Cropping practices have considerable effects on soil physical properties by influencing soil structure. The aim of this study was to investigate the effects of two soil textures, namely, clay loam (CL) and sandy loam (SL), and two crops, namely, alfalfa (A) and wheat (W) managements on soil structure stability. Two structural stability indexes of mean weight diameter (MWD) and tensile strength (Y) were determined at air-dry and 500 kPa matric suction conditions at three depths (0-10, 10-20, and 20-30 cm). Soil texture and crop managements' combination affected MWD and Y in the order of CL-A> CL-W> SL-A> SL-W at both moisture conditions. MWD decreased with depth due to diminishing the soil organic matter, whereas Y increased with depth as a result of reduced severity of wetting and drying cycles. The soil organic matter content showed the highest impact on aggregate stability indexes followed by clay and calcium carbonate content. The highest R2 obtained for the relation between Y and the intrinsic soil properties was at air-dry condition, whereas for Y and MWD it was found at matric suction of 500 kPa. Our results indicate that the considered indexes are suitable for investigating the effects of soil intrinsic properties and agricultural managements on soil structural stability. |
- خزایی، ع.، مصدقی، م.ر.، و محبوبی، ع. 1387. تأثیر شرایط آزمایش، مقدار ماده آلی، رس و کربنات کلسیم خاک بر میانگین وزنی قطر و مقاومت کششی خاکدانهها در برخی از خاکهای استان همدان. مجله علوم و فنون کشاورزی و منابع طبیعی. شماره 44 صفحههای 123 تا 135.
- صفادوست، آ.، مصدقی، م.ر.، محبوبی، ع.ا.، نوروزی، ع.، و اسدیان، ق. 1386. تأثیر کوتاهمدت خاکورزی و کود آلی بر ویژگیهای ساختمانی خاک. مجله علوم و فنون کشاورزی و منابع طبیعی. شماره 41 صفحههای 91 تا 101.
- Alperovitch, N., I. Shainberg, and R. Keren. 1981. Specific effects of magnesium on the hydraulic conductivity of sodic soils. J. Soil Sci. 32: 543-554.
- Barzegar, A.R., P. Rengasamy, and J.M. Oades. 1995. Effect of clay type rate of wetting on the mellowing of compacted soils. Geoderma 68: 39-49.
- Bouyoucos, G.J. 1962. Hydrometer method improved for making particle size analysis of soils. Agron. J. 54: 464-465.
- Bronick, J., and R. Lal. 2005. Soil structure and management: a review. Geoderma 124: 3-22.
- Causarano H, 1993. Factors affecting the tensile strength of soil aggregates. Soil Till. Res. 28: 15-25.
- Dexter, A.R. 1988. Advanced in the characterization of soil structure. Soil Till. Res. 11: 199-238.
- Dexter, A.R., B. Kroesbergen, and H. Kuipers. 1984. Some mechanical properties of aggregates top soils from the IJsselmeer polders. 1. Undisturbed soil aggregates. Neth. J. Agric. Sci. 32: 205-214.
- Dexter, A.R., and B. Kroesbergen. 1985. Methodology for determination of tensile strength soil aggregates. J. Agric. Eng. Res. 31: 139-147.
- Emerson, W.W. 1991. Structure decline of soils, assessment and prevention. Aust. J. Soil Res. 29: 905-921.
- Grant, C.D., A.R. Dexter, and J.M. Oades. 1992. Residual effects of additions of calcium compounds on soil structure and strength. Soil Till. Res. 22: 283-297.
- Kay, B.D., and A.R. Dexter. 1992. The influence of dispersible clay and wetting/drying cycles on the tensile strength of a red-brown earth. Aust. J. Soil Res. 30: 297-310.
- Lal, R. 1991. Soil structure and sustainability. J. Sustain. Agric. 1: 67-92.
- Le Bissonnias, Y. 1996. Aggregate stability and assessment of soil crustability and erodibility: theory and methodology. Erop. J. Soil Sci. 425-237.
- Mbagwu, J.S.C., and A. Piccolo. 1989. Changes in soil aggregate stability indicated by amendment with humic substances. Soil Technol. 2: 49-57.
- Oztaz, T., K. Sonmez, and M. Canbolat. 1999. Strength of individual soil aggregates against crushing forces I. Influence of aggregate characteristics. J. Agric. Forest. 23: 567-572.
- Safadoust, A., M.R. Mosaddeghi, and A.A. Mahboubi, 2006. Tensile Strength of Air-Dry Soil Aggregates as Influenced by Short-Term Management Practices in Western Iran. pp. 424-433. In: Horn, R., H. Fleige, S. Peth and X. Peng (Eds.), Soil Management for Sustainability. CATENA VELAG ISBN 3-923381-52-2, 35447 Reiskirchen.
- Sims, J.T. 1996. Lime requirement methods of soil analysis. Klute, A. (Ed). Methods of Soil Analysis. Part 1. Chemical Methods. SSSA/ASA. Madision, Wisconsin, USA. pp. 491.
- Tisdall, J.M., and J.M. Oades. 1982. Organic matter and water-stable aggregates in soil. J. Soil Sci. 33: 141-163.
- Tiplittgr, G.B.D., B. Vandoren, and B.L. Schimdt. 1968. Effect of corn stover mulch on no-tillage corn yield and water infiltration. Agron. J. 60: 236-239.
- Walkly, A., and I.A. Black. 1934. An examination of digestion method for determining soil organic matter and proposed modification of the chromic acid titration. Soil Sci. 37: 29-38.
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