table 6. According to the statistical analysis of nutrient concentration, N, Fe and Zn were not found to be significant in the first year, while N, Fe, Zn, Mn and K concentrations were not significant in the second year. In Adıyaman, conventional fertilizer application in ‘Orantes’ F1 provided higher nitrogen concentration compared to vermicompost in both years. Nitrogen concentration was measured as 6.36% in the first year and 6.53% in the second year. In ‘Robredo’ F1, nitrogen concentration was lower in conventional fertilizer application than in vermicompost application. In Pozantı, conventional fertilizer application in the ‘Orantes’ F1 and ‘Robredo’ F1 cultivars generally provided higher nitrogen concentrations. In ‘Robredo’ F1, 7.04% nitrogen concentration was obtained with conventional fertilizer. In Adıyaman, vermicompost application on ‘Orantes’ F1 provided 26707.98 ppm potassium concentration in the first year and 27862.72 ppm in the second year. In ‘Robredo’ F1, conventional fertilizer application provided 30425.45 ppm potassium concentration. In Pozantı, vermicompost application on ‘Orantes’ F1 provided 34739.57 ppm potassium concentration. In ‘Robredo’ F1, the vermicompost application provided 35887.03 ppm potassium concentration. In Adıyaman, conventional fertilizer application on ‘Orantes’ F1 provided 66258.16 ppm iron concentration. In ‘Robredo’ F1, the vermicompost application provided 311217.72 ppm iron concentration in the second year. In Pozantı, vermicompost application on ‘Orantes’ F1 provided 79345.11 ppm iron concentration. In ‘Robredo’ F1, conventional fertilizer application provided 120686.83 ppm iron concentration in the first year. In Adıyaman, conventional fertilizer application in ‘Orantes’ F1 provided 35845.47 ppm zinc concentration. The vermicompost application provided 34187.30 ppm zinc concentration in ‘Robredo’ F1. In Pozantı, vermicompost application in ‘Orantes’ F1 provided 38632.63 ppm zinc concentration. In ‘Robredo’ F1, conventional fertilizer application provided 58923.15 ppm zinc concentration. In Adıyaman, vermicompost application provided 2052.54 ppm manganese concentration in ‘Orantes’ F1. In ‘Robredo’ F1, the conventional fertilizer application provided 22441.96 ppm manganese concentration in the second year. In Pozantı, the vermicomposting application provided 32497.24 ppm manganese concentration in ‘Orantes’ F1. The vermicomposting application provided 36774.72 ppm manganese concentration in ‘Robredo’ F1.
Effects of vermicompost and conventional fertilization on nutrient elements in the cultivation of Orantes and Robredo cultivars in different locations.
| Plant nutrient contents | Fertilizers | Varieties/locations/applications | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Adiyaman | Pozanti | ||||||||
| Orantes | Robredo | Orantes | Robredo | ||||||
| First year | Second year | First year | Second year | First year | Second year | First year | Second year | ||
| N (%) | Vermicompost | 5.50 c | 5.50 b*** | 3.97 e | 5.08 c | 4.04 e | 4.15 e | 5.48 c | 5.11 bc |
| Conventional fertilizer | 6.36 b | 6.53 a | 4.42 de | 5.44 bc | 4.82 d | 4.65 d | 7.04 a | 6.74 a | |
| LSD0.05 = NS for first year; LSD0.05 = 0.36 for second year*** | |||||||||
| K (%) | Vermicompost | 26707.98 b | 27862.72 d | 18859.24 c | 31279.59 b | 29355.80 a | 34739.57 a | 27619.04 ab | 35887.03 a |
| Conventional fertilizer | 20646.86 c | 28125.41 cd | 28129.27 ab | 30425.45 bcd | 26089.09 b | 31067.29 bc | 29746.07 a | 31508.28 b | |
| LSD0.05 = 2485.77 for first year***; LSD0.05 = NS for second year | |||||||||
| Fe (ppm) | Vermicompost | 44426.70 ef | 82800.23 b | 34616.82 f | 65180.09 b | 79345.11 c | 64633.04 b | 120686.83 a | 115300.63 b |
| Conventional fertilizer | 55665.12 de | 66258.16 b | 53745.76 e | 311217.72 a | 69281.08 cd | 55887.57 b | 101680.64 b | 116183.29 b | |
| LSD0.05 = NS for first year; LSD0.05 = NS for second year | |||||||||
| Zn (ppm) | Vermicompost | 39989.98 bc | 34187.30 b | 33587.70 cd | 28548.90 c | 38632.63 bc | 37312.20 b | 51124.68 ab | 52323.36 a |
| Conventional fertilizer | 35845.47 cd | 27718.59 c | 23872.60 d | 34083.73 b | 46698.52 abc | 26375.05 c | 58923.15 a | 51639.39 a | |
| LSD0.05 = NS for first year; LSD0.05 = NS for second year | |||||||||
| Mn (ppm) | Vermicompost | 2052.54 ef | 22682.51 b | 18749.85 f | 20686.95 b | 32497.24 b | 23819.90 b | 36774.72 a | 29095.14 a |
| Conventional fertilizer | 19278.51 f | 217551.14 b | 22441.96 e | 22217.85 b | 25842.62 d | 23447.35 b | 28358.24 c | 24896.91 ab | |
| LSD0.05 = 2315.69 for first year**; LSD0.05 = NS for second year | |||||||||
p ≤ 0.001;
p ≤ 0.01;
p ≤ 0.05.Different lowercase letters within the same column (or row) indicate statistically significant differences at the p < 0.05 level. Groups sharing the same letter are not significantly different.
NS, not significant.
In Adıyaman, conventional fertilizer application in ‘Orantes’ F1 generally provided higher nitrogen, iron and zinc concentrations. Vermicompost application gave positive results, especially in terms of potassium concentration. In Pozantı, vermicompost application in ‘Robredo’ F1 provided higher potassium, iron and manganese concentrations. Conventional fertilizer application provided higher values in terms of nitrogen and zinc concentration. These results show that location, cultivar and fertilizer type selections affect nutrient element concentrations in broccoli cultivation. These factors should be carefully evaluated to obtain optimum nutrient concentration.
Among the cultivars, the highest average main crown weight was observed in the Topeka cultivar, with 678 g, followed by the Tutku cultivar at 650 g, which was statistically similar. The lowest average main crown weight was recorded in the ‘Marathon’ cultivar, with 547 g (Alan and Sönmez, 2012). Eşiyok (1996) reported in his study, conducted under Aegean region conditions, that the main crown weights ranged from 204 g to 389 g, while Eryılmaz (1999) found that the main crown weights in Tekirdağ ranged from 51 g to 576 g. Additionally, reported a range of 536–729 g for main crown weights in a study conducted in Konya.
The ‘Topeka’ cultivar also recorded the highest main crown diameter in 2008, measuring 20.23 cm, while the lowest main crown diameter was found in the ‘Monopoly’ cultivar in 2009, with 15.38 cm (Alan and Sönmez, 2012). These results align with previous studies, which indicated that the main crown diameter can vary between 5 cm and 25 cm (Günay, 1984). The highest main crown height was observed in the ‘Topeka’ cultivar in 2008, with a measurement of 16.23 cm, while the lowest was recorded in the ‘Agassi’ cultivar in the same year, with 11.28 cm (Alan and Sönmez, 2012). Based on the annual averages, the ‘Topeka’ cultivar had the highest main crown height at 15.47 cm, followed by ‘Tutku’ (13.77 cm), ‘Roket’ (13.50 cm), ‘Marathon’ (12.99 cm), ‘Agassi’ (12.77 cm) and ‘Monopoly’ (12.42 cm), all of which were similar in height (Alan and Sönmez, 2012). In line with these findings, Yoldaş and Eşiyok (2004) reported that the main crown height ranged from 11.2 cm to 16.8 cm in their studies.
Regarding side crown weight, the ‘Topeka’ cultivar again had the highest value in 2008, with 160 g (Alan and Sönmez, 2012). The highest main crown yield was achieved by the ‘Topeka’ cultivar, with 2419 kg per hectare, followed by the ‘Tutku’ cultivar with 2321 kg. ‘Marathon’ yielded the lowest at 1951 kg · ha−1. Total yield, as shown in Table 4, was also influenced primarily by cultivar, with the ‘Topeka’ cultivar yielding the highest at 4267 kg, followed by the ‘Tutku’ cultivar with 3971 kg. ‘Marathon’ and ‘Monopoly’, which were in the same statistical group, yielded 2894 kg and 2951 kg, respectively. Previous studies have demonstrated that main crown yield and total yield can vary depending on cultivar and regional conditions. For instance, Yoldaş and Eşiyok (2004) reported total yields ranging from 1929 kg · ha−1 to 4516 kg · ha−1, while Karakaya and Paksoy (2008) found yields ranging from 3835 kg · ha−1 to 4815 kg · ha−1. When the research results were evaluated overall, it was concluded that broccoli cultivation could be successfully carried out in Eskişehir’s ecological conditions as an alternative crop, achieving good yields. The region’s ecological conditions during the summer months allowed for the production of high-quality, large main crowns, which are crucial for fresh consumption. In food industry productions, the quality and yield of side crowns are also important. The proximity of the region to the Marmara region, where many processing plants are concentrated, provides an additional advantage. However, due to the region’s ecological conditions, the number of side crowns per plant is lower, and the quality decreases as temperatures drop. Therefore, in areas with limited vegetation periods and specific climate requirements for broccoli, it is suggested that future studies focusing on planting dates could be beneficial for determining optimal yield and agricultural characteristics. As a result, it was recommended that the Topeka cultivar, which exhibits both high main crown and high side crown yield, along with the ‘Tutku’ cultivar, be considered for cultivation in the region. In their study, Aouass and Kenny (2024) investigated the efficiency of nitrogen use in broccoli cultivation at the Horticultural Complex of Agadir, Morocco. Their research evaluated various fertilizer treatments to optimise nitrogen use efficiency by comparing organic compost with synthetic chemical fertilizers. The treatments included TC 8 t · ha−1 (compost at 8 t · ha−1), TC 12 t · ha−1 (compost at 12 t · ha−1), TSYN (synthetic chemical fertilizer at 200 kg N · ha−1), TC + SYN (50% compost at 4 t · ha−1+ 50% synthetic fertilizer, totalling 200 kg N · ha−1) and T0 (control). The results showed that the combination of compost and synthetic fertilizer (TC + SYN) improved broccoli growth and yield parameters, with the highest main head yield of 13.5 t · ha−1 observed in the TC + SYN treatment. Compost also enhanced soil chemical properties, with a total nitrogen content of 266 kg · ha−1 for TC + SYN, 253 kg · ha−1 for TSYN, 244 kg · ha−1 for TC 8 t · ha−1 and 234 kg · ha−1 for TC 12 t · ha−1. In terms of nitrogen use efficiency, the apparent recovery efficiency (ARE) was highest with TSYN at 0.91, followed by TC + SYN at 0.88, TC 8 t · ha−1 at 0.77 and TC 12 t · ha−1 at 0.48. These findings suggest that combining organic and synthetic fertilizers can be an effective strategy for enhancing broccoli production and nitrogen use efficiency.
Al-Chalabı and Ibraheem (2024) conducted a study in autumn 2022 at the University of Mosul, Iraq, to investigate the effects of various fertilizer combinations and plant spacing on broccoli growth and productivity. The study used two planting distances (35 cm and 45 cm) and six fertilizer treatments, including combinations of N15P15K15S15 and N10P5K7S10MgO2.5Fe0.5Zn0.019, with a control (no fertilizer).
The results indicated that broccoli plants spaced at 45 cm exhibited a significant increase in the number of leaves compared to those spaced at 35 cm. Both plant spacing and fertilizer combinations showed varying impacts on growth and yield characteristics, with the interaction between fertilizer combinations and plant spacing having a positive influence on broccoli’s growth and yield traits.
Hossaın and Islam (2024) conducted a field experiment to identify effective fertilizer management practices for producing high-quality broccoli with increased yield. They recommended the application of cow dung at 5 t · ha−1 in combination with 50% of the recommended NPK fertilizer dose, which resulted in superior yield and quality for broccoli cultivation.
In a study on broccoli cv. Calabrese, the highest vitamin C content was observed with mustard cake at 1 t · ha−1 (100.61 mg · 100 g−1), which was statistically similar to a mustard cake at 0.75 t · ha−1 (99.56 mg · 100 g−1) (Naorem et al., 2024). The application of Azospirillum at 2 kg · ha−1 resulted in a vitamin C content of 98.15 mg · 100 g−1. Notably, the combination of mustard cake at 1 t · ha−1 and Azospirillum at 2 kg · ha−1 resulted in the highest ascorbic acid content of 101.77 mg · 100 g−1, compared to the combination of mustard cake at 0.75 t · ha−1 and Azospirillum at 2 kg · ha−1 (100.76 mg · 100 g−1). The increase in vitamin C content with the addition of bio-fertilizers and organic manure is attributed to their role in fixing atmospheric nitrogen and enhancing carbohydrate synthesis, which in turn boosts ascorbic acid levels. This effect is further supported by the positive impact of Azotobacter and Azospirillum on enzyme reactions and the formation of metabolites necessary for carbohydrate and protein synthesis.
In modern agricultural production, climate change has emerged as a significant factor. Therefore, future studies on broccoli cultivation in this region should be planned based on climate change. Moreover, discussions on agricultural techniques that could increase yield in the future, such as irrigation strategies or improved fertilisation methods, would be valuable. Emphasising the importance of further research in these areas could provide useful insights for improving crop performance under changing environmental conditions.
This study demonstrates that conventional fertilizers generally yield higher broccoli production and better quality in terms of head weight, vitamin C, total phenolic content and nitrogen levels across different locations and cultivars, particularly in Adıyaman. While vermicompost showed some advantages in potassium content and certain micronutrients, conventional fertilizers consistently outperformed them in most aspects, especially for ‘Orantes’ F1 and ‘Robredo’ F1. However, vermicompost remains a viable alternative under specific conditions, offering potential benefits for sustainable agriculture. Future research should investigate the long-term effects of these fertilisation practices on soil health and crop quality and explore the combination of conventional and organic fertilisation methods. Additionally, the impact of climate change and the adoption of advanced agricultural practices could play a crucial role in optimising broccoli cultivation.