بررسی کیفیت خاک با استفاده از کربن ناپایدار و شاخص مدیریت کربن در زمین های کشاورزی منطقه نی ریز، استان فارس

نوع مقاله : مقالات پژوهشی

نویسندگان

• آناهید سلمان پور ¹
• محمد حسن صالحی ²
• جهانگرد محمدی ¹

¹ دانشگاه شهرکرد

² شهر کرد

https://doi.org/10.22067/jsw.v30i3.41898

چکیده

از مؤلفه های مهم کشاورزی پایدار در مناطق خشک و نیمه خشک، مقدار آب و شوری آب و خاک است که از عوامل مهم کاهش کیفیت خاک، محسوب می‌شوند. مواد آلی شاخصی از کیفیت خاک است، اما از آنجا که به تغییرات مدیریت خاک به کندی پاسخ می دهد، مطالعه اجزاء حساستر آن ممکن است باعث تشخیص بهتر نقش تغییر مدیریت بر کیفیت خاک گردد. از این رو تحقیق حاضر با هدف بررسی کیفیت خاک با استفاده از شاخصهای کربن ناپایدار و مدیریت کربن خاک در تعدادی از اراضی کشاورزی نیریز در استان فارس انجام گردید. برای این منظور پنج مزرعه از مزارع گندم و جو آبی در حومه شهر نیریز که مقدار و شوری آب آبیاری متفاوت داشتند، انتخاب گردیدند. در هر مزرعه، سه نقطه انتخاب و نمونه‌های خاک از عمق 40-0 سانتیمتر و نمونه‌های گیاه در مربعهای 1×1 متر، تهیه شد. نمونه آب نیز، از چاه آبیاری برداشت گردید. ویژگیهای فیزیکی و شیمیایی خاک و آب اندازه گیری و مقدارکربن ناپایدار و شاخص مدیریت کربن خاک محاسبه گردید. نتایج نشان داد کربن ناپایدار خاک نسبت به کربن آلی کل، حساسیت بیشتری به مدیریت زراعی دارد و حتی در مزارع با مدیریت زراعی یکسان و عملکرد مشابه، مقدار و یا شوری متفاوت آب آبیاری می تواند باعث تغییر در کربن ناپایدار خاک و در نتیجه کیفیت خاک گردد. براساس نتایج، مقدار بالاتر شاخص مدیریت کربن لزوماً با عملکرد بالاتر محصول ارتباط ندارد و ممکن است با ویژگیهای کیفی محصول ارتباط داشته باشد که نیاز به تحقیق بیشتر دارد.

کلیدواژه‌ها

• کربن ناپایدار
• شاخص مدیریت کربن
• کیفیت خاک
• نی ریز

20.1001.1.20084757.1395.30.3.22.6

عنوان مقاله [English]

Evaluation of Soil Quality Using Labile Organic Carbon and Carbon Management Indices in Agricultural Lands of Neyriz, Fars Province

نویسندگان [English]

• Anahid Salmanpour ¹
• Mohammad hasan Salehi ²
• jahangard mohammadi ¹

¹ Shahr-e-kord uniiversity

²

چکیده [English]

Introduction: Soil organic matter is considered as an indicator of soil quality, because of its role on the stability of soil structure, water holding capacity, microbial activity, storage and release of nutrients. Although changes and trends of organic matter are assessed on the basis of organic carbon, it responds slowly to changes of soil management. Therefore, identifying sensitive components of organic carbon such as carbon labile lead to better understanding of the effect of land use change and soil management on soil quality.
The main components of sustainable agriculture in arid and semi-arid regions are the amount of water; and soil and water salinity. Water deficit and irrigation with saline water are important limiting factors for cropping and result in adverse effects on soil properties and soil quality. Soil carbon changes is a function of addition of plant debris and removal of it from soil by its decomposition. If the amount of organic carbon significantly reduced due to the degradation of the soil physical and chemical properties and soil quality, agricultural production will face serious problems. To this end, this study was done to evaluate soil quality using soil labile carbon and soil carbon management indices in some agricultural lands of Neyriz area, Fars province, Iran.
Materials and Methods: Five fields were selected in two regions, Dehfazel and Tal-e-mahtabi, consisted of irrigated wheat and barley with different amount of irrigation water and water salinity levels. Three farms were located in Dehfazel and two farms in Tal-e-Mahtabi region. In each farm, three points were randomly selected and soil samples were collected from 0-40 cm of the surface layer. Plant samples were taken from a 1x1 square meter and grain crop yield was calculated per hectare. Water samples were obtained in each region from the wells at the last irrigation. Physical and chemical characteristics of the soil and water samples were determined. Soil labile carbon and carbon management indices also were calculated. In carbon management index calculation, a reference farm was chosen at the vicinity of two regions which were abandoned for years. Statistical analysis like analysis of variance and correlation coefficients was done using SPSS 16.0 software.
Results and discussion: Results revealed that the highest crop yield (with the average of 5.7 tonh-1) was related to the farm which was irrigated with saline water (water EC 8.1 dSm-1) with enough water crop requirement. As this farm received the highest amount of water (with thw volume of 1039.5 mm), it seems that much more irrigation water probably provided the leaching fraction and prevented salt accumulation in the the root zone. Therefore, water salinity could not be a limiting factor for crop growth in this farm. This farm also had the highest content of organic carbon but it didn’t have the highest labile organic carbon and carbon management index (the value of 161.5).
On the other hand, the farm containing the highest labile carbon and carbon management indices (the value of 284), didn’t have the highest crop yield (with the average of 2.6 tonha-1) although it has recieved enough amount of water as well as non-saline irrigation water (water EC 2.28 dSm-1). The more carbon management index represents the higher soil carbon lability and soil quality and it demonstrates that soil have better condition for living microorganisms. Therefore, it can be concluded from the results that the higher soil quality not necessarily resulted in higher crop yield. Many researchers reported that better soil properties are not always resulted in the higher productivity.
Taking everything into account, carbon management index is not related to crop yield, but since it indirectly is related to microbial activity and calculated easily, it could be a useful indicator for rapid assessment of soil quality. Meanwhile, this indicator may be associated with qualitative properties of the crops such as grain protein, which is recommended for future investigations.
Conclusion: Results showed that labile organic carbon is more sensitive to crop management than total organic carbon. Amount of irrigation water and its salinity can influence the labile organic carbon content and thus the soil quality even in the fields with the same crop yield and management. Although, a higher amount of carbon management index does not result in higher yield production, it may be associated with crop quality attributes. More investigation is needed to give better idea in this regard.

کلیدواژه‌ها [English]

• Crop Yield
• Soil salinity
• Water Salinity

مراجع

1- Benbi D.K., Brar K., Toor A.S., and Singh P. 2015. Total and labile pools of soil organic carbon in cultivated and undisturbed soils in northern India. Geoderma, 237–238: 149–158.

2- Blair G.J., Rod D., Lefroy B., and Lisle L. 1995. Soil Carbon Fractions Based on their Degree of Oxidation, and the development of a Carbon Management Index for agricultural systems. Australian Journal of Agricultural Research, 46:1459-66.

3- Bremer E., Janzenl H.H., and Johnstonz A.M. 1994. Sensitivity of total, light fraction and mineralizable organic matter to management practices in a Lethbridge soil. Canadian Journal of Soil Science, 74(2):131-138.

4- Dordipour I., Ghadiri H., Bybordi M., Siadat H., and Malakouti M.J. 2004. The use of saline water from the Caspian Sea for irrigation and barley production in northern Iran. Paper no. 986. ISCO 2004. 13th International Soil Conservation Organization Conference, Brisbane, Australia.

5- FAO. 2014. Irrigation Water Management: Irrigation water needs. Available athttp://www.fao.org/docrep/S2022E/s2022e02.htm

6- FAO. 2014a. Manual for Local Level Assessment of Land Degradation and Sustainable Land Management. Part 2 - Soil assessment. Available at http://www.fao.org/nr/kagera/tools-and-methods/lada-local-level-assessment-manuals/en/

7- Fars statistical year book. 2007. Fars management and planning Organization. Office of the president management and planning organization. (In Persian)

8- Fars statistical year book. 2007. Fars management and planning Organization. Office of the president management and planning organization. (In Persian)

9- Hassanshahi H., and Dastoor J. 1995. Reconnaissance soil survey of Neyriz basin (Fars Province). Soil and Water Research Institute. No. 1033 on technical issues. (In Persian)

10- Homaee M., 2002. Plants response to salinity. Iranian national committee on irrigaton and drainage (IRNCID). Tehran. (In Persian)

11- Jalalian A., Rostaminia M., Ayoubi S., and Amini A. 2008. Qualitative, quantitative and economic land suitability evaluation for wheat, maize and sesame production in Mehran Plain, Ilam Province. Journal of Science and Technology of Agriculture and Natural Resources, Water and Soil Science - Isfahan University of Technology, 11 (42): 393-403. (In Persian with English abstract)

12- Kumar S., Nakajima T., Mbonimpa E.G., Gautam S., Somireddy U.R., Kadono A., Lal R., Chintala R., Rafique R., and Fausey N. 2014. Long-term tillage and drainage influences on soil organic carbon dynamics, aggregate stability and corn yield. Soil Science and Plant Nutrition, 60:108–118.

13- Mirsky S. B., Lanyon L.E., and Needelman B.A., 2008. Evaluating Soil Management Using Particulate and Chemically Labile Soil Organic Matter Fractions. Soil Science Society of America Journal, 72(1):180-185.

14- Mirzaei A., Naseri R., Emami T., and Jozeyan A. 2012. Effect of salinity on germination and seedling growth of bread wheat(Triticum aestivum L.). International Journal of Agriculture and Crop Sciences, 4 (15): 1089-1091.

15- NRCS (Natural resources conservation service). 2011. Crop tolerance and yield potential of selected crops as influenced by irrigation water salinity (ECw) or soil salinity (ECe). Available at http://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/ publications/ azpmstn10485.pdf

16- Oster J.D., 1994. Irrigation with poor quality water. Agricultural Water Management, 25(3): 271-297.

17- Shahrokh V., Ayoubi SH., and Jalalian A. 2011. Qualitative, quantitative and economical land suitability evaluation for wheat and rice production and assessment of their environmental impacts in Zarrinshahr and Mobarakeh Isfahan Province. Journal of Water and Soil Conservation (Journal of Agricultural Sciences and Natural Resources), 37-59. (In Persian with English abstract(

18- Strosser E. 2010. Methods for determination of labile soil organic matter: An overview. Journal of Agrobiology, 27(2): 49–60.

19- Ullah S.M., Gerzabek M.H., and G.Soja. 1994. Effect of seawater and soil salinity onion uptake, yield and quality of tomato (fruit). Bodenkultur-wien and Muchen, 45:227-227.

20- Van Hoorn J.W., Katerji N., and Mastrorilli M. 1993. Effect of saline water on soil salinity and on water stress, growth and yield of wheat and potatoes. Agricultural Water Management, 23: 246-265.

21- Vieira F.C.B., Bayer C., Zanatta J.A., Mielniczuk J., He Z.L., and Dieckow J. 2007. Carbon management index based on physical fractionation of soil organic matter in an Acrisol under long-term no-till cropping systems. Soil and Tillage Research, 96:195-204.

22- Walkley A., and Black I.A. 1934. An examination of Degtjareff method for determining soil organic matter and a proposed modification of chromic acid titration method. Soil Science, 37(1):29-38.

23- Weil R.R., Islam K.R., Stine M.A., Gruver J.B., and Samson-Liebig S.E. 2003. Estimating active carbon for soil quality assessment: A simplified method for laboratory and field use. American Journal of Alternative Agriculture, 18(1):3-17

24- Wong V.N., Greene R.S., Murphy B.W., Dalal R., Mann S., and Farquhar G. 2006. The effects of salinity and sodicity on soil organic carbon stocks and fluxes: an overview. Regolith Consolidation and Dispersion of Ideas, 7:367-371

25- Xu M., Lou Y., Sun X., Wang W., Baniyamuddin M., and Zhao K. 2011. Soil organic carbon active fractions as early indicators for total carbon change under straw incorporation. Biology and Fertility of Soils, 47:745–752.

26- Lou Y., Xu M., Chen X., He X., and Zhao K. 2012. Stratification of soil organic C, N and C: N ratio as affected by conservation tillage in two maize fields of China. Catena, 95: 124-130.

27- Yang X., Ren W., Sun B., and Zhang S. 2012. Effects of contrasting soil management regimes on total and labile soil organic carbon fractions in a loess soil in China. Geoderma, 177:49–56.