Subsurface Drainage for Rehabilitation of Waterlogged Saline Lands: Example of a Soil in Semiarid Climate

Abstract

In irrigated agriculture of arid and semiarid regions, soil salinity, coupled with waterlogging, is a serious problem. Provision of subsurface drainage seems to be a prerequisite for optimal crop production. A study was conducted to evaluate the long term (8-year) impact of a subsurface drainage system on soil properties and yields of wheat. The study was located in a severely a †ected, waterlogged, barren, sandy loam saline soil (Comborthids). The subsurface drainage system was installed at a 1.75 m depth with three drain spacings (25, 50, and 75 m). The drains facilitated reclamation of the waterlogged saline land which had variations in salt removal with space and time. T he removal of salts from the root zone varied initially with distance from the drain and with depth. However, after a few years, the variations were reduced and the land was reclaimed sufficiently to grow most of the crops of the region. Plots provided with a drain spacing of 75 m required more time for complete reclamation compared to plots provided with 25 m drain spacing. Leaching through subsurface drainage increased soil porosity, modulus of rupture, inÐltration rate, organic carbon, available nitrogen, phosphorus, potassium, and available water, and decreased bulk density di †erently in the three drain spacings (20, 50, and 75 m). In the 75 m drain spacing plots, soil salinity and water (EC e ) content remained higher than in the 25 and 50 m drain spacing plots. Soil and EC e water content were less near the drains, were highest in areas midway between the drains, and the e †ects were more apparent in the summer season. Wheat grain yield decreased with increasing drain spacings in the initial years of reclamation. With the gradual improvement in soil salinity, yields from plots with a 75 m spacing reached those of the narrower drain spacing plots by the fourth year. It was concluded that by installing a subsurface drainage system in a monsoon climate, waterlogged saline soils can be reclaimed by the natural leaching that can take place from rainfall. T he optimum yield can be attained with a drain spacing of 75 m, which is 50% more than the design spacing of 50 m. Faster reclamation and more yield were obtained with a 25 m drain spacing and was achieved at a higher cost for the more expensive drainage system.

Electrolytic Conductivity of Semiarid Soils (Southeastern Spain) in Relation to Ion Composition

“…and anthropogenic (use of low quality water, excess of fertilizers, unsuitable irrigation systems, etc.) causes provoke an accumulation of salts in the soil (Herna´ndez & Faz, 1993;Kuchanwar et al, 1999;Pla-Sentı´s, 1997;Rhoades et al, 1999;Sharma et al, 2000;To´th & Blasco, 1998;Vairagade et al, 2002;Wienhold & Trooien, 1998). Salinization leads to a partial or total loss of the productive capacity of a soil because it causes a degradation of its chemical and physical properties.…”

Growth and yield responses of sunflower to drainage in waterlogged saline soil are caused by changes in plant-water relations and ion concentrations in leaves

“…(2021) found that the combination of shallow surface (10 cm depth) and subsurface drains (50 cm depth) alleviated waterlogging and salinity, and gave a 2-fold higher sun ower yield than the undrained treatment. While previous eld-based studies have reported the effects of drains on waterlogging, salinity, plant morphology and yield, information has not been presented on impacts on plant water relations or ion concentrations in shoots (Ritzema et al 2008;Sharma et al 2000). Hence, while Islam et al (2021) found that the combination of shallow surface and subsurface drains alleviated waterlogging and salinity and increased sun ower yield, the physiological mechanisms accounting for these responses were not determined.…”

Growth and yield responses of sunflower to drainage in waterlogged saline soil are caused by changes in plant-water relations and ion concentrations in leaves

“…Islam et al (2022) found that the combination of shallow surface (10 cm depth) and subsurface drains (50 cm depth) alleviated waterlogging and salinity, and gave a twofold higher sunflower yield than the undrained treatment. While previous fieldbased studies have reported the effects of drains on waterlogging, salinity, plant morphology and yield (Ritzema et al 2008;Sharma et al 2000), they have not reported on related changes in plant water relations or ion concentrations in shoots. Hence, while Islam et al (2022) found that the combination of shallow surface and subsurface drains alleviated waterlogging and salinity and increased sunflower yield, the physiological mechanisms accounting for these responses were not determined.…”