The use of Bacillus bacteria as biofertilizers (BF) increases since the detrimental effects of inorganic fertilizers on the agricultural environment spread out. The objective of this research was to study the influence of bio fertilizer and in combination with inorganic fertilizer on the productivity of rice fields. The experiment was a two-factor treatment arranged in a split-plot design with three replications using a randomized complete block design (RCBD). The first factor was fertilizers, which were used as the main plot. The second factor was paddy varieties as a subplot. The results showed that the combination of inorganic and bio fertilizer application of (150 kg NPK ha-1 + 75 kg Urea ha-1 + 4 L BF ha-1) and (300 kg NPK ha-1 + 150 kg Urea ha-1 + 4 L BF ha-1), improved soil available phosphorous (P) of 12.04%, 40.69%, and 44.05%, respectively compared to control treatment, the inorganic fertilizer application (300 kg NPK ha-1 + 150 kg Urea ha-1), and the bio fertilizer application (4 L BF ha-1). In addition, the application of (300 kg NPK ha-1 + 150 kg Urea ha-1 + 4 L BF ha-1) increased productive tillers per plant as 28.13% and 16.48% compared to the control and the inorganic application, respectively. Moreover, by using Mekongga variety, applying the inorganic and bio fertilizer at rates of (300 kg NPK ha-1 + 150 kg Urea ha-1 + 4 L BF ha-1) increased rice yield of 64.08% and 30.33% compared to the control and the inorganic fertilizer application; while, by using IPB 3S variety, the rice yield increased by 85.80% and 10.34%, respectively. These findings are significant as they demonstrate the potential of biofertilizers to enhance soil fertility and rice productivity, thereby advancing sustainable farming practices.

Bacillus species are rhizosphere bacteria that can fix N2, solubilize insoluble soil phosphates, and synthesize auxin, a hormone that promotes plant growth. A field research was carried out in the growing season of 2018/19 at the Bogor Agricultural University Experimental Station. The objectives of the study were to determine the effects of biofertilizer derived from Bacillus species, both standalone and in combination with NPK and UREA fertilizers, on root growth, plant height, and tillers development of rice (Oryza sativa L.). The experiment was arranged in a split-plot design, with plots arranged in a randomized complete block design (RCBD) consisting of three replications. Main plots were treated with fertilizers and consisted of 7 rates, while sub-plots consisted of paddy varieties. The findings revealed that rice plants fertilized with only Bacillus species biofertilizer, as well as those fertilized with a combination of Bacillus species biofertilizer and chemical fertilizers, were the longest and largest in volume at harvest. The root length and its volume were the shortest and lowest, respectively, in control-treated rice plants. In addition, the growth of rice plants treated with 75% of (NPK + UREA) + 4 l/ha of BF, 100% of (NPK + UREA) + 4 l/ha of BF, and 100% of (NPK + UREA) showed significant differences from those treated as control and those fertilized solely with Bacillus species biofertilizer. The number of tillers was 27 on rice plants fertilized with 75% of (NPK + UREA) + 4 l/ha of BF, 100% of (NPK + UREA) + 4 l/ha of BF, and they were significantly different compared to other treatments.

Mycorrhizae are symbiotic associations between the roots of vascular plants and fungi that facilitate the uptake of water and nutrients by host plants. However, current arbuscular mycorrhizal fungi (AMF) cultivation methods including sand culture, root organ culture, and aeroponics are complex and time-consuming. Moreover, these methods produce low spore yields hindering large-scale production and sustainable application of MF in agriculture. This study systematically evaluated the effects of biochar amendment on the propagation of AMF spores in sandy soils, focusing on how different biochar application rates influence AMF spore density and related soil physicochemical properties. The results showed that increasing biochar concentration led to higher soil pH and EC, suggesting enhanced microbial activity and dynamic adjustments in soil chemical conditions. A typical biphasic response was observed. At low biochar concentrations (approximately 1–1.8%), soil porosity, organic carbon content, and trace element availability were improved, thereby promoting AMF spore formation and hyphal growth. However, concentrations exceeding 2.5% induced physicochemical stress that inhibited fungal propagation. Polynomial regression analysis (R² = 0.996) confirmed a strong correlation between biochar concentration and AMF spore density, clearly capturing a promotion–plateau–inhibition pattern. In addition, SEM imaging revealed that AMF hyphae adhered to the porous surface of biochar, forming stable hyphal networks that enhance nutrient transport and contribute to rhizosphere microenvironmental stability.

Contemporary agricultural systems are increasingly embracing organic inputs as a sustainable and effective alternative. These inputs contribute significantly to agroecosystem health, enhance ecological resilience and support sustained crop productivity. However, limited studies exist regarding the effects of biochar (B) and organic fertilisers (F) on fruit crops when cultivated in the acidic soils of Pingtung, Taiwan. To address this gap, a study was conducted during 2024–25 to evaluate the impact of rice husk B and F on soil properties, yield and mineral content of okra. Seven treatments with three replicates were arranged in a completely randomised design (CRD) under greenhouse pot conditions. Treatments consisted of varying combinations in grams of B and F, produced from a mixture of pig, cow and chicken manure: B50 + F0, B0 + F75, B25 + F25, B50 + F25, B50 + F50 and B50 + F75, alongside an unamended control (CK) that received 0 g of either B or F. Following 90 days of amendment, the B50 + F75 treatment significantly elevated soil pH to 5.93 relative to the CK treatment, whereas B0 + F75 recorded the highest soil organic matter content of 3.95 %. B25 + F25, B0 + F75 and B50 + F25 significantly increased soil-available phosphorus (P) (253.82 mg/kg), calcium (Ca) (1047.48 mg/kg) and magnesium (Mg) (97.96 mg/kg) compared with the CK respectively. Microbial activity was also enhanced, with bacterial populations peaking at 9.39 log CFU/g in B50+F25 and fungal populations reaching 8.10 log CFU/g in B50 + F50. Interestingly, the B50 + F75 treatment significantly increased potassium (K) levels in both the soil and okra fruits compared with the CK. In contrast, fruits from the control exhibited higher iron (Fe) content (12.47 mg/100 g). The heaviest fruits (156.13 g plant-1) were harvested under B50 + F50, while fruit number peaked at 9 per plant in B50 + F25. Overall, the combined use of B and F enhanced soil health and boosted okra productivity, demonstrating their strong potential for restoring infertile soils.

Increasing fertilizer costs, climate-related stresses, and soil degradation caused by the prolonged use of chemical fertilizers threaten the sustainability of agricultural production. Organic soil amendments offer a promising approach to restoring soil health while reducing dependence on synthetic inputs. This study evaluated the combined effects of biochar and organic fertilizer on soil health and soybean (Glycine max L.) productivity under acidic soil conditions. During the 2024 growing season, a greenhouse pot experiment was conducted using a completely randomized design (CRD) comprising seven treatments. Each treatment was replicated three times, resulting in a total of 21 pots. The treatments consisted of different combinations of biochar (B) and organic fertilizer (F), applied at rates of grams per 10.5 kg of soil: control (B0F0), B35F70, B35F105, B35F140, B70F70, B70F105, and B70F140. Treatment means were compared using the Least Significant Difference (LSD) test at p < 0.05. The results showed that the highest soil pH value (5.41) was recorded under the B35F70 treatment at 45 days after amendment of the acidic soil. Application of the B35F140 treatment resulted in a significant increase (p < 0.05) in electrical conductivity (0.23 mS cm⁻¹) compared with the control. Soil organic matter and available phosphorus reached their highest values under B70F140, at 5.25% and 13.87 mg kg⁻¹, respectively, and were significantly greater than those in the control treatment. Soil available iron (Fe) and manganese (Mn) concentrations also increased significantly (p < 0.05) compared with the control, with the B35F70 and B70F70 treatments resulting in the highest Fe (371.29 mg kg⁻¹) and Mn (37.77 mg kg⁻¹) concentrations, respectively. At 100 days after amendment of the reddish-brown acidic soil, exploratory Pearson correlation analyses were conducted to examine relationships between soil health indicators and soybean performance. Soil available phosphorus and potassium exhibited positive associations with soil pH (r = 0.69 and r = 0.65, respectively; p < 0.01). Soybean growth traits, including plant height and number of leaves, were positively associated with seed yield (r = 0.56 and r = 0.77, respectively; p < 0.01). Furthermore, seed yield was positively correlated with SPAD values (r = 0.80, p < 0.01), soil pH (r = 0.56, p < 0.01), available K (r = 0.68, p < 0.01), and Mg (r = 0.47, p < 0.05). Principal component analysis (PCA) further demonstrated clear treatment clustering and consistent positive relationships among soil properties, plant growth traits, and soybean yield variables. The control treatment was clearly separated from all biochar-organic fertilizer treatments along PC1. Among all treatments, B35F140 (3.33 g biochar kg⁻¹ soil + 13.33 g organic fertilizer kg⁻¹ soil) showed the strongest positive association with soil health and plant growth and produced the highest soybean seed yield (10.77 g plant⁻¹). Overall, the combined use of biochar and organic fertilizer improved soil health, soybean growth, and yield, demonstrating its potential as a sustainable strategy for enhancing soybean productivity under acidic soil conditions.