Zeoponic: A Breakthrough Plant Growth Media for Horticulture and Seedling of Plantation

Plant growth media (PGM) are vital materials for supporting plant growth (Gruda et al., 2013). PGM have physical and chemical characteristics that play a significant role in plant growth and development. Physical properties like bulk density, air space, water-holding capacity and total porosity assess the arrangement of solid, water and air components. Meanwhile, chemical properties, such as pH, nutrient content and electrical conductivity (EC), also play a crucial role in supporting plant growth (Kennard et al., 2020).
       
The quality of PGM can have a significant impact on the availability of nutrients for plants. Therefore, it is important to selecting high-quality PGM that provide the necessary nutrients and support for plant growth and development (Thakur et al., 2020). The use of poor-quality PGM can result in reduced plant growth and yield, as well as decreased nutrient uptake by plants. The characteristics of poor-quality PGM include high electrical EC values, which can indicate high levels of salts that can negatively affect plant growth and development (Subandi et al., 2015). Hydroponics is a method of growing plants without soil, where plants are grown in a nutrient solution with or without a soilless substrate to provide physical support (Niu et al., 2022). Generally, PGM in hydroponics are replaced by replacement media such as rockwool, chaff charcoal, zeolite and various other light and sterile media. Hydroponic PGM must meet several criteria in order to support plant growth well. These criteria do not affect nutritional content, do not clog up the water system and have good pores (Jan et al., 2020).
       
Zeoponic is a PGM made from zeolite mixed with other materials such as compost, cocopeat and fertilizer (Suwardi and Pangestu 2004). Zeolite has high cation exchange capacity (CEC), ranging from 80 to 180 meq/100 g, allows for beneficial cation absorption and exchange, promoting plant growth (Suwardi et al., 2004). In addition, use of alternative growing media, such as compost can be used to improve soil structure, water-holding capacity and nutrient availability for plant growth (Grigatti et al., 2007). Cocopeat is also an organic material derived from coconut skin, making it an environmentally friendly choice for PGM. It provides good water resistance and also provides drainage, which can help improve soil structure and availability of nutrients for PGM (Kaushal and Kumari, 2020). Furthermore, as noted by Monica (2023), agricultural waste bio-adsorbents like coconut husk have high adsorption capacities and are readily abundant.
       
Horticultural crops which include vegetables, ornamental and plantation are essential in agriculture (Ali et al., 2023). These crops require specific growing conditions, including proper soil, water and sunlight, as well as pest and disease control, to ensure healthy and high-yielding plants. As each plant species has specific nutritional requirements, farmers continuously seek new combinations of PGM (Febriani et al., 2021). Evaluating PGM based on their physical and chemical properties is crucial to ensuring they provide optimal conditions for diverse plant growth. Zeoponic have chemical and physical properties that are suitable for the development of plant roots (Suwardi et al., 2023). Forestry seedlings are young trees grown for commercial or conservation purposes. They are typically grown in nurseries and then transplanted to their permanent location once they have reached a suitable size. Forestry seedlings are important for reforestation, timber production, as well as for ecosystem services such as carbon sequestration and biodiversity conservation (Grossnickle and MacDonald 2018).
       
The aim of this study is to compare the physical and chemical properties of zeoponic and commercial PGM and assess the potential of zeoponic as a PGM for various plant types, including horticulture crops and seedlings of plantation.

This study, was involved a field experiment at the Cikabayan Education greenhouse, then conducted physical and chemical property analyses of various PGM at the Laboratory of the Department of Soil Science and Land Resources, Faculty of Agriculture, IPB University. The experiment was carried out from September 2021 to March 2022.
       
A completely randomized design was employed to assess the effects of different PGM on the growth and productivity of three plant species: Solanum lycopersicum, Aglaonema sp and Swietenia mahagoni. The study utilized five different PGM, including commercially available PGM 1, PGM 2, PGM 3 and PGM 4, commonly used in Bogor, Indonesia as well as Zeoponic.
 
Composition of PGM
 
The composition of the different PGM used in the study is presented in (Table 1). Zeoponic is formulated by combining zeolite, compost and cocopeat in a 2:1:1 ratio (zeolite: compost:cocopeat). Zeolite grains with a 5 mm diameter are thoroughly mixed with compost and cocopeat using a shovel, trowel, or by hand to achieve an even distribution. The zeoponic mixture is supplemented with NPK fertilizer 16-16-16 at a rate of 1.5 g L^-1 and compound fertilizer is applied following the recommended dosage on the fertilizer packaging. Finally, all the ingredients are mixed to ensure a uniform distribution of the fertilizer within the zeoponic mixture (Fig 1).
 

 

 
Laboratory analysis of PGM
 
Before planting, the laboratory analysis of PGM included assessing bulk density, pH, EC, NH₄-N, NO₃-N, Available-P, C-organic, Exch-K, Exch-Na, Exch-Ca, Exch-Mg, base saturation, CEC, Fe, Mn, Cu and Zn. Methods included measuring bulk density by comparing weights per volume, pH with a 1:5 water ratio and a pH meter, EC with a 1:5 water ratio and an EC meter, NH₄^-N and NO₃^-N using the Kjeldahl method, Available-P with the P-Bray 1 method and vanado molybdat extraction, C^-organic with the Walkley and Black method and Exch-K, Exch-Na, Exch-Ca, Exch-Mg, CEC and base saturation using the NH₄OAc 1 M pH 7.0 method. Additionally, Fe, Cu, Mn and Zn were measured using the diethylenetriaminepentaacetic acid (DTPA) extraction method.
 
Measurement and observation of plant growth parameters
 
To assess plant growth, various parameters were measured and observed, including plant height, stem diameter, number of leaves, leaf width and leaf length. Plant height was measured in centimeters from the media surface to the tip of the highest leaf, using a ruler. Stem diameter was determined with a digital caliper. The number of leaves was counted by observing fully opened leaves, while leaf width and length were measured in centimeters using a ruler on selected leaves.

Chemical and physical properties of zeoponic compared to commercial PGM
 
All PGMs showed the pH values ranging from 6.70 to 7.78, which fall in the slightly acidic to slightly alkaline range. The optimal pH range for plant growth is from 6.0 to 7.0, which is slightly acidic to neutral (Boeckmann, 2022). The specific composition in each PGM can impact its pH. Different materials, such as zeolite, compost, cocopeat and others, have varying pH levels. Zeoponic, utilizing zeolite, helps maintain a neutral pH due to zeolite’s ability to balance pH (Pangestu et al., 2004). Soil pH directly influences nutrient availability, affecting phosphorus (P) absorption (Barrow and Hartemink, 2023). According to (Table 2), there is a notable decrease in Available-P with increasing pH.
 

       
Phosphorus is one of the essential elements for plant growth and it’s the second most crucial nutrient after nitrogen that can limit crop growth. Generally, higher available-P values generally enhance plant growth and yield, while lower values limit growth (Bai et al., 2013). Zeoponic media reported an available-P value of about 903 ppm (Lestari 2022) The application of zeolite and organic fertilizer during the initial planting increase available-P levels, with zeolite enhancing P availability alongside the residual effects of organic fertilizer (Estiaty et al., 2005).
       
The high C-organic value in the PGM is due to the use of organic materials such as compost, animal manure and cocopeat in the production of PGM. C-organic is crucial for improving nutrient availability and soil texture in agricultural practices (Darusman et al., 2018). The addition of zeolite together with animal manure fertilizer contributes to better growth and production (Estiaty et al., 2005).
       
Zeoponic has the lowest EC value because it has a high CEC (Tjahyandari et al., 2023). CEC is the soil’s ability to retain positively charged ions like nutrients. A higher CEC, as in zeoponic, means better nutrient retention, resulting in a lower EC value. On the other hand, PGM 2 has the highest EC value compared to other PGMs, high EC in PGM can be caused by excessive levels of nutrients or salts, which can lead to stunted growth, leaf damage and eventually plant death. Additionally, organic wastes and composts commonly contain high salt content, which can result in elevated nutrient levels and potential toxicity to plants (Ostos et al., 2008).
       
Generally, there is a positive correlation between EC and the concentration of NO₃-N (Baldi et al., 2020). However, in (Table 2), there doesn’t appear to be a consistent correlation between EC and NO₃^- N in PGM. This inconsistency can be influenced by the presence of organic matter in the PGM, which acts as a reservoir for nutrients, including NO₃^- N, slowly releasing it over time. As nutrient concentrations for NH₄⁺, NO₃^- and P also affect the EC levels (Wiser and Blom, 2016). PGM with higher organic matter content can have higher levels of stored NO₃^- N, even with lower EC values. Additionally, different PGM may utilize different N sources, such as organic or inorganic fertilizers, which can independently affect NO₃^- N levels regardless of EC. For instance, organic fertilizers release N gradually, while inorganic fertilizers provide N in a readily available form.
       
The N source for uptake in plants is mainly in the form of NH₄⁺ and NO₃^-  (Feng et al., 2020). The ideal NH₄⁺ and NO₃^- values in PGM depend on the plant species. In this study, the plant used were tomatoes, mahogany and Aglaonema were used. According to (Liu et al., 2017) research, the recommended concentration of NH₄⁺ in PGM for tomato plants is typically in the range of 10–30 ppm, while the recommended concentration of NO₃^- is around 100-150 ppm. The levels of NH₄⁺ and NO₃^- in the zeoponic are quite high compared to the recommended values. However, in the zeoponic contain zeolite that has the size of a cavity according to the size of the NH₄⁺, so that can absorb NH₄⁺. The NH₄⁺  that zeolite absorbs are not immediately released into the soil solution as long as the amount of NH₄⁺ in the soil is still high (Suwardi, 2009).
       
The analysis of physical properties was conducted on the bulk density of five different PGM revealed that they ranged from 0.37 to 0.54 g cm^-3, indicating a low bulk density category. Zeoponic has the lowest bulk density, indicating a less compact structure with more pore space, facilitating water flow and root penetration. In contrast, higher bulk density in other PGM may negatively impact soil physical properties and nutrient uptake (Nyéki et al., 2017). Therefore, the bulk density of PGM is an important parameter to consider when selecting a PGM for specific plants.
       
The CEC values, ranging from 45.54 cmol(+) kg^-1 to 83.21 cmol(+) kg^-1, play a crucial role in determining a soil nutrient-holding capacity. A higher CEC value enhanced nutrient retention and gradual release, reducing the need for frequent fertilization. CEC and exchangeable cations exhibit a positive correlation, as CEC represents the total amount of exchangeable cations a soil can adsorb (Solly et al., 2020). According to the (Table 3), we can observe that zeoponic has the highest CEC value of 83.21 cmol(+) kg^-1, which is accompanied by relatively higher concentrations of exchangeable cations such as potassium (Exch-K), sodium (Exch-Na), calcium (Exch-Ca) and magnesium (Exch-Mg). In contrast, PGM 3 has the lowest CEC value of 45.54 cmol (+) kg^-1, resulting in lower concentrations of exchangeable cations.
 

       
Base saturation is the sum of base cations (Ca²⁺, Mg²⁺, K⁺ and Na⁺) held onto the soil exchange sites divided by the total CEC and expressed as a percentage (Mason and Zanner, 2005). Higher concentrations of exchangeable base cations lead to a greater base saturation percentage (Zhang et al., 2023). In (Table 3), zeoponic show the highest base saturation value of 106%, reflecting its elevated concentrations of exchangeable cations (Exch-K, Exch-Na, Exch-Ca, Exch-Mg). On the other hand, PGM 3 has a lower base saturation value of 99%, indicating comparatively lower concentrations of exchangeable cations.
       
Micronutrients, including Fe, Mn, Cu and Zn are vital for plant growth (Gomes et al., 2021). The data in (Table 4) show that the concentrations of these micronutrients vary widely among the different types of PGM. Referring to nutrient sufficiency standards by (Jones, Wolf and Mills, 1991), zeoponic generally provides a balanced range of essential micronutrients for tomatoes, Aglaonema sp. and mahagony seedlings. PGM 1 and PGM 4 exceed recommended ranges for all elements, PGM 2 meets standards for Fe and Cu but has lower Mn and Zn levels and PGM 3 meets Cu standards but has lower Fe, Mn and Zn levels.
 

 
Zeoponic for pgm of horticulture crops
 
Based on all observed parameters, tomato plants with zeoponic are best compared to tomato plants in other commercial PGM. Table 5 shows the height of tomato plants in the zeoponic is very different from that of other PGM, followed by the number of leaves, leaf width, leaf length and stem diameter. Zeoponic treatment produced plants with the most significant growth, which included the upper part of the plant and the roots of the plants (Suwardi et al., 2023). Roots of the tomato plant in zeoponic are also the longest in size compared to other commercial PGM (Fatiha 2022).
 

       
Horticultural crops need NPK nutrients in order to grow and thrive. Based on the physical and chemical properties data, zeoponic has good NPK content to support the growth of horticultural crops. According to Tavallali et al., (2018) tomato plants need a significant amount of N to grow and thrive. N is an essential nutrient for plant growth and is required for the production of chlorophyll, which is necessary for photosynthesis. Zeoponic increased the efficiency of nutrient uptake, especially N, due to its great capacity for CEC to absorb NH₄⁺. According to Grunert et al., (2019) tomatoes have the ability to absorb N in the form of NH₄⁺ and NO₃^-. Additionally, tomato plants have been observed to exert an influence on, or even modulate, the nitrification activity that occurs in the rhizosphere.
       
Plants grown in soilless culture system have been found to have higher growth rates, increased yields and better quality compared to those grown in traditional soil-based systems (Gruda, 2022). Furthermore, soilless cultivation allows plants to thrive in diverse environments, making it adaptable for both outdoor and indoor settings (Suresh et al., 2023). Replacing soil with alternative growing mediums, especially for vegetable crops like cucumbers, peppers and tomatoes, facilitates better control over plant nutrition and eliminates soil-borne diseases (Rahil et al., 2020).
       
In Table 6, it can be seen that the Aglaonema sp. plants grown in zeoponic have the highest values for all growth parameters except for stem diameter. This indicates that zeoponic is highly effective in promoting the growth of Aglaonema sp. Furthermore, in the cultivation of ornamental plants, aesthetic value is a key indicator of quality, as stated by (Adaniyah, 2022). Therefore, the aesthetic value of Aglaonema sp. plants is highly valued in the ornamental plant industry and growers can command a premium price for plants with amazing colours. The aesthetic value of Aglaonema plants is rare due to their colour and leaf pattern. Aglaonema sp. with red-dominated colours can make amazing colours. The red colour of the leaf occurs due to the presence of anthocyanin. According to (Pratama and Nihayati, 2021), the use of compost may increase the anthocyanin content in plants. Therefore, using compost in zeoponic may be a way to improve the red coloration in Aglaonema sp. plants and increase their ornamental value. In addition, using zeoponic with greenish-grey zeolite can enhance the beauty of Aglaonema sp. plants in pots, while also promoting their growth and health (Suwardi and Pangestu, 2004).
 

       
Several studies have similar findings that the composition of the growth medium significantly affects the growth and quality of Aglaonema plants. (Widjaja et al., 2023) found Aglaonema siam aurora to be preferred in ttreatment ZA3, which consists of zeoponic mixed with NPK 16-16-16 at 0.375 g/l and micro compound fertilizer at 0.5 mg/l. The utilization of ZA3 media is resulting to the improved visibility of Aglaonema sp. leaf color contrast between green and red. Furthermore, in Aglaonema, ZA3 had the greatest plant height, number of leaves, leaf length, leaf width and stem diameter measurements. The composition of the growth medium greatly affects the growth and quality of ornamental plants and each type of ornamental plant has specific requirements for suitable growth media. Although the statistical analysis in Table 6 may not show significant differences, the data indicates that zeoponic yields higher measurements compared to other PGMs.
 
Zeoponic for PGM of seedling plantation
 
Mahogany plant seeds’ growth parameters include plant height, number of leaves, leaf length, leaf width and stem diameter. Based on observations of these growth parameters, it appears that mahogany seeds exhibit the most significant growth when cultivated in zeoponic medium. This finding is supported by visual assessments, as shown in Fig 2, which indicate that mahogany seeds grown in zeoponic are taller than those grown in other commercial media. To measure plant height, the distance is taken from the base of the plant to the top of the highest leaf (Palupiningtyas, 2023). The measured growth parameter results are presented in Table 7. The result showed that zeoponic consistently yielded higher measurements in plant height and leaf width compared to other PGMs, although the differences were not statistically significant. However, significant differences were observed in number of leaves, leaf length and stem diameter, where zeoponic-produced seedlings exhibited significantly higher values compared to the other PGMs used in the study.
 

 

       
Mahogany seedlings require complete nutrients, such as NPK, as well as micro-nutrients such as Fe, Mn, Zn, Cu and B. The availability of sufficient nutrients in PGM is crucial for the growth and development of mahogany seedlings. The lack of certain nutrients can slow down seedling growth and cause nutrient deficiencies in plants. Zeoponic can increase the efficiency of nutrient uptake, especially N, due to its great capacity for CEC to absorb NH₄⁺. The chemical and physical properties of zeoponic are responsible for the better growth of mahogany plant seedlings (Suwardi et al., 2023). Furthermore, the application of zeolite had a positive impact on certain soil properties, such as N, P and exchangeable K, which helped in speeding up the soil recovery process (Martelletti et al., 2019). A study conducted by (Špulák and Hacurová, 2021) found that the addition of clinoptilolite (mineral that belongs to the zeolite group) had a positive effect on the growth of forestry seedlings.

Zeoponic proves its superiority as a PGM based on several advantageous physical and chemical properties, such as low bulk density, moderate EC, neutral pH, high NO₃^- N concentration, available-P content, moderate c-organic content and high base saturation level. Compared to commercial PGM, zeoponic significantly enhances plant height, stem diameter and leaf area across various plant species, including tomatoes, Aglaonema sp and mahogany seedlings. Therefore, it can be inferred that zeoponic is the best PGM compared to others commercial PGM available in the market, indicating its potential to revolutionize plant cultivation.

The authors would like to thank the Ministry of Education, Culture, Research and Technology of Indonesia for providing the fund through the Matching Fund Program and CV Transindo Citra Utama for the collaboration.

All authors declare that they have no conflict of interest.