May 29, 2012

Agronomists Notes

Hello Reader,

Seeding has just about come to a close. Temperatures have remained cool which has slowed crop growth and limited the opportunities for herbicide application. Crop emergence has been excellent so far but a few nights of frost have stressed canola, wheat and barley a little so we’ll wait to allow them to recover before we resume spraying by the end of the week.

We’ve accumulated 169 growing degree days from May 1st until today which is 3% cooler than last year this time and 6% below the five-year average of 160 GDD’s. Average precipitation for our area is just over 3 inches or 26% above the five-year average. We are sitting well for moisture but we’ll need some timely rains by the middle or end of June.

In this week’s issue, we’ll look at the future of seed delivery systems, as well as the results from some pre-burn herbicide strategies used this spring. I’ll provide the low down on how to achieve higher yields with inter-row seeding. Last we’ll look at the importance of potassium when trying to generate tillers. Finally, we’ll finish with technical grain market news.

Have a great week.

Picture: Peas inter-rowed into barley stubble at our farm.

Crop Staging

(Calgary to Drumheller to Three Hills)

Seeded    Apr 24-30        May 1-7        May 8-15
Wheat      early 3-leaf     2-leaf            1-leaf emerging
Canola     2-leaf              1-leaf             cotyledon emerging
Barley       early 3-leaf    2-leaf             1-leaf   emerging
Peas        3rd node        2nd node       1st node

Steve's tips and tricks of the week

Follow me on Twitter for in-season updates @BeyondAgronomy

Now is the time to look for emergence patterns. Is residue management causing emergence delays? Is seeding depth highly variable? What is causing crop emergence variability?
Monitor volunteer canola in wheat and barley fields. It can get out of control fast with warm temperatures.
Start measuring plant stand densities inside each foot of row across your drill. Some drills have very uneven distribution systems and you may uncover an issue.
Avoid spraying when temperatures are about to drop below 5C at night and begin applying when daytime temps climb above 10C for optimal weed control and crop safety.
Missed a pre-burn herbicide? Apply Express SG + 0.35% v/v non-ionic surfactant to control volunteer canola, wild buckwheat, cleavers, dandelion, flixweed in 1 leaf or emerging cereals. Works excellent!
SL

The future in seed delivery systems will address in-furrow distribution

It never fails that when I begin scouting fields, I’m always surprised to see how much variation there is seed placement within each furrow. We all know that canola is notorious for being unevenly distributed within each row and the same goes for cereals and pulse crops. For example, the photo you see here is a classic example of an air delivery system that places three seeds within one inch of each other. Next to it there could be a three-inch gap with just one seed then a group of eight seeds bunched together. This unquestionably leaves a lot of room for improvement.

I have visited with Guinness World Record holders Mike Solari and Chris Dennison and each of the three records they set were seeded with a simple 12-foot hoe drill on six-inch row spacing with gravity fed metering systems that drop seed almost vertically. The reason I mention this is because six-inch row spacing and gravity distribution provide much better seed distribution in the furrow. This simple system helps to maximize soil exploration, reduce plant to plant competition and improve solar capture. All key components of building world record yields.

In our current air drills, the metering and air delivery systems do as they were designed to do but fall short with what we’re trying to accomplish with seed distribution. We’ve sacrificed seed placement and distribution in furrow with air delivery systems that send seeds of varying sizes down 30, 40 and 50 ft of air hose with bends and curves along the way. Some metering systems have improved like the SeedMaster UltraPro meter but essentially it accurately meters seeds of varying sizes that travel at different speeds inside an air stream with long stretches of hose.

Now to talk row spacing. Every time the sunlight hits the ground while missing a plant is a waste of solar energy. Even though there is research to say that 10 and 12-inch row spacing is fine, there is equal research to argue that 5 and 6 inch row spacing is better, especially in cereals. The reason is as stated above, you have less plant to plant competition in the furrow, better soil exploration by roots and better sunlight capture through higher ground covered.

So how do we build a drill that has seed singulation like a vacuum planter, uses gravity to drop seeds, has narrow row spacing but enough clearance to move through heavy residue with excellent ground contouring ability and accurate seed placement? Oh, and I would like this drill to do all of the above at 7.5 to 8 mph with 100 acres per fill. But seriously, if you were to focus on building a drill with solar capture, soil exploration and seed distribution as your mandate, you would come up with a very different design compared to the efficiency only drills build today. Food for thought. SL

Picture: Wheat seedlings planted within 1 inch of each other. Source: S Larocque

Results of pre-burn herbicide strategies

Applied a high rate of Heat (Saflufenacil) 28.4 g/ac plus Merge 200 ml/ac, ½ L/ac REL glyphosate 5 days after seeding peas and it provided residual control of wild buckwheat, cleavers and volunteer canola for two weeks after ½” rainfall. Just starting to see cleavers, volunteer canola and buckwheat pop up at my place. Peas now at 2 nodes. Very satisfied with control. Cost: $10.70 ac
Applied Authority (Sulfentrazone) at 118 ml/ac with ½ L/ac REL glyphosate May 1st prior to peas on fields with flushing wild buckwheat, cleavers and volunteer canola and some kochia. Starting to see volunteer canola and cleavers pop up now, 28 days after application. Peas now at 4 node and will be sprayed. Cost: $15.00 ac
Applied PrePare (flucarbazone) with glyphosate prior to seeding wheat and wild oat control is excellent! It does take up until the 2nd leaf for wild oats to start showing signs and taking in herbicide. The downside is its lack of flushing control on volunteer canola where a lot of wheat is grown in rotation. Photo above is wild oats light green and injured between the rows of dark green wheat. Cost: $8.50 ac SL

Setting the record straight on inter-row seeding – higher yields

There are many benefits to inter-row seeding like better residue flow, better soil closure behind the openers, warmer soil, less wind speed at the surface and less draft to name a few. However, to really drive yield higher the goal with inter-row seeding is to leave the stubble tall to maximize the yield benefit. Inter-row seeding is the tool that allows you to leave stubble height taller without plugging during seeding. If you’re inter-row seeding into stubble less than 6 inches tall, you’re not capturing the yield advantage that inter-row seeding offers.

Dr. Brian McConkey from Ag Canada in Swift Current discovered 15 years ago that crops like wheat, peas and lentils benefit from taller stubble with 6 inches tall better than no standing stubble and 12 inch tall stubble better than 6 inch. In fact the yield advantages for seeding into six inch stubble was 6%, 10%, 9%, and 12% for spring wheat, chickpea, field pea, and lentil, respectively, while the yield advantages for seeding into 12 inch stubble were 12%, 5%, 9%, and 21%. To put it plainly, McConkey found a 12% yield advantage in wheat, 9% yield bump in peas and 21% yield advantage in lentils from seeding into tall stubble.
So, if you really want to generate higher yields along with the other benefits of inter-row seeding, keep your stubble above 10-12 inches. Leaving your stubble taller means less residue on the ground, which leads to better germination and emergence. Inter-row just makes sense, especially when you do it right.

Research summary

Potassium, roots, tillers and N-use efficiency

When discussing root development and tiller formation, we tend to focus on phosphorus fertility. Unfortunately, potassium is often overlooked in our starter fertilizer program. Did you know that a potassium deficiency can significantly reduce the survival of primary tillers? Potassium plays a critical role in the formation of nodal roots which are located just below the crown and are essential to the survival of tillers.

Cereal plants have two root systems: the seminal roots that emerge from the germinating seed and the nodal roots that develop from the crown to support advanced leaf and tiller formation. High spring cereal yields are dependent on the early establishment and survival of primary tillers. Primary tiller formation can be increased with proper phosphorus and nitrogen fertility but only when adequate supplies of potassium are available.

Plants require a balance of nitrogen and potassium to obtain full yield response to applied nitrogen. If potassium supply is limiting, the uptake and utilization of nitrogen will be restricted. During rapid vegetative growth, around mid-June, the uptake of nitrogen as negatively charged nitrate ions (NO3-) is normally balanced by a similar uptake of positively charged potash ions (K+) which maintains the electrical neutrality of the plant. Careful optimization of nitrogen is a waste of time if potassium supplies are not adequate. This is true in the early stages of growth during tiller formation and during rapid vegetative growth stage.

Those of you with soil test potassium levels hovering below 350 lbs an acre or those pushing nitrogen rates above 100 lbs an acre should take a look at foliar potassium applications at tillering this year. Potassium is normally in abundance in our soils but one reason it may be overlooked. Soil test levels do not always indicate availabilty when compaction comes in to play or cool, wet soils during tillering. Who knows you may uncover a hidden hunger that is assumed not to be. SL

You can't beat a good starter K fertilizer program in furrow but if you would like to try foliar K products, here are the top two on the market: