August 7, 2012

Agronomists Notes

Hello Reader,

Who hasn’t had hail this year, raise your hands. Storms continue to rip through the territory and most of my clients have been hit to some degree. Mitch and I had half of our acres hailed out last Tuesday-- I’d say about 100% damage. Anyone want to custom combine some peas for me? Just kidding. Sort of.

Desiccation has started in pea crops. Too bad most fields in the area are laying flat after wind, hail storms and high disease pressure. I suspect early seeded barley will be pre-harvested this week with early seeded wheat to follow next week. It seems we are way ahead of schedule this year. The GDD’s to date are 1,100 which is 10% higher than normal plus we had an earlier start to seeding this year. Canola swathing is just around the corner.

In this newsletter we’ll look at generating higher yields from delaying natural leaf senescence. We’ll also look at how to value silage on hailed out crops. Next, we have some quick facts on lygus bugs in canola and lastly, we’ll look at the benefits of inter-row seeding with peas when the weather works against you.

Have a great week.

Pictured above: It's a familiar sight in some areas this year-- few stems are left standing after hail at our farm near Morrin, AB, July 31th, 2012. Source: V. Larocque

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded    Apr 24-30               May 1-7                  May 8-15
Wheat      medium dough      soft dough               milky dough
Canola     late pod                 mid pod                   early pod
Barley      hard dough            medium dough        soft dough
Peas        mature                    hard dough             late pod

Steve's tips and tricks for the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Begin scouting for blackleg symptoms in canola.
Continue scouting for diamondback moth larvae and bertha armyworm in canola.
Desicate or preharvest peas.
Stage pre-harvest timing on early seeded wheat and barley.
Continue sweeping for lugus bugs.

Generate higher yields by delaying leaf senescence

Whenever I check fields at this time of year, it’s interesting to note the order in which plants mature. Typically, you’ll find the leaves drying down or browning off, then the stems then the heads. Would you believe that is the opposite of what should occur naturally? The correct order of maturity to generate the highest kernel weights is have your heads mature, then your leaves from the tips backward followed by the stems.

The photos you see here show the natural progression of plant dry down. The kernels are below 20% moisture, the stem is beginning to dry down while the leaf is drying down from the tip back toward the stem. That is what you want to see in order to generate the highest kernel weights.

The carbohydrates developed by the chloroplasts inside green leaf tissue are transported to the kernels at grain filling. This is why it is so important to protect the top two leaves in wheat because the carbohydrates produced in these leaves produce 65% of the final grain yield. In barley, the top three leaves contribute 55% towards final grain yield. We often focus on the protecting the leaves when in reality there is 35-45% of your final grain yield coming from the carbohydrates produced in the bottom leaves, stems and heads. If you allow any of these plant parts to die early, you’ve lost yield potential.

Based on the research I’ve seen overseas, every day you can delay natural senescence, you have the ability to produce an additional 1.5 bu/ac/day of wheat or 250 kg/ha/day for the metric folks. It is for this reason we must look at agronomic practices that prevent early plant decay.

The top three practices I’ve been using to help delay natural senescence are:
1. Combining NH3 or urea N at planting with ESN or slow release N.
2. Using higher rates of phosphorus and potassium which are key drivers in carbohydrate transport in plants.
3. Applying an early fungicide at late tillering followed by fungicide at head emergence, preferably strobilurins early and triazoles later at head emergence.

I’ve had a lot of success using these practices on both wheat and barley. The photos you see here are from some of the trial fields I’ve used more of an intensive approach to management. I can tell you that pushing higher nitrogen rates without balanced P and K fertility will leave you with a heavily diseased crop and the opposite result of what you’re trying to achieve. More N is not the answer to stay green leaves.

Multiple fungicide applications are effective at keeping the bottom leaves healthy while you wait for the top leaves and head to emerge. As 10% of grain fill comes from the carbohydrates produced in the head, it must be protected as part of the program.

Last, a combination of slow release nitrogen like ESN with urea or NH3 works well to reduce heavy nitrate pools early on. Heavy nitrogen loads prior to stem elongation can increase disease pressure and reduce stem thickness. Spreading the nitrogen release is the hardest but most valuable tool we can use to help delay senescence.

I encourage you to look through your fields and observe how your wheat and barley fields are maturing. Are they maturing from the leaves upward or the heads downward? Are you losing 1.5 bushels per acre per day? Start planning for next year’s agronomy program by looking at your crops today. SL

Source: http://www.cropscience.org.au/icsc2004/poster/2/7/3/662_armourt.htm

Pictured above: The most profitable way for a plant to die? From the top down. Last year's high yield barley trial illustrates the point. Source: S. Larocque

Valuing silage after hail

At this stage of in the season, when many cereal crops are reaching milky dough, a severe hail storm could leave you with a mess. What do you do with a crop that has been hailed out 80% or more? Crops at this growth stage respond by generating new tillers and will re-grow until the first hard frost in September. You have three options depending on the severity of the hail. One is to let it re-grow and hope for a long fall to take off some feed grain. Another option is to silage it now if there is enough vegetation to warrant enough silage or third option is to wait until the fall to silage the regrowth.

The equation I use for pricing silage is:

8 × price of barley ($/bu) for a standing crop = $/ton, or
12 × price of barley ($/bu) at the pit = $/ton

A typical barley crop will yield 1 ton for every 10 bushels produced at 65% moisture content. So for example, if you had a 100 bu/ac crop you would have 10 tons of silage.

Today’s September barley price is $4.30 bu making a standing barley crop worth $34.40 a ton. If you have only 20% left of a 100 bu/ac barley crop after hail, that silage may only net you $68.80 ac with the bonus of not having to harvest it. If you were to leave the grain standing and harvest it as feed, that 20 bu/ac left standing will be worth $86.00 an acre but you have to subtract the harvest costs.

Every field is a unique case after hail. In my experience, you’re typically better off harvesting the crop for grain. On the other hand, if you’re faced a serious challenge with residue then silage could be the best option for reducing emergence problems next spring. SL

Inter-row seeding minimizes lodging in peas

Tall stubble provides a support system that's key to harvestability

The biggest issue for most producers growing peas or wanting to grow peas is the issue with harvesting severely lodged fields. No one is a fan of swallowing rocks and or likes to combine at 1.5 mph in one direction only. The answer to improving harvestability of peas is inter-row seeding into tall stubble.

Last Tuesday a hail storm carrying grape-sized hail hammered through half our acres leaving the CPS wheat stripped and peas smashed flat. The ‘before’ picture of our peas makes me tear up. In the ‘after’ picture, the crop is flattened, but the silver lining is that they are still off the ground, 5 or 6 inches at least (bottom photo).

Early in the year you could see the tendrils wrapping themselves around last year’s stubble, adding strength and standability. After the hail and three inches of rain in the past seven days, the peas are laying on top of the stubble and even starting to dry out underneath, believe it or not. I know of peas on rolled fields that are sitting right on the ground and starting to rot and will struggle to dry down under the heavy, wet canopy.

Harvesting the crop will require a few special measures. The header will have lifters spaced every twelve inches which is the row spacing of our drill. The placement of the lifters will be set by engaging the autosteer on the tram lines and dropping the header to the ground. From there we can locate exactly where the lifters should be placed on the header to remain in between last year’s stubble and this year’s pea row. This will dramatically improve the performance of the lifters as they glide between the rows while lifting the crop instead of plowing through or on top of the lodged peas. Precision lifter placement, now that’s a new one!

Inter-row seeding provides a great solution to harvestability in peas. The risk of picking up rocks is less, harvest efficiency climbs as you travel faster and more peas have the potential to be harvested. Providing a trellis for peas to lean on improves air flow under the canopy to reduce rotting and speed up drying. Combine that with precisely spaced lifters that glide between the rows and you’ll naturally do a better job of cutting and setting peas on to the table. Now add CTF to inter-row seeding and you’ve got yourself a killer system to produce pea crops. Less hail wouldn’t hurt either. SL

Pictured above: Meadow peas take a dive after hail damage but not to the ground thanks to inter-row seeding. Source: S. Larocque

Quick facts on lygus bugs in canola

I field questions regularly on Lygus bugs this time of the year. The when, the what, and the how that you need to know about their development for planning potential insecticide timing is given below:

Male lygus will live for roughly 34 days and females roughly 48 days.
Females produce an average of 133 nymphs but up to 300 nymphs in their lifetime.
It takes roughly 10 days for a lygus bug to move from egg to a nymph.
It takes 2 to 3 days for a lygus bug to move 1 instar or 8-12 days to move from 1st to 4thinstar.
It takes roughly 4 days for a lygus bug to move from the 5th instar to adult.
Small wing pads start to develop at the third instar.
Lygus bug development is highly dependent on temperature. Warmer temperatures speed up maturity.
There are typically two generations of lygus bugs in one season and in warmer years up to three.
Lygus bugs damage roughly 7% of the seed at the 3-4 per sweep threshold.
Lygus bugs will not damage firm seeds so be sure to assess the percentage of canola that is firm to see what percentage is still susceptible to lygus damage.

The illustration you see here shows the shape of the lygus bugs from the 1st (32) instar and upward to the 5th (36) instar. Since lygus bugs don't start feeding seriously until the 4th instar it's important to determine the growth stage to help you time insecticide applications. Notice the presence of wings on the 4th (35) instar. I use the development of wings as a guide to determine if they have reached the critical growth stage.

Source: Ab Agriculture , Life history of Lygus keltoni (et al 2006, H.A Carcamo, T.R. Larson, C.E. Herle)

Pictured above: Lygus bug

CTF field day

We hosted a field day with CTF Alberta back in July and www.farm.tv was there to document the epic event. It was certainly a cold and windy event. Check out this video Farm.TV to see the highlights.