The growing global population accentuates the urgency of ensuring food sustainability, safety, and security while lessening the strain on economic, environmental, and Earth resources (Shubbar et al., 2024). Conventional farming, relying on input-intensive practices, poses long-term challenges affecting production systems, biodiversity, food quality, environmental sustainability, greenhouse gas emissions, and human health (Mbow et al., 2020). In response, efforts over the past two decades have focused on exploring sustainable alternatives aligned with the United Nations Sustainable Development Goals, promoting eco-friendly living and environmental stewardship (Imran et al., 2022).

Organic farming, employing natural methods for crop cultivation and ecologically sound fertilization and pest control, emerges as a pivotal approach (Chatterjee et al., 2017). Various organic sources, including farmyard manure (FYM), paddy husk ash (PHA), and potato peel compost (PPC), derived from agricultural and industrial waste, significantly contribute to sustainable practices. FYM, composed of decomposed dung, urine, litter, and leftover fodder, enables gradual nutrient release, aligning with plant requirements (De et al., 2021). Similarly, PHA, a byproduct of rice milling, and potato peel waste from the food processing industry present disposal challenges, motivating their exploration for agricultural applications (Sharma et al., 2015).

While previous research has examined organic farming practices, our study uniquely targets the utilization of these significant industrial byproducts, which are often overlooked in traditional agricultural practices. By repurposing PHA and potato peel waste, we aim to address critical disposal challenges while simultaneously exploring their potential as enriched organic formulations in agriculture.

Composting, a microbial-mediated process accelerating waste breakdown, transforms complex materials into forms suitable for agricultural use (Zhang et al., 2016; Bhattacharjya et al., 2021). This study focuses on PHA and potato peel waste, significant global industrial wastes. Recycling these materials in agriculture not only addresses disposal challenges but also holds potential for reducing reliance on commercial fertilizers (Ayilara et al., 2020). PHA, abundantly produced in rice-growing countries, poses a disposal challenge due to its sheer volume, exacerbating air pollution, and greenhouse gas emissions and causing substantial nutrient loss (Bhuvaneshwari et al., 2019).

Similarly, potato peel waste, a byproduct of the food processing industry, contains substantial starch and nutrients (Joshi et al., 2020). Utilizing this waste in composting not only enriches soil microbes but also tackles the disposal challenges faced by the potato industry (Ezejiofor et al., 2014). By exploring these organic amendments, our research aims to contribute to ongoing efforts in optimizing agricultural sustainability, aligning with the global push toward environmentally friendly practices.

Our hypothesis posits that enriched organic formulations from agricultural waste will foster plant growth and improve soil health compared to conventional production systems. To substantiate this, our research objectives encompass a comprehensive assessment of soil quality through measuring, enzymatic activity, microbial biomass, community composition, and various physical and chemical properties. Additionally, we seek to evaluate the impact of these organic formulations on nutrient accumulation in the soil profile and their influence on the growth and yield of crops, namely, pigeon pea, veg mustard, and okra, grown in rotation.

This study comprehensively assesses the short-term effects of organic formulations on various parameters, including soil quality. The investigation extends its focus to examine how these variables influence the growth and yield of rotationally cultivated pigeon pea–veg mustard–okra crops. Aligned with the overarching goal of advancing agricultural sustainability, this research seeks to unravel the advantages associated with employing enhanced organic formulations derived from agricultural waste in a multi-crop system. By delving into soil quality, nutrient dynamics, and crop performance systematically, the research aims to contribute valuable insights and propose practical solutions to global challenges in both food production and waste management.

In present study, the impact of enriched organic formulations on growth parameters was discernible at later stages of crop growth contrast to the treatment T₁ in both 2020 and 2021. The heightened growth observed in the treatment T₄ can be attributed to escalated activities of beneficial microorganisms, facilitated by the augmented organic pool in the soil resulting from the application of nutrient sources in pigeon pea–vegetable mustard–okra cropping system. Moreover, the improved growth observed in treatments T₂ and T₆ can be attributed to the beneficial effects of organic sources. These effects are likely due to the impact of soil organic matter (SOM), which enhances the physical, chemical, and biological properties of the soil, creating a favorable environment for better plant growth in pigeon pea–vegetable mustard-okra cropping system. Furthermore, the presence of humic acids released during the decomposition of organic materials enhances the availability of soil nutrients, leading to improved growth parameters (Tiwari et al., 2023).

Yield attributes are mainly influenced by genetic characteristics of varieties and environmental factors. Treatment T₄ recorded highest increase in yield attributes and yield (seed and stover) comparable to T₆ and T₂ over treatment T₁ during 2020–2021 and 2021–2022, respectively. Organic manures serve as a reservoir of nutrients, producing organic acids during decomposition. These acids gradually release absorbed ions throughout the crop’s entire growth cycle, leading to improved yield attributes and yield under pigeon pea–vegetable mustard–okra cropping system. Additionally, the increase in yield attributes observed in treatment, T₂, T₄, and T₆ can be attributed to an increase in photosynthetic area, DMA and translocation of photosynthates toward sink tissues. The significant improvement in seed and stover yield resulting from the use of organic nutrient sources could be attributed their beneficial impact on yield attributes and their combined influence, which primarily contribute to enhanced productivity. Pradeep et al. (2018) reported increased yield attributing characters in pigeon pea when supplemented with 100% RDN through vermi-compost (2 t ha⁻¹) along with FYM @7.5 t ha⁻¹ as compared to other treatments. Findings of study done by Jakhro et al. (2017) reported that 75 kg N + 6 tons FYM ha⁻¹ resulted in higher fresh weight per plant, leaf length, and leaf yield of spinach over control. In current study, no significant difference was observed in pH and BD, but the lowest pH and BD were observed under T₄ treatment and noticeably comparable to other treatments applied with difference enriched organic formulations. The reduction in pH caused by addition of organic manure might be due to production of organic acid during breakdown of SOM, which dissolves native salts. In treatments applied with enriched organic formulations recorded increase in BD and water-stable aggregates. The use of organic nutrient sources resulted in a decrease in BD due to increased soil organic carbon (SOC) content and enhanced root biomass. The positive effects of certain polysaccharides formed during the breakdown of organic waste by microbial activity as well as the cementing action of bacteria and fungi may be the cause of rise in water-stable aggregates in the FYM treated plot. This, in turn, facilitated improved soil aeration and better soil aggregation. Nandapure et al. (2011) reported that FYM application @5t ha⁻¹ in sorghum-wheat cropping system recorded enhanced percentage of WSAs by 11.1% than unfertilized control plot. Gupta et al. (2012) also observed that FYM use @5t ha⁻¹ did not bring substantial difference in pH and EC of soil and remain at par with remaining treatments after complete rotation of maize-wheat cropping system.

Treatment T₄ registered significantly (p ≤ 0.05) highest value of MBC to the extent of 28.5% over control (T₁) and found at par with T₆ and T₂ at the end of two-year cropping cycle. The addition of readily decomposable carbon sources act as important sources of energy to carry out the activities of microorganisms, soil enzymes, and MBC. The increase in MBC in treatment T₄, T_6, and T₂ may be attributed to application of organic carbon through enriched organic formulations. Almeida et al. (2011) found that adding organic carbon to the soil from nutrient sources was closely linked to increased microbial and enzymatic activity, showing a positive relationship with MBC. Kaur et al. (2005) reported that organic manures promotes the MBC in soil whereas, Gong et al. (2009) found an increase in enzymatic activities due to addition of organic manures as compared to mineral fertilizers. The status of SOC at the end of two cropping cycle was remained non-significant under all the treatments. However, highest organic carbon was obtained under T₄ (0.41%) due to increase application of organic carbon through application of enriched organic formulations. Gupta et al. (2012) reported that FYM application @ 5 t ha⁻¹ did not bring substantial variation in SOC and exhibiting statistical parity with remaining treatments at the end of maize–wheat cropping system. The DHA and AP activity was recorded significantly superior in all the treatment applied with enriched organic formulations over control (T₁) in all the crops. The highest DHA and AP values were recorded in T₄, which was comparable with T₂ and T₆. The activities of DHA and AP were significantly affected by the amount of organic matter added to soils through various applications: 100% RDN via PHA/PPC-based formulation, 100% RDN via FYM, 100% RRC, and 75% RDN via PHA/PPC-based formulation. These formulations contain easily decomposable organic carbon components that exert a significant impact on the metabolic activity of soil microorganisms, resulting in enhanced DHA and AP activity in the soil. Applying organic source of nutrients improved the organic carbon which was correlated with higher enzymatic activity (Mandal et al., 2007).

Among different formulations, treatment T₄ demonstrated significant (p ≤ 0.05) increased values of NH₄-N and NO₃-N content in soil over control (T₁) after harvest of okra during 2020–21 and 2021–22 and also found on par with treatment T₆ and T₂. The higher mineral nitrogen content in soil under different treatment compared to control (T₁) may be due to enhanced rate of SOM mineralization in the soil which was further enhanced by the addition of enriched organic formulation, resulted in build-up of NH₄-N and NO₃-N in soil. Bhardwaj et al. (2023) reported that addition of organic manure along with fertilizers enhance the mineralization thereby increase the NH₄-N and NO₃-N in soil.

All the treatment with enriched organic formulations showed parity among each for available soil nutrient content and found significantly superior over control (T₁). Treatment T₆ demonstrated significantly (p ≤ 0.05) highest amount of available N in soil after harvest of okra crop over control (T₁). The increased availability of nitrogen in the soil could be attributed to the favorable soil conditions fostered by the use of enriched organic formulations. These conditions likely facilitated nitrogen mineralization, resulting in higher accumulation of available nitrogen. The addition of organic matter through enriched organic formulations increased Olsen-P due to its P content and perhaps by enhancing P retention in soil through release of different organic acids and CO₂ during the decomposition of SOM. Further, enriched organic formulations increased soil cation exchange capacity and decreased K fixation in soil, the increase in available K under these treatments was attributed to higher release of non-exchangeable K from the soils. The direct introduction of N, P, and K either independently or through the simultaneous application of organic nutrient sources contributes to an active soil pool, resulting in increased overall N availability as well as enhanced availability of N, phosphorus P, and K in the soil (Babu et al., 2020; Nima et al., 2020). Further, the apparent N budget showed that the highest negative N balance under control treatment (T₁) after completion of two cropping cycles due to no application of any fertilizer or organic source of nutrient. Among the treatments applied with enriched organic formulations, T₄ and T₆ recorded an apparent negative balance of 46.4 and 31.2 kg N ha⁻¹ respectively which might be attributed to increased nutrient uptake and enhanced yield. The treatment T₃ showed maximum positive balance of 98.9 kg N ha⁻¹ followed by treatment T₅ and T₇ which could be attributed to lower yield and nutrient uptake comparison to treatment T₄ and T₆.

In our study, correlation analysis showed that the relationships between organic carbon additions, soil properties, microbial biomass, and nutrient availability. The findings from this analysis provide valuable insights into the impact of organic inputs on soil health and nutrient dynamics. Firstly, we observed significant positive correlations (> 0.822) between the amount of organic carbon added through enriched formulations and the TOC content at harvest. This suggests that the application of enriched organic materials contributes to an increase in SOC levels over the course of the cropping cycles. Secondly, strong positive associations (r > 0.811) were identified between the added organic carbon and MBC and microbial counts. This indicates that the introduction of organic amendments promotes microbial activity in the soil. Furthermore, our analysis revealed substantial positive relationships (r > 0.731) among organic carbon additions, TOC, MBC, microbial counts, and nutrient availability at the end of the two cropping cycles. These findings highlight the interconnected nature of soil parameters influenced by organic inputs, suggesting that enriched organic formulations can positively impact soil health and nutrient dynamics. Overall, these correlations underscore the importance of incorporating enriched organic materials in agricultural practices to promote soil carbon sequestration, microbial activity, and nutrient availability. The observed relationships provide scientific support for the use of sustainable organic amendments to optimize agricultural productivity and environmental stewardship.

The application of 100% RDN through PHA and PPC based formulations proved to be optimal for achieving enhanced growth and yield in the pigeon pea–vegetable mustard–okra cropping system. These formulations exhibited comparable results to the traditional method of applying 100% RDN through FYM. Notably, the application of 100% RDN through PHA-based formulation emerged as particularly effective in enhancing soil quality. This effectiveness is evident in the significantly elevated activities of dehydrogenase and AP enzymes, increased nutrient availability in the soil, elevated SOC levels, improved soil aggregation, and enhanced MBC and microbial populations at the harvest of the pigeon pea-based cropping system. Consequently, these formulations are recommended for adoption in regions facing a shortage of FYM but having access to rice husk ash and potato peels, providing a sustainable solution for utilizing agricultural wastes and advancing agricultural sustainability. The findings underscore the potential of these formulations to contribute significantly to improved agricultural practices, offering a harmonious blend of environmental sustainability and enhanced food security in areas experiencing FYM scarcity.

The original contributions presented in the study are included in the article/ Supplementary Material . Further inquiries can be directed to the corresponding authors.

KG: Investigation, Writing – original draft, Formal analysis. SD: Conceptualization, Formal analysis, Supervision, Writing – original draft, Writing – review & editing, Project administration, Validation. VS: Formal analysis, Visualization, Writing – original draft. EA: Visualization, Writing – original draft. RM: Data curation, Writing – original draft. MH: Formal analysis, Visualization, Writing – original draft. DK: Formal analysis, Methodology, Writing – original draft. GA: Data curation, Formal analysis, Writing – original draft. VK: Formal analysis, Visualization, Writing – review & editing. YK: Data curation, Writing – review & editing. SA: Formal analysis, Writing – original draft. SoK: Formal analysis, Writing – original draft. HO: Formal analysis, Writing – original draft. MT: Formal analysis, Writing – review & editing. BM: Visualization, Writing – review & editing, Formal analysis. BK: Data curation, Visualization, Writing – original draft. VM: Formal analysis, Writing – original draft. SaK: Data curation, Formal analysis, Methodology, Visualization, Writing – original draft, Writing – review & editing.