Tuesday, November 6, 2007 - 3:05 PM
192-1
Advancing Our Understanding of Nutrient Behaviour in Soils Using Advanced Instrumental Methods.
Michael McLaughlin1, Ganga Hettiarachchi2, Sam Stacey3, Therese McBeath3, Bob Holloway4, and Jason Kirby5. (1) CSIRO Land and Water/University of Adelaide, PMB 2, Glen Osmond, 5064, Australia, (2) Department of Agronomy, Kansas State University, Throckmorton Hall, Manhattan, KS 66506, (3) The University of Adelaide, PMB 1, Glen Osmond, SA5064, Australia, (4) Arris Pty Ltd, PO Box 206, Highgate, Adelaide, SA5064, Australia, (5) CSIRO Land and Water, PMB 2, Glen Osmond, 5064, Australia
Examining reactions of fertilizer elements in soil, and understanding fundamental processes affecting plant acquisition of soil nutrients, has been significantly advanced over the last two decades through the use of isotopic tracing techniques, coupled with advanced spectroscopic and chromatographic ion separation techniques. We will demonstrate the application of these methods for the examination of the efficiency of P and trace element fertilizers for grain production on alkaline soils. Their use has been pivotal in explaining the mechanisms responsible for the high agronomic efficiency of soil-injected fluid phosphorus and trace element fertilizers in calcareous soils, and for understanding nutrient reactions in and around fertilizer granules that reduce fertilizer efficiency in the same environments. Micro-scale reactions in the soil can have a marked effect on crop nutrient acquisition, and some of the newer spectroscopic methods provide not only micro-scale soil analytical data, but also new information on the chemistry and reactions of fertilizer nutrients. Recent advances in isotopic tracing techniques provide us with the ability to measure ever smaller differences in elemental and isotopic composition, yet these precise measurements are changing our understanding of the soil-to-plant transfer of some nutrient elements. These techniques do not replace traditional agronomic experimentation, but when used in tandem with field experimental data, they can provide important insights into the fundamental soil and plant processes responsible for differential crop responses to fertilizers observed in field trials.