Investigating Spatial Variability of the hydraulic characteristics of Sistan plain soils

Document Type : Research Paper

Authors

1 Members of Scientific Board, Soil and Water Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.

2 Members of Scientific Board, Soil and Water Research Institute, Agricultural Research, Education and Extension Organization (AREEO)Karaj, Iran.

3 Researcher, Zabol Agricultural and Natural Resources Research Center, Zabol, Iran.

Abstract

 
Saturated hydraulic conductivity (Ks) is one of the most important soil physical properties that plays a major role in its hydrological behaviour. In this study, the hydraulic characteristics of 312 soil samples, taken from the top layer (0-30 cm), were measured. Additionally, soil texture and bulk density were analyzed in 2080 top-soil (0-30 cm) samples. The results showed that the soil texture in the region varied from sandy to clayey, with most soils classified as medium-textured. The average bulk density in the region was found to be 1.43 g.cm-3. The mean field capacity moisture content across the counties of Sistan Plain was less than 35%, placing them in the low field capacity class. The highest and lowest plant-available moisture content was observed in Hirmand and Zabul, respectively. The coefficient of variation for plant-available moisture in all surface agricultural soils of Sistan Plain was 33.83%, indicating a very high variability. Regarding the mean values of saturated hydraulic conductivity, the lowest and highest values of surface soil saturated hydraulic conductivity (Ks) were observed in Zabul (0.15 m per day) and Hirmand (0.42 m per day), respectively.

Keywords

Main Subjects

EXTENDED ABSTRACT

Introduction

Saturated hydraulic conductivity (Ks) is one of the most important soil physical characteristics that plays a major role in the soil hydrological behaviour. Analysis and interpreting spatial variability of soil hydraulic properties is important in hydrological modeling and using pollutants and nutrient flow modeling in the soil. It is very important to know the relationship between water and soil in various irrigation and drainage issues, determining the water requirement of plants, the amount of soil water, controlling salinity, irrigation management and planning, and etc. Therefore, according to leaching management programs, soil amendment and irrigation planning for Sistan plain lands, It is very important to study the physical and hydraulic characteristics of sistan plain soils.

Materials and Methods

This study was carried out in 46,000 hectares of the Sistan Plain, including the cities of Zahak, Hamon, Hirmand, Nimroz and Zabul. In this study, 312 surface soil (0-30 cm) samples were taken and their hydraulic characteristics were measured. Also, soil texture, bulk density, Electrical Conductivity (EC), Sodium Absorption Ratio (SAR) was measured in 2080 surface soil (0-30 cm) samples. Spatial variability of hydraulic characteristics were analyzed using geostatistics technique. In addition, spatial distribution of hydraulic characteristics were determined using Inverse distance weighting (IDW) method. In order to evaluate the correctness and accuracy of kriging and IDW interpolation methods in estimating hydraulic characteristics in unsampled points, normalized root mean squares error (NRMSE), R2 and MBE statistics were used.

Results and Discussion

The results showed that the soil texture of the area varied from sandy to clay and Most of the soils in the region had medium texture. The average bulk density of the region was 1.43 gr.cm-3. The average field capacity in all the cities of Dasht Sistan is less than 35%, which are in the class of low field capacity. The average and median amount of available water in the soil of Sistan plain is 4.72% and 15.21%, respectively. About 48.8% of Sistan plain lands have available water between 11.5 and 15%. The amount of available water is low according to the soil textural classes of the most area of the sistan region (silty loam, silty clay loam, and silty clay). The highest and lowest amount of available water was also observed in Hirmand and Zabul respectively. The coefficient of change of available water in all surface soils of Sistan Plain lands is 33.83% and it is in the range of very high variability. According to the average values ​​of saturated hydraulic conductivity, the lowest and highest values ​​of saturated hydraulic conductivity (Ks) of the surface soil were  in Zabul (0.15 m per day) and Hirmand (0.42 m per day) respectively. According to the spatial distribution map of saturated hydraulic conductivity of the surface soil, the southern regions and part of the eastern regions have a higher saturated hydraulic conductivity coefficient than the rest of the regions. In these areas, the percentage of sand was higher.

Author Contributions

RasoulMirkhani: Sampling, Conceptualization, Validation, Supervision, Writing manuscript

Leila Esmaeelnejad: Software, Validation, Manuscript editing

Saeed Saadat: methodology, Manuscript editing

Hamed Rezaei: Sampling, methodology, Manuscript editing

Naser Davatgar: consulting

Mojtaba Hadizadeh: Sampling

Data Availability Statement

We have no permission to release data and codes.

Acknowledgements

We would like to express our sincere gratitude to the Research and Education Center for Agriculture and Natural Resources of Sistan and Baluchistan (Zabol) and Water and Soil Deputy, ministry of Jihad-e- Agriculture for the financial and logistics supports who significantly contributed during the research project.

Ethical considerations

The study was approved by the Ethics Committee of the Soil and Water Research Institute. The authors avoided data fabrication, falsification, plagiarism, and misconduct.

Conflict of interest

The author declares no conflict of interest.

References

Abou Hussien, E., Abd El Adl, M., Omran, W., and Tawfik, S. (2022). Effect of Tillage Depth on Some Properties of Saline Soil. Menoufia Journal of Soil Science, 7(5): 81-90.
 Ahmady, T., Delbari, M., and Afrasiab, P. (2018). Mapping Saturated Hydraulic Conductivity of Surface Layer in Loam and Sandy Loam Soils of Sisitan Plain. Iranian Journal of Soil Research, 31(4), 513-526. (in Persian).
Aria, P., and Mirkhani, R. 2005. Methods of Soil Physical Analysis, Technical Bulletin, Soil and Water Research Institute, Iran No:479. (in Persian).
 Eck, D. V., M. Qin, D. R. Hirmas, D. Gimenez and N. A. Brunsell. )2016(. Relating quantitative soil structure metrics to saturated hydraulic conductivity. Vadose Zone Journal, 15(1).
 Gadouri, H., Harichane, K., and Ghrici, M. (2017). Effect of sodium sulphate on the shear strength of clayey soils stabilised with additives. Arabian Journal of Geosciences. 10(10): 218.
Mahmoodabadi, M. R. and Mazaheri, M. E. (2012). Effect of some soil physical and chemical properties on permeability in field conditions. Irrigation and Water Engineering, 2(4), 14-25. (in Persian).
Mahmoud, H. M. A. (2017). Organic amendments and their effect on status of some nutrients in soil and plant., Ph. D. Thesis, Fac. of Agricalture., Menoufia University., Egypt.
Nemes, A., RawlsG. W., and Pachepsky Y. A. (2005). Influence of organic matter on the estimation of saturated hydraulic conductivity. soil science society of america journal, 69: 1330-1337.
 Marchuk, A. 2013. Effect of cations on structural stability of salt-affected soils (Doctoral dissertation). Discipline of Soil Science School of Agriculture, Food and Wine, The University of Adelaide, 154pages.
  Pahlevanrad, M. R. (2019). Study on spatial variability of soil infiltration and saturated hydraulic conductivity in the lands of Sistan plain using geostatistical and random forest methods . Final report of research. Soil and Water Research Institute, 56390, 58 pp. (in Persian).
Rezaei, M., Shahbazi, K., Shahidi, R., Davatgar, N., Bazargan, K., Rezaei, H., Saadat, S., Seuntjens, P., and Cornelis, W. (2020). How to relevantly characterize hydraulic properties of saline and sodic soils for water and solute transport simulations. Journal of Hydrology, 125777.
Shabani, H., Delavar, M. A., Safari, Y., and Alamdari, P. (2020). Spatial variability of some soil characteristics in lands of Zanjan University. Applied Soil Research, 7(4), 164-178. (in Persian).
Shokuohifar, M., Nasab, S. B., Mohammadi, A. S., and Hooshmand, A. R. (2016). The effect of salinity of irrigation water and super absorbent polymer on some hydraulic and physical properties of sandy loam soil. Irrig Sci Eng, 39, 101-113. (in Persian).
Taghizadehghasab, A., Safadoust, A., and Mosaddeghi, M. R. (2019). Effects of saline and sodic water on hydraulic properties of clay loam and sandy loam soils. (in Persian).
Vaezi, A. R. (2014). Modeling runoff from semi-arid agricultural lands in Northwest Iran. Pedosphere 24: 595–604.
Walkly A., and Black I. A. 1934. An examination of digestion methods for determining soil organic matter and a proposed modification of the chromic and titration. Soil Science, 37: 29-38.
Walczak, A., Lipiński, M., and Janik, G. (2021). Application of the tdr sensor and the parameters of injection irrigation for the estimation of soil evaporation intensity. Sensors, 21(7), 2309.
 Weil, R. R., Brady, N. C., and Weil, R. R. 2016. The nature and properties of soils. Pearson.
Iranian Journal of Soil and Water Research
Volume 55, Issue 12
March 2025
Pages 2409-2420

Files

Share

How to cite

Statistics