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Potassium Newsheet Vol 3 Iss 1 : Summer 2005 |
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This newsheet is supported by: |
Welcome
to this edition of the Potassium Newsheet, an email
newsletter designed to keep you informed about who is doing what
in the field of potassium nutrition in Australia and New Zealand.
If you would like to inform others about a potassium nutrition issue or project contact the newsheet editor, Jonnie White. Comments or feedback about any articles are also welcome. Should you not wish to receive future editions of the newsheet please click here. If you are not currently on the mailing list but would like to be, please click here.
PotOz '05: Melbourne 15th November The second workshop on Potassium in Australian Agriculture is being held in Melbourne on the 15th November 2005. This workshop is a follow-up to the much referenced first workshop held in Geraldton in 1997, which drew a line in the sand regarding our understanding of potassium management in local cropping and grazing systems at the time. Since then, new research has been undertaken, new tools developed and responses in new regions have been observed. This workshop will be an opportunity for agronomists and researchers across the country and from New Zealand to update themselves on potassium nutrition research. In addition, keynote presentations are being made by two international guests, Dr Adrian Johnston, Northern Great Plains Director with the Potash and Phosphate Institute and Dr Sylvie Brouder from Purdue University who will discuss New Directions in Potassium Research. At the workshop dinner on the evening of the 15th, Mr Brent Alexander, a farmer from Lockhart in NSW and Nuffield scholar will give a presentation about his overseas scholarship tour researching crop nutrition, and about sourcing crop nutrition information in Australia from a farmer's perspective. A workshop program is available at the end of this newsletter. More information and a downloadable registration form are available at www.potash-info.com/potoz. Anyone still wishing to register can do so until Monday 7th November. GRDC funds K research in the Northern Grains region A new nutrient management project for the northern grains region has recently been funded by the Grains Research and Development Corporation. The project, being led by Dr Mike Bell from the Queensland Department of Primary Industries has a significant focus on K nutrition. The project aims to provide a scientific basis for determining the need for K fertilization, delineate the regional occurrence of K infertility, and evaluate appropriate K application strategies. Experimental work will include glasshouse based exhaustion and re-addition trials to evaluate measures of short and long term K supply and the fate of applied K in a range of soil types. This will be supported by a field trial program which includes replicated field trial sites and a suite of on-farm trial strips. More information on the project is available by contacting Mike Bell by email or on (07) 4160 0730. Vic: Topdressed K improves wheat yield at Hamilton A previous issue of the Potassium Newsheet reported on windrow effects showing up in cereal crops near Hamilton in Victoria. A banded or 'wave' effect, corresponding to the trash windrows of previous crops had appeared in numerous fields in the Western Districts of Victoria. At the time, one farmer had recently topdressed a field of wheat with replicated strips of 25 or 50kg K/ha perpendicular to the windrows. Whole plant samples taken from the plots in October of that year showed that plant K concentration had increased from 0.45% without topdressing to 1.03% with 50 kg K. By the end of the season, grain yields on the topdressed areas were markedly higher with 2.4 t/ha and 4.1 t/ha being harvested from the control area and 25 kg K strips, respectively. There was no statistically significant difference in yield between the 25 and 50kg/ha plots. For more information about the crop symptoms observed at Hamilton contact Craig Henson on 0427 554 968 or by email and for details about the field responses visit the Potassium in Agriculture website. DSS developed for WA cropping systems Craig Scanlan and Bill Bowden from the West Australian Department of Agriculture have developed a software package to help WA farmers decide if they need to apply K and if so, how much and how often. The decision support system is a combination of mechanistic and empirical approaches, and simulates soil water, chemistry and root and shoot growth on a weekly time-step. It includes an assessment of both the yield and profit consequences of different long-term strategies or short-term agronomic decisions. A feature of the DSS is the use of comparative scenarios and visual presentation of sensititvity analyses and animations. More information about the DSS is available by contacting Bill Bowden by email or on (08) 9690 2000. K Questions Answers to recently posed questions on K nutrition: A farmer asks: "I want to apply foliar K to cotton - is there a difference between the K fertiliser forms?" Answer: Several US studies have examined the impact of different foliar K fertiliser forms on cotton. In general, potassium nitrate increases yield more than other sources, which is likely to be an impact of the additional N. Potassium thiosulfate and potassium sulfate also increase yields when foliarly applied. Typically, foliar potassium chloride does not impact on yield, and potassium carbonate can decrease yield. The lack of response to potassium chloride and the negative response to potassium carbonate have been related to physiological effects on leaf photosynthesis and cell membrane integrity even though only very minor visual symptoms of foliar burn are observed. Recently published papers Recently published scientific papers examining issues of potassium nutrition are listed below. A searchable database of abstracts of scientific papers addressing issues of potassium nutrition is available on the Potassium in Agriculture website, where links to the home pages of relevant journals are also provided for anyone wishing to purchase full copies of individual papers. Bedrossian, S, and Singh, B. (2004) Potassium adsorption characteristics and potassium forms in some New South Wales soils in relation to early senescence in cotton. Australian Journal of Soil Research 42(7): 747-753. Brennan, R.F, Bolland, M.D.A, and Bowden, J.W. (2004) Potassium deficiency, and molybdenum deficiency and aluminium toxicity due to soil acidification, have become problems for cropping sandy soils in south-western Australia. Australian Journal of Experimental Agriculture 44(10):1031-1039 Brennan, R.F, and Bolland, M.D.A. (2004) Lupin takes up less potassium but uses the potassium more effectively to produce shoots than canola and wheat. Australian Journal of Experimental Agriculture 44 (3): 309-319. Jalali, M. (2005) Release kinetics of nonexchangeable potassium in clacreous soils. Communications in Soil Science and Plant Analysis 36 (13-14): 1903-1917. Lemos, S.G, Nogueira, A.R.A, Torre-Neto, A, Parra, A, Artigas, J and Alonso, J. (2004) In-soil potassium sensor system. Journal of Agricultural and Food Chemistry 52 (19): 5810-5815. Murray, T.P. and Clapp, J.G. (2004) Current fertiliser salt index tables are misleading. Communications in Soil Science and Plant Analysis 35 (19-20): 2867-2873 Phillips, I.R. (2004) Measurement and prediction of potassium chloride movement in an unsaturated sand. Communications in Soil Science and Plant Analysis 35 (11-12): 1663-1679 Rosolem, C, A, Calonego, J.C, Foloni, J.S.S. (2005) Potassium leaching from millet straw as affected by rainfall and potassium rates. Communications in Soil Science and Plant Analysis 36, 7-8: 1063-1074. Trehan, S.P, El Dessougi, H and Claassen, N. (2005) Potassium efficiency of 10 potato cultivars as related to their capability to use nonexchangeable soil potassium by chemical mobilization. Communications in Soil Science and Plant Analysis 36 (13-14): 1809-1822 Yuan, L, Huang, J, Li, X and Christie, P. (2004) Biological mobilization of potassium from clay minerals by ectomycorrhizal fungi and eucalypt seedling roots. Plant and Soil 262 (1-2): 351-361 Xu, R, Zhao, A, Ji, G. (2005) Effect of low molecular weight organic anions on adsorption of potassium by variable charge soils. Communications in Soil Science and Plant Analysis 36 (7-8): 1029-1039. |
The Potassium Newsheet is part of the wider Potassium Development program which provides agronomic information on potassium nutrition of crops and pastures through publications, workshops and a website. The program also supports research and development into the best management practices for potassium fertilizer use in Australian and New Zealand agricultural production systems.
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