Study On Soil Nutrient Extraction Using Ion Exchange Resin Membrane

1. Within a short-term (2h) of extraction, the P extracted by resin membrane increased quickly with extraction time, the K extracted by resin membrane increased slowly. Within a long-term (24h) of extraction, the amount of Ca and Mg extracted by imported resin membrane from U. K. increased significantly and that of K decreased with extraction time. The P and K extracted by resin membrane increased obviously with the increase of soil moisture content.2. The soil P extracted with resin membrane burying method in lab is very closely correlated with the soil P extracted with conventional chemical method. The readily available P extracted by imported resin membrane in situ was closely correlated with relative corn seed yield in the -P plots from field experiments.3. The resin membrane extracted soil K was significantly correlated with K uptake of corn seedling in pot experiment, water soluble K and ASI-K in soil. The correlation coefficient between 1 mol/L NtLjOAc extracted K and K uptake by corn plant was much lower than that with resin membrane K.4. The K adsorbed on resin membrane after extraction was easily desorbed by 0.5 mol/L HC1 solution. The K desorbed in the first time had a very significant correlation with K uptake by corn seedling in the -K treatment of pot experiment.5. With the increase of extraction time and P and K concentration in solution, the P and K adsorbed by resin membrane increased significantly. With the increase of extraction time, the amount of CuFeMnZn adsorbed by imported anion resin membrane increased. The selectivity of imported resin membrane to the four elements was in the following order: Fe>Cu>Mn>Zn.