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Table 3 Concentrations of P and cations in each extract for each soil

From: Characterizing the phosphorus forms extracted from soil by the Mehlich III soil test

  Extractant   AR-control AR-N AR-PL AR-PL-alum SK PEI Till Ref
TP Mehlich III Soil 64 (13) 84 (16) 382 (32) 675 (55) 99 (18) 244 (22) 30 (3)
  NaOH-EDTA Residue 255 (53) 306 (58) 601 (50) 1101 (90) 204 (36) 396 (36) 328 (35)
  NaOH-EDTA Soil 282 (59) 327 (62) 753 (63) 1178 (97) 340 (60) 759 (69) 360 (39)
  NaOH-EDTA Difference 27 (6) 21 (4) 152 (13) 77 (7) 136 (24) 363 (33) 32 (4)
MUP Mehlich III Soil 33 (53) 25 (33) 4 (< 1) 306 (41) 33 (39) 33 (14) 1 (3)
Al Mehlich III Soil 421 695 506 1205 671 1256 1683
Fe Mehlich III Soil 106 220 160 161 146 216 335
Mn Mehlich III Soil 112 54 113 32 174 29 179
Ca Mehlich III Soil 1152 376 1547 853 1548 441 972
Mg Mehlich III Soil 148 49 266 112 347 53 161
  1. Concentrations are given in mg kg−1 soil. MUP, concentration of molybdate-unreactive P, determined as the difference in P measured by ICP and colorimetrically (percent of total soil P recovered in M3 extract). All other concentrations determined by ICP-OES. Residue, residual soil after Mehlich III extraction; TP, total P in each extract (percent of total soil P recovered in each extract). Difference is the difference in between the NaOH-EDTA extracts of whole soils and the NaOH-EDTA extracts of the residue after Mehlich III extraction
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