Effect of potassium fertilizer dose and compost dose of empty palm oil bunches (EFB) on the growth of lemongrass (Cymbopogon nardus L.)

This study aims to determine the effect of potassium fertilizer and compost of Empty Palm Oil Bunches (EFB) on the growth of citronella (Cymbopogon nardus L.). The research was started in February-June 2022 at BPTP Banten, and the Laboratory of the Department of Agroecotechnology, Sultan Ageng Tirtayasa University. This study used a factorial Randomized Block Design (RBD) method which consisted of two factors. The first of potassium fertilizer dose has 4 levels, 0 kg/ha potassium (K0), 15 kg/ha (K1), 30 kg/ha (K2) and 45 kg/ha (K3). The second factor of EFB compost has 4 levels, 0 tons/ha (T0), 20 tons/ha (T1), 30 tons/ha (T2) and 40 tons/ha (T3). The results showed the dose of potassium fertilizer 30 kg/ha gave the best results on plant height parameters at the age of 3, 4, 5, 6 weeks after planting (WAP). Dosage of 40 tons/ha of EFB compost gave the best results on the number of leaves aged 5 and 6 WAP. There was no interaction between the dose of potassium fertilizer and the dose of EFB compost on all.


Introduction
Lemongrass (Cymbopogon nardus L.) belongs to the family gramineae or the grass family.[1] stated that lemongrass contains two main compounds, namely citronellal and geraniol, which are raw materials for making essential oil (citronella oil).Lemongrass production in 2012-2014 was 2600 tons/year, 2710 tons/year and 3100 tons/year [2].Based on this data, lemongrass production has increased every year, although the amount is still small compared to the production of other biopharmaceutical crops.Considering the high economic value of lemongrass as a raw material for essential oils, this is not balanced by the amount of production, so it is necessary to increase the productivity of lemongrass plants in order to meet the export needs of lemongrass.The available land is often unusable because of its low fertility rate.In this way, the productivity of lemongrass plants can be increased by paying attention to external factors, one of which is using the right fertilizer dosage.According to [3] Traditional agricultural practices and excessive chemical input use increased agricultural productivity, but longterm use of chemical fertilizers has been shown to have negative effects on the environment and human fitness.
Fertilizer functions to provide the nutrients plants need to support their growth.According to [4], one of the nutrients needed in large quantities in lemongrass cultivation is potassium.Based on the research results of [4], a dose of 30 kg/ha of potassium fertilizer had the best effect on the parameters of plant height of 60.91 cm and the number of tillers of 95.15 in lemongrass plants at the age of 6 month after planting.The advantages of organic fertilizer are that it is rich in macro-and micronutrients and can improve soil structure.One of organic fertilizer that can be used is empty oil palm fruit bunch compost, which is abundantly available.The results of [5] showed that applying 9 kg/plot empty palm fruit bunch compost or the equivalent of 40 tons/ha had a significant effect on plant height (cm), number of tillers per plot, and crop production per plot on lemongrass plants (Cymbopogon citratus).From the explanation above, research needs to be carried out to develop the cultivation of lemongrass plants.The purpose of this study was to determine the effect of giving doses of potassium fertilizer and empty palm fruit bunch compost (EFB) on the growth of lemongrass plants (Cymbopogon nardus L.).

Materials and Methods
This research was carried out at the Agricultural Instruments Standards Implementation (BSIP) of Banten Province, and the Laboratory of the Agroecotechnology Department, Faculty of Agriculture, University of Sultan Ageng Tirtayasa in February-June 2022.The materials used in this study were lemongrass seeds of the Sitrona 2 Agribun variety, empty palm fruit bunch compost (EFB), urea fertilizer, SP-36 fertilizer, KCl (Potassium) fertilizer, PGR, and top soil.
The study used a randomized block design method that consisted of two factors: the first factor was the dose of potassium fertilizer, and the second factor was the compost of empty palm fruit bunches (EFB).The first factor consists of 4 levels, namely: 0 kg/ha (K0), 15 kg/ha (K1), 30 kg/ha (K2), and 45 kg/ha (K3).The second factor consisted of 4 levels, namely: 0 tons/ha (T0), 20 tons/ha (T1), 40 tons/ha (T2), and 60 tons/ha (T3).This study consisted of 16 treatment combinations with 3 repetitions to obtain 48 experimental units.Each experimental unit contained 2 polybags, and each polybag contained 2 plants, so the total number of plants in the study was 192.A second test utilizing the Duncan Multiple Range Test (DMRT) at a level of 5% and 1% will be conducted if the variance findings indicate substantial to very significant differences.

Results and Discussion
The results of observations of the doses of potassium fertilizer and EFB compost and the interaction between the two showed results that were not significantly different in the parameters of shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, and root shoot ratio, as can be seen in Table 1 -5

Crown Fresh Weight (g)
From the research results, the application of potassium fertilizer and EFB compost gave nonsignificantly different results on the fresh weight of the lemongrass shoot.This is thought to be because the required nutrients have reached optimum levels.From the research results, applying 30 kg/ha of potassium fertilizer resulted in a fresh shoot weight of 10.92 g.This is in line with the research results of [6], where the application of potassium fertilizer was able to significantly increase the production of fresh shoot weight from lemongrass plants, namely 17.39-54.2%compared to the control from the 1st to 3rd harvest.The application of EFB compost gave significantly different results, where the 40 ton/ha treatment was able to produce the highest fresh shoot weight of 11.50 g.This shown that providing compost can meet the plant's nutrient needs.The organic material in EFB compost has the ability to enhance the physical characteristics of the soil, which in turn affects how well the roots absorb nutrients.
Compost alone increased the number of culms by 2.33 times above the control, while mycorrhiza inoculation alone increased the number of culms by 1.60 times.[7].

Shoot Dry Weight (g)
The K2 treatment, namely 30 kg/ha, was able to produce the largest dry weight of the canopy, namely 5.86 g.This is thought to be because potassium provides the nutrients needed by plants and stimulates the nutrient translocation process.Apart from that, the EFB compost treatment did not provide significantly different results.However, the 40-ton/ha treatment produced the heaviest canopy dry weight, namely 5.92 g.EFB compost contains organic materials and other nutrients, which, although in small quantities and available slowly, are able to support the growth of lemongrass plants.[8] explains that organic compounds are able to provide nutrients and activate soil microorganisms.The nutrients absorbed by the roots will be translocated to the vegetative and generative parts of the plant to stimulate the photosynthesis process optimally so that it can influence the dry weight of the plant.

Root Fresh Weight (g)
Plants without potassium treatment had the highest wet root weight, namely 2.51 g, and those treated with 40 tons/ha of EFB compost had the highest wet root weight, namely 2.45 g.It is suspected that the nutrients obtained from the provision of EFB compost are not optimal; the compost is able to provide nutrients for plants but is slow.In addition, the soil used easily hardens when it is dry.So it is difficult for the roots to grow and develop.This is in line with the statement of [9], who stated that the growth of the root system will deviate from ideal conditions if the soil conditions in which it grows are not optimal.

Root Dry Weight (g)
Where the treatment without potassium obtained the highest dry weight of 2.01 g and control plants or without the provision EFB compost produced the highest root dry weight of 1.98 g.The interaction between the two treatments shows that the results are not significantly different and do not influence each other.This is thought to be because the nutrients obtained have not been able to support plant growth properly.Apart from that, lemongrass is a plant whose leaves are used for pruning.Lemongrass plants are harvested periodically.So when the plant is 12 WAP, it has not yet produced the optimal fresh weight of the crown as well as the weight of the plant's roots.[10] state that harvesting lemongrass can be started when the plants are 6 months old, with subsequent harvesting ranging from 70-75 days in the rainy season and 80-90 days in the dry season.

Root Crown Ratio
Based on the results of the average root-to-stem ratio, the dose of potassium fertilizer showed that the results were not significantly different.According to the findings of this study, potassium applications of up to 45 kg/ha and plants without EFB compost had the highest root canopy ratio.The results of [10] showed that the ratio of root crowns in compost media was significantly different from the ratio of root crowns in soil media and soil compost media.Where the compost medium has greater results than the other two media.This shows that the speed of growth to the roots is faster than growth towards the crown on soil media and soil compost media.Where the distribution of photosynthesis results is faster towards the roots than towards the crown.Based on the literature, the results of this study indicate that plants with the highest ratio have a faster rate of shoot growth compared to root growth.This is thought to be because the nutrients needed by plants are not yet available, considering the slow nature of compost.Based on research results [11] When 75 kg/ha of potassium was applied, the percentage of essential oil dropped to 0.63%, The highest percentage of essential oil (0.72%) was found in plants that were given 25 kg of nitrogen and 50 kg of potassium per hectare.So there is no real difference between plants given compost and those not given compost.Given mineral NPK fertilizer was reduced, the amount of nitrogen in the plant declined dramatically, but the response of potassium and phosphorus to fertilization treatments was unclear [12].

Conclusion
There was no significant result and interaction between the doses of potassium fertilizer and EFB compost doses for all parameters at the age of 1-12 WAP.It is necessary to carry out further research using various doses of potassium fertilizer and various doses of EFB compost on different soil types and planting ages, or longer observations.

Table 1 .
. Average shoot fresh weight, in the treatment of doses of potassium fertilizer and doses of Empty Oil Palm Fruit Bunches (EFB) compost.

Table 2 .
Average shoot dry weight in the treatment of doses of potassium fertilizer and doses of Empty Oil Palm Fruit Bunches (EFB) compost.

Table 3 .
Average root fresh weight in the treatment of doses of potassium fertilizer and doses of Empty Oil Palm Fruit Bunches (EFB) compost.

Table 4 .
Average root dry weight in the treatment of doses of potassium fertilizer and doses of Empty Oil Palm Fruit Bunches (EFB) compost.

Table 5 .
Average lemongrass root shoot ratio in the treatment of doses of potassium fertilizer and doses of Empty Oil Palm Fruit Bunches (EFB) compost.