July 30, 2013

Agronomist Notes

Hello Reader

The cool, wet weather continues. There was a low of 2C at the farm last night! That likely means frost in some low-lying areas throughout our region. The 14-day trend calls for temperatures in the mid-20’s with lows in the double digits. We’ll have to rely on a decent August-September to get these crops in with good quality. The yield potential across most areas is above average.

In this week’s newsletter we’ll look at the use of plant growth regulators and vacuum planters on field peas. I’ll pass along some tips on valuing silage barley after hail as well a list of smartphone apps for ag. We’ll finish with the fundamentals on lygus bugs in canola and technical grain market news.

Photo: CDC Meadow peas stand up to my truck door handle. S. Larocque

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded May 1-7 May 8-15 May 15-22
Wheat Watery ripe Watery ripe Flowering
Canola Early pod 90% bloom 80% bloom
Barley Milky dough Watery ripe Heads emerged
Peas Early pod Late flower Mid flower

Steve's tips & tricks of the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Continue sweeping for insects in canola. Look at bottom leaves for signs of insect damage.
Now is a great time to look for late season nutrient deficiencies. Hone you’re your nutrient deficiency ID skills with this handy smartphone tool.
Wheat planted the last week of May could be susceptible to wheat midge damage. Check fields in the evenings to monitor midge levels.
Now is the time to apply late season foliar nitrogen in canola at the early pod stage.
Apply foliar zinc to wheat planned for seed as it reaches milky dough stage.

Plant growth regulator trials in field peas

In-season observations

One of the biggest struggles with growing bin busting pea yields is keeping them upright through to harvest. Every year we stand in awe of 3-4 feet tall pea crops at flowering only to watch in horror as they fall to ankle high by harvest. The main reasons for severe lodging is a combination of variety, disease plus the shear weight of the canopy becoming too much for the stems to hold. This year we applied a plant growth regulator to see if we could keep a high yielding pea crop standing all the way to harvest. After more than 12 inches of rain this season, it was a perfect time to see how a PGR would perform.

These are the details of the experiment: Chormequat, (Cycocel Extra 460 g/L) was applied on 50 acres of CDC Meadow, a yellow pea variety known for high yield and high lodging potential at a rate of 200 ml/ac. The Cycocel Extra was applied with a 160 ml/ac rate of pyraclostrobin (Headline) at the beginning of flower. The top photo shows my sweep net nestled in the canopy with the Cycocel treatment versus fungicide alone in the photo below.

Here are my observations:

The 200 ml/ac Cycocel Extra treatment shortened the pea stand by roughly 10 inches compared to the untreated check but didn't reduce the height of the actual plants. It seems like the crop is crouching down more on the PGR side.
The treated side finished flowering a week earlier than the untreated side.
Both the treated and untreated plants have 10-12 pods per plant with 4 to 6 seeds per pod.
The canopy on the treated side is a lot more open and the soil below can be seen.
The plant stand on the treated side looks slightly uneven with some small areas shorter than others.

Cycocel Extra is not registered in field peas; this is merely a trial to see what would happen. The results so far show a definite shortening of the stand but also a hastening of maturity. The 200 ml/ac rate of Cycocel Extra and the timing of application was a guess so perhaps we could try different rates and timing if we feel more trials are worth pursuing. Higher yields and better harvestability is the goal, which cannot be reached with certain high yielding varieties at this time. Time will tell whether this technique proves positive for pea yields and harvestability. SL

Vacuum planter vs. disk drill in field peas

Improved standabiity

In an effort to generate optimum yields in field peas field trails have begun comparing air disk drills versus vacuum planters. With large seeds and seeding rates above 200 lbs/ac, air distribution systems struggle to place seed evenly down each furrow. This leads to gaps, bunches and uneven densities across each furrow. In 2012 James Jackson from Jarvie, AB did a side-by-side trial comparing his JD 1870 Conservapak drill to a JD 7200 MaxEmerge vacuum planter. In 2013 James is comparing his JD 1895 disk drill to the 7200 MaxEmerge planter and this time, comparing the same row spacing.

In 2012, James planted the green pea variety Cooper with the JD 1870 ConservaPak drill on 12-inch spacing versus the JD 7200 MaxEmerge planter on 15-inch spacing.

The initial results from 2012:

Conservapak: 56 bu/ac; 88 plants m-2; 101 days to maturity; 6.75 standability
JD MaxEmerge: 53 bu/ac; 68 plants m-2; 103 days to maturity; 4.5 standability
Note: yield difference was not significant.

The results from 2012 show a significant advantage in reduced lodging with the MaxEmerge planter on 15-inch row spacing. The lodging ratings are given between 0 and 10 with 0 being totally erect and 10 totally flat. Standability improved by 50% on the MaxEmerge 15-inch planter side compared to the Conservapak on 12-inch spacing. Unfortunately, the plant stand density was 30% lower on the MaxEmerge side, which likely led to the small reduction in yield. The difference in plant stand density was said to be a calibration error, not a seedling mortality issue. In 2013, James is comparing his JD 1895 disk drill on 10-inch spacing to the JD MaxEmerge planter on 10-inch spacing to get a true comparison of the two systems.

We know air delivery systems struggle to distribute seed evenly across the drill and within each furrow. The size and uniformity of field pea seed make them an ideal candidate for vacuum planters and seed singulation. The photo above says it all with a clumped row of peas on top with the JD 1895 single disk and singulated seed spaced every three inches on the planter side shown in the photo below. If we could generate high yielding peas with excellent standability and with that harvestability, we’d have a winning combination. Food for thought. SL

SmartPhone Apps for Ag

Aussie Nuffield Scholar, Richard Heath, stopped by last week and introduced me to a list of smart phone apps put together by GRDC and NSW Department of Primary Industries. The lists are quite comprehensive and can be viewed by clicking through the links below:

GRDC: Smart Phone Apps for Farmers

NSW DPI: Smartphone Apps for Ag

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 an acre 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 would be worth $86.00 an acre, less harvest costs.

Every field is a unique case after hail. In my experience, it’s usually better 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

Lygus bug fundamentals

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 4th instar.
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 Ag , Life history of Lygus keltoni (et al 2006, H.A Carcamo, T.R. Larson, C.E. Herle)

Pictured above: Lygus bug

Reader comments

Re: Foliar nitrogen on canola at early podding

All the work over here in the UK suggests a very predictable response to foliar applied nitrogen on canola at early pod stage. The only seasons where there is not a response are when moisture is the limiting factor and the crops drought out - in these years it can even have a negative response. The average response over 8 years of trials is 0.35t/ha (3 bu/ac) including 2 years of reduced yields due to heat and moisture stress. It sounds like this year would be perfect for you to try the applications. Last year we had over 0.5t/ha (4.5 bu/ac) yield response in 4.5t/ha crops.

Tom Bradshaw, Fletchers Farm, Fordham, Essex, UK