نوع مقاله : مقاله پژوهشی

نویسنده

استادیار دانشکده آب و خاک دانشگاه زابل

چکیده

عدم مدیریت صحیح در استفاده از منابع طبیعی همچون خاک می­تواند باعث تخریب خصوصیات کیفی آن و متعاقباً کاهش حاصلخیزی خاک شود. این مسئله، لزوم پایش مکانی این خواص در راستای ارائه راهکارهای مطلوب مدیریتی جهت حفظ حاصلخیزی آن را نشان می­دهد. به همین منظور، در این پژوهش، به پایش مکانی خصوصیات کیفی خاک در لایه سطحی در اراضی آبیاری شده با پساب شهری با قدمتی طولانی بر اساس روش­های زمین­آماری و ارزیابی آن بر اساس محدوده استاندارد جهانی پرداخته شد. بدین منظور خصوصیات کیفی خاک شامل نسبت جذب سدیم (SAR)، درصد سدیم تبادلی (ESP)، هدایت الکتریکی (EC) و واکنش خاک (pH) از منطقه­ای با وسعت 190 هکتار و در پیکسل­هایی با ابعاد 150 در 150 متر برداشت شد و امکان تهیه نقشه­های رستری با روش­های میانگین متحرک وزنی (WMA)­، کریجینگ و کوکریجینگ فراهم گردید. نتایج نشان داد روش کریجینگ برای پارامتر ESP و روش WMA برای سایر پارامترها، کمترین خطای تخمین بر اساس معیارهای ارزیابی را به همراه داشت. همچنین استفاده از متغیر کمکی تأثیر مثبتی در افزایش شعاع تأثیر و افزایش دقت درون­یابی نداشت. مقایسه نقشه­های رستری تهیه‌شده بر اساس روش­های منتخب با حدود استاندارد اداره  شوری ایالات‌متحده آمریکا نشان داد، مصرف بدون مدیریت منابع آب نامتعارف در این منطقه باعث شور شدن بیش از 97 درصد از کل منطقه شده است. همچنین خطر وجود سدیم در بیش از 94 درصد از کل منطقه  مشکلات خاک­های منطقه را دوچندان کرده است. این امر می­تواند با تخریب ساختمان خاک، خسارات جبران­ناپذیری را در شرایط بحران شدید آب به همراه داشته باشد. لذا کشاورزی پایدار و امنیت غذایی در منطقه مطالعاتی مستلزم ارائه راهکارهای مدیریتی جهت اصلاح خاک همچون آبشویی در فصل غیر کشت و یا آبیاری ترکیبی با آب سالم در جهت حفظ منافع اقتصادی و محیط‌زیست طبیعی است.

کلیدواژه‌ها

عنوان مقاله [English]

Analyzing the Geostatistical Methods in Spatial Monitoring of Saline and Sodic Condition of Soils under Treated - Wastewater Irrigation

نویسنده [English]

  • Fatemeh Karandish

Assistant Professor, Department of Water Engineer, Faculty of Soil and Water, Zabol University, Iran. (Corresponding author)

چکیده [English]

Unmanaged use of natural resources such as soil would lead to deterioration of its quality and fertility. Consequently, spatial monitoring of these properties is necessary to find the optimal management options to protect soil fertility. Thus, in this study, the long-term effects of treated wastewater irrigation on qualitative properties of surface soil layer were spatially monitored using geostatistical methods and were compared with worldwide standards. Consequently, the soil qualitative properties including sodium adsorption ratio (SAR), exchangeable sodium percentage (ESP), electrical conductivity (EC) and acidity (pH) was analyzed in pixels with 150×105 meter dimension and the possibility of extracting raster maps using weighting moving average (WAM), kriging and co-kriging methods was investigated. Results showed that kriging and WMA had the least estimation error for ESP and the other parameters, respectively, based on the evaluating indices. Also using covariates does not have positive effect on increasing range of influence and interpolation accuracy. Comparing the prepared raster maps by the selected method with the standard values of Soil Survey Manual of USA showed that unmanaged use of unconventional water caused more than 97% of the study area to have saline soils. Also, hazard of sodium in the soils dominated to salinity problem in more than 94% of the study area. These could have irreparable damages under water crisis through degrading soil structure. In conclusion, for sustainable agriculture and food security in the study area it is necessary to offer management options for soil improvement such as leaching in uncultivated seasons or combined irrigation with fresh water to protect economic and environmental issues

کلیدواژه‌ها [English]

  • Spatial monitoring
  • Saline soil
  • Sodic soil
  • Sustainable agriculture
References
Alizadeh A. 2011. New drainage (planning, desining and manageming the drainage systems). 5th edition. Publication of Astan Ghods Razavi, 496 p. (In Persian).
Amini M, Khademi H and Fathianpour N. 2002. Comparing kriging and kokriging in estimating chloride concentration in soil. Iranian journal of agricultural science, 33(4): 741-747. (In Persian).
Babazadeh S, Davatgar N, Darigh-Goftar F and Peykan M. 2012. Spatial variation of some soil properties related to fertility in rice fields in GuilanProvince. Soil Management for Sustainable Agriculture, 2(1): 127- 139. (In Persian).
Barzegar A. 2008. Salt-affected soil: diagnosis and productivity. 2nd edition. ShahidChamranUniversity Press. 355p. (In Persian).
Cambardella CA, Moorman TB, Novak JM, Parkin TB, Karlen DL, Turco RF and Konopka AE. 1994. Field-scale variability of soil proerties in Central Iowa soils. Soil Science Society of America Journal, 58: 1501-1511.
Cheng X, Chen J and Li B. 2006. Spatial relationships among species above-ground biomass, N, P in degraded grassland in Ordos plateau. Journal of Arid Environments, 30: 75-88.
Davatgar N, Neyshabouri MR and Moghadam M. 2001. The analysis of information obtained from soil variables map by Use of Semivariogram Models. Iranian Journal of Agricultural Sciences, 31: 725-735. (In Persian).
Douaoui AE, Nicolas H and Walter C. 2006. Detecting salinity hazard within a semi-arid context by means of combining soil and remote – sensing data. Geoderama, 134: 217-230.
Duffera M, White JG and Weisz R. 2006. Spatial variability of southwestern U.S. Coastal plain soil physical properties. Geoderama, 128: 121-133.
Feizi M. 2001. Effect of treated wastewater on accumulation of heavy metals in plants and soil. ICID International Workshop on Wastewater Reuse Management. Seoul, Korea, pp: 137-146.
Ghanbari A, Abedi Koupai J and Taie-Semiromi J. 2007. Effect of municipal wastewater irrigation on yield and quality of wheat and some soil properties in Sistan zone. Journal of Science and Technology of Agriculture and Natural Resources, 10(4): 59-74. (In Persian).
Ghorbani-Dashtaki Sh, Homaei M and Mahdian MH. 2009. Estimating the infiltration parameters using neural network. Journal of Soil and Water Conservation, 23(1): 185-198. (In Persian).
Karandish F and Shahnazari A. 2013. Zone classification of soil salinity in maize root zone under different irrigation treatments using geostatistical methods. Water and Soil Science, 24(2): 243-256. (In Persian).
Karandish F and Shahnazari A. 2014. Appraisal of the geostatistical methods to estimate Mazandaran coastal ground water quality. Caspian Journal of Environmental Sciences, 12(1): 129-146.
Mekonnen MM and Hoekstra AY. 2012. Water footprint benchmarks for crop production. UNESCO-IHE. Research paper series, No.64. 25p.
Nash JE and Sutcliffe JV. 1970.River flow forecasting through conceptual models. Part 1: A discussion of principles. Journal of Hydrology, 10: 282–290.
Neal M, Khademi H and Hajabbasi AM. 2004. Response of soil quality indicators and their spatial variability to land degradation in central Iran. Applied Soil Ecology, 27: 221-232.
Ozgoz E, Gunal H, Acir N, Gokmen F, Birol M and Budak M. 2011. Soil quality and spatial variability assessment of land use effects in a Typıc Haplustoll. Land Degradation and Development, 26: 1115-1126.
Parchami-Araghi F, Mirlatifi SM, Ghorbani dashtaki S and Mahdian MH. 2013. Point estimation of soil water infiltration process using artificial neural networks for some calcareous soils. Journal of Hydrology, 481: 35–47.
Quine TA and Zhang Y. 2002. An investigation of spatial variation in soil erosion, soil properties and crop production within an agricultural field in Devon, UK. Journal of Soil and Water Conservation, 57: 50-60.
Sun B, Zhou Sh and Zhao Q. 2003. Evaluation of spatial and temporal changes of soil quality based on geostatistical analysis in the hill region of subtropical China. Geoderma, 115: 85-99.
126
 
Vinten AJA, Mingelgrin U and Yaron B. 1983. The effect of suspended solids in wastewater on soil hydraulic conductivity: II. Vertical distribution of suspended solids. Soil Science Society of America Journal, 47: 408-412.
Wilding LP and Dress LR. 1983. Spatial variability and pedology. In: Wilding LP, Smeckand NE, Hall GF, (ed.). Pedogenesis and soil taxonomy. I. Concepts and interactions. Elsevier Science Publication, pp: 83-116.
Yost RS, Uehara G and Fox RL. 1982. Geostatistical analysis of soil chemical properties of large land areas: I. Semivariograms. Soil Science Society of America Journal, 46: 1028–1032.
Zhou HZ, Gong ZT and Lamp J. 1996. Study on soil spatial variability. Acta Pedologica Sinica, 33: 232– 241.