Soil phosphorus includes organic and inorganic phosphorus. the inorganic phosphorous can directly used
by plants. Soil organic phosphorus is mineralized and decomposed into inorganic phosphorus. Determine
the total phosphorus, organic phosphorus and inorganic phosphorus in the same time can fully reflect the
condition of soil phosphorus nutrition.
Molybdenum blue is used to determine phosphorus. One sample of soil is taken and the content of
inorganic phosphorus is determined by extraction method. The content of total phosphorus was measured
by taking another sample after burning at high temperature. The content of organic phosphorus is
calculated by subtracting the content of inorganic phosphorus from the total phosphorus content.
Required reagents and equipment:
Spectrophotometer/Microplate reader, micro glass cuvette/96 well flat-bottom plate, centrifuge, water bath,
scale, transferpettor, 550 ℃ high temperature electric stove, distilled water and 100 meshes sieve (or
smaller).
