| Autor: |
Rachman, Achmad, Anderson, S. H., Gantzer, C. J. |
| Předmět: |
|
| Zdroj: |
Soil Science Society of America Journal; Sep/Oct2005, Vol. 69 Issue 5, p1609-1616, 8p |
| Abstrakt: |
Planting stiff-stemmed grass hedges in a watershed may reduce water runoff and soil erosion, in part by altering soil macroporosity. The objective of this study was to characterize macroporosity of soils under a perennial grass hedge system for 12 yr using x-ray computed tomography (CT) and to compare CT-macroporosity results with macroporosity estimated from water retention data. Three positions were sampled: grass hedge position, deposition zone position 0.5 m upslope from grass hedges, and row crop position 7 m upslope from the hedges. Intact core samples (76 mm × 76 mm) were collected from two depths, 0 to 100 and 100 to 200 mm, with five replicates per position per depth. Number of pores (macro- and meso-), averaged across depths, in the grass hedge were nearly 2.5 times greater than those in the row crop and five times greater than in the deposition positions; however their circularity was 8.8% lower than in the row crop and 2.6% lower than in the deposition positions. The CT-measured macro- porosity was significantly greater (P < 0.01) for the grass hedge position (0.056 m³ m-3) as compared with the row crop (0.014 mm³ m-3) and deposition positions (0.006 mm³ m-3). The fractal dimension (D) was significantly greater (P < 0.01) for the grass hedge position (D = 1.56) than in the row crop (D = 1.31) and the deposition (D = 1.12) positions. The values of all measured pore characteristics decreased with depth. Computed tomography-measured macroporosity data were comparable with macroporosity estimated from water retention data. These findings suggest that grass hedge systems have created more pores and a greater volume of macroporosity. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text