The Eleventh Regional Wheat Workshop For Eastern ... - Cimmyt

Effects ofsoil waterlogging on concentration and uptake ofnutrients - Amsal et al.
Due to the restriction of gas exchange and subsequent depletion of O 2 , some soil
microorganisms make use of electron acceptors other than O 2 for their respiratory oxidation
(Ponnamperuma, 1984; Armstrong, 1982) thereby promoting a series of chemical and
microbiological changes in the soil (Armstrong 1982). These changes result in the
accumulation ofCO 2 and several organic compounds to levels toxic to plant roots (Drew and
Stolzy, 1996; Armstrong, 1982) and reduction of N0 3 -N, Fe, Mn, and sulfate, and changes in
pH and redox potential of the soil (Armstrong, 1982; Ponnamperuma, 1984; Krizek, 1990;
Laanbroek, 1990).
The mineral composition of cultivated plants under waterlogged conditions depends largely
on soil O 2 availability. It has been indicated that soil waterlogging results in reduced foliage
concentrations of P and K in wheat (Drew and Sisworo, 1979). Stieger and Feller (1994)
reported that waterlogging during grain filling reduced grain yield as well as K, P and Zn
concentrations in the shoots and grains of wheat. Leyshon and Sheard (1974) obtained a
reduction in P and K concentration of 61 and 58%, respectively, in barley seedlings following
short-term waterlogging. Waterlogging of barley for 10 days decreased the P and K
concentrations in grains (Stepniewski and Labuda, 1984). In a field study using wheat and
pearl millet, Sharma and Swarup (1989) reported that short-term waterlogging decreased P, K
and Zn uptake by the grain and straw. Huang et al. (1995) reported a reduction in P, K and Zn
concentrations in the shoots and an increase of these nutrients in the roots of winter wheat.
Waterlogging-induced O 2 deficiency may inhibit nutrient uptake and transport in
waterlogging-sensitive crop varieties (Kozlowski, 1990) by altering root function due to the
death of root system (Drew and Lynch, 1980; Stepniewski and Przywar, 1992; Trought and
Drew, 1980a and b), causing nutrient leakage due Jo loss of integrity in root cell membranes
(Resen and Carlson, 1984), or providing sub-optimal energy for active ion uptake due to
inefficient anaerobic metabolism (Barrett-Leimard et al., 1990; Setter and Belfod, 1990).
Waterlogging is a serious environmental constraint to wheat production on poorly drained
soils (Kozlowski, 1984). Vertisols with a high montmorillonite clay content are important
agricultural soils in cool and wet wheat growing agro-ecologies of the central and eastern
African highlands (Jutzi and Abebe, 1986). Wheat genotypes differ in their tolerance to
waterlogging stress (van Ginkel et al., 1992). Wheat pro~uction on frequently waterlogged
Vertisols such as these of the eastern African highlands could likely be improved when
planted to waterlogging tolerant genotypes. Little is known about the nutrient uptake and
accumulation by wheat genotypes differing in waterlogging tolerance (Huang et al., 1995).
Hence, research is needed to determine whether a genotypic difference in waterlogging
tolerance in wheat can be related to differences in nutrient acquisition and uptake. This study
was therefore conducted to determine the effects of soil waterlogging on the Cu, Zn, P and K
nutrient concentrations and uptakes by wheat genotypes identified under field and greenhouse
conditions to differ in waterlogging tolerance.
MATERIALS AND METHODS
A vIrgm Vertisol (ca. 46% clay) was used in the greenhouse to fill three liter size
polyethylene pots perforated at the bottom. Sufficient soil from the top 0-20 cm depth layer
was collected from Glen · Agricultural College campus, located about 30 km north of
Bloemfontein, South Africa. The soil was pulverized and sieved to remove clogs and fibrous
root materials, thoroughly mixed with Nand P nutrient solution at the rate of 70 mg N as
KN0 3 and 35 mg P as K 2 HP0 4 kg"1 soil. Before filling the pots with 3 kg soil, 150 g gravel
was placed at the bottom to facilitate drainage of the pots.
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