Agronomist Notes

Last week brought needed sunshine and less wind. I am now caught up on all my fields after a tough slug of difficult weather. We are now on the tail end of spraying with a few producers already finished up. Crops around the country are average to poor shape after 30 days of cool, wet weather post-seeding. Early-May seeded canola has started to bolt and winter wheat has started to head out.

One of the biggest struggles lately has been to complete the Liberty applications in canola before bolting. Many producers have opted to apply a grassy herbicide first followed by a second application of Liberty. Contact herbicides like Buctril M, Benchmark and Liberty have not performed well in the cooler weather.

Another issue has been nutrient leaching. I have a few light textured soils in need of nitrogen top dress applications after nutrient leaching rains washed away our available nitrogen. I have a number of plant tissue samples confirming this. I suspect the crops grown on heavier textured clay soils will start to perk up and find the nitrogen after roots resume normal growth.  

This week we’ll discuss nutrient deficiencies, moisture stress and crunch some numbers on the costs of top dressing nitrogen. We’ll look at herbicide injury symptoms to help you check fields for post-herbicide efficacy. Next, I’ll give you an update on my VRT projects and then finish up with International Weather Highlights affecting world crop production.

Crop Staging Area (Calgary to Drumheller to Three Hills)

Date Seeded:	April 23-31	May 1-7	May 8-15
Wheat	1st node	6-leaf, 2 tiller	5-leaf, 2 tiller
Canola	Bolting	Bud stage	6-leaf, early bud
Barley	6-leaf, 3 tiller	5-leaf, 3 tiller	5-leaf, 2 tiller
Peas	12th node	10th node	8th node

This Week in Scouting

Continue 10 to 14 day post-herbicide application checks to analyze herbicide efficacy.
Continue monitoring for early leaf diseases in wheat and barley.
Break out your sweep net, early bolting canola means cabbage seedpod weevils are around the corner.
Fungicide applications in peas are just around the corner. Book your fungicide today.
Check areas that were under stress during spraying for possible weed escapes.
Monitor eroded knolls and sandy textured soils for possible nitrate and sulphate leaching.
Purchase your fungicide now if you plan to use any. Supplies are dwindling quickly!

Agronomy

Nutrient Deficiencies, Moisture Stress and Stress-Induced Nutrient Deficiencies

There are a number of fields throughout my area showing signs of stress. Leaves have turned yellow, plant stems are purple and leaf diseases are present. This is hardly the scenario I was expecting going into 2008. I would estimate that just over 60% of the fields in our area are experiencing symptoms of excess moisture stress and temporary nutrient deficiencies in spite of applying optimum fertility rates.

When soil profiles are completely filled with water, oxygen is displaced and nutrient flow to plant roots is significantly reduced. Cool, wet soils tend to reduce phosphorus and potassium diffusion and slow the conversion of ammonium to nitrate. To aggravate the problem, the eight inches of rain in the last 40 days has potentially leached the soil nitrogen just below the shallow root zone causing early season nitrogen and sulphur deficiencies.

A broadcast or surface application of urea, ammonium sulphate or UAN is possible but not without risks. The following conditions favour nitrogen losses following application:

• high soil temperatures
• moist conditions, followed by rapid drying
• windy conditions
• high soil pH (>pH 7.5)
• high lime content in topsoil
• coarse soil texture (sandy)
• low organic matter content
• high amounts of surface residue
• nitrogen source: urea > UAN solution > ammonium nitrate

Whether you use liquid or granular fertilizer, rain is still required after application to wash the nitrogen down into the roots. Results from Michigan, North Dakota and Minnesota studies say 2.5mm to 6mm of rain is required to incorporate surface applied urea. Research from Brandon, Manitoba, states that nitrogen losses from urea were 40% and 80% after 7 days in May and July when temperatures were 20-250C and 300C, respectively, followed by no rain. Nitrogen losses from 28-0-0-0 UAN were 7% and 50% under the same circumstances.  

Cost – Benefit Price Scenarios:
The following scenarios are based on the crop receiving 20 lbs/N per acre after potential volatilization losses. Please take these volatilization losses with a grain of salt because any number of scenarios could occur depending on environmental conditions.

Urea: $0.93/lb × 20 lbs/ac with 40% volatilization loss. = (20 lbs N ÷ (100% - 40% loss) $0.93) = $31.00/acre

Urea + Agrotain: $1.00/lb @ 20 lbs/ac with 10% volatilization loss = (20 lbs N ÷ (100% - 10% loss) $1.00) = $22.22/acre

28% UAN: $0.93/lb @ 20 lbs/ac with 7% volatilization loss = (20 lbs N ÷ (100% – 7% loss) $0.93) = $19.99/acre

UAN + Agrotain: $1.00/lb @ 20 lbs/ac with 0% volatilization loss = (20 lbs N ÷ (100% – 10% loss) $1.00) = $20.00/acre

The two most cost effective strategies are the straight 28% UAN and the 28% UAN with Agrotain. In fact, for a one cent difference, the 28% UAN + Agrotain will give you added protection in case you don’t receive rain within 7 days. An added benefit of 28-0-0 UAN is that 25% of the product is ammonium nitrate which is immediately available to plants. The risk with UAN is the potential for severe leaf burn, especially if conditions are warm and humid during and after application. Dribble band nozzles can minimize but not eliminate leaf burn.
Source: http://www.gov.mb.ca/agriculture/soilwater/soilfert/fbd12s00.html
Source: http://www.gov.mb.ca/agriculture/soilwater/soilfert/fbd13s00.html 

VRT Project Update

I have four variable rate fertilizer projects on the go this year. Three out of four look “normal” at this time with no visual symptoms to get my attention. I do have one field, though, that shows definite lines where the nitrogen turned off during the application process. This is an 85-acre field with a history of manure and we went to extremes on fertilizer rates applying anywhere from 195 lbs of urea to zero per acre. After crawling across the field during my weed inspection I noticed a few areas, possibly 5% of the field, showing early signs of nitrogen deficiency. After an inspection of the custom VRT map, these areas had zero nitrogen applied, and it showed.

The VRT process is just that, a process. Although these areas look unattractive, we’re learning when and how far we can push this technology. It also exemplifies how risky this technology could be if used incorrectly and by employing it on a large scale right from the start. Crawl, walk, run is my strategy with VRT technology. I still see its potential but I also see loads of risk if used incorrectly. SL

It’s Time to Check Post-Herbicide Efficacies

The most important role of a farmer or crop advisor during spray season is not only to apply the correct herbicides at the right time but to follow up with post herbicide checks. Follow up efficacy checks should be done 10 to 14 days after application. More wild oat or weed escapes can be corrected if only producers and crop advisors checked how well the herbicides worked after application. Calling the chemical representatives at harvest to tell them the herbicide didn’t work is futile and besides, herbicide inquiry cut off dates are usually around the 15th of July.

Below is a list of herbicide injury symptoms for the top six herbicide groups I use to help identify herbicide injury and efficacy.

Group 1: ACCase: Axial, Achieve Liquid, Horizon, Puma Super, Centurion
Symptoms: The first sign of injury on wild oats or green foxtail may appear as intervenal chlorosis or yellow striping on newer leaves. Older leaves may show red or purple. The growing point turns brown and dies. The newest leaf can be easily pulled from the crown where you will see a “pinching” at the base of the leaf. New growth dies first, such that the plant appears to take considerable time to die after application.

Group 2: ALS: Assert, Ally, Everest, Frontline XL, Refine SG, Odyssey
Symptoms: In broadleaf weeds the first visible symptom is the termination of plant growth. A few days after application you may see yellowing, reddening and purpling of the leaves. In grassy weeds like wild oats, you may see a yellow striping and purplish discoloration of the leaves. The youngest leaves die first followed by older leaves. Death of grassy weeds may take 1 to 3 weeks to occur.  

Group 4: Auxinic: 2,4-D, MCPA, Attain, Buctril M, Curtail M, Frontline XL, Target 
Symptoms: Bending and twisting of stems and petioles, stem swelling, especially at the nodes, elongation, leaf cupping and leaf curling. These signs are followed by yellowing at the growing point, growth inhibition and wilting. 

Group 6: Photosynthetic Inhibitors: Buctril M, Pardner, Thumper, Unity
Symptoms: Rapid yellowing and whitening begins at the leaf edges. Later symptoms include desiccation and a burned-off appearance of the leaves. Symptoms develop rapidly under full sunlight conditions.  

Group 9: EPSPS: Glyphosate: Roundup WeatherMax, Touchdown Total, Vantage PlusMax
Symptoms: Gradual wilting and yellowing at the growing point of the plant that advances into browning of above ground growth. Annuals may show signs within 2-4 days and perennials within 7-10 days. 

Group 10: Glutamine Synthetase Inhibitor: Liberty 150
Symptoms: Yellowing and wilting usually occur within one to three days after application, followed by necrosis or bleaching-death of plant tissue. Symptoms develop more rapidly under bright sunlight, high humidity and moist soil.   
Reference: How Herbicides Work, Alberta Ag publication

Market News

United States: On the Plains, scattered thunderstorms are heaviest across South Dakota and eastern portions of Kansas and Oklahoma. A sharp gradient exists between adequate to locally excessive soil moisture in most areas and a significant drought on the central and southern High Plains. Drought also remains a concern in parts of North Dakota. In the Corn Belt, cool, mostly dry weather prevails. Flooding continues to gradually subside along most Mississippi River tributaries, but substantial agricultural problems—including washouts, erosion, and delayed crop development persist due to lingering wetness in portions of several states, including Wisconsin, Iowa, Illinois, Missouri, and Indiana.

Europe: Widespread rain across central and southern Europe provides favorable to locally excessive moisture for filling winter grains and vegetative summer crops but maintains crop quality concerns. Showers spread into Poland, supplying much-needed topsoil moisture for reproductive winter wheat.

Former Soviet Union: Light to moderate showers favor winter grain and spring-sown crop development in Ukraine and Belarus. In Russia, drier weather helps late-season fieldwork. Light showers favor spring grains in the Urals and Siberia Districts in Russia, while drier weather prevails over major spring grain producing areas in north-central Kazakhstan.

East Asia: Mostly dry weather reduces soil moisture for corn and soybeans in Manchuria and the North China Plain. Heavy monsoon showers cause flooding in the south and slow early-crop rice harvesting as well as localized damage to reproductive single-crop rice.

Southeast Asia: Monsoon showers continue to provide favorable moisture to rice and corn in Thailand and the Philippines, while slowing rice fieldwork in Vietnam.

South Asia: Heavy monsoon rain in northern portions of India and Pakistan boosts moisture reserves for summer crop planting and emergence but causes flooding and fieldwork delays.

Australia: Widespread showers favor vegetative winter wheat and barley across much of southeastern Australia, except in southern New South Wales where relatively light rain offers little drought relief. In Queensland, warm, dry weather aids late winter wheat planting and final summer crop harvesting. In Western Australia, scattered showers maintain local moisture supplies for vegetative winter grains.

South America: Topsoil moisture remains limited for winter wheat germination and establishment in key growing areas of central Argentina. Rain maintains overall favorable conditions for winter wheat over much of southern Brazil.

Canada: Rain provides additional drought relief for emerging spring grains and oilseeds in Manitoba and
Eastern Saskatchewan.

Mexico: Rain improves corn planting prospects in western sections of the southern plateau.

Canola supplies seen tight despite record forecasts

Canadian canola supplies could still be tight at the end of the 2008-09 crop year, despite some forecasts calling for a record crop, as demand remains strong. As a result, prices for the commodity should also remain firm.
Full story: http://www.grainews.ca/issues/isarticle.asp?id=85942&issue=06192008&PC=FBC&story_id=&link_targ=DailyNews&link_source=aypr_GRN

CWB program to offer delivery period options

Prairie farmers delivering wheat and durum to the Canadian Wheat Board can choose their delivery period under a new optional delivery system. Sign-up begins August 1 for the CWB's new GrainFlo program for the 2008-09 crop year.
Full story: http://www.cwb.ca/public/en/newsroom/releases/2008/061908.jsphttp://www.cwb.ca/public/en/newsroom/releases/2008/061908.jsp