February 26, 2013

Agronomist Notes

Hello Reader

I’m writing to you from the Adelaide airport en route to Toowoomba, Queensland. We enjoyed a successful farm tour and no-till conference and found some great ideas I’ll share with you today. The temperature on the dial was 40C yesterday and sunny but now we’re headed for cooler, rainy weather up in Queensland. I hear they’re calling for eight inches over the next three days!

In this week’s newsletter, we’ll look at a kit that turns a grain bagger into a self-propelled unit. I’ll share some interesting research on the effects of soil temperature on wheat yield then notes from the CTF conference. We’ll finish with comments from the last two articles on side dressing nitrogen and then technical grain market news. Next stop New Zealand!

Picture: Kim I’Anson pouring us some water in his hidden reservoir packed underneath the deck of the ute.

Self-propelled grain bagger

In my travels last week I discovered an excellent invention, which keeps the capital costs of running a grain bagger to a minimum. A company called Vennings from Kadina, SA builds self-propelled kits for grain baggers. The bolt on kit includes a 30 hp Honda motor that replaces the PTO. It has a remote starter and an automatic mover to help with handling. The cost of the kit is about $11,000 AUS.

I see awesome value in this technology, which eliminates the need for a tractor. Many people using grain bags are farming across large distances and moving a tractor around at 35-50km/hr, which takes time and man power. A half-ton or service truck can easily transport the self propelled bagger to the next field. The Vennings website doesn’t have information on the kit but it does have contact information if you wish to find out more. SL

Warm soil temperatures reduce wheat yields

Controlling soil temperature with inter-row sowing

I was looking into the effects of temperature on wheat yield and came across some great research by Ag Canada in my own backyard near Three Hills, AB. The research measured the effects of soil temperature on wheat yield in no-till versus conventional tillage and the results were very surprising. Standing residue and soil cover during grain fill can seriously improve wheat yields in most years.

The results showed that by reducing soil temperature during the grain fill stage, increased aboveground biomass between 33-160% and wheat yield by 18-147% except in one year when heat and moisture stress were limited. The take home from the research showed that soil temperature had a greater impact on wheat yield than above ground plant temperature. In fact when soil temperature was heated to 35C for a given time, yields in wheat dropped by 60%. The same plants exposed to 35C temperatures above ground only suffered a 48% yield loss.

The research also revealed that every 1C soil temperature above 20C during grain fill dropped grain weights in wheat by 3%. So, for example, if you’re daytime high and low was 30C and 15C respectively, your average temperature would be 22.5C, which is 2.5C above the critical level. That works out to a 7.5% reduction in grain weight. On a 55 bu/ac wheat crop that works out to a 4 bu/ac loss or $33.00/ac at today’s wheat prices.

If you look at the chart above it shows soil temperature readings across five weather stations from Lethbridge (purple), Morrin (yellow), St Albert (green), Dapp (blue) and Fairview (red) from June 30 to Sept 1, 2012. Most of the province had excellent rainfall, which kept ground temperatures cool except for the south. You can see the Lethbridge average is a few degrees above 20C throughout grain fill. According to the research, grain weights in this area would have dropped 9% from hot soil temperatures. A little Steve’s quick math will tell you that’s $30 to $40/ac in lost revenue for those without proper residue cover.

In Western Canada, we rarely think about heat causing a concern except perhaps during flowering. Even fewer would think temperatures between 20C and 30C could affect wheat yield. The reality is that poor soil cover, seeding on a diagonal and exposing soil, 10 to 12-inch row spacing or SBU’s below 40% could easily put soil temperatures in this critical range during grain fill. Our black soils are heat magnets and without residue cover or standing stubble soil temperatures can rise well above 20C during grain fill.

The solution to managing soil temperature is simple. Instead of relying on combines to provide even residue spread (which they don’t), or heavy harrows to move straw (which they struggle with), inter-row seeding is the answer. Having the area between the rows filled with standing stubble is a great way to reflect light and reduce soil temperature. As you can see in the photo above, the chickpeas are growing between last years stubble. The stubble acts as an insulator and reflects heat. It allows you to cut taller and reduce the amount of residue on the surface so it doesn’t impact germination and emergence, which is a win-win. Inter-row seeding has worked very well on our farm. Reducing soil temperatures during grain fill is just another benefit everyone should be taking advantage of. There could be $30 to $40/ac in it for your time. SL

Research:

Chart: Alberta Climactic Centre: Soil temperatures down to 20cm.

Photo: Inter-row sown chickpeas. Source Robert Ruwoldt

CTF International Conference, Toowoomba, Queensland

My notes from day one

Today, February 25, 2013, was day one of the CTF International Conference where people from around the world have come to share ideas and experiences with CTF. We had presenters from Denmark, England, New Zealand and Australia. It’s been great to see the amazing results from CTF and how people have modified their system to suit their cropping system, soil type and climate. Here are some of the most interesting points I took from today:

Sorghum yields have doubled over the last ten years while average rainfall has dropped in half over that period. Little change in agronomy or genetics
The use of soil moisture probes revealed that crops under CTF were accessing soil moisture down to 48 inches versus random traffic fields that could only pull moisture from 24 inches. CTF fields could access double the moisture with the same amount of rainfall.
CTF improves seed placement, especially with tyne openers by eliminating lumps and resistance in soil which can alter seeding depth.
The top two issues in CTF are poor residue management and managing the ruts caused by equipment in permanent wheel tracks.
CTF has increased yields by 30% over random traffic in Victoria.
Contractors in Denmark have created 12, 14.4 and 24M wide slurry injection applicators that can run on 3M wide tramlines.
It is possible to cut, bale and haul big square bales in a CTF system. SL

Reader comments

Nitrogen side-dressing in narrow row crops

I’ve had a lot of positive feedback on our plans for a nitrogen side dress system and thought I would share a great response from an Australian reader. I believe, along with many others, that it will be the next revolution in nitrogen use efficiency. Please pass along your comments if you’re also venturing down this road so we can all learn from each other. It’s unchartered territory for me and I’m really excited to get started.

I think your mindset on the improved nitrogen use efficiency and profitability is spot on. I have been considering the use of side dressing broad acre crops for a little while now. To put it simply, they are still row crops; just a little narrower than typical corn/soybean/cotton rows, and with today's technology, putting an implement between the rows should not be a big ask, particularly with the CTF system.

In my farming system here in Australia, we rely on rainfall to incorporate primarily nitrogen into the soil from a broadcast operation. The trouble with this is that we are doing this coming out of winter into spring, at a time which typically sees warming temperatures along with the gamble of rainfall amount. Add to this a mat of residue from no-tilling, and how effective will a small (1/2") rainfall amount be at dissolving and taking in a broadcast urea granule, to the depth of intercepting roots? We may get some in, but at what level is our efficiency? I am currently in the process of receiving this data to put a handle on it.

So, side dressing (or inter-row dressing) with a coulter looks really attractive to me, and I have no doubt the increased efficiency will pay for the cost of the machinery to do so, as per your "Steve’s Maths" below. My challenge is that with UAN being up to 30% more expensive than granular urea, liquid side dressing may not be the most return on investment. The only drama is that the urea will not be as quickly available as the nitrate component of the UAN, but being in the soil will still be picked up fast.

I am thinking of something along the lines of the machine shown above to side dress urea with coulters and inter-row on a skip row pattern as you have outlined. Stretching out to a 60ft toolbar will also allow a high work rate. With a hydraulic drive, variable rate would be an easy process, with quick and seamless rate changes. I also agree, that the addition of the GreenSeeker system scanning out front, real time VR nitrogen on my variable soils will be the "icing on the cake". We are currently scanning management zones by hand with the handheld unit, but real time is the stuff that gets you excited!

One question plagues me: will the slight soil disturbance from the coulter increase the level of late spring/early summer weeds emerging on the next rain?
Lachlan Caldwell, NSW

An Aussie toolbar made for side dressing granular fertilizer, which may be more suitable for some areas.

Pictured: Side dress toolbar made by Australian company Aulari

Australian marketing humor

Why don’t we wrap things up with a little Aussie brilliance.
I’ve found the Aussies have a real knack for calling things as they are. If a snake is brown, they call it a Brown Snake. If it’s a red kangaroo it’s called a Red Kangaroo. I recently found a product containing ether called “Start ya Bastard”. You know if the ether can is out that’s probably what most people are saying to that cold, stubborn engine needing a start. And how about these products: Sluggoff, Mouseoff, DogGone, Pigout and Foxoff? Little explanation is required, unlike their spoken language, but I won’t make that cheap shot. I must hand it to them for telling (and selling) it like it is. It sure makes for a good laugh! SL