Sugar beet (Beta vulgaris L.) response to saline irrigation water under nano-irrigation system

Abstract

Soil and water salinity is a major threat in irrigated arid and semi-arid regions of developing countries. Novel technologies have been developed to maximise crop production with rational use of water resources, particularly saline water. We carried out field experiment using either the nano-irrigation system or drip irrigation system on a loamy sandy soil to investigate the response of sugar beet to different levels of saline irrigation water. Plots of 4 m wide and 5 m long with two irrigation water salinity treatments (S1 = 1.6 dS m^-1, S2 = 6.3 dS m^-1) in four replicates, were established in a factorial design under nano-irrigation system. The soil chemical properties and the morphological and physiological parameters of sugar beet were measured over two sampling periods. Our results show a similar pH and organic matter content of the soil under the different salinity and irrigation system treatments while the soil salinity increased considerably at the start of the experiment and then decreased especially within the 5 cm of the soil surface. At the end of the experiment, irrigation with saltwater particularly caused the accumulation of proline in the leaves, and the reduction of the chlorophyll contents, leaf area, and root yield. Our results suggest that the nano-irrigation system would be suitable for growing sugar beet provided the correct location of the laterals is chosen. They also indicate that in the short term, an irrigation water salinity of 6 dS m^-1 could be used for irrigation in order to obtain an acceptable root biomass yield without serious salinity issues on the cultivated soil.

Keywords: Salt stress, Water quality, NaCl, proline, Biosaline agriculture