مقایسه روش‎های ارزیابی پایداری خاکدانه به‎عنوان یکی از شاخص‎های کیفیت فیزیکی خاک

نوع مقاله : مقالات پژوهشی

نویسندگان

1 موسسه تحقیقات خاک

2 دانشگاه تهران

3 تبریز

چکیده

پایداری خاکدانه، توانایی خاک در نگهداری و حفظ ترتیب فاز جامد و فضای خلل و فرج بعد از اعمال تنش‎های مکانیکی است. گرچه تاکنون یک روش رضایت‎بخش جامع برای تعیین کیفیت فیزیکی خاک ارائه نشده است ولی پایداری خاکدانه می‎تواند به‎عنوان یکی از مهم‎ترین شاخص‎های کیفیت فیزیکی خاک قلمداد شود. هدف از این مطالعه، ارزیابی روش‎های مناسب و استاندارد تعیین پایداری خاکدانه است که قادر به تشخیص شرایط کیفی فیزیکی خاک‎های دارای بافت متوسط در هر دو منطقه خشک و مرطوب باشد. تعداد 120 نمونه خاک که شصت نمونه مربوط به منطقه مرطوب گیلان و شصت نمونه دیگر از استان فارس با اقلیم خشک انتخاب شدند. هر 10 نمونه خاک با بافت مشابه مخلوط شده و در نهایت یک نمونه خاک تعیین شد. بعد از هوا خشک‎شدن و الک‎کردن نمونه‎ها، تعیین بافت به‎روش پیپت و کربن‎آلی خاک به‎روش اکسیداسیون انجام گرفت. همچنین نمونه‎های دست‎نخورده با استفاده از استوانه‎های فلزی جهت تعیین ضریب آبگذری اشباع، منحنی رطوبتی و جرم مخصوص ظاهری خاک برداشته شد. تعیین هدایت هیدرولیکی اشباع به‎روش بار ثابت صورت گرفت. برای اندازه‎گیری پایداری خاکدانه، از روش‎های کمپر- رزنا، لابیزسونایس، و دی‎لینهیر-دی‎بودت استفاده شد. براساس نتایج حاصل از این تحقیق، مقادیر میانگین وزنی قطر خاکدانه‎ها در روش‎های کمپر–رزنا و لابیزسونایس برای مطالعه پایداری ساختمان در هر دو اقلیم مناسب هستند. اگر یک روش بررسی سریع و ساده از وضعیت ساختمان خاک مورد نیاز باشد، تست‎های ساده مثل کمپر-رزنا با اشباع سریع و همچنین لابیزسونایس در حالت مرطوب شدن سریع می‎توانند مورد استفاده واقع شوند.

کلیدواژه‌ها


عنوان مقاله [English]

Comparing Aggregate Stability Tests as One of the Soil Physical Quality Indicators

نویسندگان [English]

  • Saeed Saadat 1
  • leila esmaeelnejad 2
  • hamed rezaei 1
  • Rasoul mirkhani 1
  • javad seyedmohammadi 3
1 soil research institute
2 university of tehran
3 tabriz
چکیده [English]

Introduction: Soil aggregates refers to groups of soil particles which attach to each other stronger than neighbour particles. Aggregate stability shows the capability and strength of soil aggregates to tolerate breakup when disruptive stresses and destructive forces via mechanical agricultural operation such as tillage and water or wind erosion are applied. Wet aggregate stability shows how well a soil can withstand raindrop impact and water erosion, while size distribution of dry aggregates can be used to predict resistance to abrasion and wind erosion. Aggregate stability changes can act as the first indicators of recovery or degradation of soils. Aggregate stability is an indicator of organic matter content, biological activity, and nutrient cycling in soil. Generally, in small aggregates (< 0.25 mm), the particles are bound by older and more stable forms of organic matter. Microbial decomposition of fresh organic matter releases products (that are less stable) that bind small aggregates into large aggregates (> 2-5 mm). Although, there is not a unique acceptable methodology that serves and applies the entire world up to now, aggregate stability has been introduced as a soil physical quality indicator. Difficulties remain when comparison of aggregate stability from different methodologies are done. The objective of the present study was to assess appropriate and satisfactory aggregate stability tests that enable to distinguish the soil physical quality condition of both arid and moist medium textured soils.
Materials and Methods: A total of 120 soil samples which contained 60 wetland samples from Guilan province with a very humid climate, average annual rainfall of 1285 mm, and average annual temperature of 16°C, and 60 samples from Fars province with dry climate, average rainfall of 225 mm, and the average annual temperature of 27°C were provided. Soil sampling was performed from surface layer (0-20 cm). Each 10 soil samples with similar texture were mixed and one soil sample for each texture was finally obtained. After air drying and sieving, soil texture and organic carbon were determined by pipette and oxidation methods, respectively. Also, undisturbed samples were taken using metal cylinders from surface layer of 5-15 cm for determination of soil saturation coefficient, soil moisture curve, and soil bulk density. Also, in order to determine the aggregate stability, Kemper and Rosenau, de Leenheer and de Boodt, as well as Le Bissonnais were used.
Results and Discussion: Among different tested methods, wet sieving using the well known fast wetting methods of Kemper & Rosenau and of Le Bissonnais presented similar results in both climates. The mean weight diameter value of both methods for assessing aggregate stability can be considered as a dependable indicator of soil structure status for comparing soils. These aggregate stability tests were in correspondence with only one out of the eight soil physical quality indicators when the entire soils were used. It was concluded that the aggregate stability should be used judiciously and in accordance with other indicators for an overall assessing of the soil physical quality condition. The great differences in the estimation of aggregate stability between KRSW and LB2 with other methods confirm that aggregate stability increases with increasing soil moisture content. This involves reducing the amount of air condensed, which results in the reduction of compressive forces on the aggregates during rapid wetting. But the lack of similarity between the KRSW and LB2 methods in terms of MWD suggests that the results of these two methods are not comparable to dry and wet soils. The difference in aggregate size distribution from all three treatments of LB method was higher in dry areas than wet areas. Only dry soils based on LB (LB1 and LB3 treatments based on MWD) (P <0.05) are comparable. In dry soils, the LB3 method is very efficient. This method involves the use of ethanol that protects the aggregate structure against dryness stresses. The lack of similarity between the MWD and other soil quality indicators describes the complexity of the soil structure, which is dependent on the location. It seems that SOC can be considered as an indicator with high correlation with the aggregate sustainability index of LB and KRFW methods, at least in the studied medium-textured soils.
Conclusion: Since only a soil quality index (SOC) had a similar trend to the sustainability index derived from these two methods (LB1 and KRFW), it can be concluded that aggregate stability should be judged and recognized correctly, along with other used soil physical indicators for a general assessment of the conditions. In case of arid land soils, efficiency of pre-wetted methods of Kemper and Rosenau and of Le Bissonnais as well as pre-wetted Le Bissonnais with mechanical slaking and shaking were similar. If a simple and rapid analysis of the structure status is needed, single tests such as fast wetted Kemper and Rosenau and Le Bissonnais can be used.

کلیدواژه‌ها [English]

  • Aggregate stability
  • de Leenheer and de Boodt
  • Kemper and Rosenau
  • Le Bissonnais
  • Soil physical quality indicators
1- Amezketa E. 1999. Soil aggregate stability: a review. Journal of Sustainable Agriculture 14: 83–151.
2- An S., Mentler A., Mayer H., and Blum W. 2010. Soil aggregation, aggregate stability, organic carbon and nitrogen in different soil aggregate fractions under forest and shrub vegetation on the Loess Plateau, China. Catena 81: 226–233.
3- Arshad M.A., and Coen G.M. 1992. Characterization of soil quality: physical and chemical criteria. American Journal of Alternative Agriculture 7: 25–32.
4- Bartlova J., Badalikova B., and Pospisilova L. 2015. Water stability of soil aggregates in different systems of tillage. Soil and Water Research 10: 147-154.
5- Beare M.H., and Bruce R.R. 1993. A comparison of methods for measuring water-stable aggregates: implications for determining environmental effects on soil structure. Geoderma 56: 87–104.
6- Bruce-Okine E., and Lal R. 1975. Soil erodibility as determined by the raindrop technique. Soil Science 119: 149–157.
7- Cerdà A. 2000. Aggregate stability against water forces under different climates on agriculture land and scrubland in southern Bolivia. Soil and Tillage Research 57: 159–166.
8- Cornelis W.M., Khlosi M., Hartmann R., Van Meirvenne M., and De Vos B. 2005. Comparison of unimodal analytical expressions for the soil–water retention curve. Soil Science Society of America Journal 69: 1902–1911.
9- D’Haene K., Vermang J., Cornelis W.M., Leroy B.L.M., Schiettecatte W., De Neve S., Gabriels D., and Hofman G. 2008. Reduced tillage effects on physical properties of silt loam soils growing root crops. Soil and Tillage Research 99: 279–290.
10- de Leenheer L., and de Boodt M. 1959. Determination of aggregate stability by the change in mean weight diameter. Mededelingen van landbouwhoge school en de opzoeking stations van de staat te Gent 24: 290–300.
11- Deviren Saygin S., Cornelis W.M., Erpul G., and Gabriels D. 2012. Comparison of different aggregate stability approaches for loamy sand soils. Applied Soil Ecology 54: 1–6.
12- Dexter A.R. 2004a. Soil physical quality: part I. Theory, effects of soil texture, density, and organic matter, and effects on root growth. Geoderma 120: 201–214.
13- Dexter A.R. 2004b. Soil physical quality: part II. Friability, tillage, tilth and hard-setting. Geoderma 120: 215–225.
14- Dexter A.R. 2004c. Soil physical quality: part III: unsaturated hydraulic conductivity and general conclusions about S-theory. Geoderma 120: 227–239.
15- Diaz-Zorita M., Perfect E., and Grove J.H. 2002. Disruptive methods for assessing soil structure. Soil and Tillage Research 64: 3–22.
16- Emerson W.W. 1967. A classification of soil aggregates based on their coherence in water. Australian Journal of Soil Research 5: 47–57.
17- Gee G.W., and Or D. 2002. Particle-size analysis. In: Dane, J.H., Hopmans, J.W.(Eds.) Methods of Soil Analysis Part 4 Physical Methods. SSSA BookSeries 5’. Soil Science Society of America, Madison.
18- Gijsman A.J. 1996. Soil aggregate stability and soil organic matter fractions under agropastoral systems established in native savanna. Australian Journal of Soil Research 34: 891–907.
19- Greenland D.J. 1981. Soil management and soil degradation. Journal of Soil Science 32: 301–322.
20- Henin S., Monnier G., and Combeau A. 1958. Methode pour l’etude de la stabilite structural des sols. Ann. Agron., 9: 73–92.
21- Hofman G. 1973. Kritische Studie van de Instabiliteit van Bodemaggregaten en de Invloed op Fysische Bodemparameters. Dissertation. Faculty of Agricultural Sciences, University of Ghent, Belgium.
22- Horn R., Taubner H., Wuttke M., and Baumgartl T. 1994. Soil physical properties related to soil structure. Soil and Tillage Research 30: 187–216.
23- Kemper W.D., and Rosenau R.C. 1986. Aggregate stability and size distribution, In: Klute, A. (Ed), Methods of Soil Analysis Part 1, Physical and Mineralogical Methods. Agronomy Monograph N؛ 9 (2nd Edition), American Society of Agronomy, Inc., Madison, WI.
24- Lal R., and Shukla M.K. 2004. Principles of Soil Physics. Marcel Dekker, New York. ISBN 0-8247-5324-0.
25- Le Bissonnais Y. 1996. Aggregate stability and assessment of soil crustability and erodibility: I. Theory and methodology. European Journal of Soil Science 47: 425–437.
26- Leroy B.L.M., Herath H.M.S.K., De Neve S., Gabriels D., Bommele L., Reheul D., and Moens M. 2008. The application of vegetable, fruit and garden waste (VFG) compost in addition to cattle slurry in a silage maize monoculture.
27- Mueller L., Shepherd G., Schindler U., Ball BC., Munkholm L.J., Hennings V., Smolentseva E., Rukhovic O., Lukin S., and Hu C. 2013. Evaluation of soil structure in the framework of an overall soil quality rating. Soil and Tillage Research 127: 74–84.
28- Mueller L., Kay B.D., Hu C., Li Y., Schindler U., Behrendt A., Shepherd T.G., and Ball B.C. 2009. Visual assessment of soil structure: evaluation of methodologies on sites in Canada, China and Germany part I: comparing visual methods and linking them with soil physical data and grain yield of cereals. Soil and Tillage Research 103: 178–187.
29- Naseri M., Alimohammadi S., and Jafari A.A.N. 2007. Soil compaction due to sugarcane mechanical harvesting and the effects of physical soil of improvement the on subsoiling. Journal of Applied Sciences 7: 3638 -3639.
30- Nelissen V., Ruysschaert G., Abusi DM., DˈHose T., De Beuf K., Al-Barri B., Cornelis W., and Boeckx P. 2015. Impact of a woody biochar on properties of a sandy loam soil and spring barley during a two-year field experiment. Eur J Agron., 62: 65-78.
31- Niewczas J., and Witkowska-Walczak B. 2003. Index of aggregates stability as linear function value of transition value of transition matrix elements. Soil and Tillage Research 70: 121–130.
32- Nimmo J.R., and Perkins K.S. 2002. Aggregate stability and size distribution. In: Dane, J.H., Topp, G.C. (Eds.) Methods of Soil Analysis, Part 4 Physical Methods. Madison, Wisconsin, Soil Science Society of America 317–328.
33- Pierce F.J., Larson W.E., Dowdy R.H., and Graham W.A.P. 1983. Productivity of soils: assessing long-term changes due to erosion. Journal of Soil Water Conservation 38: 39–44.
34- Pieri C.J.M.G. 1992. Fertility of Soils: A Future for Farming in the West African Savannah. Springer-Verlag, Berlin, Germany.
35- Pulido Moncada M., Lobo L.D., and Lozano P.Z. 2009. Association between soil structure stability indicators and organic matter in Venezuelan agricultural soils. Agrociencia 43: 221–230.
36- Rawlins B.G., Wragg J., and Lark R.M. 2013. Application of a novel method for soil aggregate stability measurement by laser granulometry with sonication. European Journal of Soil Science 64: 92–103.
37- Reynolds W.D., Drury C.F., Tan C.S., Fox C.A., and Yang X.M. 2009. Use of indicators of pore volume-function characteristics to quantify soil physical quality. Geoderma 152: 252–263.
38- Reynolds W.D., Drury C.F., Yang X.M., Fox C.A., Tan C.S., and Zhang T.Q. 2007. Land management effects on the near-surface physical quality of a clay loam soil. Soil and Tillage Research 96: 316–330.
39- Rohoskova M., and Valla M. 2004. Comparison of two methods for aggregate stability measurement – areview. Plant Soil and Environment 50: 379–382.
40- Seybold C.A., and Herrick J.E. 2001. Aggregate stability kit for soil quality assessments. Catena 44: 37–45.
41- Shukla M.K., Lal R., and Ebinger M. 2006. Determining soil quality indicators by factor analysis. Soil and Tillage Research 87: 194–204.
42- Soil Survey Staff. 2014. Soil survey laboratory methods manual. Soil survey investigations report No. 42, Version 5. USDA, NRCS, National Soil Survey Center.
43- van Genuchten M.T. 1980. A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Science Society of America Journal 44: 892–898.
44- Vermang J., Cornelis W.M., Demeyer V., and Gabriels D. 2009. Aggregate stability and erosion response to antecedent water content of a loess soil. Soil Science Society of America Journal 73: 718–726.
45- Walkley A., and Black I.A. 1934. An examination of the Degtjareff method for determining organic carbon in soils: effect of variations in digestion conditions and of inorganic soil constituents. Soil Science 6: 251–263.
46- Yoder R.E. 1936. A direct method of aggregate analysis and a study of the physical nature of erosion losses. Journal of the American Society of Agronomy 28: 337–351.