Abstract: 【Objective】 A study was carried out to explicate the basic characteristics of ancient paddy soils at Chuodun site, in order to achieve better comprehension of the mechanisms of the sustainability of paddy soil. 【Method】 Soil age and the distribution of buried ancient paddy at Chuodun site in Yangtze River Delta were determined using 14C dating and other archeological methods. Soil pH, organic C, and nutrients were also investigated in total 20 ancient paddy soils based on the methods compiled by Society of Soil Science of China. 【Result】The oldest paddies at Chuodun site can be dated back to Neolithic age, around 6 000 aBP. These ancient fields were buried at approximately one-meter depth below top-layer, whose areas were ranged from 0.32 m2 to 12.9 m2 with an average of 5.2 m2. Differences of soil nutrients were determined depended on fields and rice planting intensity. The contents of soil total C, N, P, K, Ca, Mg, S, Fe, Mn, Cu, Zn were 9.7, 0.8, 1.58, 18.2, 7.6, 6.3, 0.1, 22.7, 0.51 g·kg-1 and 40.9, 80.8 mg·kg-1, respectively. 【Conclusion】Soil organic C, total N, and C/N ratio were obviously greater in ancient paddy (rice plant phytolith > 5 000 /g) than in less-cultivated paddies (rice plant phytolith < 5 000 /g. No significant differences were found in other nutrients, soil pH and available nutrients. Soil total N, S, Cu contents were obviously less in ancient paddy soils than those in recent paddy soils, while the contents of soil total C, P, Fe, Mn were the contrary. Available nutrient contents were generally greater in recent paddy soils than those in ancient paddy.

Key words: Chuodun relics, Ancient paddy, Ancient rice filed, Soil fertility, Nutrients