Agronomist Notes
Oh my, it’s spring. Ground conditions remain warmer and drier than normal with average soil temperatures of 2 to 4 degrees Celsius. The long term forecast is for temperatures to reach the low 20’s by the end of the week. If that doesn’t make us giddy, I don’t know what will.
Mitch, Sam and I have been busy modifying the air drill and tractor as we adapt equipment for controlled traffic farming. It’s terrifying yet exciting to see your perfectly good air drill in three pieces knowing the 10 feet you took off, won’t be put back on. And, the 4WD which had eight tires will only have four when we’re through. The photo here tells all- it’s carnage in the name of progress!
This week, I’ll discuss a unique way to improve germination and emergence this spring. Next, we’ll talk about the value of testing your seed for germ and vigour with a real life example. Last, I’ll discuss how we can improve herbicide efficacy through one simple measure.
Agronomy
Fine tuning field selection through soil temperatures and residue type
The goal of any seeding system is to create rapid and uniform germination and emergence. Aside from the standard measures of using good quality seed, seed treatment, proper seed placement and nutrition, we can utilize soil temperature to our advantage as well. I’ve often found two to four degree differences in soil temperatures depending on the type and amount of residue in each field. These soil temperature differences can mean the difference between rapid and slow germination.
Last week I documented a two degree difference in soil temperature on adjacent fields of wheat and canola stubble. The canola stubble was two degrees cooler than the wheat stubble, which is typical. Looking at the chart below, if you had a choice to seed wheat into either stubble type, the wheat stubble would give you a better chance at quicker germination and emergence.
Strategy: Take soil temperature readings just before seeding this spring to see what fields or stubble types offer the warmest soil temperatures and plan to seed into those first. This will allow the cooler soils to warm up and provide a greater opportunity to speed up germination and emergence.
I use a laser-guided point and shoot thermometer, 007 Special Issue. It takes about three seconds to get a reading.It may not seem like a big deal now, but a short drive around to measure soil temperature can provide stronger, faster emergence translating into reduced maturity and higher yield potential. SL
Source: http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex1203
A prime example for testing germination and vigour each year
As mentioned in the article above, the primary goal of any seeding system is to create rapid, uniform germination and emergence. I had a great example show up on my desk confirming why we should spend the $72.00 to test for germination and vigour. The pictures you see below are of treated barley seed; 2009 seed stock on the left and 2008 seed stock on the right. The test results on the 2008 seed stock came back at 64% germ and 58% vigour! The seed stock on the left came back at 99% germ and 92% vigour. Unfortunately, the 2008 seed stock has already been treated and the farmer will have to manage it the best he can by seeding later into warm soil and boosting the seeding rate.
As you can see in the photos, the level of germination and root development is dramatically different between the two seed lots. Which seed would you rather be planting?
To drive my point home on seed testing, let’s run the numbers to see what kind of seeding rate increase the producer will have to use to compensate for the low germination level in this example.
Steve’s quick math
Seeding rate calculation
Seeding rate (lb/ac) = desired plant population/ft2 × 1,000 K wt. (g) ÷ (%germination - %mortality) ÷ 10.4
Poor barley: 22 ft2 x 51 grams ÷ ( 64% ÷ 10% ) ÷ 10.4 = 199 lbs lbs/ac
Good barley: 22 ft2 x 51 grams ÷ ( 99% - 10% ) ÷ 10.4 = 121 lbs/ac
There is a 78 lb difference in seeding rate in this extreme example! Nobody is going to seed barley at 199 lbs/ac so I would recommend a smaller plant population target at 16 plants ft2 and push the plants to tiller more. Using a 150 lb seeding rate, which is still high, but will reduce the amount of acres covered with the seed lot under a normal rate and reduce the number of fill times with a 199 lb seeding rate! If you haven’t tested your seed yet, send it in to the lab and you’ll have the results back in ten days. The $77.00 fee for a germination, vigour and thousand kernel weight test offers an excellent return on investment. SL
Boom height has a strong bearing on herbicide efficacy
Did you know that in any given herbicide application, 50% of your weed control comes from the product, 21% from your timing, 19% from the mechanics of your application and the last 10% from fine tuning? Randy Retzlaff, Technical Field Manager for Syngenta in Calgary is looking into how we can fine tune our herbicide efficacy by looking at the effect of boom height. Optimum boom height for herbicide efficacy is 20 inches above the canopy. How many sprayers have you seen speeding down the field with the boom tip about 60 inches off the crop? I’ve noticed sprayers with auto-boom that don’t have the sensitivity calibrated correctly will often be 30 to 60 inches off the canopy on rolly terrain.
To illustrate, look at the pictures below. The picture on the left shows a sprayer with conventional nozzles spraying at 20 inches above the canopy. Now, look at the picture to the right. This sprayer was applying herbicide at 32 inches above the canopy and look at the difference in drift! Research at Syngenta’s UK research farm for sprayer technology found a six fold increase in spray drift when going from 20 inch boom height to 32 inch boom height. The results in wild oat efficacy when comparing 20 inch to 32 inch boom height was a 3% reduction in control. Under heavy wild oat infestations that could still leave you with one or two wild oats per square foot.
The word ‘drift’ automatically triggers fears of spraying beside your neighbor’s susceptible crop. In reality, drift also means you’re increasing and decreasing herbicide rates as the drift settles sporatically across the field. This can cause crop injury or a reduction in weed control. The solution: a stiff 20 inch zip tie at the end of the booms. This will keep you aware of your boom height and give you that extra edge on weed control. When dealing with tough conditions, faster applications speeds and reduced herbicide rates, simple invention like this could make or save you thousands. SL
Comment and correction from last week’s issue
RE: Optimizing pre-burn weed control
"The water conditioner named pHix will lower the spray solution to pH 3.5 or less. Below this pH level glyphosate cannot be bound up by cations in the water. This allows the maximum amount of glyphosate to enter the plant and why we have had such consistent results with pre-burn, chem-fallow, forage stand removal, and pre-harvest applications of over the last 10 years.” Randy Saskiw, Omex
RE: 2010 pre-seed burn options
I forgot to include Merge in the cost of this option last week:
½ L glyphosate plus Heat plus Merge: $7.30/ac, Group 9, 14
Crops: barley, oats, wheat, canaryseed, corn, chickpeas, peas, lentils, soybeans
Target weeds: seedling dandelions <6" across, flixweed, kochia <6" tall, lamb's quarters, narrow-leaved hawk's beard <3" across, redroot pigweed, round-leaf mallow, stinkweed, RR, LL, CF canola <8-leaf, wild buckwheat <10-leaf, wild mustard, winter and annual cleavers <4 whorl.
Residual: 7 days
Market News
Commodity Fundamentals
Technical Analysis
Canola: May futures. The short term trend is up and the long term trend is down.
HRS Wheat: May futures. The long and short term trends are down. Short term rally possible this week.
Corn: May futures. The short and the long term trends are down. Short term rally possible this week.
Soybeans: May futures. Short term trend is up and long term trend is down.
Canadian Dollar: March futures. Long and short term trends are up.
US Dollar Index: June futures. The long term trend is up. Upside move possible here.
Crude Oil: April futures. Long term trend is up. Short term up-trend looks toppy.
