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

Abstract

Drip-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 (ECe) was an average of 27.13dS/m in the 0–100cm depth. The experiment included five treatments of salinity levels of 0.8, 3.1, 4.7, 6.3 and 7.8dS/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 7.8dS/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 2.39dS/m at emergence and 2.78dS/m in the growth period after emergence. The emergence rate and dry mass decreased by 27.39 and 41.19% for each unit of ECe 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.