Sishui Sweet Potatoes

Sishui Sweet Potatoes

Sishui Sweet Potatoes is a geographical indication certification trademark.

Sishui Sweet Potatoes is a product certified under China’s Agricultural Geographical Indications.

　　Sishui County has a long history of sweet potato cultivation, with farmers accumulating rich practical experience over the years. Coupled with the region's unique natural environment—including its soil, water quality, and climate—as well as the introduction, breeding, and promotion of high-quality varieties, the sweet potatoes produced here are not only fragrant, sweet, starchy, and rich in plum flavor, but also abundant in starch, containing large amounts of soluble sugars, various types of fiber, amino acids, minerals, and other nutrients. The county’s sweet potato planting area spans approximately 70,000 to 100,000 mu. In 2004, it was designated by the national government as the “China Quality Sweet Potato Origin,” and in 2009, it received the National Agricultural Geographical Indications certificate. Currently, the main varieties include Xu Shu 18 and Ji Shu 15, with the total planting area reaching tens of thousands of mu. These are primarily distributed across towns in the northern and southern mountainous regions such as Sizhang Town, Shengshuiyu Town, Jinzhuang Town, Zhagou Town, Gaoyu Town, Zhongce Town, and Xingcun Town. Among these, Sizhang Town and Shengshuiyu Town have the largest planting areas, at 12,000 mu and 13,000 mu respectively.

　　Geographic Scope

　　The protected geographic area for Sishui Sweet Potatoes is within Sishui County, Shandong Province. The geographical coordinates are: 117°05′–117°35′ east longitude and 35°28′–35°48′ north latitude. The total area covers 1,091.79 square kilometers, with a production area of 16,666.7 hectares, involving 11 towns, 2 subdistrict offices, and 593 administrative villages. The specific geographic range extends from Liangquan Village in Quanlin Town in the east, to Xijiazhuang Village in Yangliu Town in the west, to Shilong Village in Sizhang Town in the south, and to Lianhua’yu Village in Gaoyu Township in the north, all at elevations below 160 meters.

　　Natural Ecological Environment and Humanistic-Historical Factors

　　(1) Soil and Topography: Sishui County is part of the low mountain and hilly region of the Taiyi Mountain Range extension. The soil types include brown soil, cinnamon soil, and fluvo-aquic soil, all characterized by deep layers and good structure. The plow layer is 20–40 cm thick, with organic matter content in the topsoil exceeding 1.2%, total nitrogen above 0.08–0.09%, hydrolyzable nitrogen over 70 mg/kg, available phosphorus between 20–30 mg/kg, available potassium at 110 mg/kg, and soil pH around 7.2. The soil is rich in trace elements such as phosphorus and selenium, offering excellent fertility and water retention properties.

　　(2) Hydrology: The area belongs to the Huai River water system, with most rivers flowing from east to west. The Si River is the only major river in the county, with 32 tributaries spanning a total length of 412.4 km and a drainage area of 1,015.54 square kilometers. The annual average available water resources amount to 150 million cubic meters, with groundwater recharge at 162.492 million cubic meters. Rainfall is abundant in summer but relatively scarce in spring and autumn, yet irrigation conditions are generally sufficient.

　　(3) Climate: Sishui County features a warm temperate monsoon climate, marked by ample sunshine, distinct seasons, dry and windy springs, hot and rainy summers, cool and clear autumns, and cold, dry winters. The annual average temperature is 13.4°C, with an average relative humidity of 65%. The mean annual precipitation is 755.2 mm, and the frost-free period lasts 235 days, with 2,549 hours of annual sunshine—conditions highly suitable for sweet potato cultivation.

　　(4) Humanistic-Historical Background: Sishui has a long history of sweet potato cultivation. According to Volume Eight of the *Sishui County Local Chronicles*, sweet potatoes were already being grown during the Qing Dynasty’s Qianlong era, with both spring and summer varieties—spring sweet potatoes accounting for 70%, especially in the mountainous and hilly areas of the northern and southern regions.

　　In 1936, the county planted 83,000 mu of sweet potatoes, yielding 254 jin per mu, for a total output of 21.14 million jin. By 1949, the planting area had expanded to 192,500 mu, with a yield of 180 jin per mu and total output of 34.64 million jin. After the founding of the People’s Republic of China, large-scale cultivation continued, reaching 237,700 mu by 1988, with a yield of 249 kg per mu and total output of 59.211 million kg—3.56 times the 1949 yield per mu and four times the total output. Varieties such as Xu Shu 18 replaced lower-yield, poorer-quality ones like Shengli Baihao, leading to significant increases in local production.

　　Longstanding cultivation practices have given farmers extensive hands-on experience, while the region’s unique natural environment and the introduction of superior varieties have resulted in sweet potatoes that are fragrant, sweet, starchy, and rich in plum flavor, as well as abundant in starch, soluble sugars, fiber, amino acids, and minerals. Tests by the Ministry of Agriculture’s Quality Inspection Center show that Sishui sweet potatoes contain significantly higher levels of starch, protein, total sugar, and vitamin C compared to the same varieties grown elsewhere.

　　Legend has it that Sishui sweet potatoes originated in Beibaigou Village, Yangliu Town, Sishui County. A spring with bubbling water once emerged in the village during an unknown dynasty, and locals named it the “Water Splash Spring.” During the Qing Dynasty, the Kong family migrated from Mo Village in Qufu to this village, renaming it Kongjia Village. Mo Village had originally supplied flour and flour-based products to the Confucius Mansion. The Kong family used the water from the Water Splash Spring to grow sweet potatoes and, leveraging traditional small-scale workshop techniques, produced starch and fine noodles (such as cellophane noodles and sheets) for the Mansion’s consumption. This, in turn, spurred the development of both sweet potato farming and the vermicelli and noodle processing industry in Sishui.

　　Production Technical Requirements

　　(1) Site Selection and Special Provisions: Production sites should be chosen in areas with fresh air, good vegetation cover, and a sound ecological environment. These areas must have effective isolation from external influences, abundant and clean water sources, well-developed irrigation systems, suitable soil texture and nutrients, no pollution, and minimal historical pest or disease occurrence. Additionally, production bases must maintain sustainable productive capacity.

　　(2) Variety Selection and Specific Requirements: High-starch spring varieties such as Xu Shu 18 and Ji Shu 15 are primarily selected.

　　as raw materials.

　　(3) Production Process Management: To strengthen the management of Sishui Sweet Potatoes as a geographical indication agricultural product and ensure the sweet potatoes meet green food standards, a series of management systems have been established to achieve high-quality production and refine the quality control system. These include: a production management system, an agricultural input management system, a technical guidance and extension system, and a training system.

　　(4) Product Harvesting: Harvesting occurs around the Cold Dew solar term, with immediate collection, sale, and processing. Harvest quality standards require each sweet potato piece to weigh over 2 liang (100 g), with natural impurities below 5%, bright color, and no disease spots or moldy areas.

　　(5) Production Record Requirements: Each Sishui sweet potato planting site is assigned a traceability code. Codes are based on the township’s postal code. Every planting plot maintains comprehensive records throughout the production process—including fertilization, watering, and pesticide application—for future reference.

　　Typical Quality Characteristics and Product Quality Safety Standards

　　(1) External Sensory Features: Through long-term cultivation and natural selection, Sishui sweet potatoes have developed distinctive traits. The primary variety, Xu Shu 18, produces sweet potatoes that are spindle-shaped, with red skin and white flesh, and offer a fragrant, sweet, starchy taste with a strong plum flavor.

　　(2) Internal Quality Indicators: Sishui sweet potatoes are highly nutritious, rich in starch, soluble sugars, fiber, amino acids, and minerals. Their starch content exceeds 20%, protein content is close to 3%, total sugar exceeds 13%, and vitamin C reaches 36.5 mg/100g—significantly higher than the same variety grown in other regions.

　　(3) Safety Requirements: Standards for air, soil, irrigation water, surface water, pesticides, and quality safety are enforced according to:

　　GB3095—1996 Ambient Air Quality Standard

　　GB15618—1995 Soil Environmental Quality Standard

　　GB5084—1992 Farmland Irrigation Water Quality Standard

　　GB3838—1988 National Surface Water Quality Standard

　　GB4285—1989 Safety Standards for Pesticide Application

　　Packaging labeling and related regulations

　　Products of the same variety with uniform tuber size are considered qualified. Those that are deformed or show signs of mold, disease, insect damage, or other defects are classified as unqualified and shall be handled separately. Packaging materials must comply with mandatory national technical specifications. Prior to packaging, impurities and soil shall be removed.

　　During transportation, take strict precautions against rain exposure. Storage in warehouses or transport in vehicles contaminated with residual toxins is strictly prohibited. Products must not be mixed or stored with toxic items. Ensure safe storage to prevent mold and rot. Users of the label shall mark their products or packaging with “Sishui Sweet Potato” and the agricultural product geographical indication logo.