延边朝鲜族自治州具有独特的低温近似海洋性大陆季风气候，形成了典型暗棕壤（冷凉淋溶土），其上星罗棋布大量苹果梨园，所产苹果梨为"中国地理标志"产品之一，由于气候条件的独特性和梨品种的特有性，且经历长期冻融过程，有别于国内其它地方的果园生态系统。土壤有机磷是土壤磷的重要组成部分，其形态和变化对土壤供磷能力和保障植物磷素营养举足轻重。本项目针对延边地区苹果梨园（亚洲最大）土壤，按不同土层、季节、栽培年限分别采集土样，并进行冻融交替室内模拟，采用改进的Bowman-Cole法测定土壤有机磷组分，核磁共振技术鉴定有机磷化合物，阐明土体空间有机磷组分和化合物的分异规律，随季节和栽植年限有机磷组分和化合物的演化趋势，诠释冻融过程对土壤有机磷转化的影响，联系有机磷在团聚体中的分配，分析有机磷化合物与磷组分的关系。项目结果将有助于弥补北方果园有机磷研究的不足，为全面认识我国果园土壤有机磷循环做出积极贡献。

Korean Autonomous Prefecture of Yanbian has a unique continental monsoon climate of low-temperature and approximate oceanity, has formed typical dark brow forest soil (Boric Argosols). It dots a lot of apple-pear orchards that produces apple-pear as one of "China geographic indication products". Due to unique climate conditions and pear varieties, and through long-term freezing and thawing process, it is different from other domestic orchard ecological system. Soil organic phosphorus is an important component of soil phosphorus, its forms and its changes are vital to supply ability of soil phosphorus and ensure phosphorus nutrition of plant.Aiming at apple-pear orchards in Yanbian region(the largest in Asia), this project will collect soil samples according to different soil layers, seasons, and cultivation years, and indoor simulation of freeze-thaw alternation, determine organic phosphorus fractions with improved Bowman-Cole method, identify organophosphorus compounds with nuclear magnetic resonance technology, clarify spatial variations laws of organic phosphorus fractions and organophosphorus compounds, evolution trend of organic phosphorus fractions and organophosphorus compounds with season and planting years, interpret effects of freezing and thawing on transformation of soil organic phosphorus, relate distribution of organic phosphorus in soil aggregate, analysis relationship between organophosphorus compounds and organic phosphorus fractions. Project results will contribute to compensate research shortage of organic phosphorus of orchard in North China, comprehensively understand soil organic phosphorus cycle of orchard in China.