Agronomist Notes

And hello winter! What a whirlwind couple of weeks it’s been. I had the opportunity to speak at the SACA conference in Lethbridge last Monday followed by two more meetings and a day to touch base with clients to go over Environmental Farm Plan applications for purchases. (The deadline for funding applications is quickly approaching.) 

This week’s topic will focus on the complicated but enjoyable topic of nutrients and soil properties to attain high yields. We will wrap up our nine-week Maximum Yield journey next week when Beyond Agronomy News publishes its 46th and final 2007 issue. Have a great week.

Achieving Maximum Yield – Nutrients and Soil Quality

The most difficult question I hear is “How much fertilizer do I put on?” My easy but correct answer is, “It depends.” There are many factors to consider- what nutrients to apply, how much, at what depth, at what time of year on which crop, for which variety after which rotation, on what soil type with how much organic matter- just to name a few. Here I’ll focus on sharing information that’s common to all soil zones and soil textures, and then I’ll follow with suggestions on improving nutrient use efficiencies.

Our high-yield target of 130 bu/ac spring wheat, 200 bu/ac barley and 100 bu/ac canola cannot be achieved overnight. In fact, after reviewing thousands of soil samples in my short lifetime, I can tell you that the nutrient reserves and physical properties in most soils cannot sustain the kind of yield targets we are trying to accomplish without improvements. So what can be done?

Step 1: Soil Improvement Plan

The first step requires a long term dedication to soil improvement, including physical, chemical and biological properties. Those who’ve produced record yields like 150 bushel spring wheat, 190 bushel barley, 80 bushel canola, 394 bushel corn, 154 bushel soybeans didn’t accomplish it unexpectedly or instantly. Physical soil properties like texture, structure and compaction; chemical properties such as cation exchange capacity, pH and salinity;  and finally, biological properties including animals, plants, fungi and bacteria can be all be improved, but only over a period of several years.

Step 2: Build Nutrient Levels

On your way to improving soil properties you will also be in the process of building high soil test nutrient levels. Nearly all record yields have been produced with high or very high soil test levels. Thankfully, in most soils you only need to build soil levels once, so build-up should be viewed as a capital investment or a land improvement that can be amortized over many years.

What soil test levels do we build our nutrient reserves? To give you an example, the soil test results in Table 2 are well above average. We planted InVigor 5070 at 5 lbs an acre on May 5th, 2006 with 60 lbs of nitrogen and it yielded 80 bu/ac. We didn’t apply any fertilizer the previous year to an adjacent field with similar soil test levels and it yielded 79.5 bu/ac. If you’re thinking manure, you’re correct.  
The key management practice behind the success of top yielders is the addition of poultry, swine or cattle manure along with humates and compost. Some people may roll their eyes and simply say it’s too expensive and too far to haul in. End of story. Or is it? Speaking as an advisor who manages the fertility program on 10,000 acres of previously manured fields, I believe manure is definitely worth the investment!   

Cost of Injecting Liquid Manure

The cost to apply manure is $0.0095 per gallon for anything under three miles and $0.004 per gallon for each mile over the three mile mark.

Example: You live 10 miles from a manure lagoon. 

10 miles - 3 mile base = (7 miles x $0.004) + $0.0095 = $0.0375 per gallon

$0.0375/gal x 6,000 gal/acre = $225.00 per acre

The nutrient analysis in 1,000 gallons of hog manure: (nutrient values are in pounds of actual)

180N -70P -110K - 30S - 70Ca - 40Mg - 0.5Cu - 12Fe - 1Mn - 3.5Zn

To replace those nutrients with fertilizer is not an apples to apples comparison given the slow release nature of manure and other benefits. However, with 6,000 gallons of manure you would be applying $175.00 worth of NPKS. To purchase the equivalent amount of micronutrients you would be well above the cost of the manure application. Not only do you gain valuable nutrients, you also improve all the soil properties mentioned above and there’s also no need to apply fertilizer the year of manure application.

Step 3: Managing Nutrient Availability

Plant nutrient availability is greatly influenced by soil pH. With the exception of P, which is most available within a pH range of 6 to 7, macronutrients (N, K, Ca, Mg, and S) are more available within a pH range of 6.5 to 8, while the majority of micronutrients (B, Cu, Fe, Mn, Ni, and Zn) are more available within a pH range of 5 to 7. Outside of these optimal ranges, nutrients are available to plants at lesser amounts. With the exception of molybdenum (Mo), micronutrient availability decreases as soil pH values approach 8 due to cations being more strongly bound to the soil and not as readily exchangeable. Metals (Cu, Fe, Mn, Ni, and Zn) are very tightly bound to the soil at high pH and are therefore more available at low pH levels than high pH levels.

The well known management practice to elevate soil pH is liming. Lowering pH in soil is a difficult process but involves the addition of organic matter and ammonium-based fertilizers over a long period of time.

Step 4: Applying Nutrients

One of the most interesting bits of information I’ve found ‘outside of the box’ was the use of ammonium feeding which involves applying ammonium-based fertilizers instead of products like urea that convert quickly to nitrate. Read the article excerpts below, “Ammonium Feeding a New Concept”, to find out why this approach is revolutionary. Understanding nutrient requirements for top yields is important but to find out what the soil supplies is even more important. Plants become more efficient at utilizing nutrients when soil test levels increase into the optimum range. For instance, in the example field mentioned above we were able to produce 5.2 bushels of canola per inch of water and use 2.7 pounds of nitrogen to produce 1 bushel of canola for a final yield of 80 bushels an acre.

The norm for nitrogen use efficiency in canola is 3.2 pounds of N per bushel and 4 bushels for every inch of moisture. If we were to calculate nitrogen requirements on a 100 bushel canola crop, we would overshoot our nitrogen application by 50 pounds an acre assuming normal nitrogen use efficiency. Doesn’t sound like much but over applying nitrogen decreases a plants ability to utilize nitrogen properly. That’s why the comment “just add more nitrogen” is bullocks. It’s about balance.    

What about foliar nutrients? What stands out among top yielders is that they all use foliar macro and micro-nutrient programs but they won’t tell you what kind of micronutrient program they use because it differs for each field. There isn’t a one-size fits all fertility program top yielders use. I typically apply micronutrients when soil test levels call for it but under high yielding plant demands, a supplemental foliar nutrient program may be in order. The table below shows the micronutrient response of wheat, barley, peas and canola.

Source: Manitoba Agriculture

To sum it up, we must pay close attention to the yield limiting factors in our soils. We need to develop a soil improvement plan that may include manure or compost. We need to build nutrient levels to optimum levels through strong fertility programs and manure applications. Managing soil pH through lime applications or increased organic matter will increase the availability of soil nutrients. The application of nutrients is more complex than we make it out to be. A program that pushes yield with nitrogen will have to find alternative methods like ammonium feeding to reduce lodging and improve uptake efficiencies. Finally, a well planned and timely application of foliar macro and micro nutrients may provide the supplemental nutrients your crop needs. I hope I've hit a few highlights for you to lthink of in spite of such a huge topic like crop nutrition.

Plant Breeding and Selection to Increase Nutrient Use Efficiency

Research in parts of the world has found ways of introducing nutrient use efficiencies into plant breeding and genetics. Studies have demonstrated how nutrient use efficiencies can be significantly different across varieties. For instance, durum wheat has better phosphorus use efficiency than red spring wheat, and of the red spring wheat varieties, there are some more efficient than others. The key to attaining higher yields in the future will come from plant breeding and genetics that select for varieties with greater nutrient and water use efficiencies. That being said, our high yield goal over time will become easier as plant genetics improve. To read more on these topics, I’ve included a number of research papers on nutrient use efficiency and plant genetics.

Variation in acquisition of soil phosphorus among wheat and barley genotypes. http://nue.okstate.edu/Phosphorus_Network/Singh.pdf

Functional biology of plant phosphate uptake at root and mycorrhiza interfaces. http://nue.okstate.edu/Phosphorus_Network/Bucher%20(2007)%20New%20Phytol%20173,11-26.pdf

Genotypic variation in phosphorus efficiency between wheat cultivars grown under greenhouse and field conditions. http://nue.okstate.edu/Phosphorus_Network/Gunes%20et%20al.pdf

Variation in phosphorus efficiency among 73 bread and durum wheat genotypes grown in a phosphorus-deficient calcareous soil. http://nue.okstate.edu/Phosphorus_Network/Ozturk%20et%20alP.pdf

Nitrogen utilization in spring barley genotypes. http://www.springerlink.com/content/tj12066352hw58q8/

Genetic variation in the efficiency of nitrogen utilization and photosynthetic activity of flag leaves among the old and modern germplasm of winter wheat. http://jag.igr.poznan.pl/2006-Volume-47/3/pdf/2006_Volume_47_3-231-237.pdf

The Problem with Nitrogen Use Efficiency and Plant Breeding

Genetic selection is often conducted with high nitrogen fertilizer input in order to eliminate nitrogen as a variable; however, this can mask efficiency differences among genotypes to accumulate and utilize nitrogen to produce grain. This is consistent with earlier research, noting that high yielding varieties of corn, wheat, and rice released during the Green Revolution were selected to respond to high nitrogen inputs.  Consequently, continued efforts are needed where plant selection is accomplished under low nitrogen, often not considered to be a priority by plant breeders and uncharacteristic of agricultural experiment stations.

Source: http://nue.okstate.edu/increasing_NUE_cereals.htm

Improving Nitrogen Use Efficiency

Production practices that have resulted in increased nitrogen use efficiencies when compared to conventional or standard practices are those that will counter conditions or environments known to contribute to nitrogen loss from soil-plant systems. Here’s a list of beneficial management practices that have shown to improve nitrogen use efficiency (NUE).

Rotation. Nitrogen use efficiency for wheat following legumes is greater than that for wheat following fallow or continuous wheat. Including pulses into the rotation is number one on the list.

Reduced Tillage. Under a no-tillage production system, grain yield was improved 32% when 60 pounds an acre was banded 8 to 10 cm below the seed row, and 15% when banded between the rows compared to surface broadcast urea.

Nitrogen Source. Ammonium-N (NH4) is less subject to leaching or denitrification losses compared to nitrate. Nitrogen maintained as ammonium in the soil should be available for late-season uptake. Increased N uptake during grain-fill, for N-responsive hybrids, indicates a potential advantage of ammonium nutrition for grain production and improved nitrogen use efficiency.  Wheat N uptake was increased 35% when supplying 25% of the N as NH4 compared to all N as NO3. This energy savings may lead to greater dry weight production for plants supplied solely with NH4. 

In-season and Foliar Applied N. Pre-plant N must be carefully managed to optimize grain yield, but adding excess N at preplant reduces NUE, whereas the late-season supplied N can be adjusted to increase grain protein and NUE. In-season N, with point injection or topdressing can maintain or increase NUE compared with pre-plant N in wheat.

Precision Agriculture. Conventional application of N to cultivated fields is made at a single rate based upon perceived average needs of the field, usually areas more than 5 acres. Natural and acquired variability in production capacity or potential within a field cause the average rate to be excessive in some parts and inadequate in others.  Alternatively, precision agriculture practices include the timely and precise application of N fertilizer to meet plant needs as they vary across the landscape.

Source: http://nue.okstate.edu/increasing_NUE_cereals.htm

Ammonium Feeding a New Concept

“Ammonium feeding is a new concept, one of which has huge potential for increased yields, proteins and reduced lodging to name a few. Ideally, ammonium is the preferred nitrogen source for plants since energy will be saved when it is used instead of nitrate for synthesis of protein. Nitrate must be reduced before it can be incorporated into protein. This reduction is an energy-requiring process which uses two NADH molecules for each nitrate ion reduced. Also, ammonium is less subject to losses from the soil by leaching and denitrification. Plant uptake of ammonium proceeds best at neutral pH values and is depressed by increasing acidity."

"A decline in soil pH of the rhizosphere occurs when plants are fed ammonium-N. This acidification can have an important effect on both the availability of nutrients and other biological activity in the vicinity of the roots. Differences in rhizosphere pH of up to 2.2 units have been observed for ammonium versus nitrate fed to wheat plants.” They also stress that the presence of ammoniacal nitrogen in the P placement zone has a positive influence on fertilizer-P uptake.

Source: “Soil Fertility and Fertilizers", 4th Edition, by Tisdale, Nelson and Beaton

Thanks to John Harapiak for supplying this information.

Market News

Wheat Prices Look to Rise in 2008 if Poor Weather Continues

With record low wheat ending stocks, the world cannot afford a crop failure in any country, never mind five countries. Let’s recap world wheat conditions: The US winter wheat crop has scored the lowest conditions rating ever for this time of year with patchy and poor germination caused by dry conditions. Argentina suffered from an early frost with the outcome yet to be defined, but looks like to be significant. Australia’s drought continues on into its third season with devastatingly dry weather and poor wheat crops. Many crops will be grazed or baled for feed instead of harvested. Key wheat growing areas in the EU look to be excessively wet in 2008 (low sunspot activity predictions). I’ve rarely seen a drought that cuts production by 40% and returns to normal the next year, so Russia and the Ukraine are not out of the woods yet. Also, China’s wheat production was down due to dry weather in 2007 and has the potential to see more dry weather in 2008. To sum it up, we may see reduced wheat production in the EU, Australia, the U.S., Argentina, Russia, Ukraine and China. Food for thought! SL

Risk of Dryness in South America

The U.S. Climate Prediction Centre expects La Niña conditions to continue into early 2008. La Niña conditions are likely to increase the risk of dryness is over about two-thirds of South America's soybean area, that is, the southern 40% of Brazil's soybean region and essentially all of Argentina's soybean region.
Source: Ray Garnett Crop & Climate Newsletter

Weather Outlook in South America

The weather outlook for South America is concerned about (a) conditions that are too dry in Argentina; and (b) conditions that are drying out in far southern growing areas of Brazil. Brazilian corn and soybean areas were completely dry until you got to the far north, and in that area we saw some locally heavy rains fall in sizable parts of Mato Grosso and Bahia (places that have been quite wet overall during the past week). Notable about weekend temperatures was the arrival of a 100 degree high in Rio Grande do Sul on Saturday.

Full story: http://www.agriculture.com/ag/weather/index.jhtml?pagenav=market

Coldest Canadian Winter in 15 Years

After years of warmer-than-normal winters that spurred constant talk of global warming, winter this year is expected to be the coldest in almost 15 years and should remind everyone of what real Canadian cold feels like. Environment Canada's forecast for precipitation suggests much of the country is due for normal amounts of snow, although some cities could get more than usual, including Calgary, Regina and Toronto. The forecast for cold weather is being triggered in part by La Nina and a period of lower than normal temperatures in the Pacific Ocean.

http://www.mytelus.com/ncp_news/article.en.do?pn=canada&articleID=2830954

Low Sunspot Activity Points to Wet EU Weather in 2008

The U.S. National Oceanic Atmospheric Administration (NOAA) predicts very low sunspot activity to continue during 2008. This raises the risk of wetter than normal weather to the temperate oceanic climates of France, U.K. and Germany where wetter than normal weather poses the most hazardous risk is to wheat yield prospects. France, the U.K. and Germany produce 65% of Europe's wheat and Europe is the world's second biggest wheat producer after China.

Source: Ray Garnett Crop & Climate Newsletter

Urea in the U.S. Market

In the U.S., the urea market is going through a quiet phase. Spot prices for granular urea have stayed in the range $420-422/short ton FOB New Orleans for the past two weeks. The forward market is firmer, but activity has been limited. Barges are on offer at $432-435/short ton FOB for January, with $440-445/short ton quoted for February. Trades have taken place on Direct Hedge at $440/short ton FOB for January and $445/short ton FOB for February. This tells me that urea will continue to rise over the winter. SL

Reference: http://www.fertilizerworks.com/html/market/TheMarket.pdf

Local Feed Barley and Feed Wheat Prices

The price for feed wheat in the Calgary and Red Deer area softened by $5.00 a tonne to $205 to $210 a tonne for December delivery. Feed barley prices softened by $2.00 a tonne to a range of $184 to $186 a tonne for December delivery. Feed wheat and barley values may soften as more cattle are shipped south to be fed in U.S. feedlots. The year to date total for feeder exports is 422,139 head which is 167% ahead of last year. SL

World Fertilizer Markets

Increases in fertilizer prices often are blamed on natural gas prices, but that doesn’t represent the whole story. World prices for natural gas are much lower and range from less than $1/MMBTU in parts of the Middle East to only $2-3/MMBTU in Russia. The Fertilizer Institute notes that several factors have contributed to increasing fertilizer prices, including world demand and ethanol production. World demand for fertilizer - primarily from South America, China and India - has risen 14% in the past few years. That’s the equivalent of bringing another United States on the market.

Full story: http://cropwatch.unl.edu/archives/2007/crop27/fertilizer1.htm

CWB Interim and Final Payments

Final and interim payments for 2006-07 for the wheat, durum and designated barley pools, as well as Pool B feed barley, will be combined into a single payment. Cheques are expected to be mailed December 14, with direct deposits expected to be made December 18. The interim payments amounts were announced November 16 and can be found at www.cwb.ca. They will be combined with final payments amounts, which are expected to be approved by Ottawa on December 13. The CWB has recommended final payments at the following levels for representative base grades (per tonne): $8.61 for 1CWRS 12.5; $9.17 for 1CWAD 12.5; $10.02 for special select two-row malting barley; $9.12 for special select six-row malting barley; $26.64 for Pool B feed barley.

Source: www.CWB.ca