津郊潮土磷素组成及其演变规律的定位研究

本文从１９７９－１９９３年研究了长期定位施肥对津郊潮土磷素组成及其演变规律的影响。结果表明潮土磷手组成以无机磷为主，其中又以磷酸钙盐最多，其次是闭蓄态磷酸盐，而磷酸铝盐与铁盐所占比例很少。长期定位施肥对潮土速磷影响显著，变幅也最大，并以化肥的影响高于有机肥。

LONG-TERM EXPERIMENTAL STUDY ON COMPONENTS AND CHANGES OF PHOSPHORUS IN FLUVO-AQUIC SOIL OF TIANJIN SUBURBS

Effect of long-term fertilization on components and changes of phosphorus in fluvo-aquic soil was studied in Tianjin during 1979-1993. Results showed that inorganic phosphorus was predominant, in which Ca-P occupied the largest percentage, O-P was second only to Ca-P and only small part was the Al-P and Fe-P. Long-term fertilization could significantly influence both the content of soil available P and the range of its changes. The effects of chemical phosphorus were more obvious than those of organic sources. The increasing and decreasing of soil available P depended heavily on whether chemical phosphorus was applied or not, soil available p increased or decreased at the rate of 1 mg/kg when 45kg P/ha was added or removed. In addition, our study also suggested that the changes of soil available P differed with the periods of experiment at time. Generally speaking, soil available P changed largely in the first two years, and the changes became smaller in the later 6-8 years, finally it remained in a normal value with quite small changes. Soil phosphorus could be balanced in 15 years when 18 kg/ha. year P₂O₅ was lied for per 100 kg of grain yield under the wheat-corn cropping system with the grain yield of 11400kg/ha in total.