Hook Up The Oxygen Tank

Corn fields have taken a turn for the worst since June 1.  Any where from 8-11 inches of rain has fallen through the Stratford, St Marys and Lucan neighbourhoods since the first of the month and it is not over.  Rain continues to fall outside my window.  It is now common to see patches of yellow and severely stunted corn everywhere.  Looking at the above picture everyone instinctively knows that the difference between the front and the back of the picture is caused by saturated soils.  More specifically the corn at the front has sat in waterlogged soil for an extended period while the corn at the back did not have to suffer the same condition.

It doesn't take a genius to understand why the plant above is struggling when you see the soil condition that is has to survive in.
The point of this post is not to get into all of the various reasons why water drains quickly from some areas and not so quickly from other areas.  That diagnosis is best undertaken by the farmer who has the most intimate knowledge of soil types found on the farm and past history, in terms of crop rotation, tile drainage, traffic patterns etc.  If you are still confused, then consultations with drainage contractors and agronomists may shed some additional insight.  Many times it is still difficult to pinpoint the exact reason why water accumulates here but not over there.  My observation over the years are that farmers tend to be experts about why their neighbours crops suffer from too much rain, but seem to be less insightful when their own field is poor.  That is another topic in itself.
To help shed light on what causes corn to turn yellow and more importantly is there anything you can do to immediately fix the problem, it helps to understand how soil biology and crop physiology is affected by excess water.
Healthy productive soil for corn production is composed of 50% solids, 25% air and 25% water.  The 50% solids made up of the sand silt and clay particles plus organic matter stay pretty much constant. The focus will be on the 50 % that is split between water and air.
When there is too much air and not enough water, soil biology slows to a crawl and the plant withers due to drought stress.  The cure is to add water, by irrigation or rainfall.  Soil life will bounce back fast because water will infiltrate dry soil very easily, reinvigorating the bacterial and fungal life that drives the soil processes. The drought relief though may not occur in time to repair the drought damage done to the corn plant. The loss in yield due to drought has more to do with damage to the plant itself and less to do with any sustained damage to soil life.
It gets more complicated when the reverse occurs, too much water and not enough air.

If you look at the picture above the question becomes how can air get back into the soil?  The answer is it can't, at least not very quickly.  Water is heavy and when it sits on top of the soil for extended periods the clay particles smear together creating an air tight seal. This creates the double problem of soil life drowning from lack of oxygen and root growth stopping because corn is not related to rice.  Corn does not tolerate flooding very well.  Its roots are not designed to function in an environment devoid of oxygen and they simply stop growing.  At this stage of the corn plants development a lack of root growth is a big problem because corn needs a large root system to supply enough nutrients and water after tassel emergence. Once tassel initiation commences root growth slows down and virtually stops.  If roots are not established during the vegetative growth phase the plant is not designed to regenerate roots after tassel.
Inter row cultivation will help to break the surface crust which allows some air back into the soil, but cultivation is neither a quick cure nor a practical solution.

This picture illustrates the effect of a drainage tile through the middle part of the picture which is removing the water and allowing air to take its place in a balanced manner.  This keeps both the soil life and the corn plant healthy. The lack of balance between water and air to the right and left of the tile is causing the plants to yellow. Yellowing is commonly thought of as a lack of nitrogen, which is essentially correct, but the nitrogen was evenly applied across the width of this photo.  Why is it not being taken up equally well from right to left?
Two main reasons.  As already mentioned corn roots do not function well in water logged soils.  With no root growth, leaf growth slows to a crawl.  The second reason is nitrogen becomes unavailable due to denitrification. Denitrification occurs in our soils because soil microbes that need oxygen to breathe will attack the nitrate form of nitrogen.  Nitrate nitrogen is a nitrogen molecule attached to three oxygen molecules.
The microbes strip the oxygen molecules away.  Without the oxygen molecules the nitrogen turns into a gas which escapes into the atmosphere.  The amount of nitrogen loss is dependent on the duration of the water saturation in soils.

The biggest question is can the corn plant recover from this type of stress?  Can we do anything to help it recover?  Because one of the contributing factors to the reduced growth is nitrogen loss it is assumed that adding more nitrogen fertilizer will help in the recovery.  This question has been extensively researched.  There is general agreement that applying 30-50 lbs of additional N will give a return.   Some research indicates the worst the flooding damage, the greater the return is to nitrogen. We need to be realistic about this.  Fifty lbs of N plus application costs is going to add $35 per acre to the production budget.  That eats up about 10 bushels at today's prices.

   

I come back to my badly stressed little friend shown above.  In my opinion, the chance of this corn plant producing a harvestable ear of corn is pretty slim.  But in the remaining portion of the field there is a good chance additional N can provide payback.  Many of us, including my son Brian are going to find out because investments have been made in drop pipes of many configurations and layouts, the Y-Drop system being the flavour of the month.  There is also interest in high clearance dry fertilizer spreaders.
If you listen to the debate raging on Twitter, you would think flexible drop tubes and dry fertilizer spreaders were a brand new invention.  These ideas have been around for years.  Recently there is a renewed drive to apply nitrogen later in the growing season to boost yields adding fuel to the debate. Simple drop vs Y-drop, skip row vs every row, 28% vs urea, agrotain vs no agrotain and on and on.  I am here to remind everyone that the efficiency of surface application of nitrogen is lousy and there is the constant risk of crop injury.  We have known this for a very long time and no amount of agronomic marketing glitz and glam will change it.  If July turns as dry as June has been wet, surface application of nitrogen will remain exactly where it has been put, which is not in the right place I might add.  This nitrogen is also subject to volatilization losses as well.  Research has proven this. There is no guarantee this rescue mission will be successful.  But we have to try,
I keep thinking to myself, but with no proof to base it on, that the greatest return may be in the best parts of the field.  Applying a small amount of additional N may pump enough air into the tires to carry the corn further through the grain fill process that is just around the corner.  Pioneer keeps telling us about the amount of nitrogen that the plant takes up post tassel.  Can this late season application of nitrogen make up for hidden losses and give a return on the dollars spent?  We intend to find out.  But don't count on us broadcasting the results on Twitter.

Regulation vs Implemetation

The Ministry of Environment and Climate Change, (MOECC)  has come out with OReg 139/15, the new regulations regarding neonicotinoid use under the Pesticides Act that will go into effect on July 1.
I have not had time to write recently in this space because I have been buried under a pile of new Nutrient Management Strategies.  The dairy and poultry industry is alive with livestock facility construction projects that are being scheduled for later this year, hence the need to get the documents into OMAFRA for approval.
I did take some time to review these new regulations.  They will be a huge topic of discussion going forward and it will get confusing for many producers.  I do not recommend trying to interpret the document unless you have experience reading government regulations.  The language takes some getting use to and you also need a full copy of the Pesticides Act in hand to understand the changes.
A sanitized and easier to read summary provided by the province is here.

Class 12 Regulations

While it is somewhat useful to know the regulations, the real devil in the detail is how the regulations are implemented.  To illustrate how this works I will use the Nutrient Management Act, OReg 267/03 as an example. Farmers don't read the NM Act, but if they have built livestock facilities in the past 10 years they are familiar with the process.  Once a decision is made to go forward with a project, the farmer contacts the following 4 individuals in no particular order.  The contractor, the engineer, the NM consultant and the municipal building official.  The NM consultant ensures the project satisfies the regulations as laid out by OReg267/03 and secures OMAFRA's approval of the proposed changes to the farm operation.  The engineer and contractor make sure the project meets the requirements of the farm building code, local construction by-laws and the farmer's budget.  The municipal building official provides government oversight through the whole process.  I have done hundred's of NM strategies and if everyone involved in the chain has experience in livestock facilities, the process goes very smoothly.  It was not always this way.  When OReg267/03 was passed in late 2003 there were some major growing pains thanks to people having to interpret and implement a new set of regulations.   This improved as people gained experience with how the reg's were being implemented. The implementation of these same regulations has evolved over time.  The regulations themselves have also been changed and amended several times.  It still is not perfect, but compromise is a necessary part of life.
The initial enforcement of the 267/03 is done at the local municipal level of gov't through their respective building departments.  In addition to this the province does random follow-up audits performed by the MOECC, but they have not proven to be a significant burden in the majority of cases.  Often the farmer is more at ease after the audit is finished than before.  The ominous letter stating that you have been chosen for a random audit will cause the heart to flutter, but if the NM consultant has done a satisfactory job there is not great cause for concern.  Complaints drive most of the MOECC's interaction with livestock farmers and if you cause problems and do nothing to address the situation, fines and jail time can be imposed.
While you have every right to disagree with the concept of government intervention in private business matters, I have not met a farmer yet that would disagree with the primary thrust of the NM regulations.  In a nutshell this thrust is aimed at protecting our water sources by ensuring minimum standards are met for livestock housing, manure storage capacity and land base for manure disposal.

We now have a new set of regulations to digest.  It is easy to get wound up by the latest intrusion into our affairs on the farm caused by an apparently deaf and arrogant MOECC.  It is a bigger issue than nutrient management due to the number of producers affected and the highly political nature of the new bill.  If the agricultural industry is as professional as we claim it to be, now is the time to stay calm.  One can be outraged by this new set of rules, but to some farmers and definitely to the general public, the protecting the pollinator banner flown by the new document is a worthwhile endeavor.

There are some things I do know after reading OReg139/15.
1. If you choose to not use neonic treated seed it is business as usual.  No action required.
2. For 2016 planting only, if you want to use up to 50% neonic treated seed on your corn and soybeans you need to take a free IPM course and sign a declaration form that confirms your total acreage of each crop.
3. This declaration is crop specific.  If you have an equal acreage of corn and soybeans you are NOT allowed to declare that you are using neonic treated corn seed on every acre and no neonic treated soybean seed to get to the 50% usage ratio.  It must be 50/50 on each crop.  Dumb rule #1.
4. If you want to use neonic treated seed on more than 50% of your acres you need to take the additional step of doing a pest assessment.  You can do this yourself, but I do not foresee many growers actually taking the time to conduct an assessment in the manner proposed by the MOECC.   It is a do as I say, not as I do, style of assessment and is purposely slanted to not being able to prove a need for a neonic seed treatment.  Dumb rule #2.
5. Starting in 2017 there is a phased in schedule, whereby depending on which county or counties you farm you will no longer be able to do the self assessment.  You will need to employ the services of an accredited professional pest advisor to do the assessment.  Certified Crop Advisors or Professional Agrologists qualify, but don't ask me to be your advisor.  Being a CCA in good standing for 18 years does not make the cut because a seed company pays me to sell treated seed.  I am not trustworthy enough to evaluate the risk of soil insects on my own farm, let alone anywhere else according to the MOECC.  Dumb rule #4.  In my opinion the geographical part of this regulation won't last very long because the schedule makes no sense.  I have seed clients in 4 counties, Middlesex, Oxford, Huron and Perth.  Middlesex is first to lose the self declaration ability in 2017, Oxford and Huron lose it in 2018 and Perth is last in 2019.  What that means is if you happen to farm in all 4 counties starting in 2017 you will be not able to do the self assessment on all your farm properties even though they are merely a few kilometers apart. Dumb rule #5.
6. My son Brian who holds a land exterminator's license in good standing is allowed to custom apply a variety of insecticides that are definitely not pollinator friendly.  He is now excluded from applying the new class 12 seed applied insecticides without following the new specific regulations to the letter. Dumb rule #6.

There are many things I don't know.
What does it mean for custom planting services that sometimes bring seed to customers and sometimes do not?
How are custom seed treaters going to be monitored?  Better yet is how are custom seed treaters that fly under the radar going to be monitored?
How will this new massive stack of paper be monitored and enforced?  Seed vendors and treaters are required to keep records for two years after the date of transfer to the customer.  Every October 31 vendors are required to inform the MOECC of the total amounts of neonicotinoid insecticide used and the estimated acreage of neonic and non neonic terated seed sold.   If for example, it works out in 2017 that Pioneer sold 55% neonic treated corn and 60% neonic treated soybean seed, what will happen?  Will Pioneer get a "mulligan" or face a fine?
This upper level enforcement will have a trickle down effect to the grower.  Due to political posturing on both sides of the issue there will be a number of entrepreneurial individuals out there who take pleasure in trying to beat a system that they believe to be unfair.  Will there be a "neonic snitch hotline"?
Can the MOECC force Pioneer and other companies to reveal individual customer information?  That would be crossing a line that should never be crossed.

The bottom line from where I sit is we are embarking down a very long road without a road map. OReg139/15 is bigger in scope than 267/03.  All corn and soybean producers have to deal with it.   My wish is for farm groups to huddle together and think this issue through.  The seed industry now has to plan accordingly in an attempt to minimize seed supply disruptions.  Confusion will be the order of the day because it is human nature to act without thinking.  Leaders need to do the opposite and think carefully before they act.
No one has all the answers, including the government of the day.
       

No Blanket Necessary

This little guy is an example of the most developed soybeans currently in the neighbourhood. A significant amount of angst and anxiety is being spent worrying about the possible frost for tonight and Saturday.  If temperature predictions are correct and -1 degree is the actual low everyone can stop worrying. Soybean tissue can stand frost better than corn.  Trust me.  They will be fine.

If your corn field looks like this, some action is required.  In the bad old days before glyphosate tolerance was bred into crops we had issues spraying crops like one under the current weather forecast.  Folks that made herbicide recommendations in the 80's and 90's  knew that effective weed control and excellent crop safety were two descriptions that did NOT apply to most herbicides of the day.  As a tadpole agronomist in the late 80's I could count on spending the month of June dealing with herbicide injury caused by weather interactions coming back to haunt our management decisions surrounding herbicide choices and timing.  The yield losses at times were significant.
Vlado Puskaric, the legendary Pioneer corn breeder of my generation never understood why, to use one example dicamba, was allowed to be registered on corn.  He was like a mama bear protecting her cubs and anything that hurt the children was public enemy number one and this included many herbicides of the day.  I remember not having any defense when he cornered me, other than to say weeds caused big problems too.  He would then stomp off with smoke coming out his ears.
Fast forward to today.  If we were still working with 30 year old herbicide technology, the risk of injury to emerged corn given the low temperatures of the next two nights would be substantial. Even older products like Dual are much more gentle to the crop now than they used to be and still provide excellent weed control.
Thanks to technology we can and probably should spray the corn crop shown above.  The safest route, assuming it is glyposate tolerant corn is simply glyphosate.  If you want to add a little bit of Calisto or Peak go ahead, but the more combinations you use the more the plant will have to work to break them down.  A second application will be necessary and that is when a tank mix can be applied to help out with weed resistance management.      
The risk to choosing not to spray is wet weather.  If the next week turns wet and keeps the sprayers out of the field then there will be yield loss from the uncontrolled weeds.  A wet week is hard to envision, however we need to ask what is the worst thing that could happen.  At some point it will rain and then it might not stop.  So get the weeds under control now.  The risk of herbicide injury is much less than the risk of uncontrolled weeds.  How times have changed.

The Clock Is Runnning

The 2015 crop season is off to a very quick start, at least for corn and soybeans. As of today May 13, close to half of the corn crop is emerged and 70% of the soybeans are planted with the first planted fields also beginning to emerge. Visions of 250 bus corn and 70 bus soybeans are dancing in our head.

Rainfall has been mostly non-existent except for a few non-measurable light showers in the last 3 weeks.  Concern about dry soils has been the lead topic of discussion. This grim sounding concern about soil moisture is understandable, but misplaced.  As long as the crop emerges, dry soil is of no concern to the young corn and soybean plant.  Small plants have a very low water requirement and will be very content for several weeks yet, providing the seedbed condition is good. A well structured seed bed allows the primary root system to establish and sustain the plant.  If the seed bed was too wet when you planted, the primary root system will struggle and the need for rain is greater.
If your tillage practices have left you with no soil moisture and soybeans to plant there is a decision to be made.  Soybeans can be planted 2.5 inches deep if that is what it takes to get to good soil moisture.  The risk is planting deep into soils that have enough moisture to initiate germination, but not enough moisture to sustain emergence.  Soybeans imbibe water, swell and then die under these conditions. Seeding depth in dry soils is an extremely tough call to make.  The other choice is to wait because you still have time on your side.  Lots of 50 bus soybean yields have been produced with late May planting dates.

The prospects for winter wheat is a mixed bag of extremes and ultimately a tale of two crops.  Wheat fields planted following edible beans are good to excellent.  One benefit of the dry soil conditions is low annual weed pressure. Annual weeds in the wheat crop have been a no-show for the most part.  Wheat is very competitive against weeds and at this point any weed emergence will have zero effect on yield. This only applies to the good wheat fields.

The wheat crop after soybeans is a different story that begins with planting dates.

I believe this picture paints the story more accurately than words.  The wheat on the right was planted October 13 and while not perfect is certainly acceptable.  The wheat on the left was planted on October 27. The two week break was due to a delay in harvesting IP soybeans.  Throughout this area the mid October through early November planting dates are in trouble.  The combination of late planting dates and wet soil conditions that never improved is the problem.

These fields are typically full of thin spindly wheat plants that have no vigour.  They appear to be a bunch of runts.  Instincts are telling me they will always be runts. When rains finally come, the thin spots will become weed patches.  Some, including myself have already pulled the pin on this questionable wheat and re-planted to corn and soybeans.  
Why is this wheat so poor?  Peter Johnson believes it is a lack of cold tolerance. Wheat needs to get past the one to two leaf stage in order to develop the cold tolerance required to survive a hard winter. Kind of odd since you can frost seed wheat and make a crop, but that is a different matter.  I believe there is a grain of truth in Peter's assessment, however it is a very fine line.

This is wheat planted last November 4 and protected by a bush on the south side of the field.  The same field 200 ft from the bush line had a completely different look.

This field was under 2 ft of snow all winter.  I skiied across it numerous times.  This cold tolerance or lack of cold tolerance that Peter speaks of is a matter of a few degrees.

Regardless it will be a long summer for these tough looking wheat fields.  If you need straw I can understand leaving it.  From the cash cropper point of view with the price of straw at 4-5 cents in the windrow there is really only one choice.  It is May 13.  Plant another crop.   

Too Good To Pass Up

The first opportunity to celebrate 2015 The Year of The Soil is here.  It is red clover time.  Red clover gets a bad rap because of it's inconsistency of establishment. The truth of the matter is consistency is the achilles heel of all cover crops.  We have been applying clover for so long, the short comings are easy to document. Yet it is still the most proven and cost effective cover crop for Ontario corn producers.  I do not agree with the negative publicity that is attributed to red clover. It is worth investing the time to do it right.  When it doesn't establish, there is still time for a plan B to be put into action.

David Start of Woodstock, a passionate promoter of red clover provides the following recipe for clover establishment.
1.  Seed as early as possible.  Do not be afraid to put clover on snow.  If the wheat crop has broken dormancy, you are too late.
2.  Use 6-8 lbs of good quality seed.
3.  Do not spray wheat under seeded to clover with herbicide fungicide combinations.  As a last resort use Buctril M for weed control.  Weed control should begin with a fall application of the herbicide of your choice at planting time.
4.  Wait as long as possible to kill clover in the fall.  This maximizes the return to nitrogen rate for the following corn crop.

I have had personal experience with his herbicide, fungicide comment.  I took out a field of clover in 2011 with a Buctril M plus Tilt tank mix.  Fields sprayed earlier in the day with the same sprayer were not affected.  Our suspicion is under the right temperature and humidity conditions the fungicide acts like a surfactant, heating up the Buctril M.

David regularly grows 180 bushel corn with 30-50 lbs of nitrogen.  That is a definitely a goal worth pursuing.

The following ditty is courtesy of Paul Sullivan, our resident roller coaster expert.

Red Clover Cover Crop – The Seasonal Roller Coaster of Emotions

Paul Sullivan, Agronomist - CCA ON.

I have noticed over time that we have a love/hate relationship with red clover. Here’s how the emotions seem to evolve over the season spreading red clover into winter wheat.

January to early March – Seeding red clover is a great idea. At winter meetings we hear how great it is. Plan to seed at 6 lb/acre of single cut red clover.

Late March – Frost seeding clover on a windy -12 degrees C morning riding on an open ATV…not embracing red clover so much!

Early April – Scouting fields for emergence can see the little seedlings starting to emerge. Forget about the spreading experience – It’s a great day!

Early May – Time for weed control. Had planned to use Trophy for tufted vetch control. Crap!  It will kill the clover! Have heard some have used Tropotox Plus, but its $20.00 per acre!

Finally hear from Sullivan that can use Buctril M - -all is good again!

May to July – Forget the clover is even there – all is good!

July – Check the wheat for harvest. Crap!  The clover is up 10” into the canopy. Where the wheat thinned out, it’s up to your knees! Looks like straw yields are going to be less.

Early August – Combining wheat with Red Clover – Red Clover was a terrible idea!

Late August – It’s raining. Straw is still on the field and the red clover is growing. Red Clover was a terrible idea. Find out double cut clover was what you seeded because single cut was sold out.

Late September – Drive by the field and the red clover growth is taking over the straw

Mid October – Time to spray off the field – Sullivan says have to add Distinct to kill the clover. Crap! More added cost!

Late October – Red clover is still green. Volunteer wheat is smoking – dead. What are you going to do with it? Heard at the coffee shop that it has to be plowed, but the plow is parked.

Early November – Find that the field is dry enough for tillage. Forget the plow. Use the shallow disc to darken the soil surface but leave 70% of the residue on the soil surface.

Late April next spring – Go to the field to check for soil conditions. Pick up the soil and it falls apart in your hand. Looks like one pass and you will have an ideal seedbed for corn.

Early June – It’s side dress N time. Reduce N rates by 50 lb/acre. It’s looking better…

Fast Forward to late October – The corn field after wheat underseeded with red clover is out-yielding the corn field after soybeans by at least 15 bu/ac.


Editor's Note-  Please forgive the use of the smiley icons.  They were Jean Sullivan's idea.

Just Like Holding Sand In Your Hand

"I can't believe you two talked for half and hour about nitrogen and the only thing I got from it is that weather determines the right rate." (Yawn)
These were Cathy's words after she sat through a lunch meeting we had with Paul Sullivan last Monday.  Paul is a highly respected, independent crop consultant and 2011 CCA of the Year from eastern Ontario.  I am not sure what Cathy was expecting because when you put two crop advisers at a table on a sunny day in March the conversation is automatically going to migrate to nitrogen use in corn.
Forgetting genetics for the moment, nitrogen usage has been for the most studied and debated topic in the history of corn production.  Yet we still have unanswered questions.

Most corn producers in my experience are happy with a general rate recommendation that gives them a realistic chance to getting through the growing season without shorting the crop.  There is a general consensus that 140 to 180 lbs of N per acre will accomplish this goal for the majority of producers in Ontario.  The consensus falls apart when we start to push the boundaries of N rates, both at the low and high ends of the scale.  When you add application timing, the ability now to apply variable rates and toss in a dash of environmental concern you get to the point Paul and I were at last Monday and the point where Cathy falls asleep.  I assured her that agronomists live for moments like this.

Let's review what we know for sure about nitrogen,
1. The soil's ability to supply nitrogen is extremely variable both within the field in the same year and from one year to the next. Soil health plays a huge roll in how much nitrogen is available during the growing season.  Organic matter breakdown is the main source of soil nitrogen, but OM is not consistent across a field.  Organic matter breakdown is for the most part driven by temperature.  Hot weather speeds up the process, cold weather slows down the process.
2. Nitrogen applications of fertilizer and manure are highly susceptible to losses that occur before and during the period when corn needs the nitrogen to be most available.  Moisture is the main contributor to losses.  Too much rain leads to high losses across all soil types, denitrification being the main N loss mechanism in clay soils and leaching in sand.  Another type of loss, known as volatilization occurs when we leave nitrogen on the soil surface without incorporation.  I have believed for a long time that incorporation or injection is absolutely necessary for maximum nitrogen efficiency.  Research by Dr Craig Drury presented at the CCA Conference in January confirmed this. If side dressed nitrogen fertilizer, both urea and 28% was not injected, there was a lower % of applied nitrogen that ended up in the corn plant.  The use of nitrogen inhibitors helped reduce surface application losses, but still was not as efficient as nitrogen that was injected into the soil    
3. Modern corn hybrids are more efficient at utilizing N.  Depending on which research paper you look at hybrids developed after 1990 will produce 14-28% more corn per unit of N applied than hybrids developed prior to 1990.  Practical experience over 3 decades backs this up.  We tended to apply 130 -150 lbs of N in the 80's because we thought it took one lb of N to produce one bushel of corn. Today that same rate can easily produce 200 bu of corn if weather permits.
4. Modern corn hybrids are also taking up more nitrogen after pollination than older hybrids.  They can tolerate high populations better and stay greener longer.  Approximately 66% of the total nitrogen taken up by a corn plant goes toward grain production. This nitrogen comes from two sources, soil nitrogen uptake and nitrogen from the plant's stalks and leaves.  Older hybrids tend to use nitrogen already taken up by the plant.  Researchers refer to this process as nutrient mobilization, but I think it is easier to think of it as cannibalization whereby the plant consumes itself.  I was taught years ago that part of the maturity process was the fact that the plant was consuming its reserves faster than it could make new reserves.  In modern hybrids a greater percentage of the nitrogen found in the grain comes from uptake of soil supplied nitrogen.  This has the potential to change nitrogen management strategies from both a yield and environmental point of view.

To quickly review, nitrogen availability can be extremely variable thanks mostly to environmental conditions.  This has been a source of frustration my whole career and will continue for the foreseeable future to give corn producers headaches when trying to figure out the best nitrogen rate to apply.  The game has been changed by the fact that modern hybrids help us out by being more efficient, but require more nitrogen to be available late in the growing season.

How do we insure adequate nitrogen availability late in the season?

One way is to start loading up by applying more nitrogen at planting time and crossing our fingers that enough of it will still be around in September for the plant to find.  This has appeal from a simplistic point of view, but is irresponsible from an environmental point of view.  Dr. Sandy Endicott, Pioneer's Agronomy Research Manager reported last week that the city of Des Moines Iowa is taking agriculture to court over nitrate contamination in drinking water.

DesMoines Waterworks Sue Counties Over Nitrate Pollution

Corn producers in Iowa love applying nitrogen in the fall and early spring before planting, which gives them the summer off to pursue other interests.  While it may be a convenient management practice for the farmer, the farmer should not be too surprised when this style of management comes under scrutiny. The farmer's defense has been to say it wasn't me, it was someone else.  Plus he really has shown a preference to go fishing in the summer rather than spend time applying fertilizer.  Try explaining that to a judge.  For this same reason I do not believe applying more nitrogen at planting time is an acceptable method of nitrogen management.

A second approach is to apply a base amount of nitrogen at planting and then supplement it later in the season.  For my whole career there has been the debate about the value of sidedress nitrogen and it was always my opinion that sidedressing nitrogen in June did not deliver much real value.  There was no impact on yield and while you could reduce your total nitrogen rates, the reduction was barely enough to cover the cost of application.  Now we have high clearance sprayers that are set up to apply nitrogen into late July.  Ideally as already discussed this nitrogen should be injected, but it requires a big investment when we are a long way from being convinced that it pays.  The less expensive option is the Y-Drop system that dribbles nitrogen at the base of the plant.  We do have to cross our fingers that moisture will move this surface dribbled nitrogen into the plant.  A dry summer will present a big challenge for this delivery method.  Can this later sidedress timing change the game? We don't know for sure, but it creates an opportunity to either deliver more yield by placing nitrogen closer to an important point of the corn plant's life or deliver a similar yield at a significantly reduced rate of nitrogen.  Either way it is a positive step that if nothing else demonstrates good environmental stewardship.

A third approach that we already have confidence in is the use of cover crops to capture and release nitrogen in a more timely fashion.  Red clover has been demonstrated time and time again to be a perfect match for releasing nitrogen which coincides nicely with a corn plant's needs.  Red clover is out of favour with many because of inconsistent establishment, but it is still the best and least expensive option for the first try at establishing the cover crop.  We get a second chance after the wheat comes off and can fill in with crimson clover and possibly vetch to provide a more uniform cover.  David Start at Woodstock has worked for 20 years to identify the best nitrogen rate in corn following red clover.  With a good stand of red clover his typical nitrogen rate is 30 - 60 lbs per acre. How many of you have grown 190 bus of corn on 30 lbs of applied nitrogen? David has. More than once.

For the last word on nitrogen, I turn back to Dr Craig Drury.  He said trying to hold nitrogen at a uniform level in the soil profile is just like holding sand in your hand.
I wish I had thought of this line when Cathy was telling me how bored she was listening to Paul and I at the lunch table.  Just think dear, romantically walking hand in hand while trying to hold sand in our hands paints a beautiful picture.  Right dear?

A Question of P

I recently participated in a panel at the Chatham-Kent Farm Show.  My contribution to the panel was a focus on the principles of good agronomy.  One principle I chose to discuss regarded the apparent decline in soil test P & K levels.  A farmer in the audience asked me to reconcile the recent problems with algae blooms in  Lake Erie against my argument that we are not applying enough phosphorous.
It was an excellent question.  I partially addressed it by relating back to the 80's when a similar problem occurred with too much P being washed into Lake St Clair and Lake Erie. This was caused by an explosion in corn acres accompanied by too much tillage.  Soil erosion was the main factor causing soil P to be washed along with valuable topsoil down the rivers.  The Land Stewardship program was initiated by OMAF which paid farmers to adopt no-till and conservation tillage practices to address the erosion issue.  The program had the desired effect and farmers quickly adopted conservation tillage practices.  One additional side effect of this program was unleashing Peter Johnson on the farm scene through his first job at OMAF as a Land Stewardship coordinator.  I voiced the opinion that we are heading backward in our tillage practices and have not done enough to stop the flush of sediment down the river that occurs every time we are blessed with a 2" rainfall.  I have listened to my friends from the Ausable-Bayfield Conservation Authority describe the nutrient flushes that occur with heavy run-off periods. These heavy flushes are more common now than 30 years ago thanks to the greater frequency of heavy rain events.
Recently agriculture has been front and centre regarding the environment and our effect on bees and other pollinators.  Some of the criticism is valid, however much is not.  The urban policy makers are far removed from the farm gate and will remain so. I can hear the comments echoing in my ears from some farmers that our urban neighbours are also part of the phosphorous problem, thanks to overloaded sewage systems and no one addresses that issue.  Why are we always on the hot seat?  While this argument is partially true, the fact remains that agriculture practices are a significant source of P loading in our lake water. In my opinion, we in agriculture cannot stake the moral high ground of being good stewards of the environment without taking this issue seriously.
 
We also have been learning over the last two years that the P problem is more complicated than we initially believed, thanks to something know as dissolved P.  Dissolved P is the tiny fraction of total P that is susceptible to loss in water.  Water leaves our field in the surface water run-off that may or may not contain soil particles and in our tile drains. This surplus water often contains phosphorous. Fertilizer and manure contribute to soluble P levels.  The fact that they provide readily available sources of phosphorous is why they are efficient sources of nutrients for crop production.  At the same time they are most susceptible to losses of dissolved P immediately following application.

Could it be that our increasing love with the value of tile drainage be a contributor to algae blooms?
Could it be that surface applications of P fertilizer in the fall be a contributor to algae blooms?
Could it be that surface application of manure be a contributor to algae blooms?
The answer to these questions is definitely yes.

Two different studies in two watersheds conducted over multiple years in northern Indiana and central Ohio discovered that half of the dissolved P and half of the total P in the watersheds originated from tile drainage.  More disconcerting was the amount of P coming out of those tiles was in concentrations high enough to encourage algae growth.

Measuring Phosphorous Losses from Midwest Fields

Closer to home, Ontario research by Dr Merrin MacRae has confirmed that phosphorous discharge from tile drains can be the main contributor to P losses.
In a weird twist surface applications of fertilizer and manure, without immediate incorporation leave the soluble fraction of the phosphorous more susceptible to movement into surface water. Mixing nutrients with a little bit of soil reduces the amount of soluble P that is susceptible to loss. In no-till fields surface applications of phosphorous allow the soluble P to access tile water via earthworm holes.  A little tillage can be a good thing when it comes to P.

So if we have identified a problem, what can we do to reduce the amount of dissolved P entering our watersheds?  Quite a lot, to be honest.

1.  Apply phosphorous in bands and reduce broadcast applications.  Banding P reduces the total amount of P that comes in contact with the soil water which will reduce the amount of dissolved P that is susceptible to loss.
2.  Time phosphorous applications close to when crops are actively growing.  A significant amount of dissolved P is lost through the winter months.  Fall applications of P are therefore more susceptible to loss.  A growing crop will take up dissolved P as it becomes available.
3.  Winter wheat or other types of fall and winter cover crops help to take up soluble P.  A bit of common sense, but how much difference this makes during the winter months is unknown.
4.  Use technology to identify the different yield zones in our fields and soil test according to yield zone.  Apply P according to crop removal within those zones.  Put less P on the low yielding areas and more P on the high yielding areas.

Coming back to the question posed by the farmer in Chatham, part of my thinking remains the same. Low phosphorous soil test levels still need to be addressed.  Changing our mindset to look at phosphorous buildup applications in the same way we look at nitrogen application I think is in order.
In other words apply phosphorous in the spring and summer only, apply phosphorous every year according to crop needs and if possible, use a small amount of tillage to incorporate surface applied phosphorous.

I think we can manage that.