Effects of six compost products on soil organic carbon and nitrogen levels in alfisol, rice yields, and diazotrophic endophytic populations

Vita Ratri Cahyani1 * ; Rahma Amira Zhalzhabila Wakak Megow2 ; Amalia Tetrani Sakya3

Sri Hartati1 ; Slamet Minardi1

1 Department of Soil Science, Faculty of Agriculture, Sebelas Maret University, Jalan Ir. Sutami 36, Surakarta, Indonesia.

2  Undergraduate Program of Agrotechnology, Faculty of Agriculture, Sebelas Maret University, Jalan Ir. Sutami 36, Surakarta, Indonesia.

3  Department of Agrotechnology, Faculty of Agriculture, Sebelas Maret University, Jalan Ir. Sutami 36, Surakarta, Indonesia.

* Corresponding author: vitaratri@staff.uns.ac.id (V. R. Cahyani).

Received: 2 January 2025. Accepted: 18 August 2025. Published: 1 September 2025.

Abstract

The decrease in nutrient content in the soil occurs because of an imbalance between nutrient intake and loss. This study aimed to evaluate the effect of applying six types of compost products, with different compost materials and bioactivators, on the soil organic carbon (SOC) and total nitrogen (TN) levels in Alfisol, on rice yields, and diazotrophic endophytic populations. The pot experiment was arranged in a Completely Randomized Design with a single factor consisting of 10 levels and 3 replications. The treatments compared control (R0), 6 types of compost (R1-R6), 50% chemical fertilizer (CF) (R7), 100% CF (R8), and a set combination (R9). Rice with a variety of Mentik Wangi was grown and harvested on 118 DAP. The results showed that the treatment R5 (compost C4 of a mixture of leaf litter, cow dung, peanut plant residue, and rock phosphate with bioactivator RMC) gave the highest increases of SOC and TN by 200% and 228.57%, and the highest plant dry weight and total seed weight by 247.55% and 171.16% compared to the control, respectively. Three treatments of R4 (compost C3), R6 (compost C5), and R9 (50% dosage of compost C3 in combination with mycorrhiza, zeolite, Azolla, and rock phosphate) yielded a similar effect at the second-highest levels in increasing SOC, TN, and rice yields. There was no significant effect of treatments on the population of diazotrophic bacterial endophytes in rice leaves. The present study revealed that compost enrichment with an effective bioactivator contributed significantly higher effects on soil fertility, plant growth, and yield compared to 100% chemical fertilizer (R8).

Keywords: bioactivator; chemical fertilizer; enriched compost; leaf bacterial endophytes; set combination.

DOI: https://doi.org/10.17268/sci.agropecu.2025.050

Cite this article:

Cahyani, V. R., Megow, R. A. Z. W., Sakya, A. T, Hartati, S., & Minardi, S. (2025). Effects of six compost products on soil organic carbon and nitrogen levels in alfisol, rice yields, and diazotrophic endophytic populations. Scientia Agropecuaria, 16(4), 659-670.

1. Introduction

Rice is one of the main foods for more than half of the world’s population. Rice is cultivated under the widest range of agroecosystems and soil character­istics, including flood and drought-prone environ­ments (Ahmadi et al., 2014), with various soil types, such as Alfisols, Inceptisols, Vertisols, Entisols (Jadhav et al., 2023), Ultisols (Ojobor & Egbuchua, 2020), Oxisols (Nkongolo et al., 2025), Mollisols (Guo et al., 2022), Histosols (Amgain et al., 2022), Andisols (Kamewada & Ooshima, 2024), Aridisols (Wasim et al., 2021), Spodosols (Manickam et al., 2015), Gelisols (Fujii et al., 2019).

Alfisol occupied approximately 10.1 percent of the global ice-free land area (Hatfield et al., 2017) showed high potential for the extension and inten­sification of rice production. Alfisol are charac-terized as acid mineral soil with low pH, low organic matter content, low nutrient N and P, and high ex­changeable Al, Fe, and Mn (Soil Survey Staff, 2014).

To improve rice production, many treatments have been applied to increase the soil fertility of Alfisols, including compost, biochar, zeolite, liming, and chemical fertilizer. According to (Sadegh-Zadeh et al., 2018), the application of compost and biochar of rice straw improved total N, available P concen­tration, and rice grain yield. Fertilization with liming increased soil pH, dehydrogenase activity (DHA), and bacterial population by 15.7%, 38%, and 145% respectively, than NPK (Vishwanath et al., 2022). (Behera et al., 2020) proved that lime and farmyard manure (FYM) were one of the options for the amelioration of acid soil, as liming resulted in the maximum maize biomass yield, and also the addi­tion of lime and FYM improved soil extractable Zn and maize Zn concentration.

The application of composted organic materials provides substantial agronomic and environmental benefits. Hefner et al. (2024) demonstrated that compost derived from diverse green wastes in­creased soil bacterial and fungal abundance, po­tential nitrogen (N) mineralization, and soil enzyme activities compared with untreated soil. Gil-Martínez et al. (2025) reported that compost com­posed of olive mill waste (alperujo), pruning resi­dues, and manure (2:1:1, 50 t/ha) significantly in­creased total C, N, P, and K, as well as microbial bi­omass and diversity, with these improvements becoming more pronounced after 12 months. This treatment also enhanced plant dry biomass by 24% and increased N concentration in plant tissue com­pared with unamended pots. Gewaily (2019) found that rice straw compost at 5 t/ha significantly increased filled grains per panicle and tended to increase both grain and straw yields compared with rice straw (uncomposted) applied at the same dosage. Sharma & Dhaliwal (2019) observed that rice straw compost (10 t/ha) combined with 60 kg N/ha (urea) produced the highest rice and wheat yields, soil C, and available N–P–K among all treatments. For micronutrients, this treatment performed better than the control but lower than sew­age sludge + 60 kg N/ha. Jiao et al. (2021) reported that composting reduced the phytotoxic allelochemicals of Ageratina adenophora, resulting in a compost product that significantly enhanced ryegrass seed germination, seedling and plant growth, nutrient uptake, soil nutrient availability, en­zyme activities, and microbial biomass and diversity compared with the uncomposted material.

In contrast, incorporating fresh or uncomposted organic materials can have adverse effects. Returning rice straw to flooded soils stimulates reductive reac­tions, increases soluble Fe²⁺ concentrations, and ac­celerates soil acidification, thereby inhibiting plant growth (Li et al., 2025). After 35 years of continuous application, rice and maize straws had limited ame­liorative effects and were correlated with acidifica­tion in the 0 – 10 cm and 10 – 20 cm layers of paddy soils (Dong et al., 2025). C-rich straw incorporation in wet paddy soils reduced cellulase activity and in­duced N deficiency, redirecting microbial enzyme production from C to N acquisition, as shown by the negative correlation between cellulase and ammo­nia-oxidase activities (Guo et al., 2025).

Besides effects on soil fertility, plant growth and plant production, the existence of plant endophytes is also important to be observed and analyzed to examine the effect of the application of compost or fertilizer, or an ameliorant. Endophytes are micro­organisms that inhabit the inner plant tissues. They can have beneficial (Wu et al., 2021), detrimental (Erlacher et al., 2014), or no apparent/neutral (Hardoim et al., 2015) effects on the host. However, the use of the term ‘endophyte’ remains controver­sial, with the definition often being altered to meet the needs of the user (Sikora et al., 2007).

Nitrogen-fixing bacteria are one type of endophytic microbes that have been reported in some previous studies. Shabanamol et al. (2018) found endophytic nitrogen-fixing bacteria isolated from leaf, stem, and root samples of various rice cultivars and their ability to play a role as a biocontrol potential against Rhizoctonia solani. Bianco et al. (2021) found endo­phytic nitrogen-fixing bacteria isolated from African rice (Oryza glaberrima L.) with plant growth-promoting activities such as IAA and ethylene pro­duction. Cahyani et al. (2024c) successfully isolated nitrogen-fixing endophytic bacteria from leaf and root tissues of rice on YEMA+BTB medium, with multifunctional abilities in phosphate and potassium solubilization. Ma et al. (2021) showed that different long-term fertilization affected the endophytic bacterial commu­nity in the wheat endosphere. Although many studies reported the application of compost on Alfisol for rice (Attanayake et al., 2022; Dada et al., 2014) it is still limited information about the comparative effects of various compost products made from dif­ferent compositions and bio-activators on soil fertil­ity and rice yield on Alfisols. Previously, the com­posting of five different compost material composi­tions, four of which used rice straw as the main ma­terial, was investigated, with each formulation acti­vated by either aerobic or fermentative bioactiva­tors (Cahyani et al., 2024b). The effects of these five compost products, which differ in both material composition and type of bioactivator, on soil fertility and plant yield still need to be evaluated. Furthermore, including the commonly used rice straw compost produced by local farmers as a compari­son is essential for a comprehensive evaluation.

The present study, building upon previous research on compost formulation (Cahyani et al., 2024b), aimed to evaluate the effects of five compost products resulting from that study and one commonly used by local farmers on soil carbon and total ni­trogen levels, rice yield, and the abundance of leaf-associated symbiotic and non-symbiotic diazo­trophic bacterial endophytes.

2. Methodology

2.1 Soil sampling

Soil samples for the greenhouse pot experiment were taken from a non-rhizospheric area of Alfisol soil taken from Jumantono, Karanganyar, Central Java, Indonesia (07o37'47" S and 110o56'51" E) in September 2021. Soil samples were taken at the topsoil horizon (0-30 cm), the samples were air-dried, then homogenized, and sieved using a 2 mm mesh sieve. Soil samples were distributed into plas­tic pots (d = 28 cm, t = 15 cm) with 6 kg of soil per pot. The chemical characteristics of the initial soil samples were pH H2O 6.45 ± 0.21, total organic car­bon (TOC) 0.36%, organic matter (OM) 0.62%, total nitrogen (TN) 0.03%, C/N ratio 12, and available phosphate 0.81 ppm.

2.2 Compost used for the experiment

Six compost products were used in the present study. Five of them (designated as C0 to C4) were derived from a previous study and prepared be­tween July and September 2021, with a composting period of 77 days (Cahyani et al., 2024b). The sixth compost product, referred to as C5, was obtained from the “Sri Rejeki II” Farmers Group in Kuto Vil­lage, Kerjo District, Karanganyar Regency, Central Java, Indonesia. The composition and the product characteristics of each compost product are shown in Table 1.

Additional materials for pot experiment treatments

Some additional materials were used for the pot experiment: chemical fertilizers (CF) (Urea, SP36, and KCl), rock phosphate, Azolla, zeolite, and my­corrhizal culture using zeolite media which spores originated from Andisol from Tengaran, Semarang, Indonesia.

2.3 Pot experimental design

The pot experiment was carried out from October 2021 to February 2022 at the Green House, Faculty of Agriculture, Sebelas Maret University, Surakarta, Central Java, Indonesia. This study applied a single factor of organic fertilizer treatment (R) using a Completely Randomized Design (CRD) that con­sisted of 10 levels of treatments with 3 replications. The treatments were R0 = control (no fertilizer), R1 = application compost C0, R2 = application com­post C1, R3 = application compost C2, R4 = appli­cation compost C3, R5 = application compost C4, R6 = application compost C5, R7 = application 50% chemical fertilizers (CF), R8 = application 100% CF, and R9 = application a set combination (a mixture of 50% compost C3, mycorrhiza, zeolite, Azolla and rock phosphate). The experimental design and re­search steps are illustrated in Figure 1.

Figure 1. Experimental design and research steps.

Table 1

Characteristics of the 6 types of compost used for the experiment

Remarks: RS = Rice Straw, LL= Leaf Litter, CD = Cow Dung, PPR = Peanut Plant Residue, RP = Rock Phosphate, EM4=Effective microorganism 4 (a commercial bioactivator product), RMC=microbial bioactivator isolated from rice straw, mahogany bark, and cassava peels (Cahyani et al., 2024b), NFB = Nitrogen Fixing Bacteria, PSM = Phosphate Solubilizing Microbes.

2.4 Application of organic and chemical fertilizer treatments

Pot experiments were prepared and treated according to their respective code of treatment. Compost application for each treatment of R1, R2, R3, R4, R5, and R6 was at a dosage of 40 t/ha, respectively, except for treatment R9 was given at a dosage of 20 t/ha. The treatment of R9 was also supplemented by the mycorrhizal inoculum at a dosage of 10g per plant, zeolite at a dosage of 10 t/ha (30 g/pot), rock phosphate at a dose of 75 kg/ha (0.225 g/pot), and fresh Azolla at a dose of 5 t/ha (15 g/pot). After compost application, the soil was incubated for 3 days. The treatment of R8 applied 100% CF with the recommended doses from the Indonesian Ministry of Agriculture: Urea 200 kg/ha, SP36 100 kg/ha, and KCl 100 kg/ha. The treatment of R7 applied 50% CF consists of urea 100 kg/ha, SP3650 kg/ha, and KCl 50 kg/ha. Chemical fertilizers were given one day before planting. During incubation, the soil was moistened at field capacity.

2.5 Preparation of rice seedlings, mycorrhizal inoculation, and planting

Rice seeds with a variety of Mentik Wangi were soaked in a saltwater solution for the pithy test then rinsed in clean water and soaked for 24 hours to stimulate germination. Seeds were sown on the seedling tray using Alfisol soil as media at a depth of 3 cm with an addition of a layer of mycorrhizal inoculum (Cahyani et al., 2024a). After 2 weeks, the rice seedling was planted in the experimental pots with 2 seedlings in each pot. Standing water was maintained at around 3 cm depth for 3 months until maximal vegetative and then dried to the level around 70-80% field capacity. Harvesting rice was done after the rice was fully ripe, 118 days after planting (DAP).

2.6 Observations, measurements, and analyses of plant growth and yield, populations of diazotrophic bacterial endophytes, and soil characteristics

The plant growth parameters were observed at the vegetative maximal phase on 45 days after planting (DAP), including plant height (cm), total tillers per pot, chlorophyll content, and N concentration in plant tissue. A small piece of fresh rice leaf was cut (around 1 g) for chlorophyll analysis, and some was dried and ground for N tissue analysis. Chlorophyll content in the maximum vegetative phase of rice plants was analyzed using the acetone extraction method (Chand et al., 2022). N concentration in plant tissue was analyzed using the Basal Ashing method with H2SO4 (Yadav et al., 2022). In addition, at the vegetative maximal phase, the population density of diazotrophic (Nitrogen-fixing) bacterial endophytes in rice leaves was analyzed after surface sterilization (Cahyani et al., 2024c) using the plate count method on Yeast Extract Mannitol Agar (YEMA) medium for symbiotic bacteria and Jensen medium for non-symbiotic bacteria (Aroh & Udensi, 2021).

At the generative phase, the number of panicles per clump and the panicle length (cm) were observed. Rice plants were harvested on 118 DAP. The rice shoots and roots were weighed for the plant fresh weight, then air-dried and oven-dried for further observation of the plant dry weight, the number of seeds per panicle, and the weight of 100 grains (g) was calculated.

The soil characteristics after harvest time were analyzed for soil organic carbon (SOC), soil organic matter (SOM), Total N (TN), and pH H2O. Total organic C analysis was treated with the Walkley and Black method (Indonesia Soil Research Institute 2023). Total N analysis was conducted with the Kjeldahl method (Indonesia Soil Research Institute 2023). Soil pH was measured using a digital pH meter (soil:solution = 1:2.5) (Indonesia Soil Research Institute 2023).

2.7 Data analysis

The data obtained were analyzed statistically for Analysis of Variance (ANOVA). If the results of the F test for the treatment in variance show a significant difference, then to find out the best treatment, the test is continued with the average difference test using Duncan Multiple Range Test (DMRT) at a 5% significance level. The correlations among variables were tested using Pearson correlation analysis. Statistical analysis was performed using IBM SPSS Statistics 25.

3. Results and discussion

3.1 The effects of treatment on soil chemical properties

The treatment of fertilizer types yielded a statisti­cally significant effect on the SOC, SOM, and Total N (p < 0.01), however, resulted in no significant ef­fect on pH H2O and C/N ratio (p > 0.05) (Table 2).

The treatments of compost application (R1-R6) significantly increased SOC and SOM compared to the control (R0). The highest SOC and SOM content among all compost application treatments (R1-R6) were indicated by the treatments R4 and R5, with the increase of SOC by 180% - 200%, and the increase of SOM by 176% - 201% compared to the control (R0), respectively. The treatment of R7 (50% chemical fertilizer), showed no significant effect on SOC content and SOM content compared with the control (R0). Statistical analysis showed that the treatments of R2, R3, R6, and R8 gave the same level of increase of SOC and SOM to the range 1.1 – 1.2 and 1.84 – 2.05, respectively. The treatment of R9 as the Set Combination (mixture of 50% compost C3 (RS+CD with bioactivator RMC), mycorrhiza, zeolite, Azolla, and rock phosphate) showed the same level effect on the SOC and SOM compared to R4 and R5. Thus, the treatment of R9 proved that using a 50% dosage of compost (20 t/ha) with a combination of mycorrhiza, zeolite, Azolla, and rock phosphate resulted in a similar effect with a 100% dosage of compost in the treatment R4 and R5. The present study proved that the addition of compost contributed significantly to the increase of SOC and SOM. The measurement of SOC and SOM after harvest time was considered to cover the total carbon in soil not only from the input of organic matter but also from the soil biomass from the effect of plant growth and soil microbial activities.

Morra et al. (2021) reported that the application of biowaste compost amendment at 30 t/ha on a dry matter basis during the first three years, and 15 t/ha of dry matter from the fourth year onward on vegetables and fruits, increased SOC by 38.90% after seven years compared to the control. This demonstrated that an intensive and appropriate plant management system could increase the amount of stable organic matter (Morra et al., 2021). This statement was supported by Xie et al. (2022), who stated that the addition of tomato plant residue compost at a dose of 15,000 kg/h on Burmese ginger increased SOM by 17.34% and TN by 18.75% compared to the control. Byeon et al. (2023) reported that application of rice straw compost 30 t/ha with NPK increased SOC by 121% and SOM by 116%. Compared to those three studies by Byeon et al. (2023), by Morra et al. (2021), and by Xie et al. (2022) the present study resulted in the higher increase of SOC and SOM by the treatment of compost application of rice straw based materials, which might be affected by several factors such as the differences of soil type and soil characteristics and the period of application until the measurement of soil variables. It is important to note in Byeon et al. (2023) research that the treatment of combination of NPK and compost 30 t/ha increased the SOM level from the initial level of 1.9 to 3.9.

Table 2

The effect of fertilizer type on soil chemical properties after harvest

Remarks: ** = p<0.01; * = p < 0.05; ns = non-significant = p > 0.05. Means with the same letter (s) in the same column are not significantly different at 5% level of DMRT. SOC=soil organic carbon, SOM=soil organic matter, TN=total nitrogen.

In the present study, the increase in carbon was quite high, but the highest carbon level only reached a level of 1.5, which was lower than Byeon's research that reached 3.9. In addition, Meena et al. (2016), reported the effect of the application of rice straw compost (14 t/ha) in the second year resulted in an increase in SOC to the levels 4.0 and 4.1 g/kg, whereas, the application of municipal waste compost (16 t/ha) resulted to the level 4.4 and 4.5 g/kg after mustard and pearl millet harvest, respectively.

In the treatments of compost application (R1-R6), the TN content increased significantly compared to the control by the range of 0.07% - 0.23%, with the highest TN content indicated by R5 at 0.23%. The treatment of R5 which used compost C4 (LL + CD + RMC + PP + NFB + PSM + RF) indicated the highest TN and the lowest C/N ratio compared to the other compost product (Table 1). This treatment proved a consistent quality and gave the highest ef­fectiveness in increasing TN of Alfisol in the present study. Although the chemical fertilizer treatment (R7-R8) showed a higher level of TN content compared with R0 and R1; however, the statistical DMRT analysis indicated the same level as the R0 and R1. The TN content of the set combination treatment (R9) was statistically lower than R5 but higher than the R2, R3, R4, and R6 treatments.

In the other study, Meena et al. (2016) applied compost of the mixture of rice straw and fresh cow dung with Trichoderma viride inoculation at the dosage of 14 t/ha increased TN of 11.5% and 39.7% compared to the control on sandy loam soil after the harvest of mustard and pearl millet. The result of the treatment R4 in the present study showed a higher increase of TN by 71.4% compared to the control (R0). Thus, compared with the study of Meena et al. (2016), the higher increase in TN in the present study was considered mainly by the higher dosage of applied compost (40 t/ha).

3.2 The effects of treatment on rice growth and yield

ANOVA showed a significant effect of the treat­ments of the application of a variety of compost, chemical fertilizers, and set-combination on plant height (PH) (p < 0.01), chlorophyll content (p < 0.05), leaf N concentration (p < 0.01), plant fresh weight (PFW) and plant dry weight (PDW) (p < 0.05), number of panicles (NoP) (p < 0.01), number of seeds (NoS) (p < 0.05), 100-seed weight (p < 0.01), total seed weight (p < 0.01), and but showed no significant effect (p > 0.05) on number of rice tillers (RT), panicle length (PL), (Tables 3 and 4).

Tables 3 and 4 show that the control treatment (R0) exhibited the lowest level of plant growth and yield, indicating that all applications of various compost products (R1-R6), chemical fertilizers (R7-R8), and a set combination (R9) resulted in the enhancement of rice growth and yield. Comparing the 3 treatments of R1, R2, and R3, which consisted of rice straw as the main compost material, R3 showed the highest effect on plant growth, as significantly indicated by leaf N concen­tration, PFW, and PDW. In the meanwhile, compar­ing the treatments of R3, R4, and R5, which used different compositions of materials with the same bioactivator RMC and the same additional supplement of peanut plant residue, nitrogen-fixing bac­teria, phosphate-solubilizing microorganism, and rock phosphate, it was found that R5 showed the highest effect on PFW and PDW, followed by R4 and then R3. This fact was supported by the signif­icantly higher levels of chlorophyll content and leaf N concentration yielded by the treatments R5 and R4 compared to R3 (Table 3). This finding revealed that among these 3 treatments, which used the same bioactivator of RMC and the same additional supplement, the treatment R5, which applied com­post C4 consisting of leaf litter and cow dung, gave a higher effect on plant growth compared to the compost that consisted of RS only (R3) and RS with CD (R4).

Table 3

Effects of the application of fertilizers on rice growth

Remarks: ** = p < 0.01; * = p < 0.05; ns = non-significant = p > 0.05. Means with the same letter (s) in the same column are not significantly different at 5% level of DMRT. PH= plant height, RT= rice tiller, PFW= plant fresh weight, and PDW= plant dry weight.

Table 3 shows that the 3 treatments of R4 (compost C3), R6 (compost C5), and R9 (a set combination) demonstrated similar effects on PFW and PDW at the second-highest levels after R5 (compost C4). Kausar et al. (2014) reported that compost made from rice straw and chicken manure, inoculated with ligninolytic and cellulolytic microbes and applied at 15 Mg/ha, increased PDW by 350% compared with 150% for commercial rice straw compost, relative to the control. The present study showed similar results, in which treatment R4 (application of compost C3 [RS + CD + PPR + RP with bioactivator RMC]) increased PDW by 207.1%, compared with 113.6% for treatment R2, relative to the control. The greater PDW increase reported by Kausar et al. (2014) compared with the present study might be due to the application of basal chemical fertilizers (40 kg/ha urea, 60 kg/ha TSP, and 30 kg/ha MP) before planting.

Among all the treatments, R5 yielded the highest effect on plant growth. The treatment R5 (application of compost C4) significantly increased plant height by 30.96%, plant fresh weight (PFW) by 354.38%, plant dry weight (PDW) by 247.55%, compared to the control (Table 3). The combination of leaf litter, cow dung, peanut plant residue, and rock phosphate as the main compost materials with bioactivator RMC and the supplemented ingredients of nitrogen-fixing bacteria and phosphate-solubilizing microbes resulted in the high quality of compost product (C4) (Cahyani et al., 2024b). The present evaluation in the greenhouse assessment confirmed that the application of compost C4 in the treatment R5 was more effective in promoting rice growth compared to other compost treatments. Similar trends were observed in the study by Omara et al. (2022), who reported that in the 2021 season, rice plants irrigated every 9 days and treated with foliar spray of compost tea at a dose of 140 L ha⁻¹ in combination with PGPR (Pseudomonas koreensis + Bacillus coagulans, 1:1 ratio) increased plant height by 8.11% and the number of panicles by 31.33%, 1000-grain weight 11.74%, straw yield 33.75%, and grain yield 7.01% compared to the control. On all irrigation treatments, the treatment T4 (combination of compost tea and PGPR) resulted in the highest population of total count bacteria.

The treatment of R9 (combination of application of compost C3 (50% dosage), mycorrhiza, zeolite, azolla, and rock phosphate) showed an increase in plant height by 28.26%, chlorophyll content 65.38%, leaf N concentration 167.42%, and PDW 206.25%, compared to the control (Table 3). Research by Seleiman et al. (2022) demonstrated that the combination of 50% NPK and 50% Azolla compost (treatment T6) during the 2020 growing season increased plant height by 33.58%, the number of panicles by 77.11%, and dry matter production by 147.82% compared to the control. The treatment T6 yielded the highest values of panicle weight (4.15 g), 1000-grain weight (30.94 g), and grain yield (11.32 ton/ha) compared to all other treatments. Thus, the study by Seleiman et al. (2022) reported similar trends of the effects of a mixture of compost tea with PGPR in increasing plant growth and yield, with the results of the present study.

The significant effects of the treatments on leaf N concentration and PDW indicated significant and positive correlations with SOC (r = 0.678, p < 0.01; r = 0.522, p < 0.01), SOM (r = 0.678, p < 0.01; r = 0.522, p < 0.01), and TN in soil (r = 6.77, p < 0.01; r = 0.640, p < 0.01). Thus, the increasing SOC, SOM, and TN in soil or increasing soil fertility status by the application of the fertilizer treatments significantly affected plant growth, as indicated by the higher plant biomass and N-nutrient content compared to the untreated pot.

Table 4

Effects of the application of fertilizers on rice yield

Remarks: ** = p < 0.01; * = p < 0.05; ns = non-significant = p > 0.05. Means with the same letter (s) in the same column are not significantly different at 5% level of DMRT. NoP = number of panicles, PL = panicle length, NoS= number of seeds.

Based on the statistical analysis, there was a significant effect of compost, chemical fertilizer, and set combination applied to the number of panicles (NoP), number of seeds (NoS), total seed weight, and 100-seed weight of rice, but there was no significant effect on panicle length (PL) (Table 4). Among all the treatments, R5 (compost of LL + CD (1:1) with bioactivator RMC at the dosage of 40 t/ha) significantly demonstrated the highest rice yield. Anwar et al. (2017) reported that the application of co-composted cow manure with poplar leaf litter (1:1) with the dosage of 20 t/ha enhanced spinach biomass by 62% in sandy loam soil and 39% in silt loam soil compared to the respective soil control (soil applied with manure composted without plant litter). Compared with the report by Anwar et al. (2017), the present study indicated that the treatment R5 had higher effects as demonstrated by an increase of rice PDW by 247% compared to the R0 (no compost application), and by 13.2% compared to R4 (compost of RS + CD with bioactivator RMC).

Table 4 showed the effect of the application of fertilizers, in which the treatment R5 gave the highest effect on plant yield, as indicated by an increase in number of seeds (NoS) (90.75%), 100-seed weight (178.76%), and total seed weight (171.16%), compared to the control, respectively.

The effect of treatment with 100% chemical fertilizer (R8) significantly showed higher rice growth as indicated by PFW, PDW, chlorophyll content, and leaf N concentration (Table 3), and higher rice yield as indicated by NoS, 100-seed weight, total seed weight (Table 4), than the treatment of 50% chemical fertilizer (R7). The treatment of compost application of R4 (compost C3), R5 (compost C4), R6 (compost C5), and R9 (a set combination) yielded higher rice growth (Table 3: PFW, PDW, chlorophyll content, and leaf N concentration) and rice yield (Table 4: NoS, 100-seed weight, total seed weight) than treatment R8 (100% CF). These findings demonstrated that compost enrichment either in the material compositions which mainly composed of RS or LL with CD (ratio 50:50), in the microbial composition for bioactivator, or in the supplemented ingredients that were applied in producing compost C3, C4, and C5 (Cahyani et al., 2024b) contributed to higher effects in increasing plant growth and yield compared to the treatment 100% CF. In the meanwhile, the effects of compost products which are composed of only RS as the dominant material with different bioactivators (compost C0, C1, and C2 for the treatments R1, R2, and R3) on plant yield were lower compared to the treatments of 100% CF, but lower or similar levels to those treatments for PFW and PDW.

The application of compost yielded higher plant growth than chemical fertilizer as the nutritional supply is more complete than chemical fertilizer, because it also contains compounds that support plant growth, micronutrients (Sharma & Dhaliwal, 2019), and increases soil microbes. Tahiri et al. (2022) reported that treatment of compost (produced from the green waste) could produce good plant growth, shoot dry weight, root dry weight, and yield measured by 160%, 252%, and 176% compared to the control treatment on tomato, respectively. In alignment with study by Phares & Akaba (2022) showed that application of compost (from poultry manure and elephant grass) combined with coconut husk biochar on rice plants for 3 consecutive years gave higher results on rice grain yield than NPK (15-15-15) and urea (46-0-0) chemical fertilizers, but compost alone without biochar still had lower results than chemical fertilizers. The result of the present finding was also supported by Naeem et al. (2017), who proved that the application of CF gave a higher effect than the compost of wheat straw, in detail the application of 60 mg/kg Urea, 30 mg/kg (NH4)H2PO4, and 25 mg/kg K2SO4 resulted in 13.9% and 17.7% the increase of plant height and fresh shoot on maize, whereas, the compost of wheat straw (1.5% w/w on 15kg soil media) application gave an increase of plant height and fresh shoot by 11.5% and 9.2% than control, respectively.

The treatment combination (R9) showed similar effects as treatments R4 and R6, and slightly lower effects than R5, on rice plant growth (Table 3) and plant yield (Table 4). This phenomenon indicated that R9 which applied 50% dosage of compost (consisting of RS and CD with bioactivator RMC, and additional supplement) in combination with Azolla, mycorrhiza, zeolite, and rock phosphate showed that the efficiency of organic input (50% dosage) resulted in similar effect closely with the application of 100% dosage of high quality of compost (R4, R5, and R6) by combining with biofertilizer (Azolla and mycorrhiza) and slow release mineral fertilizer (zeolite and rock phosphate). The treatment R9 increased plant height by 28.26%, PDW by 206.25%, and 100-seed weight by 159.29% compared to the control. The present results showed a similar trend compared to the study combining the same pro­portion of chemical fertilizer and organic fertilizer by Sultana et al. (2021) who reported that the com­bination of 50% chemical fertilizer with 50% municipal solid waste, 20% mustard oil cake, and 30% sugarcane press mud increased plant height by 38.51%, tillers by 56.63%, panicle length by 26.17%, grains per panicle by 42.71%, and 1000-grain weight by 17.67% compared to the control.

Hindersah et al. (2022) showed that compost of a mixture of materials (made from cow manure mixed with sawdust, fodder grass residue, and decayed cajuput (Melaleuca cajuputi) leaves with biofertilizer (composed of N2-fixing bacteria and P-solubilizing microbes such as Azotobacter chroococcum, Azotobacter vinelandii, Azospirillum sp., Acinetobacter sp., Pseudomonas sp., and Penicillium sp.) and chemical fertilizer (NPK + urea) treatments gave higher results on root length and plant dry weight compared to the treat­ment of chemical fertilizer. Moreover, this treatment of combination compost with biofertilizer and chemical fertilizer produced higher yield by 31% and 29.4% compared to chemical fertilizer in trans­planting and broadcasting methods, respectively.

Ouyabe et al. (2019) reported that the application of cow manure as a nitrogen source with a dosage of 2000 kg.10a-1 resulted in higher N content and N uptake in 2 accession numbers of Water Yam (A-18 and A-133) compared to the application of urea with the dosage of 30 kg.10a-1, on the contrary, Wa­ter Yam with accession number A-19 showed higher N content and N uptake in the treatment of urea compared to the treatment of cow manure on limestone soil. Thus, the type of the N source, the level of dosage, the type of plant, and also the type of soil/media determine the level of N content and N uptake in plant tissue.

3.3 Nitrogen-Fixing Endophytes Population

ANOVA revealed that the treatment of compost, chemical fertilizer, and the set combination had no significant effect on the population of diazotrophic (nitrogen-fixing) bacterial endophytes in the rice leaves. However, the present study found that the population density of nitrogen-fixing endophytic bacteria tended to be higher in the treatment of compost application of R4, R5, R6, and a set com­bination of R9 compared to control and chemical fertilizer application. Figure 2 shows that the popu­lation of symbiotic and non-symbiotic nitrogen-fix­ing endophytes was in the range of 105 – 106 CFU/g fresh rice leaves. Although there was no significant effect, the treatment R4 (compost of RS+CD with bioactivator RMC) tended to give the highest symbiotic and non-symbiotic nitrogen-fixing endophytic bacteria compared to other treatments (Figure 2).

The application of goat manure liquid organic ferti­lizer gave higher total endophytic bacteria on the potato and black nightshade compared to the no application treatment. Moreover, the treatment of liquid fertilizer significantly increases the endophytic bacteria on the connected stem of grafted potato and black nightshade compared to the treatment without liquid organic fertilizer. According to Yang et al. (2016), the application of chicken manure and commercial orga-nic fertilizer gave higher total bacteria, total endo-phytic bacteria, and antibiotic-resistant endophytic bacteria on pakchoi. By using Denaturing Gradient Gel Electrophoresis fingerprint, Wemheuer et al. (2016) reported that fertilizer application significantly altered the endo­phytic community structure of L. perenne and F. rubra but not in D. glomerata. Compared with the study by Piromyou et al. (2015), the population of endophytic nitrogen-fixing bacteria in rice leaf tis­sues in the present study was higher than the endophytic bradyrhizobia in the fresh rice roots of three cultivars that fluctuated at the range 102 – 105 log CFU/g among the strains and cultivars during the period of growth.

Figure 2. Population density of diazotrophic bacterial endophytes in rice leaves (Log10 CFU/g). Symbiotic bacteria were observed from the grown bacteria on YEMA medium, while non-symbiotic bacteria were observed from Jensen medium.

4. Conclusions

The application of 6 compost types increased SOC, SOM, and TN by 20% – 200%, 27.59% – 201.15%, and 28.57% – 228.57% in soil compared to the control, respectively. Overall, the treatment R5 (the applica­tion of a compost of a mixture of leaf litter and cow dung with the bioactivator RMC) gave the highest effect to improve soil nutrient status and gave the highest plant growth and yield, followed by the three treatments of R4, R6, and R9, which are at a similar level.

The treatment set-combination of R9 demonstrated the efficient input of compost (50% dosage of compost C3) in combination with mycorrhiza, Azolla, zeolite, and rock phosphate resulted in the high plant growth and plant yield at the same level with treatment R4 (100% dosage of compost C3) and treatment R6 (100% dosage of compost C5). Moreover, four treatments of R4, R6, R9, and R5 yielded higher effects than treatment R8 (100% chemical fertilizer), which indicated by higher SOC 9.09% – 36.36%, TN 9.09% – 109.09%, and higher plant growth and yield as represented by higher PDW 9.48% – 27.64% and total seed weight 16.03% – 29.53%. Although compost treatments showed higher populations of diazotrophic endophytic bac­teria than control, statistical analysis revealed that the differences were not statistically significant. Further study is needed to explore the other poten­tial sources for compost enrichment and to evaluate the effects in natural field assessments.

Acknowledgments

The five compost products (C0–C4, corresponding to treatments R1–R5) used in the present study were produced through the Community Service Grant Program of Sebelas Maret University, “Program Kemitraan Masyarakat (PKM–UNS) 2021.” The authors gratefully acknowledge the “Sri Rejeki II” Farmers Group in Kuto Village, Kerjo District, Karanganyar Regency, Central Java, Indonesia, for providing compost C5 (treatment R6). The green­house experiment was conducted using internal funds provided by the authors. The publication of the present study was supported by the funding of Dana Penelitian Non APBN Universitas Sebelas Maret TA 2025 for the research scheme of Strength­ening Research Group Capacity (Penguatan Kapasitas Grup Riset/PKGR-UNS) class A with a contract number 371/UN27.22/PT.01.03/2025.

Author contribution statement (CRediT)

V. R. Cahyani: Conceptualization, Methodology, Investigation, Supervision, Writing-review and editing, Funding acquisition. R. A. Z. Wakak Megow: Investigation, Data analysis, Data presentation, Writing-review, and editing. A. T. Sakya: Methodology, Data analysis, Supervision, Data presentation, Review, and editing. Sri Hartati: Methodology, Investigation, Data analysis, Review, and editing. S. Minardi: Methodology, Investigation.

Conflict of interests

The authors declare that they have no conflict of interest.

ORCID

V. R. Cahyani  https://orcid.org/0000-0003-3496-9015

R. A. Z. W. Megow  https://orcid.org/0000-0001-7090-0176

A. T. Sakya  https://orcid.org/0000-0001-6165-7557

S. Hartati  https://orcid.org/0000-0001-5728-6124

S. Minardi  https://orcid.org/0000-0003-1097-2033

References

Ahmadi, N., Audebert, A., Bennett, M. J., Bishopp, A., de Oliveira, A. C., Courtois, B., Diedhiou, A., Diévart, A., Gantet, P., Ghesquière, A., Guiderdoni, E., Henry, A., Inukai, Y., Kochian, L., Laplaze, L., Lucas, M., Luu, D. T., Manneh, B., et al. (2014). The roots of future rice harvests. Rice a SpringOpen Journal, 7(1), 29. https://doi.org/10.1186/s12284-014-0029-y

Amgain, N. R., Fan, Y., VanWeelden, M. T., Rabbany, A., & Bhadha, J. H. (2022). From Ground to Grain: Tracing Phosphorus and Potassium in Flooded Rice Cultivar Grown on Histosols. Agriculture, 12(8), 1250. https://doi.org/10.3390/agriculture12081250

Anwar, Z., Irshad, M., Mahmood, Q., Hafeez, F., & Bilal, M. (2017). Nutrient uptake and growth of spinach as affected by cow manure co-composted with poplar leaf litter. International Journal of Recycling of Organic Waste in Agriculture, 6(1), 79–88. https://doi.org/10.1007/s40093-017-0154-x

Aroh, K. U., & Udensi, J. U. (2021). Study on Interactive Effects of Different Levels of Lead and Mercury on Nitrogen Fixation of Some Diazotrophs. Journal of Advances in Biology & Biotechnology, 24(2), 34–42. https://doi.org/10.9734/jabb/2021/v24i230200

Attanayake, A. M. S. U. M., Duminda, D. M. S., & De Silva, C. S. (2022). Assessment of soil properties and yield under diverse input systems in Alfisols for rice (&lt;em&gt;Oryza sativa&lt;/em&gt; L.) crop. Journal of Agriculture and Value Addition, 5(1), 45–60. https://doi.org/10.4038/java.v5i1.34

Behera, S. K., Shukla, A. K., Dwivedi, B. S., Cerda, A., & Lakaria, B. L. (2020). Alleviating Soil Acidity: Optimization of Lime and Zinc Use in Maize (Zea mays L.) Grown on Alfisols. Communications in Soil Science and Plant Analysis, 51(2), 221–235. https://doi.org/10.1080/00103624.2019.1705322

Bianco, C., Andreozzi, A., Romano, S., Fagorzi, C., Cangioli, L., et al. (2021). Endophytes from african rice (Oryza glaberrima L.) efficiently colonize asian rice (Oryza sativa L.) stimulating the activity of its antioxidant enzymes and increasing the content of nitrogen, carbon, and chlorophyll. Microorganisms, 9(8), 1–27. https://doi.org/10.3390/microorganisms9081714

Byeon, J.-E., Kim, S. H., Shim, J. H., Jeon, S. H., Lee, Y. H., & Kwon, S. I. (2023). Effects of Rice Straw Compost Application on Soil Chemical Properties and Soil Organic Carbon Stock in Paddy Fields. https://doi.org/10.7740/kjcs.2023.68.2.090

Cahyani, V. R., Azzahra, N. Y., & Rosariastuti, R. (2024a). Evaluation of Arbuscular Mycorrhizal Cultures in Increasing Phosphorus Uptake and Maize Growth Compared to Chemical and Organic Fertilizers on an Andisol. AGRIVITA Journal of Agricultural Science, 46(3), 439–457. https://doi.org/10.17503/agrivita.v46i3.3867

Cahyani, V. R., Rahayu, R., Lakshitarsari, K. P., Megow, R. A. Z. W., & Azzahra, N. Y. (2024b). Composting of Rice Straw–Based Materials using Aerobic Bioactivator Isolated from Rice Straw, Mahogany Bark and Cassava Peels. Caraka Tani: Journal of Sustainable Agriculture, 39(1), 48–64. https://doi.org/10.20961/carakatani.v39i1.74297

Cahyani, V. R., Sudadi, S., Hadiwiyono, H., & Shofiyah, L. (2024c). Role of rice bacterial endophytes from organic and conventional paddy fields as biofertilizers and bio-resistance inducers againts insecticide toxicity. Australian Journal of Crop Science, 18(12), 847–857. https://doi.org/https://doi.org/10.21475/ajcs.24.18.12.p134

Chand, B., Kumar, M., Prasher, S., Sharma, A., & Kumar, M. (2022). Aprotic and protic solvent for extraction of chlorophyll from various plants: Chemical characteristic and analysis. Journal of Physics: Conference Series, 2267(1), 012143. https://doi.org/10.1088/1742-6596/2267/1/012143

Dada, O. A., Togun, A. O., Adediran, J. A., & Nwilene, F. E. (2014). Effect of Compost on Agro-Botanical Components Responsible for Rice (Oryza sativa)Grain Yield in Southwestern Nigeria. Journal of Agriculture and Sustainability, 6(1), 88–109.

Dong, Y., Liu, S., Hu, Y., Mulder, J., Adingo, S., Nie, Y., Yin, L., Ma, Y., & Peng, X. (2025). Effects of long-term straw application and groundwater management on acidification of paddy soils in subtropical China: Insight from a 35-year field experiment. Agricultural Water Management, 309. https://doi.org/10.1016/j.agwat.2025.109337

Erlacher, A., Cardinale, M., Grosch, R., Grube, M., & Berg, G. (2014). The impact of the pathogen Rhizoctonia solani and its beneficial counterpart Bacillus amyloliquefaciens on the indigenous lettuce microbiome. Frontiers in Microbiology, 5(175), 1–8. https://doi.org/10.3389/fmicb.2014.00175

Fujii, K., Matsuura, Y., & Osawa, A. (2019). Effects of hummocky microrelief on organic carbon stocks of permafrost-affected soils in the forest-tundra of northwest Canada. J-Stage Japan Academic Journal, 63(1), 12–25. https://doi.org/https://doi.org/10.18920/pedologist.63.1_12

Gewaily, E. E. (2019). Impact of Compost Rice Straw and Rice Straw as Organic Fertilizer with Potassium Treatments on Yield and some Grain Quality of Giza 179 Rice Variety. In J. Plant Production, Mansoura Univ (Vol. 10, Issue 2).

Gil-Martínez, M., Madejón, P., Madejón, E., & de Sosa, L. L. (2025). Compost and vegetation cover drive soil fertility, microbial activity, and community in organic farming soils. Plant and Soil. https://doi.org/10.1007/s11104-025-07720-z

Guo, L., Yu, Z., Li, Y., Xie, Z., Wang, G., Liu, X., Liu, J., Liu, J., & Jin, J. (2022). Plant phosphorus acquisition links to phosphorus transformation in the rhizospheres of soybean and rice grown under CO2 and temperature co-elevation. Science of the Total Environment, 823(153558), 1–12. https://doi.org/10.1016/j.scitotenv.2022.153558

Guo, X., Guo, P., Huang, S., Tong, Z., Zhang, Q., & Yang, H. (2025). Short-term tillage regime exerts stronger effects than straw return on carbon and nitrogen transformation in rice rhizosphere. Applied Soil Ecology, 206(105902), 1–13.

Hardoim, P. R., van Overbeek, L. S., Berg, G., Pirttilä, A. M., Compant, S., Campisano, A., Döring, M., & Sessitsch, A. (2015). The Hidden World within Plants: Ecological and Evolutionary Considerations for Defining Functioning of Microbial Endophytes. Microbiology and Molecular Biology Reviews, 79(3), 293–320. https://doi.org/10.1128/MMBR.00050-14

Hatfield, J. L., Sauer, T. J., & Cruse, R. M. (2017). Soil: The Forgotten Piece of the Water, Food, Energy Nexus. In Advances in Agronomy (Vol. 143, pp. 1–46). Academic Press Inc. https://doi.org/10.1016/bs.agron.2017.02.001

Hefner, M., Amery, F., Denaeghel, H., Loades, K., & Kristensen, H. L. (2024). Composts of diverse green wastes improve the soil biological quality, but do not alleviate drought impact on lettuce (Lactuca sativa L.) growth. Soil Use and Management, 40(1). https://doi.org/10.1111/sum.13016

Hindersah, R., Kalay, A. M., & Talahaturuson, A. (2022). Rice yield grown in different fertilizer combination and planting methods: Case study in Buru Island, Indonesia. Open Agriculture, 7(1), 871–881. https://doi.org/10.1515/opag-2022-0148

Indonesia Soil Research Institute. (2023). Technical Instructions for Chemical Analysis of Soil, Plants, Water and Fertilizer. Third edition. Sipahutar, I.A., Wibowo, H., Siregar, A.F., Widowati, L.R. and Rostaman, T. (Eds.). Balai Penelitian Tanah. Center for Research and Development of Agricultural Land Resources, Agricultural Research and Development Agency, Indonesian Ministry of Agriculture (in Indonesian)

Jadhav, K. P., Ahmed, N., Datta, S. P., Das, R., Ray, P., Meena, M. C., Chakraborty, D., & Shrivastava, M. (2023). Chemical and Instrumental Characterization of Humic Acid of Diverse Soil Orders under Paddy Cultivation. Environment and Ecology, 1(3), 38–44.

Jiao, Y., Li, Y., Yuan, L., & Huang, J. (2021). Allelopathy of uncomposted and composted invasive aster (Ageratina adenophora) on ryegrass. Journal of Hazardous Materials, 402. https://doi.org/10.1016/j.jhazmat.2020.123727

Kamewada, K., & Ooshima, M. (2024). A proposed method for determining potentially environmentally available trace metals in paddy soil. Soil Science and Plant Nutrition, 70(2), 123–128. https://doi.org/10.1080/00380768.2024.2304752

Kausar, H., Razi Ismail, M., Saud, H. M., Othman, R., Habib, S. H., & Siddiqui, Y. (2014). Bio-Efficacy of Microbial Infused Rice Straw Compost on Plant Growth Promotion and Induction of Disease Resistance in Chili. Compost Science & Utilization, 22(1), 1–10. https://doi.org/10.1080/1065657X.2013.870942

Li, J., Gao, S., Bao, C., Yan, S., Ma, C., Ma, C., & Yan, C. (2025). Mechanisms by Which Soil Solution Fe2+ Affects Seedling Growth of Rice Under Rice Straw Return. Agronomy, 15(2). https://doi.org/10.3390/agronomy15020271

Ma, Y., Zhang, H., Wang, D., Guo, X., Yang, T., Xiang, X., Walder, F., & Chu, H. (2021). Differential Responses of Arbuscular Mycorrhizal Fungal Communities to Long-Term Fertilization in the Wheat Rhizosphere and Root Endosphere. Applied and Environmental Microbiology, 87(17), 1–13. https://doi.org/10.1128/AEM.00349-21

Manickam, T., Cornelissen, G., Bachmann, R. T., Ibrahim, I. Z., Mulder, J., & Hale, S. E. (2015). Biochar application in Malaysian sandy and acid sulfate soils: Soil amelioration effects and improved crop production over two cropping seasons. Sustainability (Switzerland), 7(12), 16756–16770. https://doi.org/10.3390/su71215842

Meena, M. D., Joshi, P. K., Narjary, B., Sheoran, P., Jat, H. S., Chinchmalatpure, A. R., Yadav, R. K., & Sharma, D. K. (2016). Effects of municipal solid waste compost, rice-straw compost and mineral fertilisers on biological and chemical properties of a saline soil and yields in a mustard–pearl millet cropping system. Soil Research, 54(8), 958. https://doi.org/10.1071/SR15342

Morra, L., Bilotto, M., Baldantoni, D., Alfani, A., & Baiano, S. (2021). A seven-year experiment in a vegetable crops sequence: Effects of replacing mineral fertilizers with Biowaste compost on crop productivity, soil organic carbon and nitrates concentrations. Scientia Horticulturae, 290, 110534. https://doi.org/10.1016/j.scienta.2021.110534

Naeem, M. A., Khalid, M., Aon, M., Abbas, G., Tahir, M., Amjad, M., Murtaza, B., Yang, A., & Akhtar, S. S. (2017). Effect of wheat and rice straw biochar produced at different temperatures on maize growth and nutrient dynamics of a calcareous soil. Archives of Agronomy and Soil Science, 63(14), 2048–2061. https://doi.org/10.1080/03650340.2017.1325468

Nkongolo, C. K., Muyayabantu, G. M., & Kayombo, A. M. (2025). Effect of Tithonia diversifolia (Hemsley) and Inorganic Fertilizers on Morpho-Agronomic Characteristics of Rice (Oryza sativa L.) Grown on Oxisols in Democratic Republic of Congo. American Journal of Plant Sciences, 16(01), 64–75. https://doi.org/10.4236/ajps.2025.161008

Ojobor, S. A., & Egbuchua, C. N. (2020). Use of abattoir wastewater compost as organic fertilizer for rice production on a ultisol in Delta State, Nigeria. Asian Journal of Agriculture and Rural Development, 10(2), 682–689. https://doi.org/10.18488/journal.ajard.2020.102.682.689

Omara, A., Hadifa, A., & Ali, D. (2022). The Integration Efficacy between Beneficial Bacteria and Compost Tea on Soil Biological Activities, Growth and Yield of Rice Under Drought Stress Conditions. Journal of Agricultural Chemistry and Biotechnology, 13(4), 39–49. https://doi.org/10.21608/jacb.2022.138880.1025

Ouyabe, M., Kikuno, H., Tanaka, N., Babil, P., & Shiwachi, H. (2019). Endophytic Nitrogen-Fixing Bacteria of Water Yam (Dioscorea alata L.) in Relation with Fertilization Practices. Tropical Agriculture and Development, 63(3), 122–130.

Permentan-No.-40-Th.-2007-Ttg-Rekomendasi-Pemupukan-N-P-Dan-K-Pada-Padi-Sawah-Spesifik-Lokasi (2007).

Phares, C. A., & Akaba, S. (2022). Co-application of compost or inorganic NPK fertilizer with biochar influences soil quality, grain yield and net income of rice. Journal of Integrative Agriculture, 21(12), 3600–3610. https://doi.org/10.1016/j.jia.2022.07.041

Piromyou, P., Greetatorn, T., Teamtisong, K., Okubo, T., Shinoda, R., Nuntakij, A., et al. (2015). Preferential Association of Endophytic Bradyrhizobia with Different Rice Cultivars and Its Implications for Rice Endophyte Evolution. Applied and Environmental Microbiology, 81(9), 3049–3061. https://doi.org/10.1128/AEM.04253-14

Sadegh-Zadeh, F., Tolekolai, S. F., Bahmanyar, M. A., & Emadi, M. (2018). Application of Biochar and Compost for Enhancement of Rice (Oryza Sativa L.) Grain Yield in Calcareous Sandy Soil. Communications in Soil Science and Plant Analysis, 49(5), 552–566. https://doi.org/10.1080/00103624.2018.1431272

Seleiman, M. F., Elshayb, O. M., Nada, A. M., El-leithy, S. A., Baz, L., Alhammad, B. A., & Mahdi, A. H. A. (2022). Azolla Compost as an Approach for Enhancing Growth, Productivity and Nutrient Uptake of Oryza sativa L. Agronomy, 12(2), 416. https://doi.org/10.3390/agronomy12020416

Shabanamol, S., Divya, K., George, T. K., Rishad, K. S., Sreekumar, T. S., & Jisha, M. S. (2018). Characterization and in planta nitrogen fixation of plant growth promoting endophytic diazotrophic Lysinibacillus sphaericus isolated from rice (Oryza sativa). Physiological and Molecular Plant Pathology, 102, 46–54. https://doi.org/10.1016/j.pmpp.2017.11.003

Sharma, S., & Dhaliwal, S. S. (2019). Effect of sewage sludge and rice straw compost on yield, micronutrient availability and soil quality under rice–wheat system. Commun in Soil Sci and Plant Anal, 50(16), 1943–1954. https://doi.org/10.1080/00103624.2019.1648489

Sikora, R. A., Schäfer, K., & Dababat, A. A. (2007). Modes of action associated with microbially induced in planta suppression of plant-parasitic nematodes. Australasian Plant Pathology, 36(2), 124–134. https://doi.org/10.1071/AP07008

Soil Survey Staff. (2014). Keys to soil taxonomy. Soil Conservation Service, 12, 410. http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_051546.pdf

Sultana, M., Jahiruddin, M., Islam, M. R., Rahman, M. M., Abedin, M. A., & Solaiman, Z. M. (2021). Nutrient Enriched Municipal Solid Waste Compost Increases Yield, Nutrient Content and Balance in Rice. Sustainability, 13(3), 1047. https://doi.org/10.3390/su13031047

Tahiri, A., Meddich, A., Raklami, A., Alahmad, A., Bechtaoui, N., Anli, M., et al. (2022). Assessing the Potential Role of Compost, PGPR, and AMF in Improving Tomato Plant Growth, Yield, Fruit Quality, and Water Stress Tolerance. Journal of Soil Science and Plant Nutrition, 22(1), 743–764. https://doi.org/10.1007/s42729-021-00684-w

Vishwanath, Kumar, S., Purakayastha, T. J., Datta, S. P., K.G, R., Mahapatra, P., Sinha, S. K., & Yadav, S. P. (2022). Impact of forty-seven years of long-term fertilization and liming on soil health, yield of soybean and wheat in an acidic Alfisol. Archives of Agronomy and Soil Science, 68(4), 531–546. https://doi.org/10.1080/03650340.2020.1843023

Wasim, H. M., Sarwar, G., Noor-Us-Sabah, N. U. S., Tahir, M. A., Aftab, M., et al. (2021). Impact of NaCl Toxicity on Yield and Yield Components of Rice (Oryza sativa) Grown in Aridisol. Pakistan Journal of Agricultural Research, 34(1), 102–107. https://doi.org/10.17582/journal.pjar/2021/34.1.102.107

Wemheuer, F., Wemheuer, B., Kretzschmar, D., Pfeiffer, B., Herzog, S., Daniel, R., & Vidal, S. (2016). Impact of grassland management regimes on bacterial endophyte diversity differs with grass species. Letters in Applied Microbiology, 62(4), 323–329. https://doi.org/10.1111/lam.12551

Wu, W., Chen, W., Liu, S., Wu, J., Zhu, Y., Qin, L., & Zhu, B. (2021). Beneficial Relationships Between Endophytic Bacteria and Medicinal Plants. Frontiers in Plant Science, 12. https://doi.org/10.3389/fpls.2021.646146

Xie, K., Sun, M., Shi, A., Di, Q., Chen, R., Jin, D., Li, Y., Yu, X., Chen, S., & He, C. (2022). The Application of Tomato Plant Residue Compost and Plant Growth-Promoting Rhizobacteria Improves Soil Quality and Enhances the Ginger Field Soil Bacterial Community. Agronomy, 12(8), 1741. https://doi.org/10.3390/agronomy12081741

Yadav, P. K., Kumar, S., Kumar, V., Dixit, V., Verma, S., & Singh, V. (2022). Zn and B Mediated Effect on Yield Attribute, Yield, and Nutrient Uptake in Lentil (Lens culinaris Medick.). International Journal of Plant & Soil Science, 1045–1055. https://doi.org/10.9734/ijpss/2022/v34i2231468

Yang, Q., Zhang, H., Guo, Y., & Tian, T. (2016). Influence of Chicken Manure Fertilization on Antibiotic-Resistant Bacteria in Soil and the Endophytic Bacteria of Pakchoi. International Journal of Environmental Research and Public Health, 13(662), 1–12. https://doi.org/10.3390/ijerph13070662