بخش‌بندی اندازه‌ای و بیوشیمیایی کربن آلی خاکِ همراه با ریشه‌ی چند گیاه مرتعی

نوع مقاله : مقالات پژوهشی

نویسندگان

• حسن لطفی پارسا ¹
• محسن شکل آبادی ²
• قاسم اسدیان ³

¹ بوعلی سینا

² دانشگاه بوعلی سینا

³ مرکز تحقیقات کشاورزی منابع طبیعی همدان

https://doi.org/10.22067/jsw.v33i5.80484

چکیده

بخش­بندی اندازه دانه­ای و بیوشیمیایی کربن آلی روشی سودمند در شناخت و بررسی پویایی و فرایند­های نگهداشت، تجزیه و خروج آن­ها از خاک می­باشد. مراتع حاوی بیش از یک سوم ذخایر کربن زمین بوده و یکی از مهم­ترین اکوسیستم­ها جهت ذخیره کربن بشمار می­روند. از این رو این مطالعه با هدف بررسی تغییرات بخش­بندی اندازه دانه­ای و بیوشیمیایی کربن آلی خاک در فواصل مختلف از سطح ریشه­ی پنج گیاه مرتعی در استان همدان انجام پذیرفت. جداسازی خاک­های ریزوسفری از ریشه­ها انجام شد و خاک­ها به سه بخش خاک ریزوسفری، بین ریزوسفری و توده­ای تقسیم شدند. بخش­بندی اندازه دانه­ای و بیوشیمیایی کربن آلی روی خاک­ها انجام شد. بیشترین میزان کربن آلی در نواحی نزدیک به ریشه­ها و خاکدانه­های کوچک‌تر از 15/0 میلی­متر مشاهده گردید. علیرغم فعالیت بالای ریزجانداران در این نواحی، میزان کربن آلی به‌دلیل ترشحات ریشه­ای همچنان بالاتر از نقاط دورتر از ریشه بود. بخش­های مختلف بیوشیمیائی کربن و MWD دارای همبستگی بسیار معناداری با کربن آلی کل بودند که نشان­دهنده­ی اثر کربن آلی خاک بر ویژگی­های فیزیکی و شیمیایی خاک است. بخش‌های بیوشیمیایی در نزدیک ریشه­ها که شدت تجزیه­ی کمتری داشتند مربوط به کربن محلول در آب و کربن قابل دسترس بود در حالی‌که با افزایش فاصله از سطح ریشه مقادیر کربن مقاوم به تجزیه افزایش می­یافت.

کلیدواژه‌ها

• خاکدانه سازی
• کربن آلی
• ریزوسفر
• کمپلکسهای آلی-معدنی
• گیاه مرتعی

20.1001.1.20084757.1398.33.5.9.8

عنوان مقاله [English]

Particle Size and Biochemical Fractionation of Soil Organic Carbon Associated with the Roots of some Rangeland Plants

نویسندگان [English]

• Hassan Lotfi Parsa ¹
• Ghasem Asadian ³

¹ Bu Ali sina University

²

³ Agriculture and Natural Resources Research and Education Center of Hamedan

چکیده [English]

Introduction: Soil organic carbon (SOC) is released from decomposition of plant residues, while root secretion products in rhizosphere are also a substantial source of SOC input to soil. Binding SOC to clay minerals leads to increase aggregate stability and protect organic carbon against microorganisms. Organo-mineral complexes have important role in decreasing organic carbon decomposition. Assessment of organic carbon particle size and biochemical fractionation is an appropriate approach to investigate organic carbon dynamics and durability against microorganisms in rhizosphere as a hot spot of activity.  
Materials and Methods: The study area was a semi-arid rangeland with the main plants species including five perennial rangeland species: crested wheat grass (Agropyron cristatum), astragalus (Astragalus verus), sheep fescue (Festuca ovina), phlomis (Phlomis oliveri), feverfew (Tanacetum parthenium). Whole soil surrounding plant roots with all roots was taken for each plant. Three sample with different distances from root surface were taken by applying this procedure: sample A: The soil which is adhered to the root surface and separates quickly from roots after drying, sample B: The soil in root zone, which is not stuck and almost is so close to roots, sample C: The soil which is wholly far from root area and apparently not affected by roots. Intact samples removed from ground and transferred quickly to laboratory to separate roots and soils with different distances from root surface by drying the root system before shaking. Particle size fractionation was done by wet sieving of aggregates and SOC in different aggregate sizes was measured by wet combustion method. Biochemical fractionation of SOC was done by acid hydrolysis method to study organic carbon stability at different distances from root surface.
Results and Discussion: ANOVA results showed a significant effects of plants and distance from root surface on aggregate size classes. The results showed the increasing amounts of microaggregates at root vicinities compare to macroaggregates. By increasing distance from root surface, the >2 mm aggregates increased, but, the amount of <0.15 mm aggregates decreased significantly. Toward root surface from C to A locations, the mean weight diameter (MWD) of soil aggregates decreased due to decreasing macro-aggregates at root vicinity. Maenwhile, SOC increased approaching to root surface due to root exudates and rhizodeposits. The highest and lowest of SOC content were found in the A location of Feverfew and the C location of Astragalus (4.16 and 0.82%), respectively. The OC contents in root vicinity were higher than other locations due to high root exudates and rhizodeposits which had C-containing molecules. Soil OC contents had significant correlation with measured soil parameters. The highest SOC content was found in micro-aggregate and in vicinity of roots. Low-decomposed OC, which has crucial role in linking microaggregates to make macroaggregates, led to high OC contents in macroaggregates. Soil OC biochemical fractionation demonstrated higher OC contents in recalcitrant pool at further distances from root surface, while by going toward root vicinity the amounts of OC in water soluble and labile pool increased. In average for A locations, 66% of total OC was measured as water soluble fraction, while for C location, the average fraction of labile and recalcitrant pools from total OC were found 62.5% and 50%, respectively. As the root exudates had fresh OC such as carbohydrates and sugars, the concentration of OC in water soluble and labile pools were so high at root vicinity. Moreover, OC in labile and water soluble pools had high correlation coefficient and, contributed to high fractions of total OC in root vicinity. Whilst C in recalcitrant pool were found higher in further distances from root surface, because activities of microorganisms and the fresh OC were decreased toward bulk soil.
Conclusion: This study investigated the effect of root activities of five perennial rangeland plants on the particle size and biochemical fractionation of soil OC at different distances from root surface. In root vicinity due to addition of fresh OC from roots to soil and higher microorganisms’ activities, mineral particles were aggregated to micro-aggregates which contained a large fraction of soluble and labile Soil OC. But, recalcitrant OC were dominated in macro-aggregates far from root surface. Rangeland plants with various root systems and characteristics had strong impact on particle size and biochemical fractionation of soil OC which needs more investigation. Durability of biochemical C pools has important role in carbon dynamic and stability in soil.

کلیدواژه‌ها [English]

• Physical fraction
• Biochemical fraction
• , rangeland plants
• Rhizosphere
• organo-mineral complexes

مراجع

1- Azarnivand H., Joneidi H., Zare Chahooki M.A., and Maddah Arefi H. 2011. Investigation of the effects of some ecological factors on carbon sequestration in Artemisia sieberi rangelands of Semnan province. Journal of Range and Watershed Management 64: 107–127. (In Persian)

2- Baldock J.A., and Skjemstad J.O. 2000. Role of the soil matrix and minerals in protecting natural organic materials against biological attack. Organic. Geochemistry 31: 697–710.

3- Barber S.A. 1984. Soil Nutrient Bioavailability. John Wily and Sons Publication. New York.

4- Bernoux M., Carvalho M.C.S., Volkoff B., and Cerri C.C. 2002. Brazil’s soil carbon stocks. Soil Science Society of America Journal 66: 888–896.

5- Brahim N., Blavet D., Gallali T., and Bernoux M. 2011. Application of structural equation modeling for assessing relationships between organic carbon and soil properties in semiarid Mediterranean region. International Journal of Environmental Science and Technology 8: 305–320.

6- Chantigny M.H., Angers D.A., and Beauchamp C.J. 1999. Aggregation and organic matter decomposition in soil amended with de-inking paper sludge. Soil Science Society of America Journal 63: 1214–1222.

7- Chen D.Z., Zhang J.X., and Chen J.M. 2010. Adsorption of methyl tert-butyl ether using granular activated carbon: Equilibrium and kinetic analysis. International Journal of Environmental Science and Technology 7: 235–242.

8- Chenini I., and Khemiri S. 2009. Evaluation of ground water quality using multiple linear regression and structural equation modeling. International Journal of Environmental Science and Technology 6: 509–519.

9- Christensen B.T. 1996. Carbon in primary and secondary organomineral complexes. In structure and organic matter storage in agricultural soils in: Cater, M. R.; Stewart, B. A., (Eds.) 97–165. CRC Press, Boca Raton.

10- Denef K., and Six J. 2005. Clay mineralogy determines the importance of biological versus abiotic processes for macroaggregate formation and stabilization. European Journal of Soil Science 56: 469–479.

11- Dijkstra F.A., Carrillo Y., Pendall E., and Morgan J.A. 2013. Rhizosphere priming: a nutrient perspective. Frontiers in Microbiology 4: 204–216.

12- Kaiser K., and Zech W. 1999. Release of natural organic matter sorbed to oxides and a subsoil. Soil Sciences Society American Journal 63: 1157–1166.

13- Kemper W.D., and Rosenau R.C. 1986. Aggregate stability and size distribution. In: Methods of soil analysis. Part 1: physical and mineralogical methods. A. Klute (eds) (Monograph no.9,2nd edn). ASA, Madison, Wis, America.

14- Kuzyakov Y., Hill P.W., and Jones D.L. 2007. Root exudate components change litter decomposition in a simulated rhizosphere depending on temperature. Plant and Soil 290: 293–305.

15- Lal R. 2002. Soil carbon dynamic in cropland and rangeland. Environment Pollution 116: 353–362.

16- Liu YL., Yao SH., Han XZ., Zhang B., and Banwart SA. 2017. Soil Mineralogy Changes with Different Agricultural Practices During 8-Year Soil Development from the Parent Material of a Mollisol. Advances in Agronomy 142: 143–179.

17- Loeppert R.H., and Suarez D.L. 1996. Carbonate and gypsum. In D.L. Sparks et al. (ed.) Methods of soil analysis. Part 3. 3rd ed. SSSA Book Ser. 5. SSSA, Madison, WI p. 437–474.

18- Lopez-Sangil L., and Rovira P. 2013. Individual closed chamber: an alternative method for quantifying 14C in both labeled organic and inorganic carbon substrates. Biogeochemistry 112:139-148.

19- Mehra O.P., and Jackson M.L. 1960. Iron oxide removal from soils and clays by dithionite-citrate systems buffered with sodium bicarbonate. Clays and Clay Minerals 7: 317–327.

20- Okoye A.I., Ejikeme P.M., and Onukwuli O.D. 2010. Lead removal from wastewater using fluted pumpkin seed shell activated carbon: Adsorption modeling and kinetics. International Journal of Environmental Science and Technology 7: 793-800.

21- Paustian K., Levine E., Post W.M., and Ryzhova I.M. 1997. The use of models to integrate information and understanding of soil C at the regional scale. Geoderma 79: 227–260.

22- Pronk GJ., Heister K., Ding GC., Smalla K., and Kögel-Knabner I. 2012. Development of biogeochemical interfaces in an artificial soil incubation experiment; aggregation and formation of organo-mineral associations. Geoderma 189: 585–594.

23- Rovira P., Romanyà J., and Duguy B. 2012. Long-term effects of wildfires on the biochemical quality of soil organic matter: a study on Mediterranean shrublands. Geoderma 179: 9–19.

24- Safari Sinegani A.A., and Rashidi T. 2011. Changes in phosphorus fractions in the rhizosphere of some crop species under glasshouse conditions. Journal of Plant Nutrition and Soil Science 174: 899–907.

25- Safari Sinegani A.A. 2013. Soil Biology and Biochemistry. Bu-Ali Sina University Publication center, Hamadan, Iran. (In Persian)

26- Safari Sinegani A.A. 2015. Soil Organic Matter. Bu-Ali Sina University Publication Center, Hamadan, Iran. (In Persian)

27- Schuman G.E., Reeder J.P., Manley J.T., Hart R.H., and Manley W.A. 1999. Impact of grazing management on the carbon and nitrogen balance of a mixed grass rangeland. Ecological Application 9: 65–71.

28- Silveira M.L., Comerford N.B., Reddy K.R., Cooper W.T., and El-Rifai H. 2008. Characterization of soil organic carbon pools by acid hydrolysis. Geoderma 144: 405–414.

29- Turpault MP. 2006. Sampling of rhizosphere soil for physico-chemical and mineralogical analyses by physical separation based on dyeing and shaking. In Handbook of methods used in rhizosphere research. Eds. Luster J and Finlay R. pp. 196-197. Swiss Federal Research Institute WSL.

30- Turpault MP., Nys C., and Calvaruso C. 2009. Rhizosphere impact on the dissolution of test minerals in a forest ecosystem. Geoderma 153: 147–154.

31- Von Lützow M., Köegel-Knabner I., Ekschmitt K., Matzner E., Guggenberger G., Marschner B., and Flessa H. 2006. Stabilization of organic matter in temperate soils: Mechanisms and their relevance under different soil conditions—A review. European Journal of Soil Science 57: 426–445.

32- Walkley A., and Black I.A. 1934. An Examination of the Degtjareff Method for Determining Soil Organic Matter, and A Proposed Modification of the Chromic Acid Titration Method. Soil Science 37: 29–38.

33- Zhang H., and Zhou Z. 2018. Recalcitrant carbon controls the magnitude of soil organic matter mineralization in temperate forests of northern China. Forest Ecosystems, 5(1), p.17.

34- Zimmermann M., Meir P., Bird M., Malhi Y., and Ccahuana A. 2009. Litter contribution to diurnal and annual soil respiration in a tropical montane cloud forest. Soil Biology and Biochemistry 41: 1338–1340.

35- Zornoza R., Mataix-Solera J., Guerrero C., Victoria A., Garcia-Orenes F., Mataix B., and Morugan A. 2007. Evaluation of soil quality using multiple lineal regressions based on physical, chemical and biochemical properties. Science of the Total Environment 378: 233–237.

36- Zubair M., Anwar F., Ashraf M., and Chatha S. 2012. Effect of green and farmyard manure on carbohydrates dynamics of salt-affected soil. Journal of Soil Science and Plant Nutrition 12: 497–510.