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Soil series n Site index
(m)Standard deviation Coefficient of variation Stringtown 10 22.2a 2.35 10.579 Letney 10 22.6a 1.28 5.564 Tehran 10 20.0b 1.60 7.980 n = number of plots. Same letter within a column indicates no significant difference (p = 0.05). Table 1.
Means, standard deviations, and coefficient of variations for site index (base age 50) for natural longleaf pine stands on three soil series in east Texas.
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Soil series Mean site index (m) Low site index (m) High site index (m) Stringtown 24.5 20.7 26.5 Letney 24.8 21.3 32.0 Tehran 26.2 24.1 30.8 n = number of plots. Table 2.
Mean, low and high site index values (base age 50) by USDA-NRCS for Stringtown, Letney, and Tehran soils.
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Horizon Variable Stringtown Letney Tehran p-value A Thickness (cm) 14.80a 19.23ab 25.35b 0.008 WC (g·cm−3) 0.09a 0.06b 0.07ab 0.026 MS (%) 28.74a 31.77ab 40.59b 0.049 E Depth to E (cm) 14.80a 20.53ab 25.15b 0.010 Thickness (cm) 24.20a 49.17b 86.45c <0.001 B Depth to B 38.90a 70.40b 111.80c <0.001 Thickness (cm) 111.10a 79.60b 38.80c <0.001 MS (%) 20.99a 23.21a 36.14b 0.003 Silt + Clay (%) 46.11a 35.46ab 29.60b 0.014 Sand (%) 64.92a 72.58ab 78.27b 0.004 Clay (%) 26.95a 18.45ab 13.53a 0.013 Same letter within a row indicates no significant difference (p = 0.05). WC = Wilting Coefficient, MS = Medium Sand. Table 3.
Significant (p = 0.05) soil physical parameters not weighted by horizon thickness, means, and p-values.
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Horizon Variable Stringtown Letney Tehran p-value A WC (g·cm−3) 1.29 1.21 1.68 0.090 OM (g·cm−3) 0.04a 0.05ab 0.07b 0.005 E FC (g·cm−3) 3.32a 6.25a 18.94b 0.006 AWC (g·cm−3) 2.13 4.46 14.26 0.019 OM (g·cm−3) 0.06a 0.11a 0.19b <0.001 B FC (g·cm−3) 36.05a 22.24b 10.59b 0.001 WC (g·cm−3) 26.70a 12.14b 2.99b <0.001 AWC (g·cm−3) 0.32a 0.23ab 0.13b 0.012 Same letter within a row indicates no significant difference (p = 0.05). FC = Field Capacity; WC = Wilting Coefficient, AWC = Available Water Capacity, OM = Organic Matter. Table 4.
Significant (p = 0.05) soil physical parameters weighted by horizon thickness with p-values.
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Horizon Variable Stringtown Letney Tehran p-value A Total N 19.36a 24.60ab 34.64b 0.0034 P 0.03a 0.10b 0.09ab 0.0308 K 0.26a 0.53ab 0.60b 0.0345 Ca 2.41a 6.39 4.35ab 0.0444 C 181.17a 269.76ab 361.33b 0.0054 E Total N 42.84a 82.11b 152.10c <0.0001 NH4 0.10a 0.15a 0.36b <0.0001 P 0.05a 0.09ab 0.14b 0.0042 K 0.87a 1.30ab 1.70b 0.0461 C 292.42a 534.65a 959.73b <0.0001 B Total N 217.14a 164.65b 8.74c <0.0001 NH4 0.48a 0.32ab 0.22b 0.0105 K 4.75a 4.86a 1.51b 0.0062 Ca 67.87a 65.92a 14.35b 0.0026 Mg 21.21a 15.04ab 2.55b 0.0056 S 2.62a 1.54ab 0.50b 0.0254 B 0.01 0.01 0.00 0.0753 C 1577.93a 1125.85ab 669.62b 0.0118 Same letter within a row indicates no significant difference. Table 5.
Significant (p = 0.05) mean chemical parameters (mg·Kg−1) by horizon thickness by soil series.
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Variable Stringtown Letney Tehran p-value Ca 79.85a 86.93a 32.90b 0.0040 Mg 23.62a 18.01ab 5.53b 0.0048 S 3.11a 1.86ab 0.88 0.0174 Same letter within a row indicates no significant difference (p = 0.05). Table 6.
Significant mean (g) chemical parameters within the 150 cm soil profiles with means (g) by soil series.
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Axis Eigenvalue Maximum Eigenvalue % of Variation Cumulative variation p-value Physical parameters 1 13.09 7.467 20.779 20.779 0.001 2 9.683 5.829 15.371 36.150 0.001 3 6.585 5.187 10.452 46.602 0.001 4 4.892 4.895 7.765 54.367 0.002 5 4.519 4.540 7.173 61.540 0.002 6 3.243 4.075 5.147 66.687 1.000 7 2.999 3.751 4.760 71.447 1.000 8 2.525 5.532 4.008 75.455 1.000 9 2.212 3.294 3.511 78.966 1.000 10 2.082 3.050 3.305 82.271 1.000 Chemical parameters 1 16.216 7.439 23.501 23.501 0.001 2 11.560 5.986 16.753 40.254 0.001 3 9.757 5.488 14.140 54.394 0.001 4 5.822 5.112 8.438 62.832 0.001 5 4.248 4.730 6.156 68.988 0.2.92 6 3.269 4.378 4.738 73.726 1.000 7 2.649 4.074 3.838 77.564 1.000 8 2.450 3.739 3.551 81.115 1.000 9 1.890 3.500 3.500 83.854 1.000 10 1.732 3.401 2.510 86.364 1.000 Combined parameters 1 25.104 10.939 19.018 19.018 0.001 2 15.501 9.353 11.743 30.762 0.001 3 13.821 8.668 10.470 41.232 0.001 4 11.791 8.197 8.933 50.165 0.001 5 8.031 7.667 6.084 56.249 0.001 6 7.595 7.286 5.754 62.003 0.001 7 6.989 6.832 5.295 67.298 0.001 8 5.684 6.471 4.306 71.604 0.983 9 5.090 6.200 3.856 75.460 1.000 10 4.086 5.933 3.096 78.556 1.000 Table 7.
Results with p-values from each of the first 10 principal components from 999 randomizations to determine significant components based on relationship to the maximum theoretical eigenvalue vs the true eigenvalue for all physical variables, chemical variables and physical and chemical variables combined with associated % variance.
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