Nutrient status of paddy field in cold area of northeast China

A nutrient status investigation was conducted with 364 farmers’ paddy field from 2005 to 2006 in Heilongjiang Province.Results showed that organic matter content of soil varied from 14.9 to 100 g·kg-1,with the average of 41.8 g·kg-1;available N content of soil varied from 61.6 to 441 mg·kg-1,with the average of 166 mg·kg-1;available P content of soil varied from 5.0 to 74.0 mg·kg-1,with the average of 24.5 mg·kg-1;available K content of soil varied from 13.6 to 477 mg·kg-1,with the average of 127 mg·kg-1;pH values of soils varied from 4.50 to 7.78.Compared with the nutrient status of paddy field investigated in the second soil survey conducted in later 1980’s,organic matter and available N contents decreased significantly,and the acidification in paddy field was also observed.