1. Introduction
In
line with current global development efforts, the forestry sector is also
vitally involved in promoting sustainable growth, particularly through
initiatives such as reforestation and afforestation (FAO, 2020; Windyarini
& Hasnah, 2015). These projects aim to rehabilitate critical lands, often
degraded by shifting cultivation and the unplanned, irresponsible use of
forests (Chazdon, 2008). However, challenges in reforestation and greening
efforts frequently arise, with one significant issue being the inappropriate
selection of plant species (Menz et al., 2016).
Cashew
(Anacardium occidentale L.) is a promising species for rehabilitating
critical land, particularly in non-forest areas. According to Rismunandar
(2010), cashew trees are well-suited for reforestation due to their
environmental benefits, ability to grow on degraded land, low maintenance
requirements, and resistance to livestock grazing. Furthermore, cashews offer
economic benefits to farmers. Abdullah (2018) also highlights that cashew nuts
are drought-resistant and thrive in a broad range of soils and climates, making
them a viable option for land restoration.
Given
the numerous advantages of cashew cultivation, its sustainable development
holds significant potential (FAO, 2018). Although cashew trees are typically
propagated through seeds, traditional methods involving seedling transfer to
the field often result in low growth rates and vigour (Narasimhan et al., 2017).
These methods are also associated with logistical challenges, such as transport
costs and the risk of root damage during handling (Akinmolandu & Ojo, 2019).
This
study aims to explore an alternative propagation method: direct seed planting
in the field. It will focus on three treatments: seed coat incision, seed coat
splitting, and no treatment (control). The objective is to assess the impact of
these treatments on the growth of cashew seedlings and determine which method
has the most significant effect on seedling development in the field (Adebayo
et al., 2020).
2. Method
The
research was conducted in the educational forest area of Hasanuddin University,
located in Bengo-bengo, Maros Regency, over a period spanning from November
2022 to February 2023. The study utilised 270 cashew seeds as the primary
material (Windyarini
& Hasnah, 2015)and employed various tools to prepare the site and
monitor growth. Essential equipment included hoes and shovels for digging
planting holes, a machete for clearing vegetation, a ruler and a meter for
measuring seedling growth and planting distances, plastic ropes for securing
plant fences, and materials such as zinc and plastic for labelling plants.
Additionally, insecticides were used for pest control, while stationery was
utilised for recording observations (Evans & Turnbull, 2004).
The
study adopted a Completely Randomized Design (CRD) approach to assess the
effects of three treatments on cashew seed germination and seedling growth. The
treatments included slicing the seed coat (treatment A), splitting the seed
coat (treatment B), and planting seeds without any intervention as a control
(treatment C). Each treatment was repeated three times, with 30 seeds per
replication, making a total of 270 seeds. The CRD method was selected due to the
uniform and flat field conditions, and seeds were chosen based on consistent
weight and size (Gomez & Gomez 1984).
The
research began with field identification and preparation, including vegetation
clearance and the installation of planting stakes. The planting layout followed
an equilateral triangle pattern, with a spacing of 5 metres between planting
holes. Each planting hole was prepared with dimensions of 30 cm by 30 cm by 30
cm, ensuring proper separation of topsoil and subsoil to maintain soil nutrient
integrity. After allowing the planting holes to stabilise for seven days, they
were backfilled with segregated soil layers before planting the seeds at a
depth of 1 cm. A total of three seeds were planted in each hole, and a bamboo
fence was constructed around the plot to protect the seeds from pests such as
pigs.
Watering
was conducted twice daily, in the morning and evening, until germination
occurred and seedlings established themselves. In the absence of rainfall, each
planting hole received 1 litre of water per session, requiring a total of 180
litres daily for all 90 planting holes.
Observations
and measurements were carried out over a two-month period. Daily monitoring
during the first 30 days focused on seed germination, while the following 30 days
assessed seedling growth and vigour. Key parameters included the percentage of
seed germination, seedling height, and the number of leaves. Germination
percentage was calculated by counting the number of germinated seeds, while
seedling height was measured from the base of the plant to the base of the
leaves. The number of leaves was recorded from the emergence of the first leaf
until the final observation (ISTA, 2020; Leakey, 2012).
The
data collected on seed germination and seedling growth were analysed using a
CRD statistical method to determine the impact of the treatments on viability
and vigour (ISTA, 2020; Blolok et al., 2024). Germination percentage was
calculated using a standard formula to quantify seed viability (ISTA, 2020;
Leakey, 2012).
Where:
G = Germinated (%)
Data on the percentage results (%) of
germinated seeds were then entered into the Completely Randomized Design
formulation with the following formula:
Where:
Yij =
Observation of the 1st treatment and jth replication
µ =
General average
Pi =
Effect of Treatment i
eij =
Error of the ith treatment and ith replication
i =
1, 2, 3,…………………………………. p
j =
1, 2, 3,…………………………………. u
If
the treatment has a significant effect on the viability and vigor of the
offspring, then proceed with the Honestly Significant Difference (BNJ) test
according to the Turkey procedure at the 5% level using the following formula:
Where:
BNJ = BNJ Value
qz = Value in
Table for 5% level
p = Number of
treatments
db = Random
Degrees of Freedom
r = Number of
observations in each treatment/replication
KTE = Error
diversity
3. Result
and Discussion
1) Percentage
of Sprouts
The
results of the diversity analysis of viability (percentage of seed germination)
obtained the percentage value of seed germination which is presented in Table
1. The data in Table 1 was then analyzed according to the pattern of variance
as can be seen in Table 2.
The
results of the analysis of diversity in the increase in leaf number showed that
the treatments tested showed no significant effect. The calculated F is smaller
than the F table at the 5% level, this means that there are no pairs of average
increases in the number of leaves that are significantly different. For
deatails, see tha Figure 3.
Figure
3. Increase
in The Number of Chasew Sapling Leaves (Sheet)
4. Discussion
The
statistical analysis in this study demonstrated that slicing and splitting the
seed coat significantly impacted the germination percentage of cashew seeds.
Specifically, seeds left intact (control, treatment C) exhibited the highest
germination rate at 97.76%, significantly outperforming treatment B (splitting)
at 88.86% and treatment A (slicing) at 81.06%. The superior performance of the
intact seeds can be attributed to their undisturbed tissues, which maintained
the integrity of the protoplasm, enabling efficient cell division and elongation.
This ensured proper development of the radicle and plumule, vital for
successful germination.
The
intended purpose of slicing and splitting the seed coat was to enhance water
absorption and expedite germination. However, the results reveal that these interventions
were counterproductive under field conditions. This can be attributed to
environmental factors that were difficult to control, such as fluctuating
humidity, temperature, and soil conditions. Seeds consist of three critical
components: the protective seed coat, the cotyledon as a food reserve, and the
embryo. When the seed coat is sliced or split, it exposes the cotyledon and
embryo to external threats, including soil microorganisms such as fungi and
bacteria. These microorganisms, particularly in high-humidity conditions, can
interfere with the metabolic processes essential for germination, as supported
by previous studies. Abdullah (2018) emphasised that excessive humidity fosters
fungal growth, while Sutopo (2019) noted that overly wet conditions impede
aeration and promote diseases, ultimately causing seed rot.
Furthermore,
the detrimental effects of slicing and splitting are likely exacerbated by soil
conditions in the field. Damaged seeds are more vulnerable to environmental
stressors, such as water saturation, which can accelerate seed decay.
Additionally, pathogens such as fungi and bacteria can easily infiltrate
through the openings in the seed coat, further compromising seed viability.
These observations highlight the importance of maintaining the integrity of the
seed coat to protect the embryo and cotyledon from environmental and biological
hazards.
The
results also suggest that intact seeds not only perform better in terms of
germination but also exhibit superior seedling vigor. Vigorous seedlings,
characterised by greater stem diameter, leaf count, and height, were observed
predominantly in the control treatment. This underscores the importance of
undisturbed tissues in supporting early plant development. Moreover, intact
seeds are better equipped to withstand pest attacks, such as those from ants,
and to endure fluctuating field conditions.
The
findings strongly advocate for planting cashew seeds in their intact form
without any pre-treatment. This approach ensures a higher germination
percentage, better seedling vigor, and reduced susceptibility to environmental
stressors and pathogens. While the slicing and splitting of seed coats may seem
beneficial in controlled laboratory settings, the complexity and variability of
field conditions make intact seeds a more reliable choice. Future research
should explore additional factors influencing seedling success, such as soil
amendments, pest control strategies, and environmental optimisation, to further
refine cashew seed planting techniques and enhance plantation productivity
5. Conclusion
The
treatments evaluated significantly impacted plant growth, particularly seed
germination, stem diameter, leaf production, and seedling height. The control
treatment (treatment C), in which seeds were planted intact, exhibited the
highest germination rate of 97.76%, outperforming the other treatments that
involved slicing or splitting the seed coat, which did not result in
substantial improvements in germination.
In
addition to superior germination, the control treatment also led to healthier
plant development. Compared to the other treatments, seedlings from the control
treatment showed an average increase in stem diameter of 9.83 cm and produced
an average of 3.36 leaves. The seedling height also increased significantly,
indicating better overall vigor and growth.
These
results suggest that planting intact seeds is more effective in the field, as
it enhances seed protection, improves growth, and offers better resistance to
pests. The slicing and splitting treatments, which did not provide clear
benefits, can be considered unnecessary, especially in reforestation efforts
and other planting initiatives. Planting cashew seeds in their natural, intact
condition will likely improve the success of the planting process, reduce
seedling mortality, and promote plantation sustainability.
Exploring
other factors, such as soil quality and pest management strategies (Irawan
& Hidayah, 2017; Blolok et al., 2024; Suryawan & Irawan, 2017), would
be valuable in optimizing future planting efforts and could further enhance
seedling success. The planting of intact cashew seeds is the most effective
strategy to ensure high germination rates, vigorous seedling growth, and
increased resilience in the field, contributing to healthier and more
productive plantations.
6. Author
Contributions
The
first author's role involves compiling and analyzing scientific articles
derived from research findings. The second author aids the first author in
formulating research methodologies and assists in field data collection. The
third author contributes by collecting primary data in the field and gathering
secondary data as well.
7. Competing
Interests
The
process of writing scientific articles stems from collaborative research
results, ensuring no conflicts of interest among the authors due to their
shared responsibility and the collaborative nature of the research.
8. Acknowledgements
I
appreciate the contributions of my fellow writers (Nirwana, Wahyullah, Mahmud,
and Ummu Kultsum) who assisted in compiling this article.
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