اثر تغییر کاربری اراضی بر شکل‌های فسفر معدنی در خاک‌های لسی منطقه توشن استان گلستان

نوع مقاله : مقالات پژوهشی

نویسندگان

• سمیرا تجری
• مجتبی بارانی مطلق
• فرهاد خرمالی
• فرشاد کیانی

دانشگاه علوم کشاورزی و منابع طبیعی گرگان

https://doi.org/10.22067/jsw.v0i0.29183

چکیده

شکل ها و پویایی فسفر در خاک می تواند تا حدود زیادی تحت تأثیر عملیات مدیریتی کشاورزی قرار گیرد. از آن‌جائی‌که فسفر معدنی منبع غالب برای جذب گیاهی است، لذا آگاهی از شکل های معدنی در خاک ها برای درک و دانستن زیست فراهمی فسفر و پایداری عملیات کشاورزی ضروری است. هدف از این تحقیق، بررسی اثر تغییر کاربری اراضی بر شکل ها و توزیع فسفر معدنی با استفاده از روش عصاره گیری دنباله ای بود. بدین منظور از چهار کاربری (جنگل، مرتع، باغ زیتون، زمین کشاورزی)، بر پایه طرح کاملاً تصادفی با 4 تکرار نمونه‌برداری تصادفی صورت گرفت. نتایج نشان داد که از بین بردن جنگل های طبیعی و تبدیل آن ها به مزارع کشاورزی مقادیر فسفر کل و فسفر کل آلی را به طور معنی داری کاهش داد. افزون بر این، تبدیل کاربری اراضی از جنگل های طبیعی به اکوسیستم های کشاورزی موجب افزایش معنی دار فسفر کل معدنی و شکل های مختلف فسفر معدنی (فسفر لبایل، فسفر نامحبوس، فسفر محبوس در اکسیدهای آهن و آلومینیوم، فسفات های کلسیم محلول و فسفات های کلسیم کم محلول) شد. بیشترین تغییرات را فسفر معدنی لبایل از خود نشان داد، به گونه ای که میزان فسفر لبایل معدنی در اثر تغییر کاربری از 75/1 در اراضی جنگلی به 01/13 میلی گرم در کیلوگرم در اراضی زراعی تغییر یافت که نشانگر افزایش حدوداً 8 برابری نسبت به شاهد (کاربری جنگل) بود. نتایج همچنین نشان داد که فسفر معدنی مقاوم (عصاره گیری شده با اسید) شکل غالب فسفر معدنی در خاک های مورد مطالعه بوده و 50 تا 70 درصد از فسفر کل معدنی را شامل می شود که می تواند بیانگر این باشد که کربنات کلسیم فراهمی فسفر در این خاک ها را کنترل می کند.

کلیدواژه‌ها

• تغییر کاربری
• جزءبندی فسفر
• عصاره گیری دنباله ای
• فسفر معدنی

20.1001.1.20084757.1394.29.2.16.1

عنوان مقاله [English]

Effect of Land Use Change on Inorganic Phosphorus Pools In Loess Derived Soils of the Toshan Region, Golestan Province

نویسندگان [English]

• S. Tajari
• mojtaba barani
• F. Khormali
• F. Kiani

Gorgan University of Agricultural Sciences and Natural Resources

چکیده [English]

Introduction: P in soils exists in many complex chemical forms, which differ markedly in their behavior, mobility and resistance to bioavailability in the soils. The total P content of a soil provides little information regarding the behavior of P in the environment. The various forms of P present to a large degree, determine the fate and transport of P in soils. Fractionation schemes using different chemical sequential extractions have been used in order to describe the many different forms in which P can be found in the soil. The reason for fractionating and studying P forms in the soil is usually to allow a more precise description of the potentials for P release from the soil. The forms and dynamics of soil P can be greatly affected by agricultural management practices. Since inorganic P is the preferred source for plant uptake, knowledge of the inorganic form within soils is fundamental to understanding bioavailability of P and sustainability of agricultural practice. The aim of this study was to investigate the effect of land use change on the form and distribution of inorganic P using a sequential extraction procedure.
Materials and Methods: In order to study the impact of land-use change from forestland to cultivated land, composite samples in four replicates from the upper 10 cm of the different land use systems (natural forest, pasture, bower olive, farmland) were collected. We collected five subsamples from each land use in a radial sampling scheme. The five subsamples were then bulked into one sample. The spacing between the subsamples on the radii ranged from 5 to 10 m. The soil samples were transferred to polyethylene bags and transported to the laboratory where they were slightly crushed, passed through a 2 mm sieve prior to fractionation and chemical analysis. Soil texture, cation exchange capacity, organic carbon (OC), electrical conductivity, pH and calcium carbonate equivalent (CCE) were measured with standard methods. Total P and total inorganic P (Pi) contents were measured by the ignition method, for which P in the ignited (550 °C) and unignited soil samples were extracted by 0.5 M H2SO4. A modified version of the sequential extraction of Olsen and Sommers (1982) was used to fractionate inorganic P. Phosphorus was measured in the extracted supernatants by the molybdate–ascorbic acid method.
Results and Discussion: The results showed that clear-cutting of the indigenous forests and their conversion into agricultural fields significantly decreased total P and total organic P levels. Land-use changes from natural forest to farmland decreased the total P by 23% (from 644 to 495 mg per kg). Clearing and subsequent cultivation of the native woodland resulted in a marked depletion of total organic P. In addition, the land-use conversion from the natural forestland to an agroecosystem (cultivated land) led to increases in total inorganic P and inorganic P forms levels (labile P, P non-occluded, occluded in oxides of iron and aluminum, soluble calcium phosphate and sparingly soluble calcium phosphate). Labile inorganic P (NaHCO-Pi) showed the greatest changes, such as labile inorganic P in the amount of change from 1.75 in the forest land to 13.01 mg per kg of cultivated land, which represent an increase of approximately 8-fold compared to control (natural forest). The results also revealed that the refractory inorganic P fractions (HCl-Pi) were the major inorganic P pool, comprising 50-70% of the total inorganic P pool, indicating CaCO3 control over phosphorus availability in the studied soils. This study indicated that forestland degradation and cultivation caused chemical changes of P dynamics.
Conclusion: Large-scale conversion of indigenous forests to cultivated land, driven by long-term agricultural development in the Toshan region, has greatly impacted the forms and content of P in the soils. Generally, the conversion of natural ecosystem to agroecosystems, decreased the proportion of organic P (Po) in the top-soils at depth of 0 to 10 cm. The depletion in organic P from the cropped fields could be attributed to the enhanced mineralization of soil organic P caused by cultivation and removal of P in the crops. However, the conversion of natural forest to farmland led to increases in inorganic P (Pi). About 50% to 70% of the TP was bound to CaCO3, and thus this solid phase is critical to P fate in the soils and ecosystem of the Toshan Region, Golestan province

کلیدواژه‌ها [English]

• Inorganic P. Land use
• Phosphorus fractionation
• Sequential Extraction

مراجع

1- Allison L.E. 1965. Organic carbon. p.1372-1376. In: C.A. Black et al.(eds.), Methods of Soil Analysis. American Society of Agronomy, Madison, WI.

2- Allison L.E., and Moodie C.D. 1965. Carbonate. p.1379-1396. In: C.A. Black et al.(eds.), Methods of Soil Analysis. American Society of Agronomy, Madison, WI.

3- Arau´jo M.S.B. Schaefer C.E.R., and Sampaio E.V.S.B. 2004. Soil phosphorus fractions from toposequences of semi-arid Latosols and Luvisols in northeastern Brazil. Geoderma, 119: 309–321.

4- Bowma R.A., Reeder J.D., and Lober, R.W. 1990. Changes in soil properties in a central plains rangeland soil after 3, 20, and 60 years of cultivation. Soil Science, 150: 851– 857.

5- Brady N.C., and Weil R.R. 2008. Nature and Properties of Soils, 14th edn. Prentice Hall, Upper Saddle River, NJ, USA.

6- Chapman H.D. 1965. Cation exchange capacity. p.891-90. In: C.A. Black et al. (eds.), Methods of Soil Analysis. American Society of Agronomy, Madison, WI.

7- Compton J.E., and Boone R.D. 2000. Long-term impacts of agriculture on soil carbon and nitrogen in New England forests. Ecology, 81: 2314–2330.

8- Condron L.M., Frossard E., Tiessen H., Newman R.H., and Stewart J.W.B. 1990. Chemical nature of organic phosphorus in cultivated and uncultivated soils under different environmental conditions. Journal of Soil Science, 41: 41–50.

9- Crews T.E. 1996. The supply of phosphorus from native, inorganic phosphorus pools in continuously cultivated Mexican agroecosystems. Agriculture, Ecosystems and Environment, 57:197– 208.

10- Day P.R. 1965. Particle fractionation and particle size analysis. p.545-567. In: C.A. Black et al. (eds.), Methods of Soil Analysis. American Society of Agronomy, Madison, WI.

11- de Assis C.P., de Oliveiraa T.S., Dantas J.N., and de Sa Mendonça E. 2010. Organic matter and phosphorus fractions in irrigated agroecosystems in a semi-arid region of Northeastern Brazil. Agriculture, Ecosystems and Environment, 138:74–82.

12- Dehghan R., Shariatmadari H., and Khademi H. 2008. Soil phosphorus forms in four toposequences of Isfahan and Shahrekord regions. Journal of Water and Soil Science, 11 (42):463-472. (in Persian).

13- Delgado, A. and Torrent, J. 2000. Phosphorus forms and desorption in heavily fertilized calcareous and limed acid soils. Soil Science Society American Journal, 64:2031-2037.

14- Guggenberger G., Christensen B.T., Rubæk G., and Zech W. 1996. Land-use and fertilization effects on P forms in two European soils: resin extraction and 31P-NMR analysis. European Journal of Soil Science, 47: 605–614.

15- Harrel D.L., and Wang J.J. 2006. Fractionation and sorption of inorganic phosphorus in Louisiana calcareous soils. Soil Science, 171:39-51.

16- Kuo S. 1996. Phosphorus. p.869-920, In: D. L. Sparks (eds.), Methods of Soil Analysis, Part 3 SSSA; Book Ser. 5 SSSA, Madison.

17- Lee C.H., Park C.Y., Park K.D., Jeon W.T., and Kim P.J. 2004. Long-term effects of fertilization on the forms and availability of soil phosphorus in rice paddy. Chemosphere, 56: 299–304.

18- Lilienfein J., Wilcke W., Ayarza M.A., Vilela L., Lima A.C., and Zech W. 2000. Chemical fractionation of phosphorus, sulphur, and molybdenum in Brazilian savannah Oxisols under different land use. Geoderma, 96: 31–46.

19- Litaor M.L., Reichmann O., Auerswald K., Haim A., and Shenker M. 2004. The geochemistry of phosphorus in peat soils of a semiarid altered wetland. Soil Science Society of America Journal, 68: 2078–2085.

20- Maleki S., Khormali F., Kiani F., and Karimi A.R. 2013. Effect of slope position and aspect on some physical and chemical soil characteristics in a loess hillslope of Toshan area, Golestan Province, Iran. Journal of Water and Soil Conservation, 20(3): 93-112. (in Persian with English abstract).

21- Matson P.A., Parton W.J., Power A.G., and Swift M.J. 1997. Agricultural intensification and ecosystem properties. Science, 277:504-509.

22- McDowell RW., and Stewart T.I. 2006. The phosphorus composition of contrasting soils in pastoral, native and forest management in Otago, New Zealand: Sequential extraction and 31P NMR. Geoderma, 130:176– 189.

23- McGrath D.A., Smith C.K., Gholz H.L., and Oliveira F.A. 2001. Effects of land-use change on soil nutrient dynamics in Amazônia. Ecosystems, 4: 625–645.

24- Momeni M., Kalbasi M., Jalalian A., and KHademi H. 2009. Effect of land use shifting and overgrazing on loss of selected soil phosphorus forms in two regions of Vanak Watershed. Journal of Water and Soil Science, 12 (46):595-606. (in Persian).

25- Negassa W., and Leinweber P. 2009. How does the Hedley sequential phosphorus fractionation reflect impacts of land use and management on soil phosphorus: a review. Journal of Plant Nutrition and Soil Science, 172: 305–325.

26- Neufeldt H., da Silva J.E., Ayarza M.A., and Zech W. 2000. Land-use effects on phosphorus fractions in Cerrado Oxisols. Biology and Fertility of Soils, 31: 30–37.

27- Olsen S.R. and Sommers L.E. 1982. Phosphorus. p.403-430. In: A. L. Page et al. (eds.), Methods of Soil Analysis. Part 2. 2nd ed. Argon. Mongr. 9. ASA and SSSA, Madison, WI.

28- Ruiz J.M., Delgado A., and Torrent J. 1997. Iron–related phosphorus in over fertilized European soils. Journal of Environmental Quallity, 26: 1548-1554.

29- Sanyal S.K., and de Datta S.K. 1991. Chemistry of phosphorus transformations in soil. Advances in Soil Science, 16:1–120.

30- Schlichting A., Leinweber P., Meissner R., and Altermann M. 2002. Sequentially extracted phosphorus fractions in peat-derived soils. Journal of Plant Nutrition and Soil Science, 165: 290–298.

31- Sharpley A.N., and Smith S.J. 1983. The distribution of phosphorus forms in virgin and cultivated soils and potential erosion losses. Soil Science Society of America Journal, 47:581-586.

32- Sharpley A.N., and Smith S. J.1985. Fractionation of inorganic and organic phosphorus in virgin and cultivated soils. Soil Science Society of America Journal, 49:127-130.

33- Solomon D., and Lehman J. 2000. Loss of phosphorus from soil in semiarid northern Tanzania as a result of cropping: Evidence from Sequential extraction and 31P NMR spectroscopy. European Journal of Soil Science, 51: 699-708.

34- Solomon D., Lehmann J., Mamo T., Fritzsche F., and Zech W. 2002. Phosphorus forms and dynamics as influenced by land use changes in the sub-humid Ethiopian highlands. Geoderma, 105: 21–48.

35- Sui, Y., Thompson, M. L., and Shang, C. 1999. Fractionation of phosphorus in a Mollisol amended with biosolids. Soil Science Society American Journal, 63: 1174-1180.

36- Techienkoua M., and Zech W. 2003. Chemical and spectral characterization of soil phosphorus under three land uses from an Andic Palehumult in West Cameroon. Agriculture, Ecosystems and Environment, 100: 193–200.

37- Tiecher T., Rheinheimer dos Santos D., and Calegari A. 2012. Soil organic phosphorus forms under different soil management systems and winter crops, in a long term experiment. Soil & Tillage Research, 124:57–67.

38- Tiessen H., Stewart J.W.B., and Bettany J.R. 1982. Cultivation effects on the amounts and concentration of carbon, nitrogen and phosphorus in grassland soils. Agronomy Journal, 74: 83 l-835.

39- Tiessen H., Stewart J.W.B., and Moir J.O. 1983. Changes in organic and inorganic phosphorus composition of two grassland soils and their particle size fractions during 60–90 years of cultivation. Journal of Soil Science, 34: 815–823.

40- Tiessen H., Stewart W.B., and Cole C.V. 1984. Pathways of phosphorus transformations in soils of differing pedogenesis. Soil Science Society of America Journal, 48:853–858.

41- Turrion M.B., Glaser B., Solomon D., Ni A., and Zech W. 2000. Effects of deforestation on phosphorus pools inmountain soils of the allay range Khyrgyzia. Biology and Fertility of Soils, 31: 134–142.

42- Turrion M.B., Lopez O., Lafuente F., Mulas R., Ruiperez C., and Puyo A. 2007. Soil phosphorus forms as quality indicators of soils under different vegetation covers. Science of Total Environment, 378: 195–198.

43- Vaithiyanathan P., and Correll D.L. 1992. The Rhode River watershed: phosphorus distribution and export in forest and agricultural soils. Journal of Environmental Quality, 21: 280–288.

44- Walker T.W., and Syers J.K. 1976. The fate of phosphorus during pedogenesis. Geoderma, 15: 1 –19.

45- Wang G.P., Liu J.Sh., Wang J.D., and Yu J.B. 2006. Soil phosphorus forms and their variations in depressional and riparian freshwater wetlands (Sanjiang Plain, Northeast China). Geoderma, 132: 59–74.

46- Wang G.X., Ma H.Y., Qian J., and Chang J. 2004. Impact of land use changes on soil carbon, nitrogen and phosphorus and water pollution in an arid region of northwest China. Soil Use and Management, 20: 32–39.

47- Wang Y.Q., Zhang X.C., and Huang C.Q. 2009. Spatial variability of soil total nitrogen and soil total phosphorus under different land uses in a small watershed on the Loess Plateau, China. Geoderma, 150: 141–149.

48- Yang W., Cheng H., Hao F., Ouyang W., Liu Sh., and Lin Ch. 2012. The influence of land-use change on the forms of phosphorus in soil profiles from the Sanjiang Plain of China. Geoderma, 189&190: 207–214.

49- Zhang T.Q., and Mackenzie A.F. 1997. Changes in soil phosphorus fractions under long term corn monoculture. Soil Science Society of America Journal, 61: 485- 493.

50- Zheng A., Simard R.R., Lafond J., and Parent L.E. 2001. Changes in phosphorus fractions of a Humic Gelysol as influenced by cropping system and nutrient sources. Canadian Journal of Soil Science, 81:175-183.