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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