Objective The agricultural landscape in the alluvial plain of the Pearl River Delta is spread over the plains formed by the alluvial deposits of many rivers in the shallow bay. The highly developed river network and water system, while providing convenience for agricultural production, also place higher demands on the rational development of soil and water resources. In history, local residents mainly adopted the method of embankment construction and reclamation to compete with the rivers for fields, and the interaction between humans and water lasted for more than a thousand years, giving birth to an agricultural landscape with unique landscape characters. Agricultural practices have led to profound landscape changes, with corresponding landscape characters being the result of the interaction between natural and human factors. However, in the practice of rapid urbanization and agricultural intensification, homogenized and standardized construction is rapidly expanding, and modern urban landscape elements are superimposed on traditional agricultural landscape, making the landscape highly fragmented with their characters weakened or deviating from the original landscape characters, while resulting in a continuous loss of the diversity and continuity of the agricultural landscape. Character assessment is an important basis for the management and conservation of the agricultural landscape in the context of rapid urbanization.
Methods This research adopts the landscape character assessment (LCA) method to categorize the characters of agricultural landscape in the alluvial zone of the Pearl River Delta, and selects geographic evolution, river basin, and land cover as character superimposition elements. To better represent the interaction between natural processes and human activities or the degree of interaction between the two in the past, and to understand the historical influence if such interaction on landscape formation and characterization, the research superimposes the process of regional geographic evolution as one of the criteria for delineating landscape character areas. Specifically, the geographical evolution of the research area is divided into five stages: the period of the Han and Tang dynasties, the period of the Song and Yuan dynasties, the period of the Ming Dynasty, the period of the Qing Dynasty, and the modern period.
Results Through GIS analysis and manual-assisted correction, the research delineates 6 primary and 14 secondary agricultural landscape character types, and draws a regional-scale agricultural landscape character map. Meanwhile, the research carries out attribute summarization and typological classification of character types, and summarizes three agricultural landscape types, namely dike-pond landscape, field landscape, and flower and seedling landscape, which are also illustrated and characterized by typical samples (5 km × 5 km). The six primary landscape character types and their respective characteristics are described as follows. 1) Agricultural landscape in the northwestern part of the North and West River Delta: basal ponds in this area vary in size and scale. 2) Agricultural landscape in the north-central part of the North and West River Delta: The long history of agriculture enables this area to preserve the traditional pattern of agricultural landscape, with the traditional flower and tree areas combining agricultural tourism with production and operation. 3) Agricultural landscape in the central part of the North and West River Delta: As the main cultivation area in the alluvial plain of the Pearl River Delta, this area boasts highly developed agriculture, and the agricultural landscape here is characterized by a homogeneous rectangular grid; besides, a large-scale and intensive greenhouse agricultural landscape has been formed in this area. 4) Agricultural landscape in the southern part of the North and West River Delta: Most of the agricultural lands in this area are formed by swidden cultivation, and the agricultural landscape here presents regularized and standardized geometric segmentation, which is significantly different from other areas. 5) Agricultural landscape in the Tam River Delta: This area is featured by a large-scale uniform fruit tree cultivation landscape. 6) Agricultural landscape in the Dongjiang River Delta: This area has excellent soil and water resources and is dominated by fruit and vegetable cultivation.
Conclusion Dyke enclosure and the water system structure and land boundaries delineated by dyke enclosure are identified as key character elements of the agricultural landscape in the research area, and also a key part of the management strategies for agricultural landscape. This research suggests different management strategies for different types of agricultural landscapes. The dike-pond agricultural landscape is the most widespread and representative landscape type in the research area. It is most affected by urban development, and with the continuous “point – line – plane” expansion of local settlement patterns, the dike-pond texture is gradually fragmented and regularized. The management of such landscape should focus on conservation at the macro, meso, and micro levels. The field landscape takes plains and coastal mudflats as the main source of land, and is closely linked to land development and production entity. The management of such landscape should focus on regeneration, a combination of recreational activities such as agricultural tourism and picking with industrial and institutional renewal, and synergistic development with the city, to create a new type of urban field landscape. The flower and seedling landscape is a new type of agricultural landscape that combines production, sales, recreation and tourism, concentrated in traditional flower and tree areas. The management of such a landscape should focus on the maintenance of the current status. This type of agricultural landscape is minimally affected by modern urban landscape elements, with roads and settlements forming part of the corresponding transport and sales landscape.
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