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ΒΆ Introduction
Survey of analysis results from East Texas surface and groundwater samples submitted to ServiTech Laboratories during 2013 to 2022, inclusive, for analysis of Livestock Suitability. The results are grouped by National Agricultural Statistics Service (USDA-NASS) reporting districts.
ΒΆ Figure 1. East Texas USDA-NASS Districts
Interpretation of survey results:
- Median = 50th percentile
- Typical range = 25th and 75th percentiles
- Low - High = 5th and 95th percentiles
ΒΆ Table 1. Total dissolved solids, TDSc mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 740 | 600 β 2500 | 185 β 5940 |
| Blacklands | 375 | 175 β 1015 | 90 β 2190 |
| East Texas | 340 | 145 β 680 | ---- |
| South Central | 515 | 485 β 990 | 115 β 2585 |
| Coast | 385 | 270 β 895 | ---- |
| Lower Valley | 3340 | 1615 β 5195 | ---- |
| Statewide | 530 | 355 β 1560 | 145 β 5800 |
("Acceptable" = 2000 - 4000 TDS mg/L)
ΒΆ Table 2. Sulfate, SO4 mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 87 | 10 β 300 | 1 β 2100 |
| Blacklands | 33 | 11 β 96 | 1 β 480 |
| East Texas | 12 | 4 β 193 | ---- |
| South Central | 84 | 48 β 150 | 2 β 1706 |
| Coast | 63 | 14 β 360 | ---- |
| Lower Valley | 720 | 375 β 1195 | ---- |
| Statewide | 81 | 33 β 480 | 6 β 2360 |
("Acceptable" = 200 - 500 SO4 mg/L)
ΒΆ Table 3. Nitrate-nitrogen, NO3-N mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 1.3 | 0.1 β 7.4 | 0.1 β 13.1 |
| Blacklands | 0.2 | 0.1 β 0.8 | 0.1 β 1.8 |
| East Texas | 0.4 | 0.1 β 1.0 | ---- |
| South Central | 0.3 | 0.1 β 1.1 | 0.1 β 31.4 |
| Coast | 1.6 | 0.8 β 2.7 | ---- |
| Lower Valley | 1.0 | 0.1 β 16.6 | ---- |
| Statewide | 2.1 | 0.7 β 5.1 | 0.1 β 15.7 |
("Acceptable" = 30 - 70 NO3-N mg/L)
ΒΆ Table 4. Calcium, Ca mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 44 | 14 β 69 | 2 β 555 |
| Blacklands | 20 | 12 β 35 | 4 β 61 |
| East Texas | 13 | 9 β 30 | ---- |
| South Central | 81 | 43 β 117 | 1 β 225 |
| Coast | 54 | 45 β 120 | ---- |
| Lower Valley | 170 | 73 β 280 | ---- |
| Statewide | 56 | 38 β 160 | 5 β 680 |
("Acceptable" = 80 - 120 Ca mg/L)
ΒΆ Table 5. Magnesium, Mg mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 17 | 4 β 31 | 1 β 210 |
| Blacklands | 6 | 3 β 11 | 1 β 36 |
| East Texas | 6 | 1 β 13 | ---- |
| South Central | 12 | 8 β 37 | 1 β 105 |
| Coast | 34 | 24 β 42 | ---- |
| Lower Valley | 42 | 21 β 75 | ---- |
| Statewide | 33 | 22 β 70 | 2 β 246 |
("Acceptable" = 50 - 120 Mg mg/L)
ΒΆ Table 6. Potassium, K mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 6 | 3 β 28 | 2 β 121 |
| Blacklands | 5 | 3 β 7 | 1 β 24 |
| East Texas | 5 | 2 β 27 | ---- |
| South Central | 6 | 4 β 12 | 2 β 22 |
| Coast | 5 | 4 β 6 | ---- |
| Lower Valley | 20 | 7 β 24 | ---- |
| Statewide | 6 | 4 β 9 | 1 β 33 |
("Acceptable" = 80 - 120 K mg/L)
ΒΆ Table 7. Sodium, Na mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 235 | 63 β 507 | 6 β 2259 |
| Blacklands | 55 | 18 β 346 | 4 β 860 |
| East Texas | 40 | 13 β 178 | ---- |
| South Central | 91 | 64 β 215 | 16 β 597 |
| Coast | 43 | 20 β 170 | ---- |
| Lower Valley | 870 | 405 β 1550 | ---- |
| Statewide | 48 | 31 β 174 | 5 β 1224 |
("Acceptable" = Na plus Mg less than 50% of TDS)
ΒΆ Table 8. Chloride, Cl mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 105 | 91 β 590 | 18 β 2845 |
| Blacklands | 30 | 12 β 280 | 3 β 487 |
| East Texas | 44 | 17 β 103 | ---- |
| South Central | 120 | 76 β 150 | 12 β 348 |
| Coast | 37 | 13 β 180 | ---- |
| Lower Valley | 1100 | 300 β 2100 | ---- |
| Statewide | 55 | 18 β 160 | 6 β 1600 |
("Acceptable" = 125 - 250 Cl mg/L)
ΒΆ Table 9. Electrical conductivity, EC ΞΌmho/cm |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 1155 | 940 β 3900 | 295 β 9285 |
| Blacklands | 585 | 275 β 1590 | 135 β 3425 |
| East Texas | 530 | 230 β 1060 | ---- |
| South Central | 800 | 760 β 1550 | 175 β 4035 |
| Coast | 605 | 420 β 1400 | ---- |
| Lower Valley | 5220 | 2520 β 8110 | ---- |
| Statewide | 830 | 550 β 2430 | 230 β 9070 |
("Acceptable" = 1300 - 2600 ΞΌmho/cm)
ΒΆ Table 10. Iron, Fe mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 0.41 | 0.06 β 0.81 | 0.05 β 9.35 |
| Blacklands | 0.08 | 0.05 β 0.28 | 0.05 β 4.09 |
| East Texas | 1.19 | 0.16 β 2.55 | ---- |
| South Central | 0.05 | 0.05 β 0.73 | 0.05 β 4.14 |
| Coast | 0.09 | 0.05 β 0.14 | ---- |
| Lower Valley | 0.05 | 0.05 β 0.87 | ---- |
| Statewide | 0.10 | 0.05 β 0.30 | 0.05 β 2.97 |
("Acceptable" = 0.20 - 0.40 Fe mg/L)
ΒΆ Table 11. Manganese, Mn mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 0.030 | 0.005 β 0.333 | 0.005 β 3.35 |
| Blacklands | 0.008 | 0.005 β 0.025 | 0.005 β 0.422 |
| East Texas | 0.063 | 0.029 β 0.155 | ---- |
| South Central | 0.008 | 0.005 β 0.071 | 0.005 β 0.246 |
| Coast | 0.005 | 0.005 β 0.008 | ---- |
| Lower Valley | 0.008 | 0.005 β 0.049 | ---- |
| Statewide | 0.005 | 0.005 β 0.031 | 0.005 β 0.432 |
("Acceptable" = 0.025 - 0.050 Mn mg/L)
ΒΆ Table 12. Hardness, as CaCO3 grains/gallon |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 10.8 | 2.8 β 18.3 | 0.6 β 130 |
| Blacklands | 5.3 | 2.4 β 8.8 | 0.9 β 16 |
| East Texas | 3.2 | 1.5 β 6.4 | ---- |
| South Central | 14.0 | 9.1 β 30 | 0.6 β 58 |
| Coast | 15.0 | 13.0 β 28 | ---- |
| Lower Valley | 36.0 | 15.6 β 57 | ---- |
| Statewide | 16.0 | 12.0 β 41 | 1.2 β 166 |
("Moderately hard" = 3.5 - 7.0 CaCO3 grains/gallon)
ΒΆ Table 13. Hardness, as CaCO3 mg/L |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 185 | 50 β 315 | 10 β 2245 |
| Blacklands | 90 | 40 β 150 | 15 β 290 |
| East Texas | 55 | 25 β 110 | ---- |
| South Central | 250 | 160 β 510 | 10 β 975 |
| Coast | 250 | 220 β 470 | ---- |
| Lower Valley | 610 | 270 β 950 | ---- |
| Statewide | 280 | 200 β 710 | 20 β 2800 |
("Moderately hard" = 60 to 120 CaCO3 mg/L)
ΒΆ Table 14. Water pH |
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| East Texas Districts | Median | Typical range | Low - High |
| Cross Timbers | 8.2 | 7.9 β 8.4 | 5.5 β 9.0 |
| Blacklands | 8.4 | 8.1 β 8.6 | 7.5 β 8.8 |
| East Texas | 8.0 | 7.2 β 8.2 | ---- |
| South Central | 7.4 | 6.8 β 8.0 | 6.5 β 9.2 |
| Coast | 8.1 | 7.7 β 8.2 | ---- |
| Lower Valley | 7.9 | 7.7 β 8.3 | ---- |
| Statewide | 8.1 | 7.9 β 8.3 | 7.4 β 8.9 |
("Neutral" pH = 6.5 - 7.5)
ΒΆ Table 15. Conversion Factors |
| 1 mg/L β 1 ppm |
| 1 mg/L = 1,000 Β΅g/L |
| 1 mmho/cm = 1 dS/m |
| 1 mmho/cm = 1,000 Β΅mho/cm lb/ac-in = mg/L x 0.2267 lb/ac-ft = mg/L x 2.7204 |
| lime equivalent, lb/ac-ft = HCO3 mg/L x 2.2304 |
| 1 acre-inch = 27,154 gallons |
| 1 acre-foot = 325,848 gallons |
ΒΆ Table 16. Sample Count |
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| Cross Timbers | 30 |
| Blacklands | 25 |
| East Texas North | 9 |
| East Texas South | 5 |
| South Central | 23 |
| Coastal Bend | 1 |
| Upper Coast | 10 |
| Lower Valley | 13 |
| Statewide | 1687 |