Effectiveness of biofertilizer BiomeFert-1 on growth and productivity of Capsicum frutescens L.

Eficácia do biofertilizante BiomeFert-1 no crescimento e na produtividade de Capsicum frutescens L.

Abstract

This study aims to determine the effect of various biofertilizer dosages and application frequencies on the growth and productivity of Capsicum frutescens L., as well as to evaluate the RAE (Relative Agronomic Effectiveness) of these treatments. The experiment involved three different dosages of BiomeFert-1 (5, 10, and 15 mL/plant) applied at different frequencies, i.e., once (1 week after planting-WAP), twice (1 and 4 WAP), and three times (1, 4, and 8 WAP). Plant growth parameters measured included plant height, number of leaves, and stem diameter, while productivity was assessed based on the number of flowers produced. Growth data were descriptively observed, and productivity was analyzed using the one-way ANOVA. Plants treated with twice the applications of 10 mL biofertilizer resulted in the biggest height growth. The single application of 15 mL biofertilizer produced the most leaves. The largest stem diameter was achieved by plants treated with 15 mL biofertilizer applied three times. Meanwhile, a single application of 10 mL biofertilizer resulted in the best productivity, most flowers, and the highest RAE value (134%).

Keywords:
biofertilizer; BiomeFert-1; growth and productivity; Capsicum frustescens L

Resumo

O objetivo deste estudo é determinar o efeito de várias dosagens de biofertilizante e frequências de aplicação no crescimento e na produtividade de Capsicum frutescens L., bem como avaliar a Eficácia Agronômica Relativa (ERA) desses tratamentos. O experimento envolveu três dosagens diferentes de BiomeFert-1 (5, 10 e 15 mL/planta), aplicadas em frequências distintas: uma vez (1 WAP), duas vezes (1 e 4 WAP) e três vezes (1, 4 e 8 WAP). Os parâmetros de crescimento da planta medidos incluíram a altura da planta, o número de folhas e o diâmetro do caule, enquanto a produtividade foi avaliada com base no número de flores produzidas. Os dados de crescimento foram analisados de forma descritiva e a produtividade foi analisada por meio de ANOVA unidirecional. O tratamento B10F2 (10 mL de biofertilizante aplicado duas vezes) resultou na maior altura da planta. O tratamento B15F1 (15 mL de biofertilizante aplicado uma vez) produziu o maior número de folhas. O tratamento B15F3 (15 mL de biofertilizante aplicado três vezes) obteve o maior diâmetro de caule. O tratamento B10F1 (10 mL de biofertilizante aplicado uma vez) apresentou a melhor produtividade, produzindo o maior número de flores e o maior valor de ERA (134%).

Palavras-chave:
biofertilizante; BiomeFert-1; crescimento e produtividade; Capsicum frustescens L

1. Introduction

Cayenne pepper (Capsicum frutescens L.) is a horticultural plant belonging to the Solanaceae family and holds significant economic value (Undang et al., 2023). This species is recognized for its nutritional content, including fats, proteins, carbohydrates, calcium, phosphorus, iron, vitamins (A, B1, B2, C), and alkaloid compounds such as capsaicin and oleoresin. Most farmers cultivate chili peppers due to their high market value, particularly among consumers who favor spicy foods. In Indonesia, Capsicum species, including C. annuum, C. frutescens, C. chinense, and C. pubescens are major horticultural commodities with substantial growth potential (Sahid et al., 2022; Wijaya et al., 2020).

In 2020, BPS-Statistics Indonesia reported that the cayenne pepper production in Indonesia reached 1.51 million tons, marking a 9.76% increase from the previous year’s production of 1.37 million tons (BPS, 2020). Despite this increase, national chili production remains insufficient to meet domestic demand, calling for annual imports of over 16,000 tons. The growing demand, coupled with inadequate supply, has resulted in higher chili prices. Additional factors contributing to rising costs include the reduction of agricultural land, variable rainfall conditions, and land degradation due to decreased soil fertility (Akca et al., 2022).

The low yield in chili plants may indicate a lack of fertilizers or growth regulators application. In Indonesia, farmers typically utilize chemical fertilizers to address various growth challenges in chili cultivation. These fertilizers provide essential nutrients, including nitrogen (N), phosphorus (P), and potassium (K) (Sinha and Tandon, 2020). According to the commodity market review data of World Bank Group (2022), the rising cost of chemical fertilizers has created significant economic challenges for Indonesian farmers.

In contrast, continuous use of chemical fertilizers can adversely affect soil health (Roidah, 2013). Savci (2012) reported that chemical fertilizers containing NaNO₃, NH₄NO₃, KCl, K₂SO₄, NH₄Clcan damage soil structure and hinder efficient and quality production. Furthermore, synthetic chemicals can alter soil pH, increasing its acidity and potentially resulting in the death of beneficial microorganisms vital for soil health. As a result, plants become increasingly reliant on fertilizers, exacerbating soil degradation (IAARD, 2021).

To enhance soil fertility, which may have declined due to the use of chemical fertilizers, farmers can consider replacing them with biofertilizers. Biofertilizers are substances formulated with microorganisms that promote plant growth by increasing nutrient availability (Amutha et al., 2014). They enhance the capacity of plant roots to absorb nutrients from the soil and support plant growth through microbial activity or the action of living cells (Mohammadi and Sohrabi, 2012). Various factors influence nutrient availability in the soil, and the correct dosage and frequency of biofertilizer application are critical for optimizing crop yields. Proper management of biofertilizer application is essential for maintaining soil nutrient levels (Gulshan et al., 2022).

Biofertilizers typically comprise a mixture of microorganisms, including bacteria that serve as biocontrol agents and stimulate plant growth. These bacteria, known as plant growth-promoting rhizobacteria (PGPR), colonize the rhizosphere and foster beneficial interactions that enhance plant growth by supplying nutrients and plant growth hormones. The key microorganisms in biofertilizers include Bacillus sp. and Pseudomonas sp. as phosphate-solubilizing bacteria, Rhizobium sp., Azotobacter sp., Azospirillum sp., and Acetobacter sp. as nitrogen fixers, Cellulomonas sp. and Lactobacillus sp. as organic matter decomposers, and various microbes that produce antibiotics and growth hormones (Kumar et al., 2022).

This study aimed to evaluate the effects of the biofertilizer BioMeFert-1 formula on the growth and productivity of C. frutescens. The BioMeFert-1 formula is a new biofertilizer formula composed of four indigenous Indonesian bacterial strains, which serve as phosphate solubilizers, nitrogen fixers, IAA hormone producers, and organic matter decomposers. This formula was developed by Fatimah et al. (2020, 2021, 2022) and utilizes local potential microbes from mangrove plants and rhizosphere areas while providing abiotic stress tolerance (halotolerance) to the plants. It is expected that this formula can be applied to plants under varying conditions, including both salt stress and non-stress conditions.The research was designed to assess the impact of varying doses and application frequencies of BioMeFert-1 on the growth and productivity of C. frutescens under normal (non-stress) conditions.

2. Materials and Methods

This research was an experimental study with a completely randomized design (CRD). The materials used in this study included Bhaskara variety of cayenne pepper seeds, planting media, chemical fertilizers, and four bacteria strains isolated by previous studies: nitrogen-fixing bacteria (code 10), phosphate-solubilizing bacteria (code TBN13), cellulolytic bacteria (code L.II.3-4), and IAA-producing bacteria (code LMG 43) (Salsabila et al., 2022; Alawiyah, 2021; Azzah, 2019; Fatimah et al., 2022). The media utilized in the study comprised Nutrient Agar (NA), Nutrient Broth (NB), Pikovskaya Agar, Nitrogen Free Brothymol blue (NFB), and CMC Agar.

2.1. Rejuvenation of bacterial isolates

Rejuvenation of bacterial isolates was initiated by preparing NA media by dissolving 2.8 g of NA in distilled water to a final volume of 100 mL. The rejuvenation of bacterial isolates was done using one loopful of bacterial pure cultures plated onto the slant agar using the streak method.

2.2. Production of BioMeFert-1

Each rejuvenated bacterial isolate was put into a 100 ml NB media solution and incubated for 24 hours. All bacterial cultures from the slant media were then inoculated into a 2% molasses solution and incubated on a shaker for 24 hours.

2.3. Quality and quantity analysis of soil microbes before and after application of biofertilizer

The bacterial quantity in biofertilizer and soil was measured before planting using the microbial culture method on several specific media. First, the biofertilizer and soil samples were homogenized with sterile distilled water, followed by a serial dilution method for calculating the total amount of the soil bacteria. For nitrogen-fixing bacteria, 10 mL semisolid Nitrogen–Free Bromothymol Blue (NFB) medium was poured into nine test tubes. After sterilization, the medium was inoculated with 1 mL soil suspension and incubated at room temperature for 10 days. Bacterial growth was observed by the presence of a thin membrane under the surface of the medium, which resulted in a pellicle ring and a color change to blue.

Analysis of IAA-producing bacteria was carried out using NB medium supplemented with Tryptophan. One mL of soil suspension was added to a bottle containing 24 mL of liquid NB medium with 500 ppm L-Tryptophan. The mixture was shaken using a shaker at 120 rpm for 24 hours at 30 °C until the bacterial isolates grew in the media. After incubation, 10 mL of bacterial culture was centrifuged at 4500 rpm for 20 minutes. Four mL of Salkowski reagent was added to the 1 mL supernatant in the test tube, followed by homogenization and incubation at room temperature for 15 minutes.

Pikovskaya and CMCA media were used to count the phosphate solubilizer and cellulose degrader bacteria. The medium was sterilized and cooled before being poured into a sterile Petri dish. Next, a soil suspension was diluted with distilled water at 10^-6, 10^-7, and 10^-8, poured into the Petri dish and homogenized. When the inoculated media in the petri dish solidified, they were incubated for 3x24 hours. The number of microbial colonies formed from the TPC biofertilizer and soil results was calculated using a colony counter. Only colonies surrounded by a bright zone were counted. The number of microbial cells growing in each medium was calculated by using the Formula 1:

$$Numberofcells\left(CFU/mL\right)=TotalColonyx\frac{1}{\text{dilution factor}}$$ (1)

2.4. Preparation and planting of cayenne pepper

The soil was cleaned before being put into poly bags as planting medium. Several holes were prepared in the planting medium for planting the seedlings. One-month-old seedling with 7-8 leaves was then inserted into the hole and covered with a small amount of planting medium, followed by watering the plants. Cayenne pepper plants were cultivated for 80-85 days before harvesting.

2.5. Data collection

The plant height growth was done weekly by measuring the height (cm) from the base of the stem to the tip of the highest shoot. The number of leaves was calculated by adding all the leaves on the plant in the 12 WAP (week after planting). The stem diameter (mm) was measured with a caliper. The number of flowers and fruits was calculated by adding up the total of flowers and fruits produced by each plant. The weight of fruits (g) was calculated by weighing all the fruit that each plant produces.

2.6. Data analysis

A descriptive analysis was used to analyze data on plant height (cm), number of leaves (leaves/plant), and stem diameter (mm). Meanwhile, data on the number of flowers (flowers/plant), number of fruits (fruit), and fruit weight (g) were statistically analyzed using SPSS (Statistical Product and Service Solution) using One-Way ANOVA with a significance level of 5%, followed with the Duncan test.

2.7. Calculation of RAE values

The Relative Agronomic Effectiveness value was calculated using the formula of the Indonesian Ministry of Agriculture (Indonesia, 2011) (Formula 2):

$$\text{RAE}=\frac{(\text{B})-(\text{K}-)}{(\text{K}+)-(\text{K}-)}\times 100\%$$ (2)

where: B = Plants treated with biofertilizer;

K (-) = Negative control, Plants without fertilizer, only watered (B0-);

K (+) = Positive control, Plants treated with chemical fertilizer (B0+);

RAE value greater than or equal to 100% indicates an effective use of the biofertilizer. In contrast, RAE value lesser than 100% indicates that the use of the biofertilizer is not practical.

3. Results

3.1. Microbial measurements in soil treated with biofertilizer

3.1.1. Total plate count of bacteria in the sample before biofertilizer treatments

The microbial quality and quantity on soil samples were observed before planting, at the first and eight weeks. The results of measuring the quantity of soil microbes before the application of biofertilizer are presented in Table 1.

Table 1
Calculation of the quantity of soil microbes before application of biofertilizer.

Potential Types of Bacteria	Qualitative test		Total Colony (CFu/mL)
	Present	Not Present
Nitrogen Fixing Bacteria	✓		ND
IAA Producing Bacteria	✓		ND
Phosphate Solubilizing Bacteria			4.8 x10 6
Cellulolytic Bacteria			1.7 x10 6

• Note: ND = No Data (not counted).

3.1.2. Total plate count (TPC) bacteria on 1 WAP cayenne soil samples

The total population of phosphate solubilizing and cellulolytic bacteria in the soil treated with biofertilizer increased compared to the negative control. The highest cellulolytic bacteria population was shown in the treatment with a dose of 10 mL/plant, and the lowest was found in the treatment with a dose of 5 mL/plant. The highest population of phosphate-solubilizing bacteria was demonstrated at 15 mL/plant and the lowest at 5 mL/plant. Likewise, the qualitative tests of nitrogen-fixing and IAA-producing bacteria also showed positive results. The results of the bacterial count in the soil of cayenne pepper plants aged 1 WAP after administering biofertilizer can be seen in Table 2.

Table 2
Calculation of the quantity of soil microbes 1 WAP.

Soil treated with biofertilizer	Total Colony of Phosphate Solubilizing Bacteria (CFu/mL)	Total Colony of Celullolytic Bacteria (CFu/mL)	Presence of Nitrogen Fixing Bacteria and IAA Producing Bacteria
5 mL	2.3 x 10 8	3.3 x 10 8	✓
10 mL	4.0 x 10 8	3.7 x 10 8	✓
15 mL	3.9 x 10 8	4.3 x 10 8	✓

3.1.3. Total plate count of bacteria on 8 WAP soil samples

The soil that was administered with biofertilizer showed a decrease in bacterial populations. The results of microbial calculations in the soil of cayenne pepper plants at 8 WAP can be seen in Table 3.

Table 3
Calculation of the number of soil microbes at 8 Weeks After Planting.

Soils Sample	Total Colony of Phosphate Solubilizing Bacteria (CFu/mL)	Total Colony of Celullolytic Bacteria (CFu/mL)	Presence of Nitrogen Fixing bacteria and IAA
B0+	2.5 x 10 8	1.6 x 10 8	✓
B0-	1.3 x 10 8	5.0 x 10 7	✓
B5F1	3.3 x 10 8	2.9 x 10 8	✓
B5F2	3.2 x 10 8	2.6 x 10 8	✓
B5F3	3.2 x 10 8	2.5 x 10 8	✓
B10F1	4.0 x 10 8	3.4 x 10 8	✓
B10F2	4.0 x 10 8	3.3 x 10 8	✓
B10F3	3.0 x 10 8	3.0 x 10 8	✓
B15F1	3.5 x 10 8	2.9 x 10 8	✓
B15F2	3.8 x 10 8	3.5 x 10 8	✓
B15F3	3.6 x 10 8	3.3 x 10 8	✓

• Note: B0-: Water; B0+: Chemical fertilizer; B(5,10,15): biofertilizer dose (5, 10 and 15 mL); F(1, 2, 3): frequency of biofertilizer ie. once (1 WAP), twice (1 and 4 WAP), and three times (1, 4, and 8 WAP).

3.2. Plant height, number of leaves, and stem diameter of cayenne pepper

The positive control treatment (B0+) had the highest average plant height (81 cm) and number of leaves (73.33 leaves) compared to the others (Table 4). Meanwhile, the negative control treatment (B0-) without chemical fertilizer or biofertilizer had the lowest result (45 cm). The 15 mL application of biofertilizer (B15F1) also resulted in a high number of leaves (70 leaves), while the lowest leaf number was observed in the positive control treatment (40.67 leaves).

Table 4
Average plant height, number of leaves, and stem diameter at 12 weeks after planting.

Treatment	Plant Height (cm/plant)	Number of Leaves (leaves/plant)	Stem Diameters (mm/plant)
B0-	81.33	73.33	6.80
B0+	48.67	40.67	3.13
B5F1	56.50	43.33	5.46
B5F2	52.67	45.33	5.40
B5F3	54.67	45.00	5.33
B10F1	78.00	56.33	6.80
B10F2	79.00	54.00	6.63
B10F3	76.00	56.67	6.46
B15F1	61.33	70.00	7.31
B15F2	62.00	67.00	7.33
B15F3	62.50	68.34	7.63

• Note: B0-: Water; B0+: Chemical fertilizer; B(5,10,15): biofertilizer dose (5, 10 and 15 mL); F(1, 2, 3): frequency of biofertilizer ie. once (1 WAP), twice (1 and 4 WAP), and three times (1, 4, and 8 WAP).

The administration of BioMeFert-1 at a dose of 15 mL/plant with a three-time administration (B15F1) had the highest average stem diameter (7.63 mm). The lowest average stem diameter of cayenne pepper plants was 3.13 mm in the negative control treatment (B0-). This result is similar to Sinulingga et al. (2015), which reported that a 15 mL dose of biofertilizer affected the number of leaves.

3.3. Number of flowers, fruits, and fruit weight

The productivity parameter of cayenne pepper plants at 15 WAP consisted of the number of flowers and fruits and fruit weight. The data of productivity parameters were analyzed statistically using ANOVA followed by the Duncan test (Table 5). The combination of biofertilizer application doses and frequencies significantly affects the number of flowers, fruits, and fruit weight. Significantly higher productivity (20 flowers/plant, 37.33 fruits/plant, 88.33 g fruit/plant) was shown by the treatment of 10 mL biofertilizer with a one-time application (B10F1). In contrast, the lowest number of flowers was found in the negative control (7.00 flowers/plant). The positive control showed the lowest fruit production (25.67 fruits/plant) with the lowest fruit weight (61.67 g/plant).

Table 5
The average number of flowers, number of fruits, and total weight of cayenne pepper plants with biofertilizer treatment.

Treatment	Number of Flowers (Flowers/plants)	Number of Fruits (Fruits/plants)	Fruit Weight (g/plants)
B0-	7.00a	30.33c	75.33e
B0+	16.67cd	25.67a	61.67a
B5F1	14.33bc	28.67b	68.00c
B5F2	13.67b	28.33b	67.33c
B5F3	13.33b	27.67b	65.00b
B10F1	20.00f	37.33g	88.30i
B10F2	19.67f	36.00fg	86.33h
B10F3	19.33ef	34.00e	82.67g
B15F1	17.00de	32.00d	75.67e
B15F2	17.67def	34.67ef	78.00f
B15F3	16.33cd	32.00d	71.67d

• Note: B0-: Water; B0+: Chemical fertilizer; B(5,10,15): biofertilizer dose (5, 10 and 15 mL); F(1, 2, 3): frequency of biofertilizer ie. once (1 WAP), twice (1 and 4 WAP), and three times (1, 4, and 8 WAP).

3.4. RAE (Relative Agronomic Effectiveness)

The highest effectiveness value was shown by the B10F1 treatment, with an RAE value of 166% (Table 6). However, B10 (F2 and F3) and B15 (F1 and F2) treatments showed an effective use of biofertilizer with an RAE value exceeding 100%. Meanwhile, biofertilizer was ineffective in the B5 treatment (F1, F2, and F3) and B15F3 with RAE value below 100%.

Table 6
RAE value of biofertilizer influenced by dose and frequency.

Treatments	RAE Value (%)
	Fruit Weight
B5F1	63
B5F2	60
B5F3	48
B10F1	166
B10F2	159
B10F3	153
B15F1	101
B15F2	113
B15F3	77

• Note: B(5,10,15): biofertilizer dose (5, 10 and 15 mL); F(1, 2, 3): frequency of biofertilizer ie. once (1 WAP), twice (1 and 4 WAP), and three times (1, 4, and 8 WAP).

4. Discussion

Biofertilizers are fertilizers that contain microorganisms capable of promoting plant growth by increasing nutrient availability (Amutha et al., 2014). Biofertilizers contribute to soil fertility by enhancing the ability of plant roots to absorb essential nutrients from the soil, thereby supporting plant growth (Mohammadi and Sohrabi, 2012). The objectives of this study were to assess the abundance of soil microbes before and after biofertilizer application, evaluate the effects of different doses and frequencies of BioMeFert-1 on plant growth and productivity, and determine the RAE of biofertilizer application on the productivity of cayenne pepper plants.

The enumeration of phosphate solubilizing bacteria at 8 WAP revealed that the B10F1 and B10F2 treatments had the highest bacterial counts (3.5x10⁸ cfu/mL). All treatments exhibited higher populations of phosphate solubilizing and cellulose-degrading bacteria at 1 WAP compared to 8 WAP. Possibly, there are negative microbial interactions and competition, which reduce growth rates as population density increases (Feng, 2022). Bacterial growth requires essential nutrients such as nitrogen and phosphorus. A previous study (Bren et al., 2013) mentioned that limited nitrogen availability reduces bacterial growth. Gene activity associated with nutrient assimilation changes significantly before growth ceases (Morgan and Connolly, 2013). In an agricultural setting, using polybags can exacerbate nutrient limitations due to restricted soil volume, limiting nutrient availability and reducing productivity. The constrained soil area creates suboptimal conditions for both plants and microbes by reducing resources and growth space (Wang and Kuzyakov, 2024).

All soils treated with BioMeFert-1 tested positive for the presence of N-fixing microbes, indicated by the formation of a white pellicle or ring and a colour change in the NFB medium from yellow to blue, signifying microbial growth and nitrogenase activity (Reis et al., 2015). The semisolid NFB medium contains malic acid, which serves as a carbon source for bacteria (Ahmed et al., 2022). Following incubation, the formation of a white pellicle or ring indicated the bacteria’s ability to reduce nitrogen sources from the medium. Nitrogenase activity changes the medium colour from yellow to blue due to the presence of BTB (bromthymol blue) as an indicator (Cordova-Rodriguez et al., 2022).

The soil sample analysis indicated the presence of IAA hormone-producing bacteria throughout the duration of the soil treatment. All isolate culture supernatants were tested against a blank and turned pink, demonstrating qualitative IAA production. IAA production by bacteria is characterized by pink discolouration when Salkowski’s reagent is added to NB media. This occurs due to the interaction between IAA and Fe³⁺, forming complexes [Fe₂(OH)₂(IA)₄]. The intensity of the pink colour correlates with the IAA concentration (Rahayu et al., 2024). The reaction between Salkowski reagent and IAA is light-sensitive, and darker conditions prevent IAA degradation by high light intensity (Sulistya et al., 2020). In the positive control, where chemical fertilizer was applied, a decrease in the number of microbes was observed, indicating the inability of soil microbes to adapt, suggesting the detrimental effects of chemical fertilizers on soil health (Paramanik and Chikkaswamy, 2014).

In the BioMeFert-1 biofertilizer treatment, a dosage of 10 mL administered twice (B10F2) produced the highest plant height parameters compared to other treatments. The 10 mL dosage provides adequate nutrition for bacterial growth, enhancing the height of cayenne pepper plants. The bacteria at this dosage can function optimally to fulfill the nutrient requirements of chili plants. Furthermore, the absence of competition between the plants and bacteria for nutrients allowed the microbes to thrive with the 10 mL biofertilizer dose (Sinulingga et al., 2015). Biological fertilizers containing microbes can stimulate plant growth, fixate nitrogen, solubilize phosphate, and inhibit plant diseases (Reis et al., 2015; Sudiarti et al., 2019). The nutrient content of biofertilizers, particularly nitrogen, is crucial for maximizing plant height. Additionally, Bacillus sp. is known to produce the phytohormone Indole Acetic Acid (IAA) (Athfin et al., 2023). IAA significantly impacts plant height growth, even in small quantities (Sosnowski et al., 2023). It accelerates growth by enhancing root system development, promoting young root growth, and increasing the water absorption capacity of plant cells, thereby improving water potential in plant tissues and leading to cell elongation (Salisbury et al., 1992).

Regarding leaf number, the highest yield was observed with the 15 mL biofertilizer dose (B15F1). This increase is attributed to the sufficient nitrogen content, which enhances leaf production. The P-solubilizing activity of Bacillus sp. in the biofertilizer converts bound phosphorus (P) in the soil into a soluble form accessible to plants. Chlorophyll levels in plant leaves are crucial for photosynthesis and are directly influenced by nitrogen, which contributes to leaf greenness and promotes vegetative growth. Higher chlorophyll levels result in increased photosynthetic product formation and enhanced protein synthesis, which supports the production of additional leaves (Damanik et al., 2011; Simanungkalit et al., 2006).

The optimum biofertilizer dose for increasing stem diameter in cayenne pepper plants is 15 ml. The increase in stem diameter is influenced by the nutrient availability in the soil, which aids in nutrients and water provision or binding (Dwiastuti et al., 2016). The availability of phosphate (P) in the soil is often restricted due to its binding with iron, aluminum, and calcium, forming insoluble compounds. Bacillus sp. can act as a soil conditioner, facilitating this process by binding water, creating soil pores, and solubilizing phosphate, thus improving plant root development and nutrient absorption. Phosphate is essential for plant metabolism, stimulating growth, increasing diameter, improving quality, and strengthening resistance to pests and diseases (Handayani et al., 2019).

Productivity data on the number of flowers were collected at 15 WAP, while C. frutescens typically bear fruit at around 12 WAP. The exact timing can vary depending on environmental conditions, cultivation practices, and the specific variety of C. frutescens (Gustiar et al., 2023). These plants require sufficient sunlight throughout the day, with an irradiation intensity exceeding 70%, to achieve optimal photosynthesis (Simanungkalit et al., 2006). The number of flowers per plant of C. frutescens varied with different combinations of biofertilizer dose and frequency. Among the treatments, B10F1 produced the highest average of 20.0 flowers per plant, which was comparable to the B10F2 treatment. This result is likely due to the effective utilization of food reserves stored in plant stems, which support optimal nutrient supply and enhance photosynthesis during the flowering phase. In the early stage of flower formation, the reserves are converted into essential components for flower tissue development and support metabolic activities. Consequently, this accumulation in flower organ cells accelerates flower formation, leading to the production of high-quality flowers in greater quantities (Sitompul and Guritno, 1995).

In terms of fruit weight and number of fruits, the B10F1 treatment exhibited the highest average value of 36.67 fruits per plant, similar to the B10F2 treatment. The number of fruits is influenced by nutrients involved in fruit formation. Fruit yield depends on the plant's condition during the flowering period, where successful pollination and fertilization of flowers are critical (Menzel, 2023). The phases of fruit formation, including fruit number and weight, are closely related to soil nutrient availability and fertilizer application. In addition, microorganisms in biofertilizers can produce auxin hormones that facilitate fruit development. Auxin production from seeds and other fruit parts significantly impacts fruit development by acting as a food reserve to enhance fruit growth (Lingga and Marsono, 1986). Phosphorous (P) is a critical nutrient in chili plants' fruit formation, significantly affecting fruit formation and weight. The yield of large chili plants is notably affected by P levels (Khanal et al., 2021). The fresh fruit weight data indicates that BioMeFert-1 produces higher yields compared to the positive control (chemical fertilizer treatment). This is attributed to the fact that the nutrient availability provided by BioMeFert-1 meets the requirements of C. frutescens plants. Biofertilizer combinations can achieve results comparable to those of 100% NPK fertilizer treatments, demonstrating that biofertilizer application can adequately fulfill the nutrient needs of cayenne pepper plants. However, a 5 mL dose of biofertilizer has been insufficient for optimal plant growth, leading to nutrient deficiency and suboptimal plant development and production (Setiawati et al., 2023).

Biofertilizers have proven effective in enhancing plant growth during the vegetative phase (e.g., plant height and biomass) and improving yield and quality compared to other treatments, as evidenced by the Relative Agronomic Effectiveness (RAE) analysis. Different types of microbes within biofertilizers exhibit distinct functions and effectiveness. The assessment of biofertilizer effectiveness primarily focuses on agronomic technical aspects (Atieno et al., 2020). In this study, the 10 mL dose treatment administered once (B10F1) achieved the highest RAE value of 166%. Additionally, the 15 mL biofertilizer dose significantly increased the productivity of C. frutescens with an RAE value exceeding 100%. Various biofertilizers used in Indonesia have been shown to enhance nutrient availability and crop yields by 20-100% while reducing reliance on synthetic fertilizers and improving fertilization efficiency (Simarmata, 1995). Consequently, biofertilizer treatments at 10 mL and 15 mL present viable alternatives to chemical fertilizers, offering higher productivity and environmental benefits.

5. Conclusion

The application of biofertilizer increased the number of microbes present in the soil before and after applying biofertilizer. The growth of cayenne pepper (C. frutescens) was affected by administering combinations of doses and frequencies of biofertilizer BioMeFert-1. The combination of doses and frequency of this biofertilizer application affected the productivity of cayenne pepper plants. The B10F1 treatment produced the highest fruit weight of 88.33 (g/plant) and an RAE value of 166%.

Acknowledgements

The authors extend their appreciation to Universitas Airlangga for funding this work through Mandatory Research Grant (Hibah Penelitian Mandat) Universitas Airlangga, year 2023 (No. 132/UN3.LIHTR/PT.01.05/2023).

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Publication Dates

• Publication in this collection
  24 Feb 2025
• Date of issue
  2025

History

• Received
  14 Aug 2024
• Accepted
  18 Dec 2024