Integrated application of sugarcane by-product-derived organic fertilizer (SOFA) and mineral nitrogen enhances yield, fruit quality, and soil properties of eggplant (Solanum melongena L.) in sandy soil conditions

Long-Term Green Manure Incorporation with Reduced Chemical Fertilizer Enhances Soil Quality and Rice Yield by Altering Soil Microbial Communities’ Structure and Functions in Paddy Soils

Excessive use of chemical fertilizers degrades soil health and threatens sustainable crop production, which can be mitigated by partially substituting chemical fertilizers with Chinese milk vetch (Astragalus sinicus L., MV, as green manure). However, the mechanisms through which MV incorporation alters soil microbial community structure and function, enhances soil quality and crop productivity, as well as its long-term effects in paddy soils, are still not fully understood. In this study, we investigated the responses of soil physical, chemical, and biological properties (to comprehensively evaluate soil quality); microbial community structure and function; rice productivity; and the sustainable yield index (SYI) to five fertilizer treatments based on a 13-year field experiment in a paddy’s soil in Henan, China. The treatments included: CK (no chemical fertilizer and no MV), F100 (100% chemical fertilizer), MVF80, MVF60 and MVF40 (80%, 60%, and 40% of the chemical fertilizer rate combined with MV, respectively). Compared with the F100 treatment, MVF60 slightly increased rice yield by 1.71% and significantly improved SYI by 5.10%. All MV treatments significantly increased soil organic carbon (SOC, by 14.4–16.3%) and microbial biomass carbon (MBC, by 16.7–20.1%). MVF60 and MVF40 significantly reduced bulk density, and increased macroaggregate content and mean weight diameter (MWD). MVF80 significantly enriched soil total phosphorus (TP), total potassium (TK), mineral nitrogen (Nmin), and urease (UE). The improvement in these soil properties resulted in a marked increase (by 11.6–20.1%) in the soil quality index (SQI) under all MV treatments. Random forest analysis identified MBC and Nmin as the most important predictors of SQI. Moreover, MV incorporation increased the relative abundance of beneficial taxa (Firmicutes, Clostridium_sensu_stricto_1, Bradyrhizobium, and Nigrospora), which were positively correlated with SQI (p < 0.05), while reducing the relative abundance of pathogenic fungal genera such as Fusarium. Furthermore, regression analysis revealed strong positive correlations between SQI and both rice yield and SYI. In summary, long-term MV incorporation with a 40% reduction in chemical fertilizer (MVF60) constitutes an effective and sustainable nutrient management approach for rice production in southern China. This practice enhances soil quality through improved physical structure, nutrient cycling, and microbial community structure and function, ultimately resulting in higher and more stable yields.

Enhancing Growth, Yield, and Marketable Tuber Quality of Potato (Solanum tuberosum L. cv. BARI Alu-88) through Supplementary Vermicompost Application under Coastal Conditions of Bangladesh

Potato (Solanum tuberosum L.) is an important food and cash crop in Bangladesh; however, production in coastal regions is constrained by poor soil fertility and salinity stress. Vermicompost has emerged as a sustainable soil amendment capable of improving soil health and crop productivity. Therefore, the present study was conducted to evaluate the effects of different rates of supplementary vermicompost under a recommended inorganic fertilizer regime on the growth and yield of the potato cultivar BARI Alu-88 under coastal conditions. The experiment was carried out during the 2021–2022 growing season at the field of Noakhali Science and Technology University using a randomized complete block design (RCBD) with four treatments: T₀ = control (recommended inorganic fertilizer only), T₁ = recommended inorganic fertilizer + vermicompost @ 3.5 t ha⁻¹, T₂ = recommended inorganic fertilizer + vermicompost @ 5.5 t ha⁻¹, and T₃ = recommended inorganic fertilizer + vermicompost @ 7.5 t ha⁻¹, with three replications each. Supplementary vermicompost application significantly (P ≤ .01) improved all growth and yield attributes compared with the recommended inorganic fertilizer alone. The highest vermicompost rate (T₃) produced the tallest plants (56.73 cm), the greatest numbers of leaves (495.03 hill⁻¹), stems (7.60 hill⁻¹), and tubers (21.55 plant⁻¹), and the highest gross tuber yield (40.44 t ha⁻¹) and marketable yield (36.79 t ha⁻¹). Moreover, T₃ reduced the proportion of small-sized tubers (19.32%) while increasing the proportion of large-sized tubers (50.05%). The findings indicate that supplementary vermicompost application under the recommended inorganic fertilizer regime markedly enhanced vegetative growth, tuber development, and yield performance of BARI Alu-88 under coastal conditions. Although vermicompost is recognized as an environmentally friendly soil amendment, its adoption in the coastal saline areas of Bangladesh remains limited. The findings of the present study indicate that applying vermicompost at 7.5 t ha⁻¹ significantly improves the growth and yield of BARI Alu-88 under saline conditions. Therefore, supplementing the recommended inorganic fertilizer with vermicompost at 7.5 t ha⁻¹ can be recommended as an environmentally sustainable nutrient-management strategy for improving potato productivity in the coastal regions of Bangladesh.

Integrated Bentonite, Humic Substances and Bacillus polymyxa Enhance Soil Functionality, Rhizosphere Processes, Nutrient Uptake and Fruit Quality of Siwi Date Palm Under Deficit Irrigation in Sandy Soil

Arid sandy soils are characterized by poor water retention, low nutrient availability, and limited productivity, posing major constraints to sustainable date palm cultivation under increasing water scarcity. A three-year field experiment was conducted to evaluate the combined effects of bentonite (BN), humic substances (HS), and Bacillus polymyxa (BP) under three irrigation regimes (70, 85, and 100% of crop evapotranspiration (ETc)) on soil hydro-physical properties, nutrient uptake, and fruit quality of ‘Siwi’ date palm (Phoenix dactylifera L.). Twelve treatment combinations (3 irrigation regimes × 4 soil amendment treatments) were evaluated over three consecutive growing seasons. The integrated application of BN, HS, and BP significantly improved soil hydro-physical properties by increasing field capacity and plant-available water while reducing bulk density. These improvements were associated with enhanced leaf N, P, and K concentrations and greater accumulation of total soluble solids, total and reducing sugars, phenolic compounds, flavonoids, and β-carotene compared with the untreated control. The combined application of BN (12 kg palm−1) + HS (1 L palm−1) + BP (28 mL palm−1) produced the most favorable overall responses. Moderate deficit irrigation (85% ETc) provided the best balance between fruit quality and water conservation, maintaining superior fruit biochemical quality while reducing irrigation water use by approximately 15% compared with full irrigation. Multivariate analyses further supported these findings by revealing strong positive associations among soil water availability, nutrient status, sugars, and antioxidant-related compounds, while climatic variables were closely associated with seasonal variation in fruit biochemical characteristics. Overall, the integrated application of bentonite, humic substances, and B. polymyxa under 85% ETc irrigation represents an effective management strategy for improving soil performance, enhancing fruit nutritional quality, and increasing water-use irrigation efficiency in sandy soils under arid conditions.

Crop succession combinations influence soil enzyme activity, fertility, and onion yield in a long-term organic no-tillage vegetable system in southern Brazil

Conventional tillage in onion cultivation degrades physical, chemical and biological properties of soil. In response, the no-tillage vegetable system (NTVS) is increasingly recognized as efficient conservationist cropping system for onion cultivation. To determine how distinct crop successions combinations optimize soil functioning, this study evaluated a long-term organic NTVS experiment comprising eight treatments of winter (black oat, oilseed radish, or fallow) and summer crops (velvet bean, soybean, millet, common bean, or maize) succession combinations for onion production. This study assessed cover crop mulch, onion yield, soil fertility, and enzyme activities (FDA hydrolysis, arylsulfatase, and β-glucosidase). Results showed that the organic NTVS improved soil fertility, increasing organic matter by 38% (0–10 cm) and 13% (10–20 cm) compared to previous evaluations. Successions with black oat maximized mulch production, while successions combining black oat in winter with legumes (velvet bean, soybean) in summer maximized onion yield (up to 34.7 Mg·ha⁻1). Enzyme activity was influenced by crop development stage and succession combination; FDA hydrolysis peaked at 361 μg fluorescein·g⁻1·h⁻1 during onion bulbification, and arylsulfatase consistently exceeded 114 μg p-nitrophenol·g⁻1·h⁻1 across treatments. A principal component analysis confirmed that enzyme activity was regulated by crop succession combination rather than fertility attributes. In conclusion, combining winter grasses or crucifers with summer legumes optimizes soil enzyme activity, fertility attributes, and onion performance in long-term organic NTVS.

Effectiveness of a Natural Fertilizer from Organic Household Waste (Banana Peel, Orange Peel, Eggshell, and Onion Peel) versus Chemical Fertilizer on The Growth of Chili (Capsicum Annuum L.): A Comparative Analysis

Commercial chemical fertilizers are heavily relied upon to boost crop yields, but their rising costs and negative environmental impacts—such as soil degradation and water contamination—highlight the critical need for sustainable alternatives. This study evaluated the effectiveness of a liquid natural fertilizer formulated from organic household wastes, including banana peels, orange peels, eggshells, onion peels, rice wash water, and molasses, on the growth performance of chili (Capsicum annuum L.) plants. Utilizing an experimental research design, chili seedlings were divided into four groups to compare the organic formulation (at 5 mL and 10 mL concentrations) against a commercial synthetic fertilizer and a water-only control group. The plants were monitored over an eight-day treatment period using two primary metrics: plant height and leaf count.  The results demonstrated that the organic formulation is highly effective in promoting key growth parameters. In terms of plant height, the water-only control group achieved the highest average height of 8.6 inches, followed closely by the 10 mL organic fertilizer group at 8.1 inches, while both the chemical fertilizer and 5 mL organic treatments recorded the shortest height at 7.7 inches. Conversely, in the metric of leaf production, the 10 mL organic fertilizer concentration demonstrated the strongest performance, yielding the highest average of 10.6 leaves. The water-only and 5 mL organic groups resulted in 8.4 leaves, whereas the chemical fertilizer group performed the worst, recording the lowest average of 4.2 leaves. These findings confirm that the homemade organic fertilizer can rival and surpass commercial options, particularly in supporting leaf growth. The study concludes that recycling household kitchen waste into a liquid biofertilizer provides a practical, eco-friendly, and cost-effective solution for sustainable urban agriculture.  

Organic Amendments in Fruit-Based Agroforestry Systems: Impacts on Crop Productivity, Soil Properties and Climate Change Mitigation in the Vindhyan Region of India