1
Welcome to Crop Nutrition News Sourcing relevant and recent crop nutrition information is not always easy; hopefully this newsletter can help. Produced as part of the More Profit from Crop Nutrition (MPCN) program our aim is to help you quickly link to crop nutrition information associated with GRDC RD&E investments. With a strong focus on developing and extending regional crop nutrition information MPCN builds on GRDC’s previous crop nutrition investments. MPCN is a collaborative initiative supported by GRDC and is overseen by Jan Edwards, manager ‘Farm Practices’. Soil testing and understanding soil tests At recent crop nutrition workshops run in Central Queensland, as part of the MPCN northern extension project, Chris Dowling reminded growers of the role of soil tests in managing soil fertility and crop productivity. Soil tests should only be taken for a reason, eg to help identify a problem or to check that soil nutrient levels are on track. Important times to test are after: • high or low performing seasons; • several years of pulse crops; or • a run of unusually wet or dry seasons Ideally a soil test result should not produce any surprises but confirm the anticipated nutrient levels. Perhaps soil tests should be considered more like a fuel gauge, indicating what is in the tank, rather than a compass telling you where to go. Other than for mineral nitrogen, soil tests are not a measure of how much nutrient can be extracted from the soil. Instead they are an index of sufficiency indicating the likelihood and the magnitude of response from adding nutrient. Using the nutrient calibration curves produced in the Better Fertiliser Decisions for Cropping Interrogator can help provide a closer indication of the relationship between nutrient sufficiency and yield. New regional soil testing fact sheets distributed with the January-February issue of Ground Cover, provide more details of these response curves. Submitting a representative sample to a laboratory certified ASPAC proficiency for a key test method eg Colwell P and working with a Fertcare® accredited adviser can help improve reliability of the soil tests results and their interpretation. More information: Chris Dowling, [email protected] GRDC Research Code DAQ00183 Copyright © 2014 GRDC, All rights reserved. Subscribe to this newsletter Send to a Friend | Unsubscribe from GRDC Crop Nutrition Emails | Unsubscribe from all GRDC emails Grains Research & Development Corporation (GRDC) PO Box 5367 KINGSTON ACT 2604 Australia Level 1, 40 Blackall Street, BARTON ACT 2600 Australia Telephone: (02) 6166 4500 Fax: (02) 6166 4599 By bringing together projects relating to crop nutrition, MPCN’s goals are to: 1. Increase adoption of crop nutrition knowledge across Australia; 2. Improve coordination of communication and extension across the grains and fertiliser industries. 3. Improve tools that are used by grain growers and advisers to improve nutrient use efficiency; and 4. Document emerging crop nutrition ideas and capacity challenges. A list of the projects can be found at www.grdc.com.au/mpcn and more details are available in the January - February 2014 Ground Cover Supplement. As Coordinator of the MPCN I am keen to learn of your specific crop nutrition needs and to receive feedback on the program’s outputs. Spare a moment and answer the 5 questions on the survey . Simon Speirs My contacts are - 0428 647 787, [email protected] pH driving nutrient use efficiency in WA Work in WA has shown that in acidic soils, investing in lime rather than phosphorus (P) can result in a better financial return. This is because: • about 80% of soils in WA cropping zone have surface pH less than a critical level of pH 5.5. • low pH not only impacts on nutrient availability, it can result in root pruning, nutrient uptake and consequently yield. • in combination with soil problems such as water repellence and soil compaction, nutrient use efficiency in low pH soils can be low. • about 80% of soils in the WA cropping region have phosphorus concentrations above the critical level (90% maximum. production). These issues were discussed by Craig Scanlan, DAFWA, and colleagues at the ‘Get to Know Soils Deeper’ workshops run as part of the MPCN extension in the west. Craig also presented the Crop Phosphorus Model that can help tailor P requirements for specific situations. More information: Craig Scanlan, [email protected] GRDC Research Code DAW00223 While a number of different P tests are used in Australia, the vast majority of calibration data for soil phosphorus in cropping is for Colwell P. Recent research has led to the introduction of the DGT-P test for cropping. The grains and fertiliser industries are continuing to conduct fertiliser trials aimed at refining calibration criteria and understanding the differences between the measure of phosphorus obtained from DGT-P and from Colwell-P or other testing methods. Importantly, the DGT-P test is recommended for soil testing on calcarosols (soils having high levels of “free lime”). In other cases, contrasting peer-reviewed field knowledge means that more work is required before recommending either Colwell-P or DGT-P in preference to the other on a number of soil types - it is still early days. Despite this general view there are some cases where yield results may not be reflective of expectations based on an initial soil test. If the issue is indeed related to phosphorus, you may wish to run a comparative analysis with an alternative P-test such as DGT-P. However, it is crucial that growers use the same test across paddocks and across years. Currently, a proficiency program for the DGT-P test has not been established. The GRDC fact sheet Phosphorus Management produced in November 2012 provides more details for P tests and PBI. More information: Sean Mason, [email protected] or Simon Speirs, [email protected] GRDC Research Code UA00140, DAN00166 Soil Testing for P Nitrogen crucial to early phosphorus response Victorian DEPI researcher Roger Armstrong has been trying to understand why early dry matter responses to phosphorus (P) do not always relate to grain yield. His team has found that in the Southern Region, unless nitrogen (N) is applied with P, there may be no grain yield response. In trials on a P deficient Vertosol and Calcarosols in the Wimmera, despite pronounced responses to P fertiliser during vegetative growth stages, grain yield was increased only when N was also applied, regardless of soil water supply. Phosphorus is especially important in the establishment of root systems and early crop growth but if N is limiting, optimum use of the P is not made. More details can be found in Roger’s paper to the 2012 agronomy conference. In other trials it was shown that canola was better than wheat at accessing P that had become fixed in the less soluble soil P pools. More information: Roger Armstrong, [email protected] GRDC Research Code DAV00125 Crop and Pasture Science Special Issue, Vol 64, Number 5 Edited by Ken Peverill, Mark Conyers, Robert Norton and the late Doug Reuter, the papers in the Special Edition are a valuable resource for soil scientists and crop nutritionists. Arising from the Better Fertiliser Decisions for Cropping Systems in Australia (BFDC) project, these papers have collated and synthesised historical nutrient response data. This re-examination of fertiliser response surfaces and soil test interpretations are leading to an improved understanding of fertiliser management. Papers in the Special Edition have identified soil testing knowledge gaps for certain crops and nutrients and have provided a guide for developing future research projects and prioritising resources. Some of these gaps are being addressed through current MPCN projects. To source the papers visit http://www.publish.csiro.au/pid/7270.htm The key practical messages from these papers have been distilled into three regional GRDC fact sheets titled Soil Testing for Crop Nutrition, available from the GRDC website. More information: Simon Speirs, [email protected] GRDC Research Codes DAN00166, DAN00132, DAW00222, UQ00063, DAN00168 Micronutrient deficiencies can be tricky to diagnose and treat. By knowing your soil type, considering crop requirements and the season, and supporting this knowledge with diagnostic tools and strategies, effective management is possible. Micronutrient deficiencies are best determined by looking at the overall situation: region, soil type, season, crop and past fertiliser management. Tissue testing is the best way to accurately diagnose a suspected micronutrient deficiency. When tissue testing, sample the appropriate plant parts at the right time. Plant nutrient status varies according to the plant’s age, variety and weather conditions. However, the difference between deficient and adequate (or toxic) levels of some micronutrients can be very small. When applying fertiliser to treat a suspected deficiency, leave a strip untreated. A visual response or tissue testing can confirm whether the micronutrient was limiting. Useful resources: GRDC Crop Nutrition Fact Sheet - Micronutrients CSIRO publication - Plant Analysis: An Interpretation Manual More information: Rob Norton, [email protected] GRDC Research Code IPN0001 Micronutrient deficiency Micronutrient deficiency There are three regional extension projects as MPCN program Southern Extension project is led by BCG. Crop Nutrition workshops will be run across the southern region in the winter period, for details contact Ciara Cullen, 03 5492-2787, [email protected] Western Extension project is led by Craig Scanlan, DAFWA, 08 9690-2174, [email protected] Northern Extension project is led by Kaara Klepper, Department of Agriculture, Fisheries & Forestry Queensland, 07 4639-8870, [email protected] For more information on MPCN activities please visit the visit the events calendar on the GRDC website.
