Changes in Chemical Properties of Banana Pseudostem, Mushroom Media Waste, and Chicken Manure through the Co-Composting Process

: Co-composting is an effective approach to biowaste management. The co-composting potential of banana pseudostem (BPS) and mushroom media waste (MMW) with chicken manure (CM) has not been explored, let alone their suitable ratios of co-composting being determined. Mean-while, the imbalance ratios of the feedstocks used in the process severely restrict the physicochemical properties and quality of the ﬁnished product. For this reason, six different ratios of BPS, MMW, and CM, viz. 1:1:1, 1:2:1, 1:3:1, 2:1:1, 2:2:1, and 2:3:1, respectively (T 1 –T 6 ), were composted together in aerobic conditions to identify the suitable ratio by evaluating the changes in the physicochemical properties in the composting process. According to the ratio of treatments, the feedstocks were mixed on fresh weight basis. The turning process of co-composting piles was repeated at seven-day intervals to maintain the uniform aeration throughout the composting period. The piles having BPS, MMW, and CM at ratios of 1:2:1, 1:3:1, and 2:3:1, respectively, demonstrated a longer thermophilic phase, indicating more complete decomposition and earlier maturity compared to piles with higher amount of BPS. Of the ratios, BPS:MMW:CM at 1:2:1 ratio (T 2 ) resulted in the highest total nitrogen (1.53%), lowest C:N ratio (12.4), organic matter loss (54.5%), and increased CEC (41.3 cmol/kg). The highest germination index (129%) was also recorded in the T 2 compost, indicating that it was toxic-free and safe for seed germination. The nutrient-rich compost with high alkaline pH ( ≥ 10) can effectively ameliorate soils of an acidic nature, for example, the acidity of Ultisols and Oxisols. Author Contributions: Conceptualization, M.S.I. and S.K.; methodology, M.S.I. and M.A.H.; formal analysis, M.S.I., S.K., and M.A.H.; investigation, M.S.I. and S.K.; resources, M.S.I.; data curation, M.S.I., A.M.A., T.G.H., and K.M.A.; writing—original draft preparation, M.S.I.; writing—review and editing, S.K., T.G.H., and K.M.A.; visualization, M.S.I.; supervision, S.K. and K.M.A. All authors


Introduction
Agricultural waste can potentially be recycled through composting processes (composting and co-composting) that convert it into useful resources for plant nutrition and soil health (through adding humus-like materials) [1]. One of the key considerations of composting and co-composting is the sources and types of organic materials used. Mainly, co-composting involves mixing nitrogen-rich organic wastes such as nutshells, sewage sludge, and animal manure with carbon-rich organic wastes (bulking agent) such as saw-dust, crop residue, biochar [2,3], and mushroom spent substrate [4]. On the other hand, banana pseudostem has huge potential as a co-composting material [5]. The global Similarly, Czekała et al. [31] also investigated biochar with poultry manure and wheat straw in the aerobic co-composting process in their study.
However, not enough research has been published on co-composting using banana wastes and the subsequent physicochemical changes that occur during composting. Most research has been done in the laboratory, but here, the nutrient parameters are limited. Such studies' results did not truly reflect the utility of crop demand in agriculture. Banana pseudostem is a highly alkaline organic waste that contains cellulose and lignin with 75-85% moisture [32]. The addition of excessive moisture and inappropriate ratios of a mixture may lead to delaying the process through the poor window, which does not favor microbe and quality compost [33].
The inherent moisture in the banana pseudostem along with a suitable ratio of MMW and frequent turning would create a congenial condition for faster decomposition in the process. Composting of these materials together may alleviate the negative impacts of individual waste on crops and might turn the compost into a balanced organic fertilizer able to synchronize the release of nutrients with the demand of crops in acidic soil. To the best of our knowledge, no research has investigated the decomposition of banana pseudostem and mushroom media waste with chicken manure to utilize them as organic fertilizer through co-composting. Therefore, in order to make effective compost, the ratio of the substrate mixture must first be determined. The objective of the study was to identify the suitable ratio of banana pseudostem to mushroom media waste in co-composting with chicken manure.

Materials Collection, Preparation, and Pile Management
The required amounts of semi-humified chicken manure (CM), mushroom media waste (MMW), and banana pseudostem (BPS) samples were collected from QL Ansan Poultry Farm Sdn Bhd, Rawang (3 •  The day before composting, fresh banana pseudostems were chopped down into desirable sizes then crushed with a 14 HP, woodchipper machine (Model: Ohashi-GS122GB, Obashi Ecological technology, Sakimura Chiyoda Kanzaki Saga, Japan). Banana pseudostem sap was collected through the outlet pipe during the crushing of banana pseudostem. The sap was subjected to the addition of an extra 250 g urea and maintained moisture (at 60-70%) in the composting piles. In each pile, the 250 g of urea was evenly sprinkled in each layer of feedstock mixtures with pseudostem sap and water. It was uniformly spattered in different layers in the final mixture during pile preparation to promote decomposition. The piles were protected with a rainproof, non-transparent and thick plastic canvas from any unexpected weather disturbance. Turning and mixing (manually by shovel) were done weekly to allow uniform airflow throughout the composting period. The initial chemical properties of individual materials were measured prior to the co-composting process (Table 1).

Collection and Preparation of Compost Samples for Physicochemical Analysis
A 300 g of bulk sample was randomly collected from different places (6) of two compost pile in each round of turning and mixture and divided into two parts. The first part of these samples was air-dried and passed through the 0.25-and 0.1-mm sieves and sample repeated three times for physicochemical analysis. Each sub-sample was considered as replication. The second part of the compost samples was immediately preserved in a refrigerator at 4-5 • C for seed germination test.

Monitoring of Temperature Profile ( • C) and Moisture in the Composting Process
The temperature was recorded daily in the morning (before 8 am) and evening (after 5 pm) from the three places of the piles (central, mid-peripheral, and lower-peripheral positions) by portable Mercury thermometer (Alchl Thrmter, Labworld, India). In that case, half portion of the thermometer was dipped into the pile from the top centre while the whole portion was dipped from the mid and lower-peripheral position to get the actual average temperature [16]. The ambient temperature was also recorded by the same thermometer at the same times. The daily six readings per compost pile recorded in the morning (3) and evening (3) were averaged.The compost moisture was measured by the gravimetric method where sample was dried at 105 • C until reaching the constant weight [34]. The moisture (%) was calculated following the equation: moisture (%) = (W 1 −W 2 ) W 1 × 100, where weight of compost before oven drying (W 1 ) and weight of compost after oven drying (W 2 ).

Chemical Analysis of the Compost Samples
The pH was measured from the compost samples by a digital pH meter (HI 2211 pH meter, Hanna instrument, Woonsocket, RI, USA) at the ratio of 1:10 (w/v) water-soluble extract, whereas 1:20 (w/v) ratio of the sample with water was used to determine EC by digital EC meter (Hanna 2300) as described by Gaind [35]. The total C, N, and sulfur (S) were determined by Leco TruMac CNS analyzer. The C:N ratio was calculated from the total C and total N values. The TOC and OM contents of compost samples were estimated by loss on ignition method [36]). The CEC was determined by the ammonium acetate (pH 7.0) leaching method [37]. Inorganic N was determined using the method of Keeney and Nelson [38]. The total contents of K, Ca, Mg, Na, Mn, Cu, and Zn were determined by atomic absorption spectrophotometer (A Analyst 800, PerkinElmer Corporation, Norwalk, Sustainability 2021, 13, 8458 5 of 17 CT, USA) followed by dry ashing method, based on Cottenie [37], and the amount of P was determined by auto-analyzer (Yellow method) from the same sample.

Compost Toxicity Test
The germination index of radish seeds was tested via the water extraction procedure as suggested by Guo et al. [39]. Briefly, the compost samples and deionized water at the ratio of 1:10 (w/v) was centrifuged for 15 min at 4000 rpm and filtered through 0.45 µm filter paper. A 5 mL of filtrate was pipetted in to 20 mm × 100 mm triplicate sterilizer Petri dish after placing double filter papers on it. Thirty randomly selected radish seeds were placed evenly on filter paper, sealed, and kept on the Petri dish in a dark place for 72 h at room temperature. The total number of germinated seeds were counted in the Petri dish and recorded as a percentage. Root length of the germinated seeds was measured by image J. software [40]. The germination index (GI) was calculated by the following equation: where SG = seed germination of treatments, RL = root length of the treatments (cm).

Statistical Analysis
Data were subjected to analysis by PROC ANOVA in the RCBD design (SAS, 9.4). The treatment means were compared by protected Least Significant Difference Test (LSD) at the 5% probability level [41].

Monitoring Temperature Profile during the Composting Period
Irrespective of treatments, the temperature rise from the first day and reached the peak at 4-5 days. The use of BPS, MMW, and CM at different ratios had varied temperatures over the co-composting period (Figure 1a

Changes in pH and EC during the Co-Composting
During the composting period, the pH levels in the piles were consistently varied. An increase in the pH and EC levels was observed in each co-compost pile (treatment) (Figures 2 and 3). In the primary stage of composting, pH values revealed a slight decline

Changes in pH and EC during the Co-Composting
During the composting period, the pH levels in the piles were consistently varied. An increase in the pH and EC levels was observed in each co-compost pile (treatment) (Figures 2 and 3). In the primary stage of composting, pH values revealed a slight decline or remained unchanged up to 7 days in the T 2 pile having increased the amount of MMW followed by the T 3 pile, where the T 4 pile, with a larger amount of BPS, showed a sharp increase in pH value. In the secondary stage, the pH increased gradually up to the final compost. Generally, pH varied from 7.69-8.74 in the initial stage and from 10.0-10.6 in the final stage. However, in the final compost, the lowest pH level (10.0) was recorded in the T 2 pile having an increased amount of MMW (1:2:1 of banana pseudostem, mushroom media waste, and chicken manure) followed by the T 3 (1:3:1 BPS:MMW:CM) pile, while the highest pH (10.6) was recorded in the T 4 (2:1:1) pile where BPS was used in an increased ratio. The EC increase was accompanied by the rising temperature in the co-compost under process (Figure 1a,b). In the final compost, EC ranged from 2.38 to 3.71 dS m −1 in the compost piles, while the T 2 pile mixed with the increased amount of MMW displayed the lowest EC value (2.38 dS m −1 ), followed by T 3 (2.68 dS m −1 ) treatment. In the last stage of the co-composting process, the highest EC (3.71 dS m −1 ) was recorded in the T 4 pile, which was mixed with increased BPS substrate.

Changes in pH and EC during the Co-Composting
During the composting period, the pH levels in the piles were consistently varied. An increase in the pH and EC levels was observed in each co-compost pile (treatment) (Figures 2 and 3). In the primary stage of composting, pH values revealed a slight decline or remained unchanged up to 7 days in the T2 pile having increased the amount of MMW followed by the T3 pile, where the T4 pile, with a larger amount of BPS, showed a sharp increase in pH value. In the secondary stage, the pH increased gradually up to the final compost. Generally, pH varied from 7.69-8.74 in the initial stage and from 10.0-10.6 in the final stage. However, in the final compost, the lowest pH level (10.0) was recorded in the T2 pile having an increased amount of MMW (1:2:1 of banana pseudostem, mushroom media waste, and chicken manure) followed by the T3 (1:3:1 BPS:MMW:CM) pile, while the highest pH (10.6) was recorded in the T4 (2:1:1) pile where BPS was used in an increased ratio. The EC increase was accompanied by the rising temperature in the co-compost under process (Figure 1a,b). In the final compost, EC ranged from 2.38 to 3.71 dS m −1 in the compost piles, while the T2 pile mixed with the increased amount of MMW displayed the lowest EC value (2.38 dS m −1 ), followed by T3 (2.68 dS m −1 ) treatment. In the last stage of the co-composting process, the highest EC (3.71 dS m −1 ) was recorded in the T4 pile, which was mixed with increased BPS substrate.

Organic Matter Degradation
The mixing of BPS, MMW, and CM in different ratios significantly influenced the OM degradation in the process (Figure 4). Throughout the composting period, the rapid reduction of OM was recorded in the T2 pile with 1:2:1 BPS:MMW:CM (79.4% to 36.13%),

Organic Matter Degradation
The mixing of BPS, MMW, and CM in different ratios significantly influenced the OM degradation in the process (Figure 4). Throughout the composting period, the rapid reduction of OM was recorded in the T 2 pile with 1:2:1 BPS:MMW:CM (79.4% to 36.13%), which was followed by the T 3 pile, while the slowest decomposition was recorded in the T 4 pile having a larger amount of BPS used (2:1:1 BPS:MMW:CM). The decomposition of the initial substrate biomass fell from 66.8% to 49.29% in the T 4 pile. However, the highest (54.5%) relative loss of OM was calculated from the initial to the final stage of the T 2 pile of co-compost with double the MMW used compared to the T 4 pile.

Organic Matter Degradation
The mixing of BPS, MMW, and CM in different ratios significantly influenced the OM degradation in the process (Figure 4). Throughout the composting period, the rapid reduction of OM was recorded in the T2 pile with 1:2:1 BPS:MMW:CM (79.4% to 36.13%), which was followed by the T3 pile, while the slowest decomposition was recorded in the T4 pile having a larger amount of BPS used (2:1:1 BPS:MMW:CM). The decomposition of the initial substrate biomass fell from 66.8% to 49.29% in the T4 pile. However, the highest (54.5%) relative loss of OM was calculated from the initial to the final stage of the T2 pile of co-compost with double the MMW used compared to the T4 pile.

Changes of Total N, NH4-N, and NO3-N
Changes of N were influenced by different ratios of feedstocks used in co-composting. The highest total N was recorded in T2 having 1:2:1 of BPS, MMW, and   Table 2). In all piles, the total N loss varied from 11.1% to 23.6% from the initial to the end of the composting, which was recorded in the T 2 and T 1 piles with an equal amount of feedstocks, respectively. NH 4 -N ranged from 452-738 mg kg −1 in the first two weeks and decreased gradually to 120-179 mg kg −1 at the end of composting ( Figure 5). However, T 2 , having a higher amount of MMW, had the largest amount of NH 4 -N (179 mg kg −1 ) while the pile having higher BPS (T 4 pile) had the lowest (120 mg kg −1 ) at the final stage ( Figure 5). The trend of NO 3 -N increased with the decline of NH 4 -N in all compost piles, and finally, significantly higher values of NO 3 -N were recorded in the T 2 (51.9 mg kg −1 ) pile, followed by the T 3 pile (48.5 mg kg −1 ), and the lowest (35.55 mg kg −1 ) in the T 4 pile ( Figure 6).

Changes in Moisture
Among the treatments, the moisture content, total C, total N, and the C:N ratio fell from the initial to final stage whereas the CEC was increased significantly (p ≤ 0.05) (Table 2). The moisture content varied from 68.5% to 79.3% in the initial stage and 36.3% to

Changes in Moisture
Among the treatments, the moisture content, total C, total N, and the C:N ratio fell from the initial to final stage whereas the CEC was increased significantly (p ≤ 0.05) ( Table 2). The moisture content varied from 68.5% to 79.3% in the initial stage and 36.3% to 50.1% in the final stage. The minimum moisture (36.3%) was observed in the final compost at T 3 pile, which was statistically similar to the T 2 (38.6%) pile, while the maximum moisture of 50.1% was recorded from T 4 compost (50% banana pseudostem, 25% mushroom media waste, and 25% chicken manure).

Changes in Total C
A remarkable decrease in TOC was found from the beginning to the final compost and it ranged from 25.9-53.9% in the piles where 31.7%, 53.9%, 52.8%, 25.9%, 41.4%, and 46.5% were recorded in the T 1 , T 2 , T 3 , T 4 , T 5 , and T 6 piles, respectively. The highest reduction of 53.9% appeared in the T 2 (1:2:1 ratio) pile and 25.9% in the T 4 (2:1:1 ratio) pile. Of the six compost mixtures, however, the lowest content (18.9%) of organic C was recorded in T 2 , and the highest was 25.6% in T 4 , followed by the T 1 (24.1%) co-compost pile.

Changes in C:N Ratio
All the compost samples had a C:N ratio below 20 except for T 4 (23.3), while the lowest C:N ratio (12.4) in T 2 was statistically identical to (1:3:1) the T 3 (13.8) pile at the end of composting (Table 2). Moreover, the C:N ratio of the compost significantly decreased by 10.6%, 48.7%, 45.7%, 4.31%, 30.3%, and 35.3% in the T 1 -T 6 treatments, respectively. Among the treatments, the highest C:N ratio decreased (48.7%) in T 2 and the lowest (4.31%) was in T 4 from initial to final compost.

Changes in CEC
The CEC for all treatments has shown a significant increase in the final compost ( Table 2). The piles T 2 (1:2:1 BPS:MMW:CM), T 3 (1:3:1 BPS:MMW:CM), and T 5 (2:2:1 BPS:MMW:CM) showed statistically identical results of CEC where the numerically higher value was obtained from T 2 treatment (41.3 cmol kg −1 ) and a lower value was found in the T 4 treatment (32.1 cmol kg −1 ). In the final compost, CEC was higher by 45% than that of the initial condition.

Germination Index (%) under the Compost
The germination index showed a parallel or straight trend up to the 14th day in all piles except the T 4 pile (with a higher amount of BPS), which experienced a slight decline up to the 19th day. In the study, the GI (%) started to increase from 14-19 days in all piles (T 1 -T 6 ) towards the end of composting (Figure 7). The order of the GI values was 129, 125, 115, 93.4, 87.5, and 72.4% in T 2 , T 3 , T 6 , T 5 , T 1 , and T 4 piles, respectively. The maximum germination index (129%) was recorded in T 2 pile having a higher amount of MMW used, which was statistically similar to T 3 (125%), while the T 4 pile showed the lowest 72.4% from the final compost.

Discussion
The final composts, which had banana pseudostem (BPS), mushroom media waste (MMW), and chicken manure (CM) at the ratios of 1:2:1 and 1:3:1, did better in compost production and germination of sweet corn seeds. Based on the physical and chemical changes recorded during the co-composting, it emerged that the compost piles having more MMW was transformed into a compost of good quality. These composts showed better maturity and stability based on the temperature, C:N ratio, CEC, weight loss (CO 2 evolution), nutrient concentration, and seed germination. These features are discussed in more detail below.

Monitoring Temperature during the Composting
Temperature during composting is an important indicator of its maturity and quality [42]. An ideal composting process consists of three phases of temperature, namely, the thermophilic (>50 • C), mesophilic (40-50 • C), and cooling phases (<40 • C), where the thermophilic stage represents the rapid decomposition of organic matter through microbial activity and the mesophilic and cooling phases may cause increased nitrous oxide emission [43]. The decline of the temperature below 40 • C expressed the maturity of compost [44]. In our study, the T 2 pile showed a faster rise in temperature and longer thermophilic phase lasting up to 30 days followed by T 3 due to the incorporation of 50% mushroom media waste (MMW) as a C source. The microbial degradation of added OM materials that released CO 2 led to an increase in the compost temperature [45]. Some researchers even showed that two stage co-composting has double thermophilic stages indicating even faster decomposition and maturity of compost [44]. Throughout the whole process, T 4 treatment did not reach the thermophilic stage due to the addition of a higher amount (50%) of BPS while excess moisture was evident in BPS. However, the early drop in temperature by the 49th day to cooling phase (<40 • C) indicated 13 days earlier maturity of the T 2 compost compared to T 4 . The declining temperature also meant that the small portion of the easily degradable composting materials remained in the cooling phase [46].

Changes in pH and EC during the Co-Composting
The pH and EC are important parameters in composting, and they indicate the rate of decomposition of compost as well as the suitability of its application in soil. Overall, the compost piles resulted in an alkaline pH (≥10) and a higher EC value from 2.38-3.71 dS m −1 due to the use of alkaline materials rich in K and Ca (Table 1, Figure 3). During the initial stage (1-21 days), the pH showed an unchanged or slightly increasing trend. After 21 days of co-composting, the pH significantly increased with the decrease in the temperature, the mineralization of organic N, and the release of NH 4 ions. A similar trend was detected by Jolanun and Towprayoon [47]. In the present study, T 2 (1:2:1) had the lowest value of pH (10.0) followed by the T 3 (1:3:1) pile, which received 25% BPS, 50% MMW, and 25% CM in the process (Figure 2). This outcome was consistent with the pH (9.3-9.7) of banana peel compost as studied by Kalemelawa et al. [15], who reported that high K concentrations in banana waste forms a strong base (KOH) that increases the pH value. However, the T 2 compost with moderately alkaline pH could be effective in diminishing the acidity of acidic soil. In addition, T 1 (33.33% BPS) and T 4 (50% BPS) piles were BPS-dominated composts which recorded higher EC values. The added BPS and/or CM contained a higher amount of K and Ca salts (Table 1), which increased the EC of the composts. The release of mineral salts due to volume loss via decomposition, increased the EC values studied by Silva and Brás [13]. Considering the individual EC of the piles, T 2 resulted in the most suitable value of 2.38 dS m −1 , followed by the acceptable limit of EC < 3 dS m −1 [48]. Thus, the T 2 compost having 25% BPS, 50% MMW, and 25% CM is suitable as an organic fertilizer.

Changes in OM, TOC, C:N, and CEC during the Co-Composting
Due to the long-term persistence of thermophilic temperatures, more organic matter is lost in the T 2 pile (1:2:1 BPS:MMW:CM), resulting in a lower OM (36.1%) content in the final compost ( Figure 4). In this study, the T 2 pile having a higher proportion (50%) of MMW contained the various type of enzymes (results are included in another manuscript under review), and fungus mycelium [9], thereby resulting in 54.5% of OM loss. This amount of reduction in OM in the present study is consistent with the reduction of OM (47-52%) in the study conducted by Kulcu et al. [49]. A more than 42% reduction in OM was considered able to stabilize the process [16]. Fang et al. [9] also recorded the reduction of OM in the mushroom substrate composting material. Moreover, the addition of a higher proportion of MMW with lower BPS may create a favorable microbial environment through better aeration in the composting and facilitate the faster degradation of OM [42]. On the other hand, the T 1 (33.3% BPS, 33.3% MMW, and 33.3% CM) and T 4 (50% BPS, 25% MMW, and 25% CM) piles were recorded with the higher OM content in the final compost than the T 2 pile. It strongly suggests that those piles were partially decomposed due to a limitation in microbial activity or higher moisture content (72 to 79%). In addition, the existing lignin and cellulose in banana pseudostem [32] were slowly degraded and persisted for a longer period of time, thus confirming higher OM contents in the T 1 and T 4 piles.
In the composting process, the C content promotes the degradation of OM. A low C concentration can restrict biomass formation and compromise degradation [16]. The greater reduction of total organic carbon (TOC) content in T 2 (53.8%) and T 3 (52.8%) piles (Table 2) indicated the higher bio-oxidation of OM maintained by the thermophilic temperature ( Figure 1a). In this study, the reduction of the C:N ratio is mainly due to the decomposition of organic matter (loss of C as CO 2 via transformation). In the course of decomposition during composting, the increase of the total N% was associated with the volume reduction. The increase in inorganic N in the T 2 co-compost pile (having higher MMW) may contribute to the total N increase as well as the low C:N ratio. The strong sorption capacity of the added MMW bulk material may also help adsorb N on its large surface area. The highest reduction of C (53.8%) through OM decomposition was also associated with the low C:N ratio (12.4) ( Table 2). These outcomes reflect the result of composting of wood chips with green waste as documented elsewhere [18]. The compost with a < 20 C:N ratio is more acceptable as noted by Gaind [35].
On the other hand, as the BPS had lower C content, even under high moisture (79.3%) content in it, the OM decomposition and loss of C did slow down ( Figure 4 and Table 2). The higher C:N ratio (23.3) in the T 4 compost (2:1:1 BPS:MMW:CM) is associated with these. The N loss through volatilization might also affect the low C:N ratio obtained in the final compost. The results are consistent with Mohee et al. [48] who discovered that microbial consumption of C decreased the C:N ratio of the compost. In the present study, the CEC was increased in all treatments from the initial to final compost (Table 2), and it varied from treatment to treatment and with the amount of added banana pseudostem and mushroom media waste. The CEC was greater of those treatments due to higher decomposition of added banana pseudostem and mushroom media waste, particularly in the T 2 compost. This may explain the high content of exchangeable cations in BPS and MMW (Table 1).
Zhang and Sun [18] obtained a 45% increase in CEC from the co-composting of wood chips and green waste compared to green waste that was similar to the T 2 compost. Bahtiar et al. [7] studied banana waste as a vital source of Na, K, Ca, and Mg as possibly increasing the CEC in compost. Moreover, the carboxyl and phenolic functional groups may emerge from the humification of organic materials which can increase the CEC in T 2 compost. This finding appeared to agree with what Steiner et al. [50] found. The greater CEC value also represents the higher decomposition rate and nutrient retention capacity of compost [50]. Although the T 4 (2:1:1 of BPS, MMW, and CM) compost contained BPS in greater amounts, the CEC was comparatively lower than that of T 1 (1:1:1) and T 2 (1:2:1) compost. However, at the initial stage, the addition of 50% BPS in the T 4 treatment may lead to having excess moisture that ultimately leached down some cations and lowered the CEC value (Table 3).

Changes in TN and Inorganic N during the Co-Composting
The stimulated microbial activity under high temperature and alkaline pH degrades the organic compounds and might induce ammonia volatilization and reduced TN in the pile having an increased amount of MMW (T 2 pile). The loss of TN 11.1% was much lower than that of TN loss 21-40% from the co-composting of biowaste and sugarcane filter cake [16]. Composts with 1-2% N have minimal effect on N fertilizer requirements for crop production [51]. However, TN in T 2 (1.53%) compost remained within this range for agricultural use. In addition, the T 2 pile receiving a higher proportion of MMW, which could assimilate NH 3 on its large surface and in turn contribute NO 3 -N [18] as well as TN. A similar finding was noted by Guo et al. [39]. Most of the inorganic N remained in the form of NH 4 -N and low levels of NO 3 -N were detected in the compost.
During the composting, a reverse trend of NH 4 -N and NO 3 -N production was evident in all the piles followed by a typical composting process [52]. A similar trend was observed by Kalemelawa et al. [15] from banana peel compost. In the final stage, T 2 showed a significantly (p < 0.05) higher value (179 mg kg −1 ) of NH 4 -N over the other piles, which increased NH 4 -N by 28.5% from the initial value (140 mg kg −1 ) due to the decomposition of organic compounds ( Figure 5). This increase in NH 4 -N was due to the degradation of protein and amino acid by NH 4 + ions [53]. After 14 days, NH 4 -N decreased with the volatilization of NH 3 due to high temperature (>40 • C) and high alkaline pH (10) as mentioned by Meng et al. [46]. Furthermore, the fall in temperature may have activated the nitrifying bacteria for nitrification [54], which might be attributed to the highest NO 3 -N (51.9 mg kg −1 ) in the T 2 compost at the final stage. On the other hand, excess moisture from BPS may inactivate nitrifying bacteria that can affect the NO 3 -N production in the T 4 pile where increasing use of BPS was evident.

Changes in Nutrients Density during the Co-Composting
The content of macronutrients is a very important variable of compost [51]. Macro and micronutrients in the final compost were significantly (p < 0.05) influenced by the amount of BPS and MMW in the composting process (Table 3). Results indicated that the T 2 (25% BPS with 50% MMW) compost increased the highest percentages of nutrient concentrations (P 79.23%, K 73.30%, Ca 44.67%, Na 41.18%, and Zn 86.10%) followed by T 3 from the initial to final compost (Table 3) compared to other piles. It was due to the complete decomposition of OM through a longer thermophilic phase [55] (Figure 1a,b). These results agreed with the findings of Kalemelawa et al. [15], who observed the increase in P (86%) and K (34%) in banana peel with cow dung compost. Ultra et al. [56] detected extremely large amounts of K, Ca Mg, and Na in banana waste compost. Moreover, the T 2 and T 3 composts resulted in extremely large amounts of Zn, Cu, and Mn through the humification of the added BPS and MMW. These outcomes were similar to Chimuka and Manungufala [57], who suggested that Cu and Zn have a strong affinity to adsorb with organic and carbonate fractions in compost. In another study, Hsu and Lo [58] indicated that decomposition of OM increased the amount of Cu, Mn, Zn in compost by almost two-to threefold, which resulted in a greatly improved compost product. On the other hand, the T 4 pile, which received 50% BPS, showed the incomplete decomposition of OM due to the limitation of C (34.55%) and excess moisture ( Table 2). The excess moisture (79%) from BPS created a poor window system and microbial inactivity for OM degradation [39]. Moreover, excess moisture in T 4 (50% BPS) compost influenced leaching loss of K (7.08%), Ca (14.90%), Mg (8.56%), and Na (1.87%), so the value of the final content was lower than that of the initial one. This is despite the banana pseudostem being rich in cations [59]. Thus, the T 1 and T 5 piles showed a higher increment of K, Mg, and Na in the final product. However, all the nutrients in the T 2 compost (1:2:1 i.e., 25% BPS, 50% MMW, and 25% CM) can be potential sources of organic fertilizer for crop production and especially for low pH soil.

Changes in Germination Index during the Co-Composting
The seed germination test is the most sensitive indicator for evaluating the phytotoxicity and maturity of compost [60]. This study showed that the GI declined or remained unchanged in the initial stage, and it may have been due to the formation of organic acids or salts at a high temperature, prevailing up to 19 days in the compost pile. This result is consistent with the findings of Guo et al. [39]. After 19 days, GI started to increase in all piles mainly due to the degradation of toxic substances [61] throughout the study period. In the final stage of composting, all the compost piles with varied feedstock ratios (T 1 -T 3 ) and (T 5 -T 6 ) showed a GI value above 80%, except T 4 , which documented higher BPS. T 2 and T 3 resulted in higher GI values of 129% and 125%, respectively, with the addition of 20-25% of BPS in the composting. The higher GI might be attributed to their maturity and being free of toxic substances or less toxic to germination of seedlings, as found by Zorpas and Loizidou [62]. The GI value showed <80% in the T 4 pile, which means that the BPS might not have been decomposed properly, excessive salts were present in it, and/or toxic substances were added from the higher amount of BPS (2:1:1 of BPS:MMW:CM) to the process. In short, 20-25% of BPS with 50-60% MMW had higher seed germination that can be safe for application in agricultural soil.

Conclusions
The present study examined the optimal ratio of banana pseudostem, mushroom media waste, and chicken manure for the composting process, which was monitored in connections with temperature, pH, EC, OM, TOC, C:N ratio, CEC, TN, and other nutrients as a function of time. Around half the proportion of BPS to MMW enhanced composting process by extending the duration of thermophilic phase; improved the pH, EC, CEC values; and increased the macro-and micronutrient concentrations. Of the six combinations of feedstocks, the addition of BPS, MMW, and CM at a 1:2:1 ratio (25% BPS, 50% MMW, 25% CM) decomposed earlier and performed better in terms of acceptable pH value (10), suitable C:N ratio (<15), nutrients content and showed no toxicity to crops. That is why the optimal seed germination was associated with the improved compost properties. The highly alkaline pH of the compost samples suggests that it could be employed for the upgradation of acidic soils. However, the effectiveness of these alkaline composts has yet not been tested in the field level. Thus, the next research would be forwarded to using this compost in a soil-plant system in acidic soil, especially Ultisols and Oxisols.