Effects of long-term fertilization on availability of micro-elements in vegetable soil

Under field condition,a long-term trial with fixed position experiment was carried out to study long-term fertilization on the availability of microelements on a vegetable soil.The experiment started from 1988.The result showed that the micro-elements availability(Avail.Cu,Zn,Fe and Mn) of vegetable soil might be enhanced by long term N fertilization since N application exacerbated soil acidity,which in turn enhanced the availability of Fe,Mn,Zn and Cu in the soil.P and K application increased the availability of soil Fe and Mn,while it did not affect the the content of available Zn.Soil available Cu was observed to increase to certain extent with P and K application,however,there was no statistical significant.Effect of long-term manure application on the availability of micro-elements depended on the type of fertilizers combined.The contents of soil available Fe,Mn,Cu was significantly negative correlation to soil pH at 1% level,but there was no correlation between soil available Zn and soil pH.We can concluded that the soil pH was the dominant factor affecting the availability of soil micro-elements.