Soil Salinity Variations in an Irrigation Scheme during a Period of Extreme Dry and Wet Cycles

Sheyda Chamaki,Hailin Zhang,Saleh Taghvaeian,Jason G. Warren

doi:10.3390/soilsystems3020035

Abstract

Salinization of irrigated lands is a major challenge towards supplying required food and feed to meet the needs of an increasing global population. In this study, the changes in soil salinity and several other chemical properties were investigated in an irrigation scheme during a period that experienced severe drought followed by above-normal precipitation. Soil salinity, represented by the electrical conductivity (EC) of the saturated paste extract, decreased for the top layers and increased for the bottom layers during the study period, suggesting some level of leaching had occurred. However, the change in the average EC of top 1.5 m of the soil was not statistically significant. The change in exchangeable sodium percentage (ESP) was not significant over the study period either. In contrast, average pH and calcium concentrations increased and decreased significantly during the study period, respectively. EC and ESP data were used in soil classification. The percentage of all sampled sites classified as saline was 60 at the beginning of the dry–wet period, but dropped to 50% at the end of this period. All tested parameters were temporally stable, preserving their spatial rank during the study period.

Highlights

Ever increasing world population in recent decades has led to intensification of competition over water resources between agriculture, industries, and municipalities
The present study explored the dynamics of soil salinity and associated chemical properties across an irrigation district in southwest Oklahoma over eight growing seasons
The area studied was the Lugert-Altus Irrigation District (LAID), which occupies over 190 km2 in southwestern Oklahoma [15]

Summary

Introduction

Ever increasing world population in recent decades has led to intensification of competition over water resources between agriculture, industries, and municipalities. Irrigation has enabled increased yields and multiple cropping in traditionally single-cropped regions [1]. This in return has provided a sense of stability and security for utilization of fertilizers and pesticides, ensuring a viable crop yield even in areas with unstable and non-uniform precipitation patterns [2]. Salts and nutrients in the water are added to the soil during each irrigation event. The salts already present in the soil are mobilized in the irrigation process. Irrigation can raise the water table and bring the salts in the groundwater to within the root zone, affecting crop growth [2,3,4]

Methods

Results

Conclusion