AGRIS Co-operative Ltd. & Wanstead Farmers Co-operative Volume #10 Issue #8 April 5, 2018

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1 : Volume #10 Issue #8 April 5, R Nitrogen management in wheat By Kent Wolfe - CCA-ON, CCS Crop Sales Specialist AGRIS Co-operative Dutton Monitoring Black Cutworm moth arrival with Pheromone traps Nitrogen management is a very critical part of winter wheat production. Spring N demand in winter wheat basically has two important functions, one is to help manipulate population through the tillers and secondly it must supply nutritional needs to that plant through all stages of growth so that it can maximize both yield and protein content. This can typically be one of the most difficult challenges a grower faces each spring. What is the right time, right rate, right source and right place? This approach is referred to as the 4 R s of Nutrient Stewardship. We always take these factors into account when making crop plans for your farm. The whole nitrogen system availability can be a very complex issue, so the more we look at these factors the more we learn, allowing use to make better recommendations. What is the right time? Often times we are tempted to go early on frozen ground to avoid compaction and avoid making ruts. However, by going too early before green up leaves the N application open to environmental losses. Nitrogen application timing should be aimed with a onetime application by Zadok s 31 (stem elongation) which is typically 15 to 20 days after green up. It is from this stage to Zadok s 58 (early flower) that the majority of N is required by the plant. If going with a split application often times applying an initial amount based on tiller count at early green up then taking a plant tissue leaf sample prior to stem elongation can assist in determining the final split application timing and rate. One of the key observations in determining both timing and rate is the crop condition and plant density or population of your crop, this involves doing both plant and tiller counts in your fields. This is the only way to answer the questions of, Do you have full stand? What is considered a full stand? Is it well tillered or mostly single stems? 2018 GROWMARK, Inc., AGRIS Co-operative Ltd., Ltd. The information provided in this letter is general in nature and specific information should be obtained by review of product labels and consultation with the manufacturer. Such information can be materially affected by inaccurate data or assumptions, varying circumstances, known or unknown risks and uncertainties, and many other factors which are beyond the control of GROWMARK, Inc., AGRIS Co-operative Ltd., Ltd. and results can vary widely. The user will not rely on any information provided herein and GROWMARK, Inc., AGRIS Co-operative Ltd. and Wanstead Farmers Ltd. will not be liable for any reliance on that information. The FS logo is a registered trademark of GROWMARK Inc. and all trademarks contained herein are the intellectual property of their respective owners. Content is property of GROWMARK, Inc., AGRIS Co-operative Ltd., Ltd. and reproduction or copies of Crop Solutions that Work, in whole or in part is strictly prohibited, except with written permission from AGRIS Co-operative Ltd. or Wanstead Farmers Co-operative Ltd.

2 If plants are well tillered as it would appear a lot of fields are in our territory are due to earlier planting, normal temperatures and an adequate amount of available N last fall, the recommendation would suggest delaying the application until later in April and also use the lower end of the recommendation. The rationale is that these thick stands exist because the N supply is already high. In contrast a thin stand with very little tillering would suggest an earlier application at the higher end of the recommendation to support biomass production and force some more spring tillers to form.

3 What is the right rate of N that I should be applying to my wheat this year? There are two parts to this question. Are you pushing for maximum yield? Then that means higher N rates and higher N rates in turn mean a fungicide application to maintain plant health and allow the plant to utilize the additional nitrogen. Higher N rates, high yield and fungicide need to be a coordinated effort. We have conducted trials over the last few years comparing rates of N, it would suggest that the average number is 120 lb/ac of actual N in normal crop conditions, this value can be adjusted by (+ or 25 lbs) when looking at some of the other factors like expected yield, plant stand, plant health, application timing and wheat prices. Adding a fungicide at either T1 or T3 will result in greater returns in high yield environments.

4 What is the right source of fertilizer to supply the wheat crop with its nitrogen requirement? In our territory basically, it comes down to one of two sources urea or UAN, each product comes with their own advantages and disadvantages. The first product is urea (46-0-0) this is a dry product that is popular in some areas because it is the most economical form of N. It can also be applied easily with pull type spreaders or custom applied with airflow units and can also have other dry fertilizer products blended with it for a one pass program. The main disadvantage of urea is that it can be subject to losses from volatilization, this occurs during the conversion process to nitrate nitrogen. These losses can be as high as 30 per cent under the right conditions which are dry soil surfaces, higher ph soils, warmer soils, windy days and high trash cover. The other N source is UAN 28% which is a combination of urea and ammonium nitrate in a liquid form. This form of N has shown a slight yield advantage when compared to the dry forms of N over the last couple of years. It does however require special sprayer tips to apply the product (jet or streamer tips are what they are referred to) These tips get less product on the leaf surface of the plant which greatly reduces the leaf burn that we would see with tradition fan or flood jet nozzles. UAN can also be subject to volatilization losses in dryer conditions and will cost you a little more per acre. Whatever the N source always remember to add Sulphur at 20 lbs/ac in total including any fall rates. Field trials conducted by your co-operatives over the past 6 years shows on average a six-bushel yield response to S. Another consideration would be treating your nitrogen with Agrotain Ultra, this product is a urease inhibitor that blocks the urease enzyme thus reducing volatilization loss. If you are applying your nitrogen in dry conditions and no rain is in the forecast this treatment will protect your nitrogen investment and maximize full nitrogen availability for wheat crop.

5 What is the right place? For the majority of us a spring top dress application of N at green-up is the only option. Make sure application equipment is calibrated to ensure uniform application, this is very important in maintaining uniform, consistent maturity, reduce lodging and maximize the yield. This a living crop so it is imminent that applied nitrogen will be used shortly after green-up. Efficient nitrogen fertilization and fungicides are crucial for economic wheat production. Over applying N not only could cause environmental concerns, it will also increase your cost of production and could possibly reduce your yield by increasing the chance for lodging and the risk of increased disease pressure. Lowering N rates to address these situations can lead to insufficient N being available to the plant at critical stages such as grain fill, which would significantly reduce your yields and profits. If you have any questions regarding your wheat N management call your local AGRIS or branch. We are here to help.