The proportion of moringa leaves and empty oil palm fruit bunches for making good bokashi and its application dosage for okra

This study aimed to obtain the appropriate proportion of moringa leaves and empty oil palm fruit bunches for making good bokashi according to standard organic fertilizers and their application dosage to okra plants. The experiment of the combination of moringa leaf and empty palm oil fruit bunches (1:1, 1:2, and 1:3) and the application dosage to okra plants (10, 15, 20, and 25 tons ha−1) were arranged according to a completely randomized design with three replication. The results showed that single moringa leaf bokashi with a C/N ratio of 2.8 became 6-7.5 in moringa leaves-empty oil palm fruit bunches bokashi. The mixed bokashi in a ratio of 1:1 had a crumb texture and was black. Bokashis in a ratio of 1:2 and 1:3 had a slight crumb texture and blackish-brown colour. Only the number of leaves was affected by the ratio of moringa leaves and empty palm oil bunches and the application dose. The composition of moringa leaves and empty oil palm fruit bunches and the application dosage did not significantly affect the growth and yield of okra plants. However, the growth and yield of okra plants tended to be better at a 1:2 ratios of 10 tons ha−1 application dose.


Introduction
Okra has recently become a trend for functional food plant lovers.Okra was found to be efficacious as a cholesterol and diabetes drug.This plant has the economic potential to be developed for national functional food sources and export needs.Okra has long been known and in demand in various countries, so it has high export potential.The potential for okra development is supported by the wide-growing environmental requirements from areas with tropical to sub-tropical climates.In addition, okra can grow from fertile to marginal land with the addition of nutrients [1][2][3][4].
The addition of plant nutrients can be sourced from inorganic and organic materials.Organic matter as fertilizer can improve soil chemical, physical and biological fertility.Organic materials are used as fertilizer after going through various processes, one of which is fermentation, and the result is known as bokashi [5][6][7].
Considering that the primary purpose of applying fertilizer is to add soil nutrients, organic matter with a high nutrient content needs to be found as a primary ingredient for bokashi.In 100 g, moringa leaves contain 204 mg P, 1324 mg K, 440 mg Ca, 368 mg Mg, 1.1 mg Cu, 28.[8,9].However, moringa leaf bokashi has a low C/N ratio of around 2.8 [10].Conditions with a C/N ratio that are too low (<10) can cause a loss of nitrogen in the form of oxidized ammonia [11].For this reason, a material that has a high C/N ratio value is needed for the combination of moringa leaves bokashi.One of them is the empty fruit bunches of oil palm.
Empty oil palm fruit bunches contain 1.06-1.34%total N with a 35.16-46.13C/N ratio, 0.02-0.08%P, and 0.83-1.38%K [12].The high C/N ratio and the abundant availability of empty palm oil bunches can be used as a combination ingredient with moringa leaves.There is a lot of palm oil mill waste in various regions in Indonesia, considering that Indonesia is one of the largest palm oil producers in the world.The proportion of empty palm fruit bunches is 22-23% [13].Bokashi of empty oil palm bunches applied to green bean plants has increased growth and yield [14].In addition, using bokashi of empty palm oil bunches and cow dung applied to oil palm plants can affect the leaves' N, P, K, and Mg content and increase crop production.
Based on the previous studies which proved the success of using empty oil palm bunches and moringa leaves alone, further research is needed to combine moringa leaves and empty oil palm bunches.This study was intended to obtain the proportion of moringa leaves and empty oil palm fruit bunches for making good bokashi, which has a C/N ratio according to standard organic fertilizers and the dosage of its application to okra plants.

Experimental Design and Procedure
The research was conducted from January to April 2021 in Bengkulu City, Indonesia.The ratio of 1:1, 1:2, and 1:3 of moringa leaves and empty palm oil bunches and application doses of 10, 15, 20, and 25 tons ha -1 on okra plants were arranged according to a completely randomized design with three replications.Each experimental unit consisted of 5 polybags, so the total was 180 polybags.Each pot was filled with 10 kg of soil.
Moringa used in this recent study was Bengkulu accession.Empty oil palm bunches were obtained from smallholders' oil palms in Seluma District, Bengkulu Province, Indonesia.Moringa leaves and empty oil palm bunches were chopped into small pieces ± 3 cm.The chopped moringa leaves and empty palm oil bunches were mixed according to the combination proportion of the treatments.The decomposer solution was made from a composition of 100 ml EM-4 + 100 gr sugar + 1 liter of water and allowed to stand for 3-5 hours.After that, the decomposer solution was poured and stirred evenly into the mixture of chopped moringa leaves and empty palm oil bunches.The mixture was fermented for two weeks (14 days).
Harvested bokashi was mixed with topsoil with the dose according to the treatment and put in a polybag.The planting media was incubated for seven days while waiting for the okra seedlings to be transplanted.Plants are maintained until harvest.

Measurement and Data Analysis
The characteristics of bokashi based on the proportion of moringa leaves and empty palm oil bunches were observed through smell, color, texture, temperature, and nutrient content.The response of okra plants to the different ingredients and their application dose was observed in plant height, number of leaves, dry weight, fruit length, number of fruits per plant, fruit weight per plant, and fruit potential per hectare.All observations were made on 3 sample plants for each experimental unit, so there were 108 samples.
Data were firstly tested for homogeneity of variance and normality of distribution.Then, homogeneous and normal data were analyzed for variance at the 5% level.Furthermore, the mean values between treatments were compared using Duncan's multiple range test at the 5% level on data that showed a significant effect according to the analysis of variance.Data recapitulations were presented in the form of tables and graph.

Characteristics of Bokashi
Bokashi produced in this experiment had different characteristics due to differences in the proportions of the ingredients, i.e., moringa leaves and empty oil palm fruit bunches.During fermentation, the material underwent physical (texture and color) and chemical (smell and nutrient content) changes.The fermentation process observed every two days showed changes between moringa leaves and oil palm proportion.All proportions of ingredients produced the same smell.However, the color of bokashi from the 1:1 ratio was blacker with a crumb texture compared to 1:2 and 1:3 (Table 1).Microbes carry out the changes resulting from decomposition processes.This process generated heat.The temperature increase occurred at the beginning of the fermentation process, reaching 67 o C and then decreasing to around 37 o C at harvest (Figure 1).The process of decomposing materials by microbes increases with increasing temperature, but the temperature must be kept not too high by opening and watering it [5,6,15,16].
Differences in nutrient content in each ingredient ratio of the bokashi marked chemical changes during the fermentation process.The different proportions of the primary ingredients caused different nutrient content and chemical reactions of bokashi, even though the difference was not high.The levels of N, P, K, C-organic, C/N ratio, and the acidity of the bokashi produced met solid organic fertilizer standards.P2O5 levels in 1:2 bokashi were 1% higher than 1:1 and 1:3 bokashi.The ratio of C and N (C/N) bokashi made from a combination of moringa leaves and empty palm oil bunches was 6-7.5% (Table 2).This C/N ratio increased from standalone moringa leaves bokashi, around 2.8 [10], and decreased from standalone empty palm oil bunches bokashi, ranging from 35. 16-46.13 [12].This C/N ratio is neither too low nor too high but meets the standard of solid organic fertilizer.Due to the abundant potential availability of empty palm fruit bunches, further research with higher ratios can be carried out so that the C/N ratio of bokashi will be high.

Okra Plant Growth and Yield
In general, the growth of okra plants applied bokashi 1:2 combination tended to be better with higher plant height, number of leaves, and plant dry weight, even though plant height and plant dry weight were not statistically significant (Table 3).The tendency for better growth in 1:2 bokashi was in line with higher P2O5 levels in 1:2 bokashi (Table 2).Plants need P2O5 nutrients for root growth.In plant metabolic processes, the nutrient P plays a role in cell division and energy transport [17,18].The growth of okra applied 10, 15, 20, and 25 tons ha -1 of doses did not match the experimental level pattern.Doses of 10 and 25 tons ha -1 were higher, with more leaves and heavier.Yields for all combinations ratio of Moringa leaf and oil palm empty fruit bunches were in line with vegetative growth.Fruit weight per plant and production potential per hectare of okra plants fertilized with 1:2 bokashi tended to be higher than 1:1 and 1:3 bokashi.High yields tended to be obtained on okra plants that were applied bokashi as much as 10 and 25 tons ha -1 (Table 4).

Conclusion
The bokashi made from moringa leaf and empty palm oil bunches with the proportions 1:1, 1:2, and 1:3 release different physical and chemical characteristics.The 1:1 composition was blacker and crumbier than 1:2 and 1:3 but with the same smell.The application of bokashi from the three portions of the composition and the dosage did not cause different growth and yield of okra plants.However, the growth and yield of okra plants tended to be better at a 1:2 ratio of 10 tons ha -1 .

Table 1 .
Smell, color, and texture of bokashi of moringa leaf and empty oil palm bunches.
10The edge is lumpy, and the Middle is a crumbThe edge is lumpy, and The middle is a crumbThe edge is lumpy, and The middle is a crumb12The edge is lumpy, and the Middle is a crumbThe edge is lumpy, and The middle is a crumbThe edge is lumpy, and The middle is a crumb 14 Crumb Crumb Slightly crumb

Table 2 .
Nutrient content of moringa leaf and empty oil palm bunches bokashi.
Note: * Indonesian National Standard Nu. 7763:2018 released by National Standardization Agency

Table 3 .
Vegetative growth of okra plants at various doses of moringa leaf and empty oil palm fruit bunches bokashi

Table 4 .
Yields of okra plants at various doses of moringa leaf and empty oil palm fruit bunches of bokashi