Shades of Area 51! Have I run across a vast government conspiracy?

Sadly it’s nothing so exciting – MASC Risk Area 32 is simply the heavy clay soils in MASC Risk Area 12. These yield differently than the lighter soils and are therefore recorded separately even though they’re in the same geographic area.

One omission that struck me as odd is that they didn’t mention how much land is lost to urbanization. The focus of the article was how poor agricultural practices have caused soil losses and how good, site specific practices can help bring it back. However, one of the problems that faces us with an expanding population people need more land just to live on. Perhaps better land use management can help with this?

One of the big questions that I have about soil surveys is where are the updates? Soil survey stuff is going on across the province. The Manitoba Soil Survey Field Procedures Manual was revised in 2007. There are presentations up there from late 2010. However the last detailed soil survey available is from 1993. What’s been going on for the last 17 years? I demand answers!

Nutrient Trends – Using the Data.  John Heard

John Heard led off by letting us know that Better Crops Magazine has recent nutrient trends.

Currently nitrogen removal in Manitoba is very close to nitrogen fertilizer applied.  He also showed some long-term trends – currently nitrogen addition and removal is roughly in balance.  Farmers applied more nitrogen in the 90s than they removed in crops.  Prior to that farmers removed more nitrogen with the crops than what was added as fertilizer.  Two factors that aren’t accounted for in this are that manure adds about 7-8% to the total nitrogen supply and pulses and forages also fix nitrogen.

Phosphate has a similar trend – currently net exporting P2O5.  Manure adds about 15% to phosphorus supply.  We’ve been removing K2O from soils for years and are still drawing it down at rates of roughly 4 removal to 1 add.

Fertilizer prices spiked in 2008 – but are currently close to normal levels.

Soil testing has gone up a lot in recent years (about 5.2 million soil tests in US in 2010).  In Manitoba, soil samples have roughly tripled in the last 10 years: 2001: 14,999, 2005: 36,155, 2010 42,392.   Almost 40% of Manitoba samples are coming from zone/grid managed fields.  Soil test results on hay fields are biased because most hay fields aren’t sampled.  They’re mostly only sampled for manure management.  It’s likely that the current upward trend in phosphorus is due to manured fields rather than fertilizer application.  Soil test K levels have increased 10 ppm in MB in the last 10 years, again probably due to manure application.

Tracking Soil Nutrient Levels for Your Clients.  John Heard

Nutrient removals are exceeding nutrient application.  On a short-term basis low analysis starters can work, but you’re going to need make up the removed phosphorus somewhere!  When growers are costing fertilizer, they should look at the purchasing power per bushel.  It’s not the cost of the fertilizer; it’s how much fertilizer you can buy with a bushel!

Phosphorus and the 4Rs.  Rigas Karamanos

Probability of wheat response to application of phosphorus as a function of soil test P:  <5 ppm 100% response, 6-10 71%, 11-20 ppm 50%, 21+ 25%.  The response to phosphorus for peas is similar to that for wheat.

Soil chemistry and precipitation play a huge role in the behavior of phosphorus in the soil. If soil test phosphorus numbers are not correlated to the yield, they mean nothing (soil tests show potentially available, not necessarily what the crop can actually get to).  There are tests to show available (soluble) phosphorus but they will give very small numbers because available phosphorus is a tiny part of the soil’s phosphorous pool.  Pop-up effect is a temporary increase in solubility

It takes about 10-20 days for plants to get to soil phosphorus (no roots), then there’s a huge uptake, and then it slows down.

What determines maximum crop yield?  Genetics (each crop has a genetic max), solar radiation (tends to be constant), water (variable), nutrients (somewhat controllable)

Rules of thumb:

• If it’s too good to be true, it probably is.
• Beware of hype – hype hurts.
• Don’t trust testimonials because they are anecdotes not data.
• What did the opposing side say?
• Ultimate standard: is there published peer review evidence.
• There is no substitute for thinking critically and thinking for yourself.
• At the end it is YOUR decision!

Polyphosphate fertilizer is very similar to orthophosphate. Polyphosphate converts to orthophosphate very quickly in a day or two. Unless you’re applying the phosphorus after seeding, by the time the plant takes up the phosphorus from the fertilizer all the fertilizer products have the same extractable P.  No difference between products.

When midrow banding be careful as the high concentrations of nitrogen can keep the plant from reaching the P.  You can end up with large hot bands where nitrogen needs to migrate out before phosphorus is accessible.  Shallow banding is better than deep banding (12-year study)!  Seed row placement is generally a bad idea (reduced yield in 8 out of 12 years).  When the field is tilled, in row is better, when direct seeded mid-row is better (30 year study).  Why?  Don’t know.

Liquid fertilizer has spacing issues just like dry fertilizer – it comes out as droplets not a steady stream!

Some phosphorus is required for maintenance as well as crop needs.  Extensive leaching of phosphorus and K is expected on soils with a pH less than 4.5.  However long-term movement and stratification is possible (largely through erosion).  Phosphorus uptake is not significantly different under different tillage systems

Once Around the Nitrogen Cycle.  Les Henry

He spoke about how grossly contaminated wells have to be before things such as blue baby start to be a problem.  In almost all cases the problem comes from wells and not from aquifers. It is possible that it’s the bacteria and not the nitrogen directly that was responsible for blue baby.

The efficiency of the mineralized nitrogen is probably 100% – now we need a better measure of mineralization.  Mineralization rate doubles for every 10 degree rise from 5-35 C.  Moisture: On a % basis mineralization and moisture content linear between WP and field capacity.   Les has a simple nitrogen Mineralization Test – take sample in fall, place moist soil in loosely tied plastic bag and leave sit at room temperature for 4 weeks, dry and analyze as normal.  This only works if soil is at field capacity to soil test depth.

Project Smorgasbord.  John Heard.

John Heard told us a bit about Ray Bittner’s P Ramp Calibration strips in the Interlake area.   More phosphorus = More Alfalfa – less phosphorus = more bare patches.  If alfalfa feed tests < 0.2% phosphorus there is phosphorus deficiency in the soil.  Increasing phosphorus increases protein content (vs. check).  John emphasized how easy it is to set up a ramp calibration strip – it takes roughly 18 minutes/plot.

He also gave us a quick report on damage affecting ESN. John noted that there is lots of damage to ESN during application.  A simple test for checking amount of damage is to take ESN that’s come out of your fertilizer applicator: add water to 3g ESN, weigh it, and wait about 24h.  Weigh again.  What’s dissolved is lost. Minnesota and Alberta reported averages of 24% and 13% damage, with more damageat the end of booms and at higher air flows.  This damage to the ESN coating didn’t reduce crop yield.
The Manitoba test showed less damage than in other regions

Residual Soil nitrogen Levels as a Yield Sufficiency Tool?  Rule of thumb is that less than 30 lbs. residual nitrogen indicates under fertilized crop.  However there is no research cited. Initial research shows if residual nitrogen >60, then more nitrogen than needed was applied.  However, underfertilized and optimally fertilized left roughly same amounts of residual N.

Wheat Grain Nutrient Content.  Tom Jensen.

Tom Jensen gave us results for an experiment trying to show a relationship between soil test nutrient level and grain nutrient levels.  The hypothesis is that soil content will affect grain content.  The results didn’t show this for most nutrients:  negative correlation for N, some correlation for P and K, good correlation for Boron, no good correlation for Cl, Fe was significant correlation, there were no Cu deficient sites, so no good test, not a good correlation for Mn, and Zn has the best correlation between soil test and grain.  This needs more research!

Effect of Nitrogen Fertilizer Source and Management on Grain Yield and N2O Emissions.  Don Flaten.
N2O is a very powerful greenhouse gas. Agriculture is about 9% of Canada’s greenhouse gas emissions.  In Manitoba agriculture is about 1/3 of greenhouse gas emissions.

A lot of N2O is released when soils thaw.   There are concerns with fall spreading because of late fall / early spring losses.  Denitrification doesn’t contribute much to N2O if it’s too wet or too dry.  Research so far shows no significant effect of nitrogen source or timing on N2O emissions at Winnipeg and Brandon 2001-2003.  N2O emissions are highly variable by site, year, and so on.  Don suspects nitrification is responsible for most emissions, but can’t prove it yet. Two main emission processes – Denitrification, Nitrification

As far as grain yield goes, there is no convincing evidence showing any agronomic penalties for fall application vs. spring.

A few key events that might only be a few days long seem to account for most of the emissions

Despite the lack of evidence, greenhouse gases from agriculture will attract lots of attention in Manitoba in the next few years.

Crop Scene Investigation.  John Lee

Analyzing Plant Tissue results is tricky.

When collecting samples:

• Store or ship immediately
• Never test plant roots!
• Don’t ship soil
• Fill out information completely
• Bags need holes to prevent rotting/mold
• Be sure to include enough plant material

Sufficiency ranges are established for almost all crops and nutrients.  A second test, DRIS is available for some crops.  DRIS -20 to +20 is considered normal, lower than -20 is deficiency.  It is very helpful to pair tissue tests with soil tests taken at the sites where tissue was collected.  Plant analysis can sometimes show us what’s limiting and the degree of the limitation.  Plan tissue analysis works better when combined with a site specific soil test and visual data.

H. Asgedom’s talk on Nitrogen Oxide Emissions from Urea and Dairy Manure compared nitrous oxide emissions from five treatments:  control unamended, ESN, Solid Dairy manure, Urea, SuperUrea.  Urea and SuperUrea  showed higher cumulative nitrous oxide, ESN plots had least cumulative nitrous oxide.  For manure, nitrous oxide release was triggered by fall manure application.  Yield seemed to correspond to cumulative emissions – higher nitrous oxide = higher yield.

Krista Hanis discussed Eco-system Scale Methane Flux.  Her research was up north near Churchill.  2009 spring results show a gradual increase in methane, not a burst.  2010 fall results show no big burst during freeze-up either.   Their current hypothesis is that a high water table decreases methane losses through consumption or trapping methane in bubbles.  The greatest losses were when the water table was 10cm below surface and air temperatures were warm.

Mario Tenuta asked Is it possible to create profitable Green House Gas (GHG) Neutral Agroecosystems?  Why pursue Green House Gas (GHG) Neutral Agroecosystems?  Three possible answers are: Carbon trading, improving system efficiency and profitability,  and being good neighbors and limiting atmospheric GHG.  The current Agricultural problems with GHG are problems of design: crops are poor competitors, most are annuals (not active in winter), most crops don’t fix N, N in residues is subject to losses, farmers tend to maximize useful yield/land area.  Crops will be dependent on N inputs for some time.  Alfalfa brings down net GHG, as do most other perennials.

Ikechukwu Agomoh discussed research into Coagulant/Floculant effects on swine manure separation.  The conclusion was that most of the solids settle out by 8 hours regardless of additive (including control).

Ray Bittner talked about his experience with Phosphorous Ramp Calibration strips in the Interlake.  In the Interlake all crops are dependent on supplemental P.  Extra P promoted alfalfa growth (vs. grass).  With low P soils (4-5 ppm) there was definite yield response, soil with 15 ppm or higher of P showed no yield response, and soils with around 10 ppm had some yield response.  P removal in feed was higher in high P soils.
General trend is increased soil test P with increased application.  They got two different results:  Hilbre site – never worth applying extra P; Arborg site – always worth applying P.

Waraidzo Chiyoka studied Nitrogen Uptake by Barley amended with anaerobically digested manure.  Objective: Determine uptake in anaerobically digested manure versus raw manure.  Pelletization reduces moisture wchich increases haul distance.  Nitrogen uptake increased for everything except pellets.  N availability did not differ between raw manure and separated solids.  Yield increased with increased N regardless of the form of N.

D. Ige’s talk on Use of wheat dried distillers grain with and without enzyme supplement in pig diet: effect on phosphorus solubility in manure amended soil had interesting results.  P in DDGS has been shown to be more available to animals than that in grains.  Five diets were formulated.
Feces and urine collected and applied to different MB soils.  DDGS had no effect on P solubility in coarse soils, influenced P solubility in fine soils,
Caution must be exercised in assessing effects of diets as effects can vary with soil.

Xiaopeng Gao talked about Producing Crops with Low Cadmium and High Zinc on the Canadian Prairies.  There are health concerns with excess Cd or insufficient Zn.  He studied the effects of common ag practices on Cd and Zn levels.  Cultivar and soil type has effect on CD and Zn  (lower Cd, higher Zn in Clay vs FSL).  More Cd in fertilizer = more Cd in crops.  N fertilizer increased grain Cd at all site-years. N fertilizerdecreased grain Zn at all site-years. Selection of suitable source, timing, and placement of N is important.  Effect of preceding crop depends on crop species.  Grain Zn was higher after flax than after canola, grain Cd not affected.  Either long term or immediate P fert increased grain Cd , decreased grain Zn.  Tillage had little effect on either ZN or Cd.

I love listening to Rigas Karamanos’ talks – he always has interesting stuff to report.  Updated Phosphorus Recommendations for Wheat, Barley and Canola in Manitoba.  Hi goal here is attaching economic analysis to agronomic response.  All crops have a point where yield response is unlikely.  The current figures for P removal are: Barley P removal = .4 lb/bu, Canola 0.9, CWRS =0.55.   Rigas has written a paper showing probability of response to P fert based on soil test:

Soil Test P :  Probability of Response

<5 ppm : 100%

 6-10 : 71%

11-15 : 50%

16-20 : 50%

21+  : 16%?

Net return = (crop price x yield increase) – (nutrient price x nutrient rate).  Rigas has a P rate of return calculator available.

Karimi Dehkordi spoke on Measuring the magnitude and variability of nitrate leaching using field core lysimeters.   N leaching into drinking water is health concern.  Objective is to determine influence of liquid manure, solid manure, and conventional fertilizer on N leaching.   A Lysimeter is essentially big pipe put vertically into the ground.   Two plant samples were collected: early and at harvest. Leachate was collected at 5 intervals
Leaching of N is much greater on annual crops than on perennials.  Water leaching in perennials was also less than in annuals.  Perennials had greater biomass.

S. M. Sayem discussed their research on In-situ measurement of nitrogen mineralization from manures using anion exchange resin.  The problem is that we need better measurements of nitrogen release from manures.  The study took place at Glenlea and Carman and used resin and soil analyses.  Ammonium N declined with time andapproached background levels after two weeks.  Nitrate N increased with time due to nitrification and mineralization.
Total Mineral N was 4 times greater at Carman than at Glenlea.  Anion resin worked at Carman but not at Glenlea – it appears that it works in light soils but not clays.

Daniel Rheault gave some preliminary results for Quantifying the Relationship between Soil P Measures and P Loss by Runoff for Manitoba Soils under Field Conditions: Year 1 Preliminary Results.  The study used four sites plus one baseline (Rosser).  The general trend is that higher soil P means higher runoff P.  They used Total Disolved P (TDP) rather than just Total P as it gave a slightly better relation to runoff P.    All three agronomic methods (olsen, kelowna, melich) of measuring soil P were pretty close.  Environmental methods were similar.  0-5cm gave better relationship than 0-15cm (but they are highly correlated).  They didn’t see evidence of a point at which runoff P increased greatly.  Increased residue meant decreased runoff at 3 of 4 sites (with the exception being a no-till site).  As time goes on runoff reduces.  Site is a huge factor for P runoff (soil texture, topography).

M.D. Timmerman decided to go for the long title challenge with Managing fourteen hundred-pound bundles of fertilizer bound with twine – MAFRI investigates bale grazing and other extensive fall/winter feeding practices.  Early extension in this area dealt with swath grazing.  Why not keep the cattle in the yard? Potential cost reductions, potential contamination risk reduction, soil fertility, soil quality, agronomic driver is better crop growth, better plant diversity.  Bale grazing gives lots of soil test variability (concentric rings).  Are the nutrients beter managed in the field or in the yard?  Mitchell was able to give a definite it depends.  I didn’t get to ask a question but the one that pops to mind here is how do the overwintering cattle losses from bale grazing compare to standard overwintering losses?

I.D. Amarakoon studied Chlortetracycline, sulfamethazine and tylosin losses in surface runoff following field application of beef cattle manure.  Antibiotics are powerful tools to treat and prevent disease in livestock. 75% of livestock antimicrobials are excreted, which may lead to increases in antibiotic-resistant diseases.  In this study manure from cattle given three different antibiotic treatments was broadcast or incorporated.  Broadcast versus incorporation had different effects for different antibiotics – i.e. broadcast was not always worse than incorporation or vice versa.

Lindsey Andronak looked at Urban Atmospheric Deposition of Selected Pesticides.  This study looked at bulk atmospheric deposition – rainfall and particulate matter from non-point sources.  Tests were done for 72 chemicals from May to Sept.  There was also work done on correlating amount of rainfall to deposition amounts.  In their two sites in south Winnipeg, 19 pesticides were detected.  The rainfall/pesticide correlation was decent R^2 of 0.5824. Particulate matter deposition remained a factor – on one of the few rain-free weeks they still had chemical residue deposited.  Atmospheric deposition is a mjor source of non-point contamination. There were both rural and urban sources for the chemicals.

Xuelian Bai gave us a rundown of Sorption and Degradation of 17B-Estradiol-17Sulfate in Agricultural Soils.  E2 is a natural compound from women, dairy cattle, sows.  Half life in lab is 1/2hour to a few days, in the wild seems to last longer.  Organic carbon content is a big contributor in the dissipation of E2

P. Messing presented A Regional Study on the Pesticide Concentrations in Air.  As opposed to Lindsey Andronak’s study, this one looked at chemcal traces in the air, not deposition.  They used Passive Polyurethane Foam samplers (very low flow) at seven sites in manitoba (mostly in the south).  In their northern sites, they mostly found traces of de-registered chemicals.  In the east (experimental lakes) no pesticides were found.  Spatial variablity of active ingredients is evident across the province and there are also small-scale variations.  Current pesticides seem to breakdown more quickly than older ones.

Adam Guy gave us a study of the Impacts of major flooding on an urban environment.  The flloding in Fargo had many factors: heavy Autumn precipitation, heavy winter snowfall, unfavorable melting pattern, heavy rain on melting snow, maybe urbanization, maybe land management (better drainage).  What is the effect of flooding on water quality? What is the effect of flooding on sediment contamination? They did analysis of new sediment and existing soil and concluded that sediment was generally richer in nutrients and carbon than existing soil.

Alison Murat showed the results of an early study of Germination and Early Survival of Brassica Species in Organic and Mineral Soils Contaminated with Multiple Trace Elements.  The site they were looking at had contamination due to idustrial activity and conventional remediation.  Objective: evaluate three species to germinate and survive in contaminated soils and adjust conditions to improve plant growth.  In general organic soil was more contaminated than mineral soil.  Contaminated soil negatively impacted growth of Brassica – i.e. all the plants died.   Future work will need to improve plant growth and survival – add nutrients, different species.  Their next try will be with  tufted hairgrass.  Future work – looking at multiple growth cycles and experimental factors (soil type, fertilizer tpe, EDTA rate)

Yi Zhang spoke on Soil survey data for managing soil salinity. Manitoba has 0.6 million saline acres, Sasktachewant has 3.3 million, and Alberta has 1.6 million acres.   Soil surveys evalute salinity in several ways: site observation, soil sampling, lab test, field instrument survey.  Electromagnetic induction is used to map salinity, but it has to be coupled with lab tests.  They use DUALEM with GPS and GIS to map salinity.  Salinity survey is often used with precision farming.  Electrical conductivity maps to soil textures as well as salinity.  Salinity levels correspons inversely with crop yield in many cases (there are other factors too).  In extreme cases, salinity affects Ag Capability class.

(Image from Veris Site)

I heard about this at a conference today.  Veris has a soil probe that uses Near InfraRed to analyze and record soil properties on the fly.  It appears that  so far they just measure carbon but I can see this being tremendously useful for measuring phosphorous levels across a field.

Cliff Loewen and Scott Dick demonstrated that phosphorous levels can vary wildly on manured fields.  A tool such as this one could be used for cost-effectively monitoring phosphorous levels on manured fields.  With the phosphorous regulations coming into effect across the whole province, I’d love to have a better picture of hot spots without spending several hundred dollars per field to get grid soil tests done.

One of the things that makes glyphosate such a useful herbicide is that it breaks down very quickly.  Even crops that are glyphosate intolerant can be seeded within a few days of application.  If glyphosate residue is lingering, it can severely affect subsequent crop yield.

One of the ways that glyphosate residue can remain in the soil is when plants sprayed with glyphosate take the glyphosate into their roots.  The roots then store the glyphosate as the plant dies.  The glyphosate does not break down quickly in the roots, so when the roots themselves decompose some time later they release the glyphosate into the soil.  This can kill the crop.   Tillage practices are key for reducing the risk.

Another point raised in the study is that glyphosate can accumulate in low phosphorous soils by binding with the soil.  If the soil phosphorous is too high, the glyphosate does not bind and is therefore at a greater risk of leaching.  This is an important point to keep in mind for manured fields as they tend to have high phosphorous.

Glyphosate is still a tremendously useful product.  This study just highlights further considerations to bear in mind when spraying a field.

John Heard discussed the age of Manitoba’s soils in a recent print article. Unfortunately, I didn’t keep a copy of it, but as I recall he said that soils on the Canadian prairies are fairly young. Given that a lot of soil development is due to organic activity that slows or stops during our cold winters, prairie soil is at a much younger developmental stage than tropical soils.

Regardless of the age of your soil, be sure to take good care of it!

Here’s the problem: In the Agricultural Interpretation Database by Municipality for Hanover (hanover_shp), the Agricultural Capability Class for Glenhope soils (GHP) does not match page 50 of report D82 Municipality of Hanover, e.g for GHP xx2x it’s 2M versus 2W. Also Weiden xx1x is listed as 5W in the same file while page 51 of report D82 has it as 3W.

Here’s the reply I received from Peter Haluschak of MAFRI:

The Glenhope soil (GHP) is probably better described as a 2W. This soil has a slight wetness limitation as well as a lack of moisture in drier conditions.

The Weiden soil is poorly drained and is rated as 5W, however with improved drainage the rating is 3W.

Some of the polygons in the D-82 map require a subscript of d for the improved state.

WDN/xx1x = 5W, WDNd/xx1x = 3W.

If your site has improved drainage, use 3W for the Ag. Cap. rating.

If this information was useful to you, please let me know as I would be extremely curious to find out who else might possibly have to know this kind of thing.

Crop uptake of a nutrient is the amount of a nutrient used by a crop when it’s growing.  For example, the Manitoba Soil Fertility Guide lists nitrogen uptake for a 400 cwt/ac potato crop at 205-251 lbs./ac.   This means that if you’re planning to grow a 400 cwt/ac potato crop, you should have that much nitrogen available for the potatoes or you will be limited by the available nitrogen.  Under ideal conditions, a potato crop with only 150 lbs of available nitrogen might only produce 300 cwt/ac of potatoes. 

Crop removal is a measure of the amount of nutrients actually removed from a field by the harvested crop.  Using the potato example again, nitrogen removal is listed at 115-141 lbs./ac.  This means that roughly half of the nitrogen taken up by the potato plant remains in the field after harvest.   The nitrogen from the potato plants apart from the tubers goes back into the soil.  Preventing the escape of these nutrients is one of the reasons why erosion control is emphasized for potato production.

The difference between uptake and removal plays a big role in manuring fields.  One of the problems that we’ve encountered is a rise in phosphorus levels in manured fields.  Pasture fields have very little removal of phosphorus from the soil because the cattle take up very little phosphorus from the grass.  A typical hay field where the grass is baled up and hauled away has removal rates of around 30 lbs. P2O5 per acre.  A typical pasture with only grazing and no hay removal has removal rates of around 10 lbs. P2O5 per acre. 

If you want to maximize nutrient recycling within a field, remove as little of the crop as you can.  One example of this would be to work crop residues back into the field after harvest.  If you want to maximize nutrient removal, remove as much of the crop as you can.  For example, bale up the straw and ship it elsewhere.  The choice of crop and of practices can have dramatic effects on the levels of crop update versus removal.