Abstract:The integration of Internet of Things (IoT) technology with large language models (LLMs) offers transformative potential for precision agriculture. It introduced an intelligent crop growth diagnosis and decision-making system that combined IoT sensors with the GLM-4 large model to enhance agricultural efficiency and management. The system analyzed crop conditions to provide real-time agronomic recommendations, bridging the gap between advanced research and smallholder farmers. The system architecture comprised four layers: field control, system modeling, data analysis, and decision support. The field control layer used multi-source sensors to collect soil and air parameters, and crop phenotypes, uploading data via an ARM processor and 4G module. The system modeling layer integrated literature, expert knowledge, and real-time data to create crop growth and environmental response models. The data analysis layer employed temporal alignment algorithms to compare ideal templates with actual data, quantifying deviations and generating prompts for the large model. Leveraging the GLM-4-Plus model, it provided solutions for environmental regulation and pest/disease management, implemented through actuators for closed-loop control. The system's core innovation was its collaborative analysis framework combining “sensor-based quantitative monitoring + farmer natural language description + large model intelligent diagnosis”. This approach integrated quantitative sensor data with farmers' qualitative observations of crop abnormalities, overcoming traditional IoT limitations in detecting subtle growth anomalies. The domestically developed GLM-4-Plus was applied to an agricultural decision support system, using structured prompt processing for precise diagnosis of issues like nutrient deficiencies and environmental stresses, and targeted interventions such as irrigation adjustments and fertilizer optimization. A two-month field trial in Shouguang City, Shandong Province, validated the system's effectiveness across tomatoes, sweet peppers and strawberries. A case study demonstrated the system's ability to diagnose yellowing tomato leaves, attributing it to suboptimal temperature, low humidity, and insufficient light. Implementing GLM-4-recommended measures significantly improved plant health. The system also addressed uneven fruit development and excessive stem elongation, demonstrating adaptability across growth stages. Future research aimed to expand crop coverage, enhance environmental robustness, and explore edge computing for real-time control. By synergizing IoT-based sensing with LLM-driven decision-making, the system democratized advanced agronomic knowledge, offering a practical pathway for data-driven sustainable agriculture. Empirical results confirmed its potential as a key technology for global agricultural transformation.