47 1 Vol147, No11 2010 1 ACTA PEDOLOGICA SIN ICA Jan., 2010 3 1, 2 1, 2g 3 (1, 100101) (2, 100101) (3, -, 100193) ( 20 cm 40 cm 80 cm 120 cm), (012 0133 015 0171), 16, :, ;,,,, 20 cm, 80 cm 120 cm,,, ; ; ; S152 A [ 1 ] [ 225 ] ), :, Swartzendruber O lson [ 627 ], 6,,, [ 12 ] Marshall Stirk [ 8 ] Youngs [ 9 ] W u [ 10 ],,,, K s, :,,W uest [ 11 ], : ; ; ; ( [ 13 ],, Sharma [ 14 ] 4517 cm 7612 cm Oklahoma 916 hm 2 26 3 (No. 90502005) 863 (No. 2007AA10Z223) (LENOM07YC - 04) g, E2mail: luoyi. cas@ gmail. com, 11,, 100101 : (1977 ),,,, : 2008-08 - 01; : 2008-12 - 01
20 47 Shouse [ 15 ] Haws [ 16 ], :, Lai Ren [ 17 ] 7 28,,:,80 cm,,,,, ( ),, 1 b,, 4, : 0120 0133 0150 0171; 1 ( 1),,, 0 cm 160 cm, 011cm, 180 cm,14 cm 20 cm 20 cm 40 cm 14 cm ; 80 cm 120 cm 20 cm, 5m in 30m in 111, Lai Ren [ 17 ] 4 ( 20 cm 40 cm 80 cm 120 cm) 20 50 cm 16 Swartzendruber O lson [ 7 ] : b = ( d o - d i ) / d o (1), d o d i 1 Table 1 Basic parameters of the double2ring infiltrometers Buffer index b (1) d i d o Outer2ring diameters ( d o ) corresponding to different inner2ringsπ ( d i ) ( cm) 20 cm 40 cm 80 cm 120 cm 0120 25 50 100 150 0133 30 60 120 180 0150 40 80 160 240 0171 70 140 280 420 (1) b = ( d o - d i ) / d o 1 ( d i = 120cm, d o = 420cm) Fig11 Photograph of the double2ring infiltration ( d i = 120cm, d o = 420cm) apparatus, 16 20 50 cm 16,, 0 160 cm, 2 [ 18 ]
1 : 21 2 Table 2 Basic soil p roperties of the soil layers of a soil p rofile at the test site Dep th ( cm) Sand Silt ( % ) Clay Texture Bulk density (Mg m - 3 ) 0 20 13100 86100 1100 Silt 1135 20 40 13100 86100 1100 Silt 1143 40 60 11100 88100 1100 Silt 1145 60 80 15100 83100 2100 Silt 1145 80 100 14100 85100 1100 Silt 1145 100 120 13100 85100 2100 Silt 1145 120 140 13100 86100 1100 Silt 1145 140 160 9100 89100 2100 Silt 1145,, 0 160 cm 10 cm,, 0, 0 100 cm 10 cm,, t ( i = t - 0 ), ( z i = 10 cm ), 0 160 cm = N ( i z i ) (2) i =1 112 (, Green2Amp t [ 19 ] ; Philip [ 20 ] ), Philip, [ 14 ] Philip [ 20 ], t I : I = S t 015 +A t (3), I L; t T; S L T - 015, A L T - 1, ( 3), A [ 21 ], A K w [ 2 ] ( 3), K w 2 211,, 0 t, 2 2, 137 m in, 50 cm, ; 50 cm, 2 Fig12 Soil volumetric water content p rofiles at the start and the end of infiltration
22 47,4199 cm, 4184 cm, 3%, 212,, 3 3,: Lai Ren [ 17 ] Shouse [ 15 ] Haws [ 16 ] : Mar2 shall Stirk [ 8 ] Youngs [ 9 ] W u [ 10 ],,,,,,,, 3 :,,, 3(: a) 20 cm, b) 40 cm, c) 80 cm, d) 120 cm) Fig1 3 Cumulative infiltration curves of infiltrometers different in inner2ring diameters1 a) d i = 20 cm, b) d i = 40 cm, c) d i = 80 cm, and d) d i = 120 cm with different buffer indices 213 4,,,,,, 90 m in,,
1 : 23 4 (: a) 20 cm, b) 40 cm, c) 80 cm, d) 120 cm) Fig1 4 Variation of infiltration rate in infiltrometers different in outer2ring1a) d i = 20 cm, b) d i = 40 cm, c) d i = 80 cm, d) d i = 120 cm, 5 5,, d i = 80 cm d i = 120 cm, b = 0171,, ; b = 0171, d i = 80 cm d i = 120 cm, d i = 20 cm d i = 40 cm,,,, (3) 6 6,,, d i = 20 cm, d i = 120 cm 3 16,,,,,, b = 0171, d i = 20 cm, b, d i = 80 cm d i = 120 cm
24 47 5 ( b : a) 0120, b) 0133, c) 0150, d) 0171) Fig15 Cumulative infiltration curve of infiltrometers different in inner2ring for Buffer index: a) b = 012, b) b = 0133, c) b = 015, d) b = 0171,, ( 1), ; (2), ( 80 cm ) [ 1 ] Mualem Y. A new model for p redicting the hydraulic conductivity 6 b Fig16 Variation of measured saturated hydraulic conductivity of the soil with increasing buffer index b, d i = 20 cm, d i = 80 cm d i = 120 cm of unsaturated porous media. W ater Resour Res, 1976, 12: 513 522 [ 2 ] Bouwer H. Intake rate: Cylinder infiltrometer. In: Klute A. ed. Methods of soil analysis, Part 1. 2nd ed. Agron. Monogr. 9. Madison, W I: ASA and SSSA, 1986: 825 844 [ 3 ],,.., 2000, 37 ( 1 ) : 24 32. Fan G S, Zheng X Q, Jia H J. Experimental study on the freezing and tha2 wing features and reduction infiltration characteristics of seasonal
1 : 25 freezing and thawing soils ( In Chinese). Acta Pedologica Sinica, 2000, 37 (1) : 24 32 [ 4 ] D irk S M, Carlson D A, Cherkauer D S, et al. Scale dependen2 cy of hydraulic conductivity in heterogeneousmedia. GroundW a2 ter, 1999, 37: 904 919 [ 5 ] Ben2HurM, A ssouline S. Tillage effects on water and salt distri2 bution in a Vertisol during effluent irrigation and rainfall. Agron J, 2002, 94: 1 295 1 304 [ 6 ] Swartzendruber D, O lson T C. Model study of the double ring in2 filtrometer as affected by dep th of wetting and particle size. Soil Sci, 1961, 92: 219 225 [ 7 ] Swartzendruber D, O lson T C. Sandy2model study of buffer effects in the double ring infiltrometer. Soil Sci Soc Am Proc, 1961, 25: 5 8 [ 8 ] Marshall T J, Stirk G B. The effect of lateral movement of water in soil on infiltration measurements. Aust J Agric Res, 1950, 1: 253 265 [ 9 ] Youngs E G. Estimating hydraulic conductivity values from ring infiltrometer measurements. Journal of Soil Science, 1981, 38: 623 632 [ 10 ] W u L, Pan L, Roberson M, et al. Numerical evaluation of ring2 infiltrometers under various soil conditions. Soil Sci, 1997, 162: 771 777 [ 11 ] W uest S B. B ias in ponded infiltration estimates due to samp le volume and shape. Vadose Zone J, 2005, 4: 1 183 1 190 [ 12 ] Zhang R D. Scale2dependent soil hydraulic conductivity. In: No2 vak M M, Dewey T G. eds. Fractal Frontiers. London: World Scientific, 1997. 383 392 [ 13 ] B iggar J W, N ielsen D R. Spatial variability of leaching charac2 teristics of a field soil. W ater Resour Res, 1976, 12: 78 84 [ 14 ] Sharma M L, Gander G A, Hunt C G. Spatial variability of infil2 tration in a watershed. J Hydrol, 1980, 45: 101 122 [ 15 ] Shouse P J, Ellsworth T R, Jobes J A. Steady2state infiltration as a function of measurement scale. Soil Sci, 1994, 157: 129 136 [ 16 ] Haws N W, L iu B W, Boast C W, et al. Spatial variability and measurement scale of infiltration rate on an agricultural land2 scape. Soil Sci Soc Am J, 2004, 68: 1 818 1 826 [ 17 ] Lai J B, Ren L. A ssessing the size dependency of measured hy2 draulic conductivity using double2ring infiltrometers and numeri2 cal simulation. Soil Sci Soc Am J, 2007, 71: 1 667 1 675 [ 18 ] Gee G W, Bauder J W. Particle2size analysis. In: Klute A. ed Methods of soil analysis. Part 1. 2nd ed. SSSA. Book Series No. 5. Madison, W I: ASA and SSSA, 1986: 383 411 [ 19 ] Green W H, Amp t G A. Studies on soil physics I. The flow of air and water through soils. J Agric Sci, 1911, 4: 1 24 [ 20 ] Philip J R. The theory of infiltration 1. The infiltration equation and its solution. Soil Sci, 1957, 83: 345 357 [ 21 ] Koorevaar P, Menelik G, D irksen C. Elements of soil physics. Amsterdam: Elsevier Science, 1983 EFFECTS O F BUFFER2I ND EX O F THE DO UBL E2R I NG I NF IL TROM ETERS O N SATURATED HYD RAUL IC CO ND UCT IV ITY M EASUREM ENTS Lai J ianbin 1, 2 Luo Yi 1, 2g Ren L i 3 (1 Institute of Geographic Sciences and N atural Resources R esearch, Chinese A cadem y of Sciences, B eijing 100101, China) (2 Key Laboratory of Ecological N etwork O bservation and M odeling, Chinese A cadem y of Sciences, B eijing 100101, China) ( 3 Departm ent of Soil and W ater Sciences, Key Laboratory of Plant2Soil Interactions, M inistry of Education, China Agricultural U niversity, B eijing 100193, China) Abstract The double2ring infiltrometer is widely used to measure soil saturated hydraulic conductivity1 To investi2 gate effects of ratio of the outer to the inner rings, i1e1 the buffer index of double2ring infiltrometer, on measurement of saturated hydraulic conductivity, 16 sets of field experiments were laid out and conducted using 16 double2ring infiltrome2 ters with 4 inner2ring diameters (20 cm, 40 cm, 80 cm, and 120 cm) and 4 buffer indices (012, 0133, 015 and 0171). Results show that uncertainty of the measured saturated hydraulic conductivity decreased with increasing diameter of the inner2rings1 Saturated hydraulic conductivities in the infiltrometers with an inner2ring diameter of 20cm varied in a broad range, while those in the infiltrometers with inner2ring diameters of 120cm and 80cm were always close to each other and less in variation1 However, no rising or falling tendency was observed for the increasing buffer indices1 It is concluded that the inner2ring diameter is a more important factor to be considered than the buffer index in p ractice, and a larger inner2 ring diameter, such as 80cm, is p roposed as a lower lim it of the inner2ring size to obtain reliable in2situ measurement of hydraulic conductivity1 Key words Soil; Saturated hydraulic conductivity; Double2ring infiltrometer; Buffer index