We employed a silver sand soil column experiment, and studied the transport characteristics of conservative solutes (Cl-and
Br-) in this test.Firstly, KBr solute was added instantaneously into the soil column at two periods, namely, 5 min and 15 min, respectively. Secondly NaCl and KBr solutes were mixed continuously into the soil column (240 min). Based on the instantaneous experiment, only about 91.5%of total input perforated the soil column sections at z=30 cm and z=80 cm, while the rest part of 8.5%resided in
immobile water. The results showed that transportation of the solutes in both mobile and immobile water in soil and the immobile water of soil may temporarily reserve or release solutes, influencing the transport process of solutes in soil. Simultaneity, calculated results from mathematical models under both
considering and ignoring immobile water were compared with observed data from soil column according to thecontinuous experiment. We have found that breakthrough curves (BTCs) of Cl-and Br-were coincident. The mean difference of comparison of observed data (Cl-and Br-at z=30 cm, 80 cm and 150 cm) with calculated data under considering and ignoring immobile water, with mean correlation coefficients of 0.981 2 and 0.965 3 (n=45), were in a range of 5～10%and 9～15%respectively. Consequently, the mathematical model considering immobile water, which reflects compatibly the solute transport process in the soil, overmatches ignoring immobile water in some studies.