Analysis on Ecological Suitability Planting Area of Chinese Medicinal Yam

Abstract

Chinese yam (Dioscorea opposita Thunb.) is consumed and regarded as medicinal food in traditional Chinese herbal medicine, Chinese medicinal yam especially is one of the most important Chinese herbal medicines, it accounts for 10%-20% of total Chinese yam and its medicinal needs have been increasing recently with the improvement of people's living standards and the enhancement of health awareness. In addition, Chinese medicinal yam is sensitive to ecological environment, which will further influence its growth, yield, quality and distribution of planting areas. However, in the past 30 years, the economic structure and ecological environment of the genuine and most important producing areas of Chinese medicinal yam have undergone significant changes. Introduction and expansion of yam varieties without careful agro-ecological planning has resulted in some disorder of Geo-authentic varieties and planting areas, causing uneven quality of Chinese medicinal yam production. There are many factors affecting the yield and quality of Chinese medicinal yam, among which climate condition is the most important factor affecting the yield and quality of Chinese yam except soil factors. Therefore, a better understanding and regionalization of the agro-ecological suitability of Chinese medicinal yam under the impact of climate change is of both scientific and practical importance to spatial development and geographical deployment of Chinese medical yam. In this study, based on the site observations including 30 years' (1981–2010) climate data from over 700 meteorological stations nationwide (source from Chinese Meteorological Data Center) and Harmonized World Soil Database (HWSD), we first analyze the optimum range of the 13 ecological indicators such as relative humidity, annual precipitation, mean annual temperature, January mean temperature, July average temperature, January minimum temperature, July maximum temperature, accumulated temperature, sunshine duration, soil type, PH, organic carbon and cation exchange capacity of the 42 sampling sites we surveyed in the Geo-authentic and main producing areas of Chinese medicinal yam. We then applied the Geographic Information System (GIS) technology to evaluate the ecological suitability planting area through the classification of the similarity with the optimum grow range of Chinese medicinal yam. Results indicate that regions with high ecological similarity to the Geo-authentic producing areas of Chinese medicinal yam include northeastern Henan, southeastern Hebei and western Shandong, mainly distribute in the lower reaches of the Yellow River and other major floodplains. In the future, these areas are suitable for planting Chinese medicinal yam. This study offers strategical guidance for the establishment of standardized planting base of Chinese medicinal yam and provides scientific bases for government programming and decision making, contribute to the sustainable development of Chinese yam.