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  1. Key Resource
    2002-01-01 Acidification of soil is a natural process with major ramifications on plant growth. As soils become more acid, particularly when the pH drops below 4.5, it becomes increasingly difficult to produce food crops. As soil pH declines, the supply of most plant nutrients decreases while aluminum and a...
  2. 1969-08-01 160 pages, illustrated, tables Agriculture Handbook no. 60