中文摘要：

滩涂围垦是沿海地区开拓土地资源和缓解人地矛盾的重要措施，土壤环境也因此发生剧烈变化。以江苏如东县沿海不同年限的垦区土壤为研究对象，探讨土壤pH值、有机质和氮、磷、钾速效养分的分布情况，pH值、有机质和速效养分之间的关系，以及这种相关性随垦区围垦年限而发生的变化。结果表明：如东滩涂围垦区土壤呈碱性，土壤养分较为缺乏；随着围垦年限的增加，垦区土壤pH值下降，土壤养分呈增加趋势，垦区围垦年限对土壤pH值、有机质与速效养分之间的相关性存在一定影响，其中10a围垦期是pH与有机质、速效磷之间相关性变化的转折点。围垦年限不仅对垦区土壤pH值、土壤有机质和速效养分的绝对含量有着明显影响，还影响土壤pH值、有机质与土壤速效养分之间的相关关系，随着垦区围垦年限的增加，人为活动影响程度加深，土壤逐渐从自然的滨海盐土向农业土壤演化，土壤要素间的相关关系逐渐向一般耕作土壤靠近。

英文摘要：

Tidal flat reclamation is one of the most important methods for coastal countries and areas to increase the land and reconcile the conflict between human and land. Large-scale reclamation activities have extremely severe impact on the tidal-flat soil environment, and then affect the carbon, nitrogen, phosphorus, potassium and other soil nutrient cycle. Studying the changes of soil environmental has important implications in this area. The tidal flat land resource of Jiangsu Province is abundant and the reclamation activities have been lasting for many years, and these reclamation activities will continue to exist for a long period of time in the future. Based on the distribution of soil pH value, organic matter content and available nutrients of reclamation soils with different reclamation years in Jiangsu Rudong coastal intertidal zones, the relationships between pH value, soil organic matter and available nutrients were analyzed. The results indicated： firstly, soils of Rudong intertidal reclamation zones were slightly alkaline to alkaline, and available potassium was abundant while the contents of other soil available nutrients were below the average level of Rudong county. With increasing reclamation years, a series of soil improvement measures were adopted, and pH value decreased and the surface soil nutrients increased. Secondly, at the beginning of the reclamation, there was positive correlation between soil pH and organic matter, and negative correlation between soil pH and available phosphorus, however it was the opposite in the zone with longer reclamation years. The correlation between pH and alkali solution nitrogen was negative, and pH was negatively related to available potassium except for the reclamation zone with 20 years. Finally, in the reclamation zone that was reclaimed long years ago, the relationship between soil organic matter and available nutrients was much more significant than that in the initial reclaimed zones. Ten-year-reclamation was the turning point of the correlation between o