Wheat (Triticum aestivum L.) growth and yield response to saline irrigation water under controlled conditions

Abstract

Serious agronomic problems occur where saline water is used for irrigation. The effect of irrigation water salinity on wheat was investigated using electrical conductivity (EC_i, mS m⁻¹) as a salinity indicator. A pot experiment was conducted at the University of the Free State during 2003 and 2004 to determine the effect of the different irrigation water EC_i levels on the growth and yield of wheat (cv. SST 806) in a sandy loam soil. The pot experiment was laid out as a complete randomised design with five EC_i levels viz. 15(control), 150, 300, 450, 600 mS m⁻¹, replicated three times and conducted over two seasons. The effects were tested at three growth stages viz. tillering, flag leaf and maturity. Various morphological indicators were used to quantify the effect of saline irrigation water on the below ground growth of wheat, viz. root mass and root length. For above ground growth, plant height and leaf area index were recorded. All indicators were expressed on a relative basis and showed a decrease in growth with an increase in the EC_i of the irrigation water used. At EC_i levels of 300 and 600 mS m⁻¹ seed yield were reduced by 18 and 36%, respectively.