长江三角洲绰墩遗址埋藏古水稻土肥力特征研究

 【目的】了解绰墩遗址古水稻土的基本性质，阐明水稻土的可持续利用机理。【方法】以绰墩遗址埋藏的古稻田土壤为研究对象，根据14C和考古学方法确定了土壤成土年龄和分布；按照中国土壤学会编汇的《土壤农业化学分析方法》测定了土壤pH，有机碳、营养元素含量。【结果】碳化稻和土壤有机质中14C分析证实绰墩遗址最古老水稻土为距今6 000年马家浜时期，该时期古稻田位于表层以下1 m左右，平均每块稻田面积5.2 m2。古水稻土（每克土中水稻植硅体含量>5 000颗）有机碳平均含量9.7 g·kg-1；N、P、K、Ca、Mg、S、Fe、Mn、Cu、Zn的全量平均含量分别为0.8、1.58、18.2、7.6、6.3 、0.1、22.、0.51 g·kg-1和40.9、80.8 mg·kg-1。【结论】古水稻土的有机碳、全氮含量、C/N比显著大于同期种植强度较弱的古水稻土（水稻植硅体含量<5 000颗/g），其它元素差异不显著；不同种植强度古水稻土有效态养分含量和pH差异不显著。古水稻土N、S、Cu全量含量显著低于现代表层水稻土，而有机碳、P、Fe、Mn全量含量则相反；现代表层水稻土有效态养分含量一般大于古水稻土。

Characteristics of Soil Fertility of Buried Ancient Paddy at Chuodun Site in Yangtze River Delta

【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.