Organic Matter Unstability (Ripening) Evaluation in Histosolsof South-west Shahrekord

Document Type : Research Article

Authors

• J. Givi
• F. Raeisi
• F. Dehghani

Shahrekord University

https://doi.org/10.22067/jsw.v0i0.30852

Abstract

Purpose of this research was evaluationof organic matter unstability (ripening) of Histosolsof south-west Shahrekord,using humusunstability indices, including ratios of humic acid (HA) to fulvic acid (FA), sum of organic material types, soluble in alkali (AE=FA+HA) to humin fraction (HUM) and also ratio of optical density at 465 (E4)tooptical density at 665 nanometer (E6) of organic matter and its components.The studied area has cool and semi-arid climate. Some of the soils formed in the studied area are Histosols.Five soil profiles were described down to depth of 2 m and soil samples were collected from their different horizons. Chemical fractionation of organic matter to fulvic acid, humic acid and humin was done and the content of each of these three components and the amounts of E4and E6 were measured.In all of the soil profiles, variations of the fulvic acid, humic acid and humin contents are similar to variations of organic matter contents. More than 94 percent of the soil organic matter has changed to humus. Increase of HA/FA with increase of soil depth indicates high degree of polymerization and humification (stability) of organic matter in underlying layers and higher rate of humic material decomposition (unstability) in surface layers. Lower rate of humic material decomposition in underlying layers is due to increase of clay content with increase of soil depth and adsorption of humin by clay particles. E4/E6 of the whole soil also decreased regularly from soil surface towards soil depth. This decrease is another evidence for increase of organic matter stability. Highest organic matter unstability was observed in the profile 5. This profile contains hemic but the others have sapric organic material.

Keywords

• Humic material
• HA/FA, E4/E6
• Organic matter unstability (Ripening)

20.1001.1.20084757.1394.28.6.12.2

References

1- دهقانی س. 1389. نقش پستیوبلندی وپوشش ‌گیاهی در تشکیل وتکامل خاک‏های آلی در مقایسه با سایر خاک‏های یک ردیف پستی وبلندی در اطراف شهرکرد.پایان نامه کارشناسی ارشد مهندسی علوم خاک،دانشکدهکشاورزی،دانشگاه شهرکرد.

2- فرقانی ا. 1382. مطالعه تغییرات بیوشیمیایی و خصوصیات اسیدهای هیومیک و فولویک خاک‏های مختلف تیمار شده با مواد آلی مختلف. مجموعه مقالات کوتاه هشتمین کنگره علوم خاک ایران، 9 تا 12 شهریور ماه، دانشگاه گیلان، صفحات 78 تا 79.

3- گلچین ا.، بشارتی ح. و شفیعی س. 1389. عوامل مؤثر بر دینامیک مواد آلی و تأثیر آن بر ویژگی های خاک. اولین کنگره چالش های کود در ایران: نیم قرن مصرف کود، 10 تا 12 اسفند، هتل المپیک تهران، صفحات 1-17.

4- لکزیان ا. 1387. میکروبیولوژی خاک. انتشارات دانشگاه فردوسی مشهد، مشهد.

5- Anderson D.W., and Schoenau J.J. 2007.Soil humus fractions. p. 675-680. In M.R. Carter and E.G. Gregorich (eds.), Soil Sampling and Methods of Analysis. Saskatoon, Saskatchewan, Canada.

6- Bockheim J.G., and Gennadiyev A.N. 2000. The role of soil-forming processes in the definition of taxa in Soil Taxonomy and the World Reference Base for Soil Resources.Geoderma, 95: 53-72.

7- Buol S.W., Hole F.D., and McCraken R.J. 2003. Soil genesis and classification.5thed., Iowa State University Press, Ames, Iowa.

8- Caldwell P.V., Vepraskas M.J., and Gregory J.D. 2007. Physical properties of natural organic soils in Carolina Bays of the Southeastern United States. Soil Science Society of America Journal, 71 :1051-1057.

9- Chen Y., Senesi N., and Schnitzer M. 1977. Information provided on humic substances by E4/E6 ratios. Soil Science Society of America Journal, 41: 352-358.

10- Everett K.R. 1983.Histosols. p. 1-53. In L.P. Wilding et al. (eds.).Pedogenesis and Soil Taxonomy:II. The Soil Orders. Elsevier, New York.

11- Maryganova V. 2000. Impact of various genesis on chemical structure of peat humic substances. p. 618-626. In L. Rochefort and J.Y. Daigle (eds.). Sustaining our peatlands.Proceedings of the 11th International Peat Congress, Quebec, Vol. II.

12- Nelson D.W., and Sommers L.E. 1982. Total carbon, organic carbon and organic matter. p. 539-579. In A.L. Page et al. (eds.). Methods of Soil Analysis.Part 2.2nd ed. Agron.Monogr. 9.ASA and SSSA, Madison, WI.

13- Richardson J.L., and Vepraskas M.J. 2001.Wetland Soils Genesis, Hydrology, Landscapes and Classification. LEWIS/CRC,NewYork.

14- Riger S., Schoephorster D.B., and Furbush C.E. 1979.Exploratory Soil Survey of Alaska. USDA-SCS, Washington DC.

15- Soil Survey Staff. 1998. Keysto Soil Taxonomy.8thed. USDA-NRCS.U.S. Govt. Printing Office, Washington DC.

16- Soil Survey Staff .2010. Keys to Soil Taxonomy.11thed. USDA-NRCS.U.S. Govt. Printing Office, Washington DC.

17- Szajdak L., Brandyk T., and Szatylowicz J. 2007.Chemical properties of different peat-moor soils from the Biebrza River Valley. Agronomy Research, 5:165-174.

18- Valladares G.S., Anjos L.H., Pereira M.G., Benites V.M., Ebeling A.G., and Mouta R.O. 2007. Humic Substance Fractions, Attributes of Histosols and Related High-Organic-Matter Soils from Brazil. Communications in Soil Science and Plant Analysis, 38:763-777.