Abstract:
Cultivated land quality monitoring is one of the most critical steps for the food security. The resource allocation of the cultivated land can be optimized to promote the sustainable agriculture. It is ever increasing pressure on the cultivated land resources, particularly with the global population, accelerated urbanization, and frequent extreme climate events. It is the urgent demand for the precise and dynamic monitoring of the cultivated land quality. However, the traditional monitoring can rely primarily on the field surveys and laboratory analysis. Specifically, the low data acquisition, limited coverage, insufficient timeliness, and high costs cannot fully meet the needs of the cultivated land protection in the modern agriculture. Alternatively, the remote sensing, ground sensors, and the Internet of Things (IoT) can be expected towards the high precision, intelligence, and three-dimensional monitoring in recent years. Satellite remote sensing can also offer the macroscopic perspectives, dynamic monitoring and long-term time-series analysis, suitable for the large-scale monitoring of the cultivated land quality. Among them, the aerial drones are ideal for the localized and detailed monitoring, due to their high resolution, low cost, and flexibility. Ground sensors can also provide the real-time data on the critical parameters, such as the soil moisture, nutrients, and salinity. The precise support can be expected to offer the quality monitoring of the cultivated land. The IoT technology can be utilized for the real-time collection, transmission, multi-source monitoring data, and intelligent management. However, the application of these technologies is still remained on the specific dimensions. It is also lacking on the systematic analysis of the conceptual connotation and the key characteristics of cultivated land quality. Additionally, the multi-source heterogeneous data can be expected to effectively integrate with the unified standards. Nevertheless, some challenges are related to the data scale mismatch, information redundancy, and high complexity on the data processing. Therefore, this study aims to construct a multi-source integrated, intelligent, and dynamic monitoring framework, according to the conceptual connotation and key characteristics of the cultivated land quality. Five key characteristics were proposed: continuity, resilience, high productivity, stable productivity, and ecological sustainability. A "Space-Air-Ground-Network" integrated monitoring was constructed to monitor the cultivated land quality. A systematic review was also made on the satellite remote sensing, aerial drones, mobile monitoring vehicles, ground sensors, and data transmission networks. According to the concepts of the cultivated land quality, the monitoring framework was also utilized to clarify the understanding of its core connotations. Furthermore, an integrated system of the "Space-Air-Ground-Network" was constructed to coordinate the monitoring at multiple scales, levels, and data sources. A technical architecture was also proposed for the multi-source heterogeneous data fusion. The data processing workflows were optimized to ensure the accuracy and reliability of the monitoring outcomes. In addition, a technical framework was designed for an intelligent monitoring of the cultivated land quality for the early warning platform, in order to realize the dynamic monitoring and smart management of the cultivated land. The finding can provide the theoretical support for the standardization, precision, and intelligent analysis of the cultivated land quality monitoring. A scientific foundation can be offered for the cultivated land protection and food security in the sustainable agriculture.