Jurnal Akademika Kimia, 14(2): 64-69, May 2025
ISSN (online) 2477-5185 | ISSN (print) 2302-6030
http://jurnal.fkip.untad.ac.id/index.php/jak/

OPEN ACCESS

1

Analysis of Nitrogen and Potassium in Liquid Organic Fertilizer from
Rice Washing and Mature Coconut Water
Pinkan K. Bolang, *Vanny M. A. Tiwow, Paulus H. Abram, & Yuli Nurmayanti

Chemistry Education Study Program/Faculty of Teacher Training and Education – Universitas Tadulako, Palu –
Indonesia 94119
Received 31 October 2024, Revised 28 February 2025, Accepted 05 March 2025
doi: 10.22487/j24775185.2025.v14.i2.pp64-69

Abstract
Mature coconut and rice washing water contain nitrogen and potassium, which are helpful for plants. This study aims to
determine the levels of nitrogen and potassium in liquid organic fertilizer from a mixture of mature coconut water and rice washing
water. Nitrogen content was analyzed using the Kjeldahl method. Potassium levels were analyzed using a flame photometer. The
results indicated that the best nitrogen and potassium levels were obtained in liquid organic fertilizer with a mixture ratio 50:50,
namely N 1.26% and K 1.27%. The highest nitrogen content was obtained in liquid organic fertilizer (LOF) with a mixture ratio
of 25:75, 1.40%, and the highest potassium content was obtained in liquid organic fertilizer with a mixture ratio of 50:50, 1.27%.
When mixed, the increase in nitrogen and potassium levels was caused by the bacteria in the liquid organic fertilizer, which breaks
down protein during digestion.
Keywords: LOF, nitrogen, mature coconut water, potassium, rice washing water

optimal yields. Innovative and targeted organic
matter and fertilizer applications will avoid waste
and environmental pollution due to excessive
fertilizer use (Moe et al., 2019; Ridwansyah et al.,
2020).
According to where they come from, fertilizers
can be classified as either organic or inorganic.
Farmers frequently apply artificial fertilizers to their
soil because they believe they can speed up the
planting season and boost crop yields without
considering the long-term effects. Examples of
waste or agricultural products used to make organic
fertilizers include manure, green manure, crop
residues, and agricultural waste. There are two types
of organic fertilizers: liquid and solid. The benefits
of LOF include their ability to supply nutrients
swiftly, ease of application, and efficient
remediation of nutritional deficits. Even when
applied frequently, LOF typically does not harm
plants or soil. LOF is natural and synthetic
(Andriyani et al., 2022). Providing all the nutrients
required for plant growth, enhancing soil structure,
and promoting the health of soil microorganisms
are just a few benefits of using LOF.
LOF is derived from animals and plants as the
basic material that has been fermented. The
advantages of using liquid organic fertilizer in the
agricultural sector are that it contains nutrients that
plants easily absorb and contains many
microorganisms. Making organic fertilizers requires

Introduction
Indonesia is known as an agricultural country
because it has abundant natural resources and
strategic geographical conditions. Most of
Indonesia's population works in agriculture (Anwar
& Firmansyah, 2020). Meanwhile, in the coming 40
years, farming emissions will increase by almost
60% so that people can be provided with the correct
quantity and quality of food. Farm productivity and
soil fertility are necessary with this increasing
population and food shortage. There are many
strategies to increase soil fertility and productivity,
including using beneficial microbes and fertilizers
(Ilahi et al., 2021).
Fertilizer, though one of the most essential
inputs for increasing agricultural production, is a
leading cause of nitrous oxide emissions from
agriculture, contributing significantly to global
warming. Therefore, understanding factors
affecting farmers’ use of fertilizers is crucial to
developing strategies to improve efficiency and
minimize adverse impacts (Aryal et al., 2021).
It is known that besides the macronutrient
phosphorus (P), nitrogen (N), and potassium (K)
are the most important nutrients for plant growth
and development (Ye et al., 2019). Therefore,
farmers can ensure plants get the nutrients they
need by adjusting the dosage and type of fertilizer
applied more effectively and efficiently to achieve

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

*Correspondence:
Vanny M. A. Tiwow
e-mail: Vanny.Tiwow@gmail.com
© 2025 the Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons
Attribution-NonCommercial-ShareAlike 4.0 International, which permits unrestricted non-commercial use, distribution,
and reproduction in any medium, provided the original work is properly cited.

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Jurnal Akademika Kimia

a short time, and their application in agriculture is
essential. An easy farmer only needs to spray
organic fertilizer in agricultural areas (Tanti et al.,
2019). Rice washing water is a household waste that
can be used as liquid organic fertilizer because rice
washing water contains nutrients needed for plant
growth, including N, P, K, phosphorus, iron,
protein fiber, amino acids, and zinc (Pitaloka et al.,
2022).
Manganese (Mn), which is essential for protein
synthesis and aids in plant N use, and phosphorus
(P), which is involved in cell division, albumin
creation, and the formation of flowers, fruits, and
seeds, are among the minerals found in rice washing
water that are generally beneficial. Furthermore,
phosphorus increases plant resistance to disease,
improves plant quality, strengthens stems and roots,
speeds fruit ripening, and improves glucose
metabolism. Iron (Fe) contributes to the respiratory
process of plants and the production of green
substances called chlorophyll; nitrogen (N) content
contributes to the stimulation of plants' overall
vegetative growth, particularly the growth of roots,
stems, and leaves, as well as the production of
chlorophyll, which is crucial for the process of
photosynthesis and the synthesis of proteins and
fats. In addition to helping plants transport
phosphate, magnesium (Mg) synthesizes the green
molecules called chlorophyll and the carbohydrates,
lipids, and oil components that plants require. In
addition to strengthening plants so that leaves,
flowers, and fruits do not fall off easily, potassium
(K) content aids in forming proteins and
carbohydrates. Finally, calcium (Ca) content helps
stimulate root hair formation, harden plant stems,
and stimulate seed formation in stems and leaves
(Adlian et al., 2023).
Based on research conducted by Dewi et al.
(2021), it was found that the application of rice
washing water waste increased the number of leaf
blades, stem height, and wet weight of mustard
plants. The higher the rice washing water waste
concentration, the more these three parameters
increase. This is due to the higher content of
nutrients absorbed. In conclusion, rice washing
water waste can increase the vegetative growth of
mustard plants, so it has the potential as an LOF.
Besides rice washing water, coconut water can
also be used as LOF. This is because coconut water
contains auxin and cytokinin hormones and has
complex nutrients needed by plants, such as vitamin
C, sodium, thiamine, phosphorus, calcium, and
riboflavin. Researchers have extensively researched
the application of coconut water LOF (Sari et al.,
2021).
We divide coconut water into two categories:
young coconut water and mature coconut water.
Compared to young coconut water, mature coconut
water is the leftover coconut milk that is often
discarded or unused and ends up as waste. In fact,
mature coconut water contains natural growth
regulators that promote growth (Banna et al., 2023).
One of the many advantages of mature coconut

water, according to Mergiana et al. (2021), is that it
includes hormones that, when administered in the
right amounts, can promote plant development,
making it a natural plant growth regulator (PGR).
Gibberellins, auxin, and cytokinin are hormones
found in aged coconut water. These three hormones
trigger cell division, bud development, and stem
elongation (Setyawati et al., 2020).
Based on experimental results, applying
coconut water as a liquid organic fertilizer
significantly affects the growth of tomato plants,
especially plant height (Sari et al., 2021). In addition,
the application of coconut water liquid organic
fertilizer and gold snail gives a positive response to
the growth of mung bean plants (Vigna radiata)
Hidayanti et al. (2022), and had a significant impact
on the growth of cocoa seedlings, affecting the
number of leaves, plant height, number of roots,
and length of roots (Baid et al., 2022).
Based on the explanation, the researcher is
interested in analyzing nitrogen (N) and potassium
(K) levels in liquid organic fertilizer derived from
rice washing water and mature coconut water.
Methods

Tools and materials

The tools used in this study were plastic jars,
jerry cans, bottles, clear hoses, digital scales, a
spectrophotometric Flame Photometer, a UV-Vis
spectrophotometer, a Kjedahl destruction
apparatus, a dropper pipette, a beaker, and a
measuring flask. This research used mature coconut
water, rice washing water, EM4 (Effective
Microorganism 4), brown sugar, clean water,
concentrated sulfuric acid, Kjedahl tablets, aquades,
and iron glue.

Sample collection and preparation

The samples used in this study were aged
coconut water taken from coconuts in Bancea
Village, Poso Regency, and rice washing water from
Super type rice, which also came from Bancea
Village, Poso Regency.

Making liquid organic fertilizer

Making LOF by washing 1 liter of Super type
rice 2 times with 750 mL of clean water. Then the
sample was filtered, cleaned, and put into a jar. Each
sample was added 50 mL of EM4 and 50 mL of
liquefied brown sugar, then stirred until
homogeneous. Next, mix the mature coconut and
rice washing water with a mixture ratio of 50:50,
75:25, and 25:75, respectively. Then, I added 100
mL of EM4 and 100 mL of brown sugar solution.
Next, mix mature coconut water and rice washing
water with a ratio of 50:50 and add 100 mL of
brown sugar solution. EM4 is not added to this
mixture because it will be used as a comparison.
Furthermore, fermentation is carried out for 14 days
until the fertilizer smells of tapeh. The addition of
EM4 functions as a bioactivator to accelerate the

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Pinkan K. Bolang et al.
fermentation process, and the addition of brown
sugar solution serves as a source of nutrition for
microorganisms (Tanti et al., 2019).

ppm curve = Sample content obtained from the
curve of the relationship between
standard series content and readings
after correction
100
= Conversion to %
fk
= Moisture content correction factor
fp
= Dilution factor

Nitrogen analysis

The sample of LOF fermented was weighed as
much as 1 gram and put into a Kjedahl flask, then
10 mL of 1 M H2SO4 from a Kjedahl tablet was
added. Then it is destroyed or heated until it boils,
and the solution changes color to clear. After
completion of destruction, the sample extract
solution was allowed to stand for a while until the
solution cooled. Furthermore, the sample extract
solution was diluted to 100 mL. Then the diluted
sample will be distilled. The sample extract solution
was taken as much as 10 mL and put into a
distillation flask. 10 mL of 40% NaOH was added
to the distillation flask containing the sample extract
solution and immediately closed tightly. Next, a
solution of 10 mL H3BO3 1% was prepared in an
Erlenmeyer flask as a reservoir for NH3, and two
indicators of BCG + MR (bromocresol Green +
Methyl Red) were added. Distillation is carried out
until all nitrogen is distilled (blue). Then the distillate
is titrated with 0.1 N HCL until the endpoint of the
titration is reached, which is a color change from
blue to pink.
N% =

(𝑉𝑠−𝑉𝑏) × 𝑁 𝐻𝐶𝐿 ×14.008 × 𝐹𝑃
𝑤

Results and Discussion
A LOF made from a combination of mature
coconut water and rice washing water is the end
product of examining these two sources' nitrogen
and potassium content. We use fermentation in our
production of LOF.
Fermentation,
specifically
ammoniation
fermentation, aims to improve the quality of animal
feed ingredients. Biochemically, fermentation is the
formation of energy through organic compounds.
At the same time, application to the industrial field
is defined as the process of converting basic
ingredients into products by microbial cell mass, so
that the fermentation process can occur if there is
contact between the microorganisms that cause
fermentation and the appropriate organic substrate
(Rasyid et al., 2022).
In this study, coconut and rice washing water
were divided into several mixing ratios, and fertilizer
from each sample was added as a comparison. The
samples were fermented for 14 days at room
temperature. The nitrogen content in liquid organic
fertilizer was analyzed using the Kjeldahl method,
starting with digestion, distillation, and titration.
Potassium levels were analyzed using a Flame
Photometer.
The following table contains nitrogen and
potassium obtained from this study. Based on
Table 1, the nitrogen content of mature coconut
water is 0.56% and the nitrogen content of rice
washing water is 0.91%. It can be seen that the rice
washing water contains more nitrogen than mature
coconut water. This is due to the protein content in
the rice washing water, which decomposes into
nitrogen during digestion. This study obtained the
highest nitrogen content in a mixture of aged
coconut and rice washing water (Ratio 25:75),
1.40%. The increase in nitrogen levels when the two
samples were mixed with a ratio of 75% rice
washing water and 25% aged coconut water was
caused by bacteria that decomposed during
digestion.
However, the nitrogen content obtained in this
study did not meet the standards for trading. In the
Regulation of the Minister of Agriculture of the
Republic of Indonesia No. 70 of 2011 concerning
"Organic Fertilizers, Biological Fertilizers, and Soil
Improvements", the quality standard for nitrogen
content is 3 - 6%. However, liquid organic fertilizer
from a mixture of mature coconut water and rice

× 100

Description: Vs = Sample titration volume (mL)
Vb = Blank titration volume (mL)
FP = Dilution factor
W = Sample weight
(Amalia & Fajri, 2020).

Analysis of potassium

The fermented sample was weighed as much
as 5 grams and put into an Erlenmeyer flask. 4 mL
of HNO3 and 2 mL of HCLO4 were added and
stirred until homogeneous. Then it was heated until
the sample extract solution was clear. Then the
solution was cooled and diluted by adding distilled
water to 25 mL, shaken until homogeneous, and
filtered with W-41 filter paper to obtain a clear
extract. Then 1 mL of the sample was taken and put
into a test tube, 9 mL of distilled water was added,
and the mixture was shaken with a vortex until
homogeneous. Analysis of K levels in samples of
LOF from mature coconut water and rice washing
using a Flamephotometer at the Laboratory of the
Faculty of Agriculture, Tadulako University, with a
wavelength of 766.5 nm, with K standard series
concentrations of 0, 2, 4, 8, 12, 16, and 20 ppm
(Zakiyah et al., 2019).
K% = ppm kurva ×

𝑚𝐿 𝑠𝑎𝑚𝑝𝑙𝑒
100
×
× 𝑓𝑝 × 𝑓𝑘
1000 𝑚𝑙
𝑚𝑔 𝑠𝑎𝑚𝑝𝑙𝑒

Description:

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washing water in this study can be used in everyday
life.
Table 1. Nitrogen content in POC samples of mature coconut water and rice washing water
Sample Repeat
No.

Sample

Average

Content Test (%
I

II

1.

Mature coconut Water

N

0.56

0.56

0.56

2.

Rice Washing Water

N

0.84

0.98

0.91

3.

Mixed mature coconut water and Rice washing water (Ratio
50:50)

N

1.40

1.12

1.26

4

Mix of aged coconut water and rice washing water (Ratio
75:25)

N

0.70

0.84

0.77

5

POC of Mixed coconut water, aged coconut water, and rice
washing water (Ratio 25:75)

N

1.54

1.26

1.40

6

Mixture of aged coconut water and rice washing water
without the addition of EM4(50:50 ratio)

N

1.12

0.84

0.98

Based on Table 2, the potassium content
obtained in mature coconut water is 1.26% and the
potassium content of rice washing water is 0.271%.
Potassium levels in mature coconut water are higher
than in rice washing water. This is because mature
coconut water contains many minerals. Previous

research also showed that potassium levels in aged
coconut water were higher than in rice washing
water. Gultom & Prabatiwi (2017) showed that
potassium levels in aged coconut water were 2.18%
and in Jannah et al. (2018), the potassium level in
rice washing water was 2.02%.

Table 2. Potassium content in POC samples of mature coconut water and rice wash water
No.

Content
Test (%)

Sample

Sample
Repeat
I

II

Average

1.

Mature coconut Water

K

1.225

1.3

1.26

2.

Rice Wash Water

K

0.259

0.283

0.271

3.

Mix of mature coconut water and rice washing water (Ratio 50:50)

K

1.20

1.34

1.27

4.

Mix of aged coconut water and rice washing water (Ratio 75:25)

K

0.925

0.912

0.918

5.

Mixture of mature coconut water and rice washing water (Ratio
25:75)

K

0.63

0.645

0.637

6.

Mix of aged coconut water and rice washing water without the
addition of EM4(50:50 ratio)

K

0.325

0.35

0.337

This study obtained the highest potassium
levels in a mixture of aged coconut water and rice
washing water (50:50), 1.27%. However, the
potassium levels obtained in this study can be used
in daily life even though they do not meet the
standards for trading because the Regulation of the
Minister of Agriculture of the Republic of Indonesia
No. 70 of 2011, which states that the standard level
of potassium in organic fertilizers is 3 – 6%. The
results of measuring potassium levels in this study
are relatively low compared to previous studies. The
fermentation process may not be perfect, so the
material's decomposition is slow (Sulfianti et al.,

2021). The decrease in potassium levels in this study
may also be caused by the type and location of
growth of the two samples used, because each type
of coconut and rice has different potassium levels.
Conclusions
The results indicated that the best nitrogen
and potassium levels were obtained in liquid organic
fertilizer with a mixture ratio 50:50, namely N
1.26% and K 1.27%. The highest nitrogen content
was obtained in LOF with a mixture ratio of 25:75,
namely 1.40%, and the highest potassium content
was obtained in LOF with a mixture ratio of 50:50,
namely 1.27%. When mixed, the increase in

67

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nitrogen and potassium levels was caused by the
bacteria in the liquid organic fertilizer, which breaks
down protein during digestion.
Acknowledgment
The author thanks Tadulako University for
supporting laboratory facilities and providing
technical assistance during this research. Thank you
are also extended to the supervising lecturer for
their invaluable guidance, suggestions, and input
during the preparation of this article. Moreover, the
author also appreciates the contributions of
colleagues who assisted in data collection and
analysis. This research would not have been possible
without the support of all the parties involved.
Conflict of Interest
The authors state that there is no conflict of
interest related to the publication of this paper.
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