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03/18/2009 12:29 9702475104 DMG DURANGO OFFICE PAGE 09/21 <br />USDA criteria f c, primo fermtaud mate that theme] topsoil plus subsoil dopib must equal or minced y • l'1 n `t m t w <br />40 inches. Those criteria were used to modify the soil suitabilitycritMa table (Table 2.04.9 -2) in the <br />DBMS permit. -aOg <br />All soil samples during the March 5 sampling event were within suitable ranges for selected aesdytcs <br />and field parameters. The upper two feet of subsoil was investigated, but there was na change <br />abacrvod to the tend soil pit depth in any soil pit, suggesting that the soil suitability criteria would be <br />met in the three W four test of observed subsoil w all or most sampling locations. <br />Resnmpring fore %and E/cc&iml CondaeNviry <br />Comments from the DBMS in a letter dated May 28, 2008 revealed that the March 5 subsoil analyses <br />utilized 1:1 extract for the soil pH and clmttiml conductivity (EC), ether than the premil-mquined <br />paste method for these analytu. Walsh discussed the situation with DBMS and NRCS personnel and <br />determined that there is a proportional relationship between 1+1 extras[ and paste eahect EC results. A <br />published formula was applied to the 1:1 EC results, and rovcaled that up W four sample points may <br />usccod the paste EC criteria of 4.0 (samples 21. 26, 32, and 33). Based on this, the eight sample points <br />that had 1:1 EC higher than 1.2 were ruse mpled and analyzed for peace RC (Table 2). WFC personnel <br />resampled soil at the original sampling points using a 2" hand auger for a total depth of 24 ". A <br />fraction of the ex[nceed sample was placed in a zip -Inc bag and shipped W Servi -Tech Labs of <br />Hastings. Nebraska. The sampling points were heated with a survey -grade OPS W match the March 5, <br />2008 sampling points The sampled areas had not yet had topsoil placed at the time of sampling. <br />Of the eight Samples ubtamcd, two exceeded the topsoil permit criteria of 4. These wore sample 21 <br />with a puts EC of 4.34 and sample 32 with a Plate EC of 7.33. The ample 32 location is our a top- <br />soil pile. which may have affected this local,.. The Samplers noted Nat as many as five attempts <br />were made at .sample 32 to Sm s eomplcW hole due to refusal orthe hand auger. This suggests that <br />sample 32 may not be representative of the subsoil in the area. <br />The orig nal c survey Qntomennnt prime t o IevenWrle6, Inc ale st& O d laboratory <br />n e soil profiles within the prime farmland unit south h of of8B BB Road. Of these three, four <br />individual S s Once <br />horizons from the approximately Percent inch subsoil e l warn ed. panic EC <br />ranged from 0.7 to 3.8. wish an average of percent Cage] ranged from 3 to naly 36%, with an averag <br />of No stones, or set til a were observed in f2 0OY and lab a naly sis afgKVel <br />ra nged jisid 9.1 to 31 <br />ra from 9.1 [0 31 S %, with an avmage grovel content o 20.7Yo Th is This indicates that the <br />replacement subsoil has higher average paste EC (3.1 %), lower CSCO) (2 %4 %), and lower tonne <br />fraction (11.7 %) Nan the original tested subaeil, Sample avemilu are shown on tables 1 and 2. <br />Walsh discussed the impact of EC on crops with Mr. Dave Deuatyne ofthe NRCS, who indicated that <br />crops Sea mare Sensitive to ciovaled EC in topsoil than in subsoil. Elevated BC in subsoil can impact <br />established crops but not establishing crops, and established crops are ganorally more tolerant of <br />elevated EC than amcblishfng crops. Mr. Dearslyne stated that subsoil with Stage EC up W G would <br />not be detrimental to gnaws or alfalfa Ax such, establishing -lute EC criterion o£6 far subsoil in <br />prime farmland for th permit may be appropriate. <br />4 Wl1.a�11 14- W•i� (117 {�4dfL.C�- l��l Yr`�]Yl r� �4 r��a -tyh� <br />n�v�ronnx:ntol Sne.ara aoa gnP ^^^rE.I.LC C'6 A�- i <br />S.bso.l mac 4 be <br />(n <br />• (Ramscd No, 2008) Attachment 2.05.4(2)(d) -1-4 <br />