Reuse of Drainage Water for Irrigation: Results of Imperial Valley Study: II. Soil Salinity and Water Balance

Soil and Tillage Research

et al. 2015

A B S T R A C THigh salt content in soil, poor soil structure and fresh water shortage are the restricting factors for construction of ecological landscapes in coastal regions with very heavy saline silt-soil. The aim of this work was to develop a method to reclamate the very heavy coastal saline soil using drip-irrigation with saline water for salt-sensitive plants. A field experiment with five treatments of salinity levels of 0.8, 3.1, 4.7, 6.3 and 7.8 dS/m of irrigation water was imposed in the very heavy saline silt-soil in 2012-2014. The initial soil in experimental plots was tilled and broken, and a gravel-sand layer was created at 120 cm depth. Chinese rose (Rosa chinensis) is very sensitive to salt and was chosen as the representative plant. Soil indexes (electrical conductivity of soil saturated extract (EC e ), pH and sodium adsorption ratio (SAR)), growth characters and dry matter production of rose were determined. The results showed that the level of salinity in water had no significant effect on salt leaching in the 0-120 cm soil profile, and significant effects only occurred in shallow soil layers. EC e and SAR of soil profile decreased with irrigation time, but pH of soil initially increased and then decreased. Rose growth and dry weight decreased with increasing of irrigation water salinity. The values of soil salt tolerance threshold were 2.24 dS/m at emergence and 4.48 dS/m in the growth period after emergence. The emergence rate decreased by 53.30% for each unit of EC e increase in the root zone, and dry weight decreased to zero when EC e exceeded 5.36 dS/m. A regulatory method was scheduled for drip-irrigation of saline water to control the soil matric potential (SMP) under a gravel-sand layer for initially saline soils and was effective in reclamation of very heavy coastal saline soil (silt soil) for sensitive species such as Chinese rose. An SMP higher above À5 kPa at 20 cm depth under the emitter in the first year and À10 kPa in the second year, and 6 mm of irrigation water of salinity up to 4.01 dS/m can be used for rose drip-irrigation scheduling, while also maintaining a 50% survival rate.

Section: Introductionmentioning

confidence: 99%

Reclamation of very heavy coastal saline soil using drip-irrigation with saline water on salt-sensitive plants

Soil and Tillage Research

et al. 2015

“…However, irrigation of increasing amounts of landscape will consume a large quantity of water, and fresh water resources are very limited in coastal regions. Some non-conventional water resources such as saline water, brackish groundwater and treated wastewater should be sought as alternatives to fresh water (Rhoades et al, 1988). Saline water is an ideal alternative in coastal regions, where saline water resources are plentiful, and have been successfully used for irrigating crops and other plants.…”

Section: Introductionmentioning

confidence: 99%

Effect of drip-irrigation with saline water on Chinese rose (Rosa chinensis) during reclamation of very heavy coastal saline soil in a field trial

et al. 2015

Scientia Horticulturae

a b s t r a c tDrip-irrigation with saline water was used for reclamation of very heavy coastal saline soils and its effects on salt-sensitive plants were also evaluated in a three-year trial in the coastal region of east China. The original soil salinity expressed as electrical conductivity of the saturation paste extract (EC e ) was an average of 27.13 dS/m in the 0-100 cm depth. The experiment included five treatments of salinity levels of 0.8, 3.1, 4.7, 6.3 and 7.8 dS/m of irrigation water. Chinese rose (Rosa chinensis), a salt-sensitive species, were planted in the sandy loam soil to determine the effect of saline environment on growth characters and dry matter production. Drip-irrigation had a significant positive impact on salt leaching, and the very highly saline soil became mildly saline after reclamation in root zone of soil profiles irrigated with water of salinity up to 7.8 dS/m. An increase in salinity of irrigation water had adverse effects on plant height, stem diameter, survival rate and dry matter production. Root:shoot ratio increased with increasing water salinity. The values of soil-salt tolerance threshold were 2.39 dS/m at emergence and 2.78 dS/m in the growth period after emergence. The emergence rate and dry mass decreased by 27.39 and 41.19% for each unit of EC e increase in the root zone, respectively. These results implied that drip-irrigation with saline water by controlling soil matric potential under a gravel-sand layer was effective in reclamation of this very heavy coastal saline soil for sensitive species such as Chinese rose.

“…Many approaches including engineering, chemical and biological methods to reclaim saline soils have not yielded desirable results due to water limitations (Li et al, 2015). Non-conventional water resources such as saline water, brackish groundwater and treated wastewater are alternatives to fresh water (Rhoades et al, 1988). Saline water has been successfully used for irrigating crops and other plants (Crescimanno and Garofalo, 2006;Darvishi and Dadnia, 2012;Hadi and Raijadhav, 2007;Niu et al, 2011Niu et al, , 2012Niu et al, , 2013Ozrad et al, 1972;Sa et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Response of a salt-sensitive plant to processes of soil reclamation in two saline–sodic, coastal soils using drip irrigation with saline water

Agricultural Water Management

et al. 2016

a b s t r a c tThe aim of this study was to evaluate the impact of soil types and properties on coastal saline soil reclamation and the response of plant growth to the reclamation processes in two soils. Two very heavy coastal saline soils were reclaimed in a three-year trial using drip irrigation with saline water. Chinese roses (Rosa chinensis) were planted, and soil indexes, growth characters, ion absorption and dry matter production were determined. Our results showed that significant salt leaching occurred in both soils, and the effect during the early period of reclamation was better in sandy loam than silt soil. There were higher emergence and survival rates of plants in sandy loam soil due to the rapid reclamation process, while plant growth and dry mass were greater in silt soil due to good fertilizer and water conservation. Most roots were present in the 0-20-cm profile in both soils, but the fine root length value in silt soil was relatively high. These results indicate that water and nutrient management differed in the two soils. During soil reclamation, more attention should be paid to nutrient supply and maintaining soil moisture in sandy loam and to rapidly establishing suitable soil root-zone environments for plant emergence in silt soil.