Abstract
The intensity of chemical stress of chemical fertilizers to soil under vinyl-house cultivation was examined by beaker and pot experiments. High-stress-type fertilizer was composed of ammonium sulfate, superphosphate and potassium chloride, and low-stress-type fertilizer was composed of ammonium nitrate, potassium phosphate and potassium nitrate. Application of high-stress-type fertilizer increased the EC value and lowered the pH value in soil, but application of low-stress-type fertilizer did not change the EC and pH values in soil. Continuous application of high-stress-type fertilizer at transplanting increased the EC value and lowered the pH value in soil progressively. On the other hand, continuous application of low-stress-type fertilizer hardly changed the EC and pH values in soil even after cultivation 6 times. Low-stress-type fertilizer give a slight chemical stress on soil because of lack of concomitant, i. e., SO_4^<2-> and Cl^-.
