Ivan McLeod1, Graeme Blair2 and Donald MacLeod2
1 Aurizon, 2/4-10 Adams Dr. Welshpool, WA, 6106
2 Agronomy and Soil Science, School of Environment and Rural Science, University of New England, Armidale, NSW, 3250
A growth chamber study was undertaken with a Vertosol soil to investigate the effect of a 7-day waterlogging (WL) period on soil redox, soil solution P, K, Na and Mn concentrations and 33P and 86Rb applied immediately prior to flooding used to trace uptake into the plant. Soil redox potentials fell from 370 mV to 30 mV throughout the waterlogging period. Waterlogging increased the soil solution concentration of P, K, Na and Mn with the greatest increase in Mn (145 fold). Uptake of 33P into the tops was reduced by 90% and 86Rb by 63% during the waterlogging period compared to the –WL treatment. In the waterlogging treatment the majority of the P taken up was translocated to the developing fruit (61.5%) compared to 21.4% of the 86Rb. The majority of 86Rb (57.1%) accumulated in the stems of the plants. It is not possible to conclude what effect that the substantial increase in soil solution Mn concentration had on ion accumulation. Waterlogging during boll fill has been shown to have marked effects on the P and K dynamics, the two nutrients implicated in “premature senescence” and suggests both nutrients are involved in the process.