Abstract: Soil acidity（pH） is one of the most important indexes of soil physical and chemical properties, which has an important effect on the nutrient form and availability of planting soil. In this research, international and national standards were used to measure soil pH in five cultivated land soils and the influencing factors were studied. We also discussed their difference between international and national standards. The results showed that the pH value was mainly affected by the ratio of soil and water, and the oscillation time and filtration had no significant effect on the determination results. There was a good correlation between the two standards. In addition, most of the test liquid was in a clear state after filtration, the stability time of the instrument test shortened, and the repeatability well.

Key words: pH, different types of cultivated land, method comparison, influencing factors