Reducing chemical fertilizers is critical for maintaining soil health and minimizing environmental damage. Biochar-based organic fertilizers reduce fertilizer inputs, improve soil fertility, increase crop productivity, and reduce environmental risks. In this study, a pot experiment was conducted in a greenhouse to assess the potential of biochar-based organic and inorganic fertilizers to improve soil fertility and Okra yield. Seven treatments with three replicates were arranged in a completely randomized design (CRD). Three treatments included biochar-blended formulations (i) biochar mixed with mineral NPK fertilizer (BF), (ii) biochar mixed with vermicompost (BV), and (iii) biochar mixed with goat manure (BM); two treatments included biochar enrichment formulations (iv) biochar enriched with cow urine (BCU) and (v) biochar enriched with mineral NPK fertilizer in aqueous solution (BFW), and the remaining two included control treatments; (vi) control (CK: no biochar and no fertilizers) and (vii) fertilized control (F: only recommended NPK fertilizer and no biochar). Mineral NPK fertilizers in BF, BFW, and F were applied at the recommended rate as urea, di-ammonium phosphate (DAP), and muriate of potash (MOP). Organic fertilizers in BV, BM, and BCU treatments were applied in equal quantities. All biochar-amended treatments showed improved soil chemical properties with higher pH, organic carbon, total N, and available P and K compared to the two non-biochar control plots (CK and F). Biochar blended with goat manure (BM) showed the highest effect on soil fertility and fruit yield. BM (51.8 t ha⁻¹) increased fruit yield by 89% over CK (27.4 t ha⁻¹) and by 88% over F (27 t ha⁻¹). Similarly, cow urine-enriched biochar (BCU) (35 t ha⁻¹) increased fruit yield by 29% and 28% compared to CK and F, respectively. Soil pH, OC, and nutrient availability (total N, available P, and available K) showed a significantly positive relationship with fruit yield. The study suggests that using biochar-based organic fertilizers, such as BCU and BM, could outperform recommended mineral fertilizers (F) and produce higher yields and healthy soils, thereby contributing to mitigating the current food security and environmental concerns of the country.

Organic based fertilizers is crucial for maintaining soil fertility, increasing crop production, and mitigating climate change. Among various organic fertilizers, vermicompost (VC) has been found to be one of the promising options for enhancing soil fertility and productivity. However, there are limited studies on the agronomic effects of vermicomposts in Nepal. In this study, a pot culture experiment was conducted inside a greenhouse to assess the agronomic and economic effects of four different commercially available vermicomposts, available in both reduced and original moisture forms, on okra. Nine treatments with three replications were arranged in a completely randomized design (CRD). These treatments included Divya vermicompost with both reduced (DvRM: 28.82 %) and original moisture (DvOM: 62.17 %); Praramva vermicompost with reduced (PvRM: 29.63 %) and original moisture (PvOM: 54.65 %), Bio-Comp vermicompost with reduced (BvRM: 26.75 %) and original moisture (BvOM: 49.77 %), Sathi vermicompost with reduced (SvRM: 28.52 %) and original moisture (SvOM: 65.18 %), and a control (CK: non-fertilized treatment). All VC treatments, whether in reduced or original moisture forms, showed better performance on plant growth parameters and fruit yield compared to the control. There was no significant difference between the four types of VCs, in either moisture form. The average number of fruits per pot in VC treatments (ranging from 5.5 to 8.0 fruits per pot) increased by 94 % compared to CK (3.5 fruits). Similarly, total fruit yield increased by 126 % in VC treatments (ranging from 16213 kg ha⁻¹ to 23193 kg ha⁻¹) compared to the CK (8260 kg ha⁻¹). The benefit to cost ratio (B:C) of all the VCs was above 1 (B:C > 1), ranging from 1.00 to 1.59, illustrating the economic benefit of using vermicompost in okra cultivation. The findings suggest that farmers should consider the widespread use of vermicomposts to increase both crop productivity and farm profitability, thereby sustaining their livelihoods.