Agronomist Notes

I’ve been busy preparing for the upcoming Advanced Agronomy conference and getting ready to leave for my Australian CTF tour next Saturday. My Kiwi guest Chris Dennison arrived on Saturday and I’m picking up my Aussie guest Michael Eyres tonight. I’m really looking forward to hosting this conference and seeing many of you there. 

In this issue of Beyond Agronomy News, we’ll be taking a second look at the way we apply urea to the soil after some interesting research from Ag Canada hit my desk recently. Next, we’ll look at the impact of canola root density on yield. After a small writing hiatus, Bruce Love of Preferred Carbon will describe the risks carbon aggregation firms face. We’ll finish with fundamental and technical grain market news.

Next week’s newsletter will be written from Oz so there may be some issue delays should I get bitten by a snake or shark or be taken by living a day ahead. Wish me luck, mates.  

Agronomy

Banding urea at seeding is still at risk of volatilization through soil pores 

Back in the early days of direct seeding, around 1985, research discovered that banding urea in the soil was more efficient than broadcasting and led to less nitrogen loss through volatilization. This research was the cornerstone of double shoot opener design because it allowed application of nitrogen at seeding which was more efficient and reduced also the cost of separate pass to apply nitrogen. That is, up until now. A study in 2009 revealed that placing urea in a band can actually lead to an increase in nitrogen loss as a gas through volatilization. This may have a profound effect on the way we manage nitrogen in our current double shoot direct seeding systems. 

The research by Rochette et al. from Ag Canada discovered that in drier soil conditions, up to 27% of the banded urea can be lost as a gas (NH3) through volatilization in the first 25 days. To explain it briefly, when urea is applied to the soil, the process of hydrolysis will convert the urea to ammonia (NH3) first, which is a gas and then to ammonium (NH4+) which is solid. Without sufficient soil moisture, the ammonia finds its way to the surface through soil pores and is lost to the atmosphere. 

Here’s the issue with our situation and why we need to take a second look at our placement of urea. First, we typically band urea at a shallow depth of roughly 0.75 to 1.5 inches using low-draft, mid-row, Stealth or side-band openers. Next, the porosity of the soil in the top 1.5 inches is normally very high due to the high organic matter content, which leaves plenty of room for gases to escape. Third, whenever you band urea in the soil, the process of hydrolysis will increase the pH around the band. As pH increases in the soil around the band of urea, the speed of hydrolysis increases and more urea is converted to ammonia. The rapid production of ammonia requires soil moisture to convert into ammonium which is stable. If little soil moisture is present, then nitrogen will be lost to the atmosphere in spite of being banded in the soil.

The graph you see here compares the amount NH3 lost to the atmosphere when comparing banded urea to broadcast/incorporated, polymer coated urea (ESN) and Agrotain (NBPT). The results suggest that banded/Incorporated urea which is another term for banding with no second pass involved actually produced the highest level of NH3 loss among the treatments. In fact the bandedincorporated treatments released 10 times as much NH3 as the broadcast/incorporated treatments.

Now, don’t think I’m going to start recommending we broadcast and incorporate urea! There’s more to this research. The greatest success with reducing NH3 losses from banded urea was found with a combination of urea coated with Agrotain (NBPT). The ESN polymer coated urea reduced NH3 losses as well as Agrotain but in a dry situation, did not release much nitrogen into the soil. The polymer coating of ESN requires moisture to break down and release urea, but with little soil moisture, little N was produced. On the other hand, the Agrotain coated urea was able to reduce NH3 losses similar to ESN but had the added advantage of allowing urea to convert to ammonium and supply nitrogen to the soil in spite of low soil moisture.

In the end, we need to take a closer look at the depth we’re applying urea with our double shoot openers, and look to alternative urea products like Agrotain. The research I presented here shows a 27% loss in nitrogen as NH3 from banding urea, something we’ve never addressed before. At today’s urea price, that could be a loss of $10 to $15 an acre, never mind yield and protein losses. So, could we be losing more nitrogen than we thought from volatilization and could we bump nitrogen use efficiency up by 5, 10 or 15% with a change in placement or product? I don’t know. What I do know is that banding nitrogen does not equal a reduction in volatilization and once again, our assumptions weren’t completely correct. We’re letting money vaporize and it shouldn’t be ignored. SL

Source abstract: http://www4.agr.gc.ca/abstract-resume/abstract-resume.htm?lang=eng&id=32347000046347

How big are your canola roots?

During my canola scouting routine every year I like dig up and inspect canola plants to assess insect damage and root growth. I wonder how often other agronomists and farmers are doing this; it’s something we should be doing routinely. When I pull up canola plants for comparison, 95% of the time I find largest roots on the biggest plants with the deepest podding depth. 

To prove my point I came across some interesting research from England that studied the effects of root length density on canola yield. The study found that as canola root diameter and length increased, so did yield. For example, the graph you see here shows an average yield increase of 1.3 bu/ac for every inch that root length density increases. 

I put that theory to the test in 2010 and started comparing the root systems of large plants to smaller plants. If you look at the picture here, the plant on the left is noticeably larger than the plant on the right which has a smaller root system. I counted the pods on both and found 290 more pods on the plant with a larger tap root. Now I ask the question, could I get every plant to set a big deep tap root?  And then, what are the limiting factors of small root systems?

First, we know that root development is limited by a number of things such as increased soil bulk density, increased penetration resistance, reduced porosity, reduced soil aeration, lower soil oxygen levels, poor nitrogen, phosphorus and calcium availability, high plant stand densities and low pH levels.

We have the ability to address all these barriers. The challenge is to go through the process of elimination to find out which is the most significant and what the cost is to correct it.  If a one-inch increase in root density can add 1.3 bu/ac to yield, that’s an additional $15 to $20 acre. If it’s soil compaction, will a $40 an acre investment in a deep ripping pay? Is phosphorus limiting root growth in your heavy clay, high calcium soils and would it pay to use a phosphate inoculant like JumpStart? Are your plant stand densities consistently too heavy and will it pay to reduce your seeding rate? Would it pay to purchase a separate canola drill with dual shank openers which allow you to carve a channel three to five inches below the seed and open up the soil to better aeration? The answer may be one or all of the above. But the bottom line is that a very small change in canola root density could net us a tidy profit if we just pay attention to the little things. SL

Carbon News

Aggregator Risk - November 20, 2010

Aggregator risk from a farmer's perspective flows from the reliance a farmer has on the aggregator to market their carbon credits, limit risk, and get good value. This is made more complicated by the immaturity of the Alberta carbon market as it is known today as it’s only been around since the fall of 2007. Let's see if we can shed some light on this fascinating topic.

An aggregator typically contracts with a farmer to monetize their potential carbon credits from qualifying activities like no-till farming. The aggregator then "aggregates" a number of farms together to get a large enough quantity of carbon credits to create an "offset project" and justify a transaction. The farmer relies on the aggregator to collect the right data and to ensure its accuracy to create the farmer's carbon credits. The aggregator then has the data and calculations verified by a qualified firm to test the accuracy of the carbon credits being created before serializing the credits and selling them.

Aggregator risk starts with the ability of the aggregator to create the carbon credits in such a way that they withstand the scrutiny of the Alberta Government when audited. The carbon credits get audited after they are submitted by a large final emitter (LFE) to help meet their compliance requirements to reduce their greenhouse gas emissions, recall these are the folks that bought the carbon credits from the aggregator. If the aggregator's project(s) is identified by Alberta Environment as having deficiencies, the aggregator is obliged to restate their project after addressing the deficiencies. There are five (5) projects on the Alberta Emissions Offset Registry today with identified deficiencies: one tillage project from the 2007 audit and three tillage projects and one composting project from the 2008 audit. The results of the 2009 audits have not yet been released to the public yet, but are expected shortly.

To date none of the projects with identified deficiencies have been resolved which makes understanding the risk of dealing with a particular aggregator or understanding the risk of a particular aggregator's method of creating carbon credits very difficult to quantify. However, a farmer's risk can be generally be categorized under two general headings; 1) for carbon credits that have already been created and sold and, 2) for carbon credits that have or are about to be contracted and have not been sold.

For existing carbon credits that have been created and sold, the recourse to a farmer involved in an aggregator's project that has been identified as having deficiencies will depend on the contract they signed. The aggregator may choose to re-examine the entire project and require farmers to pay back monies paid for carbon credits that where created in error plus and an administrative penalty, or charge nothing at all. Without any history on the outcome of offset projects identified by the Alberta Environment as having deficiencies it is difficult to predict the consequences for farmers.

For carbon credits that have not yet been sold, the aggregator's reputation and track record will have a significant impact of the value received for the credits when they are sold. Farmers are wise to ensure that the track record of the aggregator they choose to work with is a good one. Aggregators with poor track records will be discounted by the market to account for the risk that their projects will require restatement. The risk here is that the aggregator will not be able to make up the shortfall in the project after it is restated. Therefore, the buyer will adjust the price of future projects from the aggregator to account for this. Again, placing a value on this is difficult given that to date all projects that have been identified as having deficiencies are still outstanding. 

However, there is hope that more information is on its way to help everyone make better decisions. The 2009 Alberta Environment offset project audits are due out to the public any day now and likelihood that the offset projects currently identified as having deficiencies will be resolved is much greater.

Reference: Bruce Love, Preferred Carbon

Disclaimer: The views expressed in this article are those of the author only and are not intended to represent financial advice.