磷酸铵在三种典型土壤中的转化及其有效性

Transformation and availability of ammonium phosphate fertilizer in three typical soils

研究了磷酸二氢铵(MAP)和磷酸氢二铵(DAP)在3种典型土壤中的转化,并评价了其有效性。结果表明:施用磷酸铵可改变肥际微域土壤的pH值,并且这种效应可持续几个月;MAP在黑土中,反应产物主要为Al-P,占38.8%,其次为Fe-P,占12%;在潮土中,Ca2-P是主要形态,占34%,其次为Ca8-P,占28%;在水稻土中,We-P是主要形态,占50%以上,其次为Ca2-P,占20%。在黑土中We-P在DAP处理中所占的比例较MAP处理中高,而Al-P和Fe-P所占的比例正好与之相反;在最初的10 d里,We-P下降显著,随反应时间延长,DAP和MAP处理间We-P所占的比例差异减小;MAP在水稻土中的有效性最高,其次是潮土和黑土;在黑土中DAP的有效性较MAP要好,MAP主要转化成了Al-P。

The present work was conducted to investigate the transformation and availability of ammonium phosphate fertilizer after application to three typical soils.The results indicated that application of ammonium phosphate fertilizer to the soil could change soil pH in the fertisphere,which could persist for several months.When monoammonium phosphate（MAP） was added to black soil,the reaction product was mainly aluminum phosphate（Al-P） and iron phosphate（Fe-P）,taking about 38% and 12% respectively;if to fluvo-aquic soil,it was mainly dicalcium phosphate（Ca2-P） and octocalcium phosphate（Ca8-P）,taking about 34% and 28% respectively,and if to paddy soil,water soluble P（We-P） took the dominant position,which was over 50%,followed by Ca2-P,taking about 20%.After reaction with black soil for the same period,more We-P was extracted from diammonium phosphate（DAP） treatment than that from MAP treatment,while Al-P and Fe-P extracted were just in reverse.At the end of the first 10 days,We-P decreased significantly.With the increase of reaction period,differences of extracted We-P between MAP treatment and DAP treatment narrowed appreciably.After application of MAP,the availability was better in paddy soil than that in fluvo-aquic soil and black soil.In black soil,the availability of DAP was better than that of MAP,which was mainly transformed to Al-P.