The Response of giving Gamal, Calliandra, and Lamtoro leaves compost fertilizer to Stevia plant (Stevia rebaudiana Bertoni) growth

Stevia (Stevia rebaudiana Bertoni) is a herbaceous plant, a sweet plant that can replace cane sugar. This plant is a shortday crop that can be harvested within 40-60 DAP. Compost is an organic fertilizer that is made by utilizing the weathering process from the interaction of microorganisms and decomposing bacteria. One of the litters can be utilized include gamal, calliandra and lamtoro. The purpose was to determine the effect of the three composts on the growth and productivity of the stevia. The analysis method used a completely randomized design (CRD) with one factor and four treatments. The results showed that compost had a significant effect on all observed variables including height, diameter, number of leaves, fresh weight and plant biomass. The highest growth and productivity of stevia plants were produced by stevia plants in treatment P3 (lamtoro compost), which influenced all observed aspects, including height and diameter (21.7 and 2 cm), number of leaves (152 leaves), total wet and dry weight (16.54 and 3.58). The lowest yields were produced in treatment P0 (control), which only increases the height and diameter by 5.81 and 1 cm, with only 60 leaves and 6.25 and 1.28 grams for dry and wet weights, respectively.


Introduction
Sugar is one of the most strategic commodities in Indonesia which has become the oldest and leading industry even since the colonial era [1].Sugar is one of the basic ingredients of Indonesian society and the world, especially in fulfilling calories.Sugar is often used as an additive in food to add flavor.In addition, on a large scale, sugar is an important ingredient for food and beverage businesses.Sugar is popular because of its sweet taste which tends to make consumers addicted.
The need for sugar in Indonesia will continue to increase every year [2].The increase in demand for sugar is of course related to the power of sugar consumption in Indonesia.According to data from the Ministry of Industry in 2021, the domestic demand for sugar is 6.43 million tons per year.Meanwhile, the sugar production figure is only 2.35 tons per year, meaning that domestic sugar production can only cover one-third of the demand for its needs.High demand and low production is a problem.One of the solutions made by the government is to import sugar cane and also through self-sufficiency in sugar in the form of revitalizing the on-farm sector, in the form of expanding the area for planting sugarcane and research on plants that can be used as a substitute for sugar, one of which is stevia [1].The stevia plant is expected to be a solution in meeting domestic sugar needs.
Other advantages of stevia include stevioside and rebaudioside A, which make stevia sugar 300 times sweeter than cane sugar, but low in calories, non-carcinogenic and anti-diabetic.So that stevia sugar is safe for daily consumption as a natural sweetener for diabetics [3].Based on these reasons, this research appears to find out the best types of forestry plants to combine with stevia plants, in order to support the plant growth and productivity especially in an agroforestry system.The forestry plants consist of three types of energy wood plants.It is hoped that the results of this study can serve as a guideline for planting stevia to support agroforestry and forest plantation.

Data collection
This research was conducted from December 2022 to April 2023 in the nursery of the Department of Silviculture, Faculty of Forestry and Environment, Bogor Agricultural University.The tools used in this study included barrels, cutting tools (knives, scissors), shovels, polybags, laptops, smartphone, ovens, calliper, rulers and tally sheets.The materials are dry leaves from three types of forestry plants, topsoil, rice husk charcoal, water, liquid EM4 fertilizer, sugar, and stevia plant seeds.

Research procedure
This research consisted of several stages, starting from making compost, preparing planting media, transferring stevia plant seeds and providing treatment, maintenance and data collection.
The research began with making compost from three types of forestry plants, gamal, calliandra, and lamtoro.The selected plant leaves are leaves in good condition.Gamal leaves were obtained from Ciampea village, while lamtoro and calliandra leaves were obtained around the IPB campus.The leaves are then dried under the sunlight.Then the leaves are put in a closed container such as a barrel or bucket to avoid contamination, along with a mixture of sugar water and EM4 liquid.The use of EM4 is based on the journal [4] who suggested using this liquid, because it can speed up the decomposition process.The ratio of each ingredient is 50:1:1 (v/v) (order from leaves, sugar water and EM4).Furthermore, the material in the bucket is stored for approximately 30 days or until the compost is mature, due to differences in composting time, which is influenced by leaf size, where gamal leaves take the longest time to decompose completely.Mature compost is characterized by changes in color, a crumbly texture, and an earthy smell [5].
The medium used for planting stevia seeds is a mixture of soil, husk charcoal, and compost, with a ratio of 2:1:1 (v/v).The treatments consisted of P0 (control), P1 (gamal compost treatment), P2 (calliandra compost treatment), and P3 (lamtoro compost treatment).The stevia seeds used are seeds from the Nikofarm garden, which can be obtained online.Nicofarm Gardens is a nurser located in the City of Kediri, East Java.The location of the plantation is at an altitude of about 200 meters above sea level.The stevia seeds used were two weeks or 14 days after planting (DAP).The seeds were then planted in polybags measuring 15 x 20 cm containing planting media with each treatment which had been left for one day.The last stage, the seeds are stored in the nursery of the Silviculture department under a 60% paranet, so that the plants are not exposed to rain and direct sunlight.The layout for planting in the fields presented in Figure 1.Furthermore, the last stage is the maintenance and observation of plant growth.Maintenance consists of watering and cleaning weeds as well as observing pests and diseases.Watering is done every day outside of rainy days in the morning or evening.While weed cleaning is done as necessary.The observed data is used to show plant growth.Plant growth is defined as the quantitative increase in biomass.Several variables that can be used include height, diameter, number of leaves and biomass.These variables are used in this study.
Observation of height and number of leaves was carried out once a week for 5 weeks.Height was measured using a ruler from the base of the stem to the apical bud.The number of leaves was counted manually on compound leaves that grew at each observation.The leaves that are counted are leaves that are green, healthy, and not dry.Diameter observations were carried out 3 times at weeks 0, 3 and 5 using digital calipers.Other observations were made at the end of planting.Determining the type of data observed refers to previous research [6].
The last observation is the fresh weight and plant biomass.The data is generated by weighing the total fresh weight and total dry weight of the plants.The total wet weight is obtained by weighing the fresh roots and shoots of the plants when they are harvested, starting by washing the plants from adhering dirt and then weighing them using a digital balance.Total wet weight is the result of the sum of shoot wet weight and root wet weight.The total dry weight was obtained by weighing the dry weight of roots and shoots.
The data analysis method used in this research is an experimental method using a complete randomized design (CRD) with one factor and 4 treatments.Each treatment consisted of 6 replicates, so the total plants were 24 seedlings.Data analysis was carried out using SAS software and Microsoft excel to see the effect of treatment on the observation parameters through variance analysis testing that had a significant effect on the F test.The results of the analysis of variance that significantly influenced the F test were then tested using the Duncan test at the 95% confidence interval or at the 5% error level, to determine the difference in the effect of each level on the parameters tested.After drying in an oven for 72 hours, at 80°C to a constant weight [7].

The Effect of Compost Fertilizer on Height and Diameter Increase of Stevia Plants
Plant height gain is the value of the result of reducing the total height of plants in the observation week with the previous week.Height gain is very important because it will affect other factors, such as the number of leaves and wet weight of plants [8].Height gain is one of the variables to show the quality of a place to grow for plants [9].The diameter increase can also indicate the quality of the growing site for the plant.This is because diameter increase is directly proportional to how the plant absorbs nutrients and stores them in the form of plant biomass and volume, which can be used to describe how the plant grows [10].Sufficient or even excess nutrients will be utilized by plants in this process.
The results of data analysis showed that fertilizer had a significant effect on the increase in plant height and diameter.In general, plants require two types of nutrients to support their growth, namely macro and micronutrients.Nitrogen, phosphorus and potassium are essential macronutrients for plants.Nitrogen together with phosphorus will be utilized by plants in regulating overall plant growth, especially vegetative growth, such as height and diameter [10,11].This is because nitrogen plays a role in the formation of plant cells, tissues and organs, while phosphorus is used for generative processes, energy transfer and absorption of nutrients in the soil [12].Based on these reasons, it can be concluded that the higher the nutrient content in the planting media, the more optimal the increase in plant height and diameter.
Figure 2 shows that the best height increase results were produced by stevia plants grown in the P3 treatment, or in media with a mixture of top soil and lamtoro compost.Likewise with the increase in the diameter of stevia plants, which was also produced in the P3 treatment.These results are thought to be due to the high content of macro nutrients in the compost.Research by Ningsih et al. [13] supports this assumption.This study tested the macro nutrient content (Ca, N, P, K) in lamtoro compost, and found that the macro nutrient content was very high.The criterion for N content was mentioned as very high with a percentage of 2.14%, as well as nutrients P (0.35%) and K (0.71%) which were in the high category.In contrast to the content of N, P, K in gamal compost which is medium and low, where the percentage is 0.24% (N), 0.039% (P), 8.38% (K) respectively [14] This statement can explain why the height and diameter of stevia plants grown in P3 treatment are dominant among plants in other treatments.Figure 1 shows that the height of the arrowroot (M.arundinacea) seedlings at the end of the week of planting, with the control treatment (100% soil) had the lowest value with a plant height of 16.8 cm.While the gamal compost treatment had the highest value with a plant height of 74.6 cm.

Figure 2. Graph of average height and diameter gain of stevia plants
The lowest value of height gain in the data was produced by treatment P0, or the control.The control media consisted of a mixture of topsoil and rice husk charcoal.The results showed that the average height gain in the P0 treatment was only 1.16 cm, very far when compared to the P1, P2 and P3 treatments which each produced an average value of 3.92 cm; 3.65 cm; and 4.34 cm.The lowest diameter increase was also produced in plants with treatment P0, with an average diameter increase of 0.018 cm, which was also very far when compared to P1 (0.037 cm); P2 (0.042 cm); and P3 (0.059 cm).
Topsoil is the upper soil formed through the process of weathering and decomposition of organic material by soil decomposers.Generally, topsoil contains nutrients, but the amount depends on the geographical location and environmental conditions.The nutrients contained also tend to be low because they are limited [15].Because the nutrient content tends to be low, plants grown using topsoil need to be given additional nutrients, either using compost or inorganic fertilizers.The reason is because topsoil gets nutrients for a long time and in small amounts.Nitrogen in the soil is produced through several processes, including symbiotic, non-symbiotic nitrogen fixation, or from rain.This process takes a long time.Likewise with other nutrients such as phosphorus and potassium, which are produced through a long process.This statement explains that topsoil is not yet able to optimally support plant growth.

The Effect of Compost Fertilizer on the Number of Leaves of Stevia.
The stevia plant is a plant that utilizes its leaves, where the leaves of the plant will be dried and then used as a sweetening agent, therefore the number of leaves is an important indicator to see the productivity of the stevia plant.Stevia leaves contain steviosida and rebaudiosida A, which make the plant sweet.This advantage is an opportunity to make stevia sugar as a substitute for cane sugar, because it is safe for consumption for diabetics.Based on these statements, it can be concluded that the higher the NPK nutrient content in the soil, the higher the number of leaves produced.In addition, the taller the plant, the more the number of leaves produced.This statement is proven through the results in Figure 3, that the highest number of leaves is produced by stevia in the P3 treatment, as well as the highest number of leaves.
Lamtoro fertilizer has more NPK content than the other two fertilizers, especially for the P0 treatment.Therefore, it can be concluded that the highest productivity of the number of stevia leaves is produced by the P3 treatment, because this fertilizer contains sufficient nutrients to be utilized by plants in the multiplication of leaf blades.In contrast, the P0 treatment consisting of top soil is not good enough to be used in supporting the productivity of the number of leaves of stevia plants.

The Effect of Compost Fertilizer on the Wet Weight of Stevia Plants
Plant wet weight can be defined as the fresh weight of plants measured when the plants are harvested or before drying.Wet weight is the result of growth activity whose value is influenced by the water content in the tissue and biomass [16].Wet weight information can be used to measure plant growth rate.The higher the wet weight value, the better the plant growth rate [17,18].Total wet weight is the sum of the wet weight of shoots and the wet weight of plant roots.The test results in the study presented in Table 2 show that compost fertilizer has a significant effect on plant wet weight.4, the highest wet weight was produced by stevia plants grown in the P3 treatment, using lamtoro compost.BB stevia in the P3 treatment produced a total average weight of 16.54 g.This figure is very high when compared to plants P1 (12.05 g), P2 (15.97 g) and P0 (6.25 g).Plant wet weight is influenced by many factors, including the content of water and nutrients in the soil, photosynthesis rate and physical properties [2,19].These factors are important materials for plants that will be converted into biomass, and produce an increase in plant wet weight.Therefore, if these materials available to plants, the wet weight of plants will also increase explained the relationship between photosynthesis and plant wet weight gain.The study concluded that the higher the rate of photosynthesis, the higher the biomass produced.Photosynthesis is highly dependent on water and nutrient content in the soil, CO2, root quality and the number of leaves on the plant.These factors are interconnected in supporting the rate of photosynthesis.Stevia planted in the P3 treatment is thought to have all the things needed to support the increase in biomass production.The previous discussion explained that stevia plants in the P3 treatment had the highest number of leaves, allowing the photosynthesis rate to be higher than other treatments.The more leaves on the plant, the higher the photosynthesis rate, the higher the wet weight of the plant [20].
Another factor that also affects this is the nutrients in the soil.These nutrients will be utilized by plants to support their photosynthesis process and then converted into plant biomass.[21] explained that the higher the nutrient content (NPK) in the soil, the higher the plant height, diameter, and wet weight produced.The reason is because the higher the nutrients or organic matter, the better the physical, biological, and chemical properties of the soil, so that the soil can store water better and help plant growth and development.Based on these reasons, it can be concluded that stevia plants in the P3 treatment have all the factors necessary for plant wet weight gain in higher amounts than the other three treatments.Based on this, it can also be concluded that stevia in the control treatment or P0 is not good enough to support plant growth, especially in plant wet weight gain.

The Effect of Compost Fertilizer on Stevia Plant Biomass
Plant biomass level is the total weight or volume of organisms in a given area.Biomass is also often defined as the total amount of aboveground living matter in a plant and is expressed in units of weight, tons per unit area [22].Calculation of plant biomass is considered as one of the important steps that must be known to determine the quality of growth of a plant.[23] stated that the calculation of biomass is a measure that is most often used to describe and determine the growth of a plant because plant biomass is relatively easy to measure and is a combination of almost all events experienced by a plant during its life cycle.Wet weight total Plant biomass can be measured through plant dry weight.The higher the dry weight of the plant, the higher the biomass value produced.The higher the value of plant biomass, the better the place to grow plants [3].This is because biomass can describe the efficiency of plant physiological processes during its lifetime, including the quality of nutrients in the soil which is the accumulation of fuel from photosynthesis [19].Biomass reflects the accumulation of organic compounds that plants successfully synthesize from inorganic compounds (nutrients, water, and carbohydrates), so the higher the dry weight value, the better the plant growth [2].The results in Table 3 show a correlation between fertilizer and dry weight yield of stevia plants.Based on the results shown in Figure 5, the highest total dry weight value was produced by stevia plants in the P3 treatment, or on lamtoro compost media.The dry weight produced is very high when compared to other treatments, where P3 produces an average BK of 3.58 g, while P1, P2 and P0 are only 2.56 g; 3.42 g; 1.27 g, respectively.The results also showed that the type of compost fertilizer had a significant effect on plant dry weight.
Dry weight has a correlation with plant wet weight, where the higher the wet weight, the higher the plant dry weight.Similar to wet weight, dry weight is also influenced by many factors, but the most important are the rate of photosynthesis, nutrient and water content in the soil, as well as the number of leaves and root quality [24].If all these factors can be fulfilled, the dry weight of the plant will be higher.The previous discussion explained that lamtoro compost fertilizer or P3 treatment was able to provide a significant value to the increase in plant wet weight.The reason is because in the previous discussion it was discussed that lamtoro compost has the best nutritional content that can support the growth of stevia plants.
Lamtoro compost is known to have a higher percentage of NPK fertilizer content than other treatments, followed by calliandra and gamal [13,25] support this, where the NPK content in the planting media will affect overall plant growth, starting from plant vegetative growth (height and diameter), the number of leaves that will increase the rate of photosynthesis, and plant health, so that in the end it will encourage the quality of biomass in plants.It was also explained that this was thought to be due to the higher nutrient and water content in the planting media compared to other treatments.This can explain why the dry weight in the P3 treatment was superior to the other treatments.Therefore, it can be concluded that lamtoro compost fertilizer is once again superior to other fertilizers, in this case, especially in plant dry weight.In contrast, the control treatment or P0, is still not able to support plant growth and productivity well, as seen from its low dry weight [2].

Conclusion
Application of compost (kaliandra, gamal, lamtoro) can increase the growth of the stevia plants.The application of compost fertilizer to the planting media can encourage the growth and productivity of stevia plants.Compost fertilizers can contribute macro nutrients needed by plants, including N, P and K.The sufficiency of these nutrients allows plants to carry out their physiological processes and support optimal plant growth.The best compost in this study was lamtoro compost, followed by calliandra, and finally gamal.The lamtoro compost is considered capable of increasing productivity from all aspects observed, including height and diameter (21.7 and 2 cm), number of leaves (152 leaves), total wet and dry weight (16.54 and 3.58).Eventually all three composts were able to provide significant growth, when compared to soil without additional compost (control).As a comparison, the control treatment was only able to increase the height and diameter of the stevia plants by 5.81 and 1 cm, as well as the number of leaves and biomass that tended very low.The control treatment is indeed can be used to grow stevia plants, but it is not able to encourage optimal plant growth and productivity.

P31 Figure 1 .
Layout of stevia plant planting.P0 = Control, P1 = Gamal compost treatment, P2 = Calliandra compost treatment, P3 = Lamtoro compost treatment.The last number in the plant code represents the replicate in that treatment.

Figure 3 .
Figure 3.The addition of the number of leaves of the arrowroot plant chart

Table 1 .
Duncan test results of the effect of compost fertilizer on the increase in height and diameter of

Table 2 .
Duncan test results of the effect of compost fertilizer on the wet weight of stevia plants TreatmentsFigure 4. Grafik total berat basah tanaman stevia pada akhir pengamatan Based on Figure

Table 3 .
Duncan test results of the effect of compost fertilizer on the dry weight of stevia plants