Application of various concentration of liquid organic fertilizer on vegetative growth of cocoa

Availability of sufficient nutrients will support uniform seedling growth. One way to improve seedling growth can be done by adding plant nutrients or nutrients through fertilization. The purpose of this study was to determine the vegetative growth of cacao (Theobroma cacao L.) seedlings after application of various concentrations of Amal Bajang liquid organic fertilizer (LOF). This experiment was conducted from March to April 2022, in Pallantikang Village, Rumbia District, Jeneponto Regency, South Sulawesi Province. The experimental method used a Randomized Block Design (RBD) consisting of 5 treatments (r), namely, (r0): control, r1: LOF 25 ml/l, r2: LOF 50 ml/l, r3: LOF 75 ml/l, and r4: LOF 100 ml/l. The results showed that the application of LOF Amal Bajang with different concentrations did not significantly affect the increase in height and diameter of the cacao stem, but had a significant effect on the increase in the number of cacao leaves.


Introduction
Cocoa is one of the plantation commodities in Indonesia which has an important role in improving the welfare of many people, especially for cocoa farmers with good market prospects.Cocoa is one of the export commodities that can contribute to increasing Indonesia's foreign exchange.Indonesia is the world's third largest cocoa producer and exporter after Ghana and Ivory Coast.Cocoa production in Indonesia in the last decade has experienced instability in 2018 which is 658,399 tons, decreased in 2017 to 585,246 tons, then increased in 2018 to 767,280 tons.Furthermore, in 2019 it decreased from the previous year to 734,795 tons, and in 20 20 cocoa production was still in decline from the previous year, which was 720,660 tons [1].
According to, The low cocoa production is related to the quality of cocoa seeds.Cocoa nurseries have an important role to produce good quality seeds.The seeds that are currently produced sometimes have poor cocoa quality due to the level of preparation and the process of providing seeds that have not been implemented properly.A good nursery is expected to produce cocoa plants with high quality and produce good production quality [2].
One way to provide good seeds is to meet the nutrient needs of plants.Availability of sufficient nutrients will support uniform seedling growth.One way to improve seedling growth can be done by 1230 (2023) 012212 IOP Publishing doi:10.1088/1755-1315/1230/1/012212 2 adding plant nutrients or nutrients through fertilization.Plants will thrive when the nutrients needed can be fulfilled [3].
Types of fertilizers can be divided into two, namely, organic and inorganic fertilizers.However, the continuous and excessive use of inorganic or chemical fertilizers will result in damage to the soil structure.Meanwhile, organic fertilizers are friendly to the environment, contain important ingredients needed to improve and create soil fertility both physically, chemically and biologically.Therefore, it is necessary to limit the use of chemicals including by utilizing natural materials raw materials) that exist in the surrounding environment as organic fertilizer.Another advantage of liquid organic fertilizer is that it can be given more evenly and its concentration can be adjusted according to plant needs.Nutrient absorption runs faster, and can be directly utilized by plants because the nutrients in it have been decomposed .Each agricultural area has biological raw materials that have the potential to be used as organic fertilizer.Abundant biological raw materials in the surrounding environment such as gamal leaves, banana heart, banana stems, brown sugar, rice washing water [4,5].

Making Liquid Organic Fertilizer (LOF)
The gamal leaves are mixed with enough rice washing water, then crushed and sliced so that all the substances contained come out then squeezed and filtered, then the brown sugar is mashed by grating and the banana stems and banana heart are chopped and mixed with grated sugar.The liquid fertilizer mixture is then put into a jar along with the juice of the gamal leaves and the rest of the rice washing water used on the gamal leaves and kept away from sunlight.After being fermented for 2 weeks, LOF was separated from the dregs by filtering and diluting with water according to each treatment.

Experimental method
This experiment was arranged using a Randomized Block Design method which consisted of five concentration of Amal Bajang's LOF (r) r 0 : control/ without LOF Amal Bajang r1 : LOF 25 ml/l.r2 : LOF 50 ml/l.r3 : LOF 75 ml/l.r4 : LOF 100 ml/l The research place in the green house that the enviroment factor have been controlled.Each treatment consisted of 2 (two) experimental units and was repeated 4 times, resulting in a total of 40 experimental units.

Application LOF to cocoa seeds
LOF was given 4 times starting at 1.5 months old seedlings as the first treatment.Subsequent applications are given at intervals of 2 weeks and the last time when the cocoa seedlings are 3 months old.The method of application to cocoa seeds is by watering around the stems of cocoa seeds according to the concentration of treatment.

Maintenance
Maintenance carried out is weeding , watering , and fertilizing.Weeding is done if there are weeds that grow in the around the cocoa plant watering is done twice a day, in the morning and evening or depending on the conditions of the growing media, while fertilization using LOF Amal Bajang is done every 2 weeks.

Observation parameters
Observations on the parameters of plant height (cm), stem diameter (cm), and number of leaves were carried out 5 (five) times.Starting in the first week before treatment and subsequent observations made 3 after treatment, namely at weeks 2, 3, 4, and 5. Furthermore, analysis of variance was carried out to determine the effect of the application of liquid organic fertilizer (LOF) on cocoa seedlings.

Content of Amal Liquid Organic Fertilizer
Analysis's Content of Amal Bajang Liquid Organic Fertilizer after fermenting 2 weeks, can show in Tabel 1.

Plant height
Based on the results of analysis of variance, it was shown that the experimental application of liquid organic fertilizer (LOF) on cocoa seedlings with different concentrations gave no significant effect on plant height, stem diameter, and significantly affected the number of leaves.
The results of the analysis of variance showed that the application of LOF had no significant effect on the increase in the height of cacao seedlings .The increase in plant height can be seen in the following figure 1 .

Figure 1. Average of Plant Height after application LOF
In figure 1 showed that the increase in the height of cacao seedlings in each treatment showed the highest increase in the treatment with a concentration of 75ml/L water by 2.463 cm.This is because the application with this concentration optimally stimulates the increase in plant height due to sufficient nutrients.The dominant nutrients contained in the liquid organic fertilizer used were N of 0.83% and K of 0.25%.According to [3,4], that the growth of a plant will be optimal if the nutrients needed are available in quantities and forms that are in accordance with the needs of the plant.Meanwhile, the lowest increase in plant height was found in treatment r 4 with a concentration of 100 ml/l (1.863 cm).It is suspected that by giving this concentration it exceeds the maximum limit of plant nutrient uptake as described by [6], that excessive nutrients can cause poisoning for plants and root growth will be 0,000 0,500 inhibited so that plant growth become abnormal.Fertilizer concentrations that are too high also inhibit the absorption of other nutrients, causing elemental deficiency.Plants also have certain limits to absorb the nutrients they receive [6].This is in line with the opinion of [7], that maximum plant growth and production will be achieved if the supply of nutrients to plants is in optimal conditions.because the lack or excess of one nutrient will reduce the efficiency of other elements and can reduce the quantity and quality of plants.

Diameter of stem
The results of observations and analysis of the variance of the increase in stem diameter showed that the application of LOF had an effect on not significant for the increase in stem diameter of cocoa seedlings.
The increase in stem diameter can be seen in the figure 2.

Figure 2. Average of stem diameter after application LOF
In figure 2 showed that the increase in diameter of cocoa stems in each treatment showed that the highest diameter increase was found in treatment 75 ml/l.That is, 0.246 cm.Possibility with treatment This optimally stimulates the increase in the required stem diameter in large enough quantities.This is related to the concentration contained in each treatment and the nutrient content contained in it is further explained by [6], that good plant growth can be achieved if the nutrients needed for growth and development are balanced, and in optimal conditions and supported by environmental factors.The increase in stem diameter is also influenced by the availability of potassium, because potassium is a nutrient that is absorbed in the same amount as nitrogen.If potassium deficiency will inhibit plant growth [7].Meanwhile, the lowest increase in stem diameter was found at control (without LOF), i.e., 0, 225 cm.This might be due to the absence of LOF treatment so that the availability of nutrients in the planting media is low which affects plant growth.This is in line with the opinion of [8] that the availability of sufficient nutrients to affect plant growth is further explained by [2], that a good growing medium is a medium that is able to provide water and nutrients in sufficient amount for seedling growth, the availability of nutrients in low growing media can cause less than optimal growth.

Number of leaves
The average variance of the number of leaves showed that the application of LOF have a significant effect on the increase in the number of cocoa seedling leaves.After further testing using the Smallest Significant Difference Comparison Value 5% (NPBNT 5%), it shows that between control, concentration LOF with 25 ml/l water, 50 ml/l and 75 ml/l were not significantly different, but significantly different from treatment concentration LOF 100 ml/l water.The average increase in the number of leaves of cocoa seedlings with various POC concentrations after the 5% Least Significant Difference test (BNT 5%) can be seen in the Tabel 2  On the table 2 shows that the application of LOF significant effect on the increase in the number of leaves.This is presumably due to the nutrient content contained in the materials used, especially the N element.Nitrogen is the main macro nutrient of plants that can accelerate plant vegetative growth .Nitrogen is one of the constituent elements of chlorophyll.If N uptake increases, then the chlorophyll content also increases so that photosynthesis is produced and chlorophyll is allocated to the plant growth also increases.Its effect on plant vegetative growth is indicated by an increase in the number of leaves.Leaf growth is one category of plants experiencing vegetative growth, so to meet their needs, the number of leaves is strongly supported by the content of nitrogen nutrients [9].

Conclusion
1.The application of Amal Bajang's LOF with different concentrations did not significantly affect the increase in height and diameter of the cocoa stem, but had a significant effect on the increase in the number of cocoa leaves.2. Concentration LOF 75 ml/l showed the highest increase in plant height and stem diameter of cocoa 3. On the number of leaves parameters after further testing, that between various treatments og LOF : r 0 (control), r1 (25 ml/l ), r2 (50 ml/l), and r3 (75 ml/l) was not significantly different, but significantly different from concentration r4 (100 ml/l).

Table 1 .
Results Analysis of Contens's Amal Bajang Liquid Organic Fertilizer

Table 2 .
Least Significant Difference test (BNT 5%) of the number of leaves of cocoa seedlings