Exploratory Factor Analysis on Characteristic Indexes of Rice-irrigated Management Zones

Good irrigation-management zone is the basis of agricultural water management, which can lower cost of irrigation management effectively. Irrigation management is influenced by a lot of factors (such as topography, geomorphology, climate, irrigation level and soil characteristics etc.), which makes zone partition very difficult. The paper proposes a method to conduct a proper application of Exploratory Factor Analysis (EFA) to the key index system, in which appropriate and adequate sampling data is used. The following principles or steps are adopted: Reduce the dimension of the factor space by ranking score for each of 7 indexes and then selecting factors that their accumulative contribution rate exceeds 0.8; Investigate the irrigation factors according to data acquired during the period 1952~2004 from 37 rice-irrigated experimental stations of Heilongjiang province, China; Select the key irrigated management factors depending on their factor score; and analyze the rationality of rice irrigated management zones. Three common factors are extracted that account for 81.2% of the total variation, and they are: the first common factor that includes 10°C accumulative temperature and frostless period, the second common factor that consists of regular irrigation quota and seepage quantity, and the third principal factor for rainfall of growth period. The results from EFA provide insights into the issue of rice-irrigated management level for large-scale zones, and give a good reference to agricultural zone partition on irrigated management.