Study on Available Phosphorus Content and Changing Pattern in Tobacco Planting Soils

Available phosphorus contents of 8 992 soil samples of flue-cured tobacco fields from 1987~2003 in Heilongjiang province were tested. The results showed that mean contents of available phosphorus increased. The current mean was greater than 50 mg/kg, and increased 10 mg/kg every five years. Percentage of land with >40 mg/kg available phosphorus increased at a rate of 10% every three years. The percentage of land with <10 mg/kg available phosphorus content decreased. Available phosphorus is sufficient in tobacco planting soil in Heilongjiang.