[Purpose/Significance] The effective flow of agricultural knowledge from innovation sources to fields is a core component of agricultural modernization. However, a persistent "structural knowledge gap" exists between macro-level knowledge supply and the micro-level needs of farmers, which traditional top-down extension systems often fail to bridge due to issues such as information decay, a lack of feedback, and poor contextual adaptation. In the context of promoting the high-quality development of rural public cultural services, grassroots reading spaces (e.g., rural libraries and village reading rooms) face a critical imperative to evolve beyond their traditional role as static repositories of books. This study reimagines grassroots reading spaces as dynamic "knowledge nodes" within rural socio-information ecosystems. The primary significance of this research lies in its innovative integration of public governance and knowledge management theories to construct a novel "node-interface-flow" analytical framework. It moves the discourse forward from predominant concerns with resource allocation or technology access to a deeper investigation of how internal governance mechanisms fundamentally shape these spaces' capacity to process and diffuse knowledge. By doing so, it positions the study at the intersection of rural studies, public administration, and knowledge science, offering a refined theoretical lens to understand and design rural knowledge infrastructure. Its practical importance stems from providing evidence-based, mechanistic explanations and actionable pathways for transforming these ubiquitous facilities from venues of "cultural provision" into active agents of "knowledge empowerment" for rural communities. [Method/Process] To uncover the mechanisms through which collaborative governance influences knowledge flow, this study employed a sequential explanatory mixed-methods design (QUAN → QUAL). The research was empirically grounded in a comparative case study of three rural reading spaces in China, deliberately selected through theoretical sampling to represent three distinct ideal-typical governance models: Jiangyin (exemplifying a deep contractual model involving long-term institutional agreements between local government and a vocational college), Liancheng (representing an administrative-dominant model operating within a standardized county-branch library system), and Yuhang (illustrating a social collaborative model based on government-purchased services from local social organizations). The methodological appropriateness of this multi-case comparative approach lies in its capacity to maximize variation in the key independent variable (governance model) while controlling for contextual factors, thereby allowing for clearer causal inference regarding the model's impact. Data were collected from March to August of 2024. The quantitative phase involved a structured questionnaire survey administered to 438 farmers across the villages served by the three case spaces (from 480 distributed, 91.3% valid response rate). The survey instrument was designed to measure key variables derived from the theoretical framework, including perceived interface quality (e.g., resource relevance, expert accessibility), knowledge acquisition, community knowledge sharing, and technology adoption intention. Reliability and validity tests (e.g., Cronbach's α, K-R20) confirmed the robustness of the measures. The subsequent qualitative phase comprised 38 in-depth, semi-structured interviews with space managers, active farmers, and key partners, supplemented by participatory observation and archival analysis. This phase aimed to provide rich, contextual insights into the operational mechanisms linking governance rules, interface functioning, and knowledge flow patterns. Quantitative data were analyzed using SPSS for ANOVA and regression analysis to test performance differences and mediation effects, while qualitative data were thematically coded using NVivo to elucidate underlying processes. [Results/Conclusions] The findings confirm the proposed "governance model → interface characteristics → flow efficacy" mechanism. The deep contractual model, through its "embedded interface," successfully couples strong formal institutional guarantees (e.g., mandated expert deployment, resource co-selection) with derived informal trust relationships from long-term embeddedness. This combination significantly drives the deep, closed-loop flow of highly complex, codified knowledge, completing cycles from external input to local application and feedback. In contrast, the social collaborative model's "networked interface," characterized by vibrant informal community networks activated by skilled social organizers, proves far more effective in stimulating the horizontal sharing, exchange, and co-creation of tacit knowledge within the community. The administrative-dominant model, with its standardized formal interface and underdeveloped informal connections, demonstrates limited efficacy, often resulting in interrupted, one-way knowledge flow. Based on these insights, the study proposes a two-dimensional model of "institutional depth" versus "networked breadth" to describe the unique effectiveness of different governance models. Based on these empirical results, three concrete policy and management recommendations have been proposed to foster responsive rural knowledge nodes: 1) shifting performance evaluation and resource allocation from static input metrics towards a focus on dynamic "interface capability"; 2) designing and institutionalizing specialized "knowledge broker" programs to staff these interfaces with trusted, skilled intermediaries; and 3) initiating collaborative "local knowledge repository" projects to systematically capture, digitize, and valorize indigenous community wisdom. The study acknowledges limitations regarding the generalizability of findings from a three-case comparison and suggests future research directions, including longitudinal studies to observe interface evolution, social network analysis to precisely map relational structures, and exploration of how digital "smart interfaces" might integrate with the social interfaces examined here to create new paradigms for rural knowledge service.