IN SITU EVALUATION OF ENBEDDED CARRIER IN SOIL TO REDUCE NITRATE LEACHING FROM CROPLAND

摘要

In situ experiments using no-bed lysimeters were carried out during two years to evaluate the efficiency of embedded carriers in soil to reduce nitrate leaching from upland agricultural area in Japan where volcanic ash soils (Umbric Andosols) are widely distributed. Two carriers embedded in the soils are a polyethyleneimine-coated cellulose with continuous micropore structure and a calcined fine particle of diatomaceous earth. Under the fertilizer application rate of 300kg nitrogen per ha without crop cultivation, the values of nitrate concentra- tion and relative abundance of ~(15)N of the water samples taken from the soils at different depths in the lysimeters and also the number of vital count of denitrifying bacterias revealed that denitrification processes in the carriers as well as in the soils were positively enhanced by the embedded carriers in the soils.