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Farmer Tries Seeding Cover Crops with Nitrogen Applicator

Farmer Tries Seeding Cover Crops with Nitrogen Applicator | Corn Yield |

Plant crimson clover and several other annual cover crops with a drill after harvest and you have the best chance of getting an excellent cover crop stand. There's just one problem. You also have an excellent chance of not having time for the crimson clover to grow before cold weather sets in. It may affect what net benefit you get out of the crop next spring.

That's why farmers are having cover crops flown into standing crops, delivered into standing crops using high-clearance sprayers and seeding off of corn heads, grain platforms and in front of vertical tillage or minimum tillage tools – anything to get an advantage of getting the seed out there early.

Corn Illustrated 7/22: Two Ears Per Stalk? This Could Be a Good Year for Corn!

Mike Starkey is one of the farmers playing with the idea of getting it started much earlier – at sidedressing time in corn in early summer. He actually applied crimson clover off of his N applicator on some acres this summer to test the concept.

He rigged up a seeder and plumbed hoses to drop seed every 30 inches. He used diffusers to help spread the seed out over more width than just where it would otherwise drop.

At least some of the clover has germinated. The jury is still out on whether this will be a viable approach or not. Meanwhile, he's already thinking about next year. He needs to modify the seeder to be able to seed annual ryegrass with it. He may try to make those modifications before next year. The annual ryegrass seed was too big for the particular seeder to handle.

Related: Where You Live May Affect Cover Crop Choice

Starkey also experimented with broadcasting soybeans between corn rows on a few acres. Picking up the idea from another innovative farmer, the idea is to see if growing soybeans between corn rows would help make more nitrogen available for the corn crop. That's another idea where the jury is still out.

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Is spraying by moonlight effective?

Is spraying by moonlight effective? | Corn Yield |

It’s midnight in the canola field and all is quiet, except for the distant chirping of crickets — and the rumble and hiss of the sprayer.

Equipment technology has evolved to where night spraying is no harder than day spraying, which can be handy when timing is crucial and acres are many.

But does spraying at night provide effective weed control?

A three-year study undertaken by the Farming Smarter research group based in Lethbridge sought to find the answer.

Now wrapping up Year 3, researchers have bad news for early birds. The common practice of morning spraying for pre-seeding burn-down is less effective than either midnight or midday, with midday showing best results.

Initial results for in-crop spraying show midday herbicide applications have the highest efficacy in peas and canola, while midnight applications provided best control of grassy weeds.

Information about the trials was a topic of discussion at the Farming Smarter field school, which ran June 24-26 in Lethbridge.

“The advent of autosteer has sort of expanded the opportunity to spray at night time, and some guys are crazy enough to do it,” said director Ken Coles.

“You do the outside round (first), you make sure you know where your potholes are, and it does give you an expanded window of operation.”

However, most registered herbicides were tested for daytime application, so trials designed by Agriculture Canada research scientist Bob Blackshaw sprayed crop plots at dawn (4 to 5 a.m.) noon (12-1 p.m.) and midnight (12-1 a.m.)

Plots included Liberty Link and Roundup Ready canola, peas and wheat. Various types and rates of chemicals were tested, creating reams of data that will be crunched over the coming months.

“When I started off in this endeavor, I really didn’t think, to be honest, that we would see the differences that we have,” said Coles.

“I think it’s one of these opportunities that if we have a better understanding of which herbicides work under which conditions, we might be able to come up with a bit of a schedule that will maximize our efficacies.”

Differences between the spray timings were more significant in early growth stages, but tended to level out before harvest, according to early data.

Blackshaw said research results brought surprises but also assurances about night spraying.

“Some of this research has shown that in some cases with some herbicides there’s not a large negative effect, so I think producers that still want to do that, especially if they get behind because of adverse weather conditions … it’s not an absolute no-no.”

However, he said for some herbicides, spraying in the daytime provides better results.

“I think that’s especially true for early in the year … when we have cooler conditions.”

It has proven more difficult to analyze how herbicides with different modes of action respond to spray timing. Blackshaw said he thinks it plays a role, but more research is needed for definitive answers.

However, temperature at time of spraying definitely makes a difference, Blackshaw told farmers at the field school.

He said daytime temperatures of at least 10 C are needed for herbicides to be effective.

“The crop needs to grow so it can metabolize the herbicide and break it down so it’s not injured, and the weed needs to grow so that the herbicide can actually do the job on it.”

It means reasonably warm, sunny conditions. The more actively weeds are growing, the better the herbicide can kill them.

Coles said temperatures generally reach their 24-hour lows in the early morning, when relative humidity is highest and dew is heaviest. That will affect chemical efficacy.

Dew might help the chemical spread on the plant, and leaves may be more hydrated, but that doesn’t necessarily mean the plant is efficiently translocating the ingredients because it is not photosynthesizing.

The Alberta Canola Producers Commission and the Alberta Barley Commission funded the night spraying research.

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Estimate nitrogen losses in wet corn fields

Estimate nitrogen losses in wet corn fields | Corn Yield |

The Upper Midwest has received higher-than-average rainfall over the past few weeks, causing flooding and ponding in many corn fields. John Sawyer, professor of agronomy at Iowa State University, says that wet soils in June are more conducive to nitrate loss, reminding growers that corn plants “do not respond well to saturated soils, and therefore can express symptoms similar to N deficiency when they really are showing excess water stress.”

Growers can calculate nitrogen loss estimates to offer guidance for supplemental nitrogen applications, Sawyer says.

To estimate N loss, the first step is to estimate the amount of ammonium converted to nitrate-N. By now, one could assume late fall anhydrous ammonia and manure ammonium to be nearly converted to nitrate, and with early April preplant N applications a majority converted to nitrate. Less conversion to nitrate would occur with use of a nitrification inhibitor. Recent ammonium applications (within the last two weeks) would still be predominantly in the ammonium form, especially for anhydrous ammonia. Recent application of nitrate-containing fertilizers would result in more nitrate being present. Urea-ammonium nitrate solutions (28 or 32 percent UAN) contain one-quarter nitrate-N, and nitrify more rapidly. The second step is to estimate the percentage of nitrate-N loss as described in research from University of Illinois. The amount of nitrogen loss is calculated from these two estimates.

Read more about calculating nitrogen loss from Iowa State University.

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Bayer launches its first soybean seed to address resistant weeds

Bayer launches its first soybean seed to address resistant weeds | Corn Yield |

In an online press conference broadcast live this week byBayer CropScience, the company announced the launch of its first-ever Bayer-branded soybean seed called Credenz. The announcement was made at the company’s U.S. headquarters at Research Triangle Park, North Carolina, in Greenhouse 5, where many of its new products are being developed.

“When we entered the soybean seed and trait business, there hadn’t been much innovation for the past few years,” says Diego Angelo, director of Bayer CropScience U.S. soybean operations. “New challenges in weed management required new solutions. Credenz soybeans will not only yield well but also be tolerant to both Liberty and glyphosate herbicides.”

The seed product is stacked with traits that make it hold up to the applications of Liberty and glyphosate herbicides while offering growers high yields. Angelo says the yields will come through smart seed genetics combined with a product portfolio that includes seed traits, seed treatments, and pesticides.

Bayer CropScience purchased Hornbeck Seed Company in 2011 to develop the new soybean seed. HBK Seed, a brand of Hornbeck Seed Company, will be sold now under the Credenz brand name. 

This is not the first seed variety that the company has branded. It also has seed brands in cotton, canola and rice.

Bayer’s investment in soybeans is in response to the population growth estimated to take place in the next 10 years that will cause a growing demand for food. Soybeans are a main source of protein consumed globally.

Chris Tinius, who heads up the company’s soybean breeding program, says Credenz is a huge launch that will change the seed buying landscape.

“I’ve been in soybean research for 25 years, and I’m as excited today as I have ever been in the last 25 years.” He says the strength of Credenz is found not only in the soybean seed but also in the chemical package that comes with it. “That package will result in high yields for growers,“ Tinius says.

Liberty herbicide has a different mode of action than glyphosate, making it effective against weeds that have become resistant to glyphosate. The new mode of action has no documented cases of weed resistance so far in the main crops in the U.S., Bayer CropScience says.

Future generations of the seed will provide tolerance to HPPD herbicides, which Tinius says is a first for the industry.

“One of the key introductions you will see with Credenz in coming years is it will be the first ever HPPD herbicide tolerance product in the market,” Tinius says. “HPPD is being used today in corn and we are taking a leading position [in that market],” he says. “We will bring that same technology to soybeans.”

Tinius says the seed product also will bring tolerance to soybean cyst nematode in next couple of years to give growers more ways to control weeds and also manage their insects and diseases. Dicamba-tolerant soybeans also are on the docket.

Says Bayer’s Angelo, “We believe in choice in addressing growers needs. Growers will need as many tools as they can get their hands on in their weed management programs, including herbicide rotations. The more tools we offer, the more choice, the better off the farmers and the companies will be long term.”

Credenz will be available for planting in 2015 in southern states and select states in Midwest. The company says it will expand the offering to more states in 2016. Initial varieties are designed for Maturity Groups 2 to 7. Price has not been finalized.

Growers who want more information on the product should contact their local dealer. You also can learn more in the next few weeks, when the company says will start a media blitz around the new product.


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Six Seedling Pests That Don’t Need Seed Treatments

There are no major insect pests of soybean seedlings, but occasionally we do run into problems. Some folks use an insecticidal seed treatment in soybeans. While these products are effective to kill insects, they will not provide a yield benefit. To my knowledge, there has never been a single university field trial that showed a yield benefit to using an insecticidal seed treatment in any Southeastern state.

Tobacco thrips lives on both corn and cotton. Some of these thrips are resistant to some insecticidal seed treatments in the Midsouth. We can expect to drive resistance in our system if we use seed treatments where they aren’t needed. Let’s save the seed treatments for corn and cotton. Finally, insecticidal seed treatments don’t do anything for non-insects like slugs, deer, etc.

Here are some descriptions of injury you might encounter:

1. Thrips can pucker soybean leaves and silver them when densities are high. They will not cause a yield loss and no treatment is needed.

2. Bean leaf beetle is a pest that should be managed later in the season. It will almost never reach economic threshold in the early season for soybean.

3. Grasshoppers, katydids, and cutworms tend to be a problem on fields with lots of residue (think no-till) and fields that have not been properly rotated. They are also more of a problem on field edges. These should be controlled with a pyrethroid if they begin to reduce stand levels to densities below those recommended by NC Cooperative Extension (see adjacent graph).

4. Slugs, which are also more of a problem in no-till fields, are more difficult to control, as insecticides are ineffective. They are more of a problem when conditions are cool and wet. Slugs are difficult to sample, not only because of their small size, but because they are active in low light conditions, like cloudy days and at night. One thing that you can do is to move the residue around to find the slugs and to look for the slime of their trails where they have moved. The dried slime will shine in the sun.

Slugs will feed on the margins of plant leaves and once they have consumed this tissue, they can move to rasp and feed on terminals. Sometimes you will see chunks missing from the seedling stem where they have fed. In severe cases, slugs can consume entire seedlings.

The best management action to reduce slugs is to till. If you’re producing under no-till, slugs are probably not going to change your tillage practices. Basically the more trash you can clean away from the seedlings, the fewer problems you will have. Consider strip till. Less drastic steps are focusing on good residue removal with the row sweepers and using starter fertilizer. The only known remedial measure for slugs, besides waiting for warmer and dryer weather, is to use Deadline M-Ps (AMVAC).

5. Three-cornered alfalfa hoppers feed on seedling and are generally discovered after the fact, when plants lodge later in the season. Seed treatments and foliar pyrethroid sprays can effectively manage these insects. The problem is that it takes EXTREMELY high densities to impact yield. So your money is wasted 99.9% of the time targeting a seed treatment for these critters. In short, if you’ve had a problem with these in the past, do not waste your money with a seed treatment. Scout your beans and treat if you need to.

6. Finally, lesser cornstalk borer can give us problems, especially in late-planted soybeans, on droughty soils, and/or during hot and dry periods. Unfortunately we do not know of any remedial control measure (including pesticides) that is effective for this insect.

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Vidéos sur la fusariose de l'épi (Partie 1 et Partie 2) : Comprendre la fusariose pour mieux y faire face

Vidéos sur la fusariose de l'épi (Partie 1 et Partie 2) : Comprendre la fusariose pour mieux y faire face | Corn Yield |
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Cover crops increase profitability

Cover crops increase profitability | Corn Yield |

Cover crops not only improve soil health and bump yields, but also increase profitability, a U.S. farmer told farm show delegates in San Antonio.

Jamie Scott was part of a panel at the 2014 Commodity Classic this past February. Scott uses cover crops on his Indiana farm and coordinates the seeding of cover crops on another 100,000 acres.

Scott presented yield data from nine side-by-side trials conducted in 2012. The farmers involved had been growing cover crops for more than a year and had a good handle on the management, he said. Other than half the corn field being under a cover crop, everything else in the side-by-sides was the same, Scott said.

“We gained 19.8 bushel per acre average over those trials,” said Scott. Based on that year’s corn prices, the yield increase added up to about $100 per acre.

Scott isn’t the only one who’s seen yield jump with cover crops. Rob Myers, University of Missouri agronomist and regional director of extension with the U.S. Department of Agriculture, worked with about 750 farmers in the 2012 crop year. Myers and his colleagues did side-by-side comparisons of fields with cover crops and bare fields.

Myers told delegates that in 2012 corn grown with cover crops averaged about 11 bushels more than nude corn crops. Soybeans saw a five-bushel bonus with cover crops. Two years of national surveys of hundreds of farmers also revealed cover crops raised corn and soybean yields by five to 10 per cent on average, Myers added.

Myers cautioned that some farmers lost yield or maintained status quo with cover crops. “It kind of depended how long they’d been doing it, the approach they took to cover crops.”

Although yield alone often seems to pay for cover crops, Myers said “grazing is the single best way to make them pay for themselves right away. It’s a really good economic return from the studies I’ve seen.”

Winter cereals, such as cereal rye, are the most popular cover crops in the U.S., Myers said. Legumes are also a popular choice. Brassicas such as radish and turnips are becoming more popular, Myers added.

“And the longer farmers used cover crops, the more they tend to move towards mixes of cover crops, because of the benefits there,” Myers added.

About half of the farmers surveyed drilled cover crops to establish good stands by the fall, Myers said, but many are broadcasting to establish the crop early. About 14 per cent of surveyed farmers used a plane to seed. Three per cent used corn and soybean planters to precision seed and Myers said that number was likely to rise.

Seeding the cover crop early was Scott’s priority, either with a plane or a high-boy sprayer, he said. He added there was a benefit to establishing the cover crop “before the crop comes off, to increase organic matter scavenging, more nutrients and have some footing to work off of in harvest.”

Agronomic benefits

Panelists cited agronomic benefits such as more organic matter and better water infiltration and retention. Scott said even with continuous no-till “we were struggling to get our organic matter levels up where we wanted them. When we add cover crops, we do that extremely fast.”

Mike Plumer, a conservation agriculture consultant based in Illinois, has been working with cover crops since 1980. In Plumer’s neck of the woods, mare’s tail is resistant to glyphosate, 2,4-D and all ALS herbicides.

For the last seven or eight years, Plumer’s been looking at using cover crops to control the herbicide-resistant weed. Cereal rye can “completely control the resistant mare’s tail or horse weed to the point where we get 100 per cent control without a herbicide at all,” he said.

Plumer said cover crops can also control nematodes and disease in soybeans. Research at Purdue University found annual ryegrass can drop soybean cyst nematode populations as well as weeds that host the pest, such as purple deadnettle. And a three-year study funded by the U.S. Department of Agriculture found cereal rye had the most potential to suppress sudden death syndrome and rhizoctonia root rot in soybeans.

Scott encouraged farmers to use cover crops as a safety net when applying nitrogen. “If we over-applied (nitrogen) in the year of the drought, we didn’t use it all. Instead of losing it, we kept it on our farm,” said Scott.

Scott also discussed a watershed study in his area that soil tested in the field, and measured nutrients in the main flow of the ditch and tile lines. “Time and time again, the no-till cover crop field has a higher nutrient level in the field, but it is not coming out in the tile,” he said.

Benefits during droughts

While some people assume cover crops hurt cash crops in dry years because they transpire water from the soil, the opposite seems to be true. Deeper-rooting cover crops can lead to deeper-rooting cash crops.

“So if you can get an extra foot of rooting depth on corn or beans, think of all the extra moisture it can access through a dry year,” said Myers. Some cover crops also blanket the soil in residue, cutting evaporation, he added.

Just as with any other new practice, there will be times when farmers aren’t happy. For example, in the dry spring of 2012, Scott initially thought the cover crop was pulling moisture from the cash crop.

“I told people at one point in time the only way I thought I was going to have income was if I put up a toll booth at the end of our road and charged people to look at the disaster,” he said. “But because of the soil health, because of the rooting depth that we had, that plant got down to moisture, got down to nutrients.”

Lisa Guenther is a field editor with Grainews based at Livelong, Sask. Contact her at .
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Fomesafen Carryover Injury In Corn

Fomesafen Carryover Injury In Corn | Corn Yield |

May 14, 2014 — Numerous people have called to report carryover injury from applications of herbicides that contain fomesafen made last season. 

Fomesafen is the active ingredient in the herbicides Dawn, Flexstar, Flexstar GT, Prefix, Rhythm, Marvel and a variety of other generic products, and in recent years has become one of the most common active ingredients applied post-emergence for the control of glyphosate-resistant waterhemp in soybean. 

Of the herbicides that we typically apply post-emergence in soybeans, fomesafen is one of the most persistent and has one of the longest periods of soil residual activity. Because of this soil persistence as well as the sensitivity of corn to fomesafen residues, the label of most fomesafen products like Flexstar and Prefix requires a 10-month rotational interval between fomesafen applications and corn planting.  


For some of the calls and complaints related to fomesafen carryover, this 10-month rotational interval between application and planting was not followed. However, in some of these instances, there has been more than 10 months elapsed between application and planting.

There are two primary factors that influence the likelihood of fomesafen carryover injury to corn: 1) dry conditions following application, and 2) the rate and timing of the herbicide application. I also think that we should consider the impact of our colder-than-normal winter on fomesafen carryover.  We can't find any research data to support this, but it makes sense that microbial degradation may have been reduced in response to the extended winter we just experienced.

There’s no question though that the number one factor that influences the likelihood of fomesafen carryover is precipitation between application and planting. Soil moisture is critically important for herbicide degradation. If adequate rainfall is not received after application, then the chemical and microbial processes responsible for herbicide degradation are reduced significantly and the herbicide molecules are more likely to become bound (adsorbed) to soil particles.  

All of this results in less herbicide degradation and increases the likelihood of herbicide carryover.  Injury may also be more noticeable on sandy soils, as these areas are usually better drained and hold moisture for shorter periods of time. In some of the locations that have reported fomesafen carryover this week, precipitation totals have been off by as much as 17 inches from the 15-year average for the time period following application to now.

The rate and the timing of the fomesafen application are two other factors that influence the likelihood of carryover injury to corn. Simply put, the higher the rate of fomesafen applied and the later the herbicide application was made, the greater the chance that some fomesafen may remain to cause carryover injury to corn. Since the labels of most fomesafen-containing products require a 10-month rotational interval between application and corn planting, late-season applications of these products in soybeans and early planting of corn the following spring can often make satisfying these intervals difficult. 

The most common corn injury symptom caused by fomesafen carryover is a whitening of the leaf veins, commonly referred to as veinal chlorosis (Figures 1 and 2). Affected areas of corn leaves often take on a striped appearance, can become necrotic, and tissue near the leaf midrib may totally collapse in that region. The root system of affected plants usually remains normal, and plants can take on somewhat of a “droopy” appearance as well.

The real question everyone is asking about is, “Is this going to kill my corn?” Rarely has a fomesafen carryover issue in corn been bad enough to justify killing the corn and starting over. And I don’t believe this is warranted for any of the fields or photos I’ve seen this week either. Usually the most effective thing we can do is wait for the corn to get some good growing conditions and heat units, and the roots will grow out of that fomesafen “zone” and plants will recover. Monitor the new growth closely in the next 5 to 7 days and as long as the new leaves have a healthy green color, you should be fine for the rest of the season. 

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Do soybeans need nitrogen fertilizer?

Do soybeans need nitrogen fertilizer? 

URBANA, Ill. – According to a University of Illinois crop sciences researcher, there has been a great deal of interest recently in the idea of using nitrogen fertilizer during the growing season to increase soybean yields.

“This is somewhat surprising given that there has been so little evidence from published and unpublished reports showing that this practice increases yields, let alone provides a return on the cost of doing this,” said Emerson Nafziger.

Soybean plants in most Illinois fields produce nodules when roots are infected by Bradyrhizobium bacteria early in the season, Nafziger said. Bacteria growing inside these nodules are fed by sugars coming from the plant. “In one of the more amazing feats in nature, these bacteria are able to break the very strong chemical bond between nitrogen atoms in atmospheric nitrogen gas (nitrogen gas makes up some 78 percent of the air but is inert in that form.) This ‘fixed’ nitrogen is available to the plant to support growth,” he said.

The soybean crop has a high requirement for nitrogen; the crop takes up nearly 5 pounds of nitrogen per bushel, and about 75 percent of that is removed in the harvested crop. Nafziger explained that it is generally estimated that in soils such as those in Illinois, nitrogen fixation provides 50 to 60 percent of the nitrogen needed by the soybean crop. A small amount of nitrogen comes from atmospheric deposition, including some fixed by lightning. The rest comes from the soil, either from that left over from fertilizing the previous corn crop or from soil organic matter mineralization carried out by soil microbes.

Nitrogen fixation takes a considerable amount of energy in the form of sugars produced by photosynthesis in the crop. “Estimates of the amount of energy this takes range widely but could be in the vicinity of 10 percent of the energy captured in photosynthesis, at least during part of the season,” Nafziger said. “Because photosynthesis also powers growth and yield, it seems logical that the crop might not be able to produce enough sugars to go around, especially at high yield levels, and that either yields will suffer or nitrogen fixation will be reduced.”

Would adding nitrogen fertilizer fix this problem and result in higher yields?

Nafiziger explained that he has looked at adding nitrogen fertilizer in a series of trials over the past several years, with some of the research funded by the Illinois Soybean Association. These studies involve application of urea, in some cases with Agrotain® (urease inhibitor) or as ESN (slow-release nitrogen) during mid-season, usually in July.

Yields ranged widely among these studies, from in the 30s to nearly 90 bushels per acre. But in only one case did adding nitrogen fertilizer significantly increase yield (by 6 bushels per acre), he said. There was no relationship between yield level and response to nitrogen fertilizer.

“These results provide no support for the idea that the higher the yield, the more response to fertilizer nitrogen. In fact, yields above 70 bushels seemed more likely to show yield decreases from adding nitrogen, though these differences were small and not statistically significant,” he said. 

While these results don’t prove that adding nitrogen fertilizer can’t increase soybean yields, Nafziger said it’s clear that it shows that an increase cannot be expected.

“It is possible that soils often contain more nitrogen than we realize, especially under good mineralization conditions, which are also good growing conditions. It is also possible that we don’t really understand the photosynthetic capacity of soybeans under field conditions, and that our guessing that yield is limited by photosynthetic rates when the plant is also fixing its own nitrogen is just incorrect,” he said.

The usual signal of nitrogen deficiency in crops – light green leaves – is rarely seen in soybean plants during the period of pod setting and seed filling, unless the crop is under prolonged drought stress. Late in seed filling, leaves start to mobilize their nitrogen as chlorophyll and photosynthetic proteins break down and much of this nitrogen moves to pods and into seeds as photosynthesis winds down. Nafziger said if there was a way to get more nitrogen into the leaves early in this process, it might be possible to maintain photosynthesis longer and move more material into seeds. “But it is clear that getting this to happen consistently will be difficult, especially under an unpredictable water supply,” he said.

“Until and unless we find a way to learn to make nitrogen application to soybeans work consistently, or in most cases to work at all, this practice increases both economic and environmental risk. Under dry late-season conditions, such as those we experienced in 2013, much of the nitrogen we apply will fail to get into the plant, but will stay in the soil and become part of the mobile pool of soil nitrogen going into the fall,” Nafziger said.

The crop scientist recommends putting in strip trials in farm fields to get a better look at nitrogen on soybeans over a wide range of fields and soils. He explained that these can be done using aerial or ground application but that ground application is easier to track.


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FieldScripts : New Planting Technology will Accompany Hoosier Farmers

Indiana farmers are anxious to get in the field and start the 2014 planting season, and some of them will have new technology onboard this year. FieldScripts® from Monsanto provides seed selection and a variable rate seeding prescription right in the cab. Dave Rhylander says it will roll out in Indiana, Iowa, Illinois and Minnesota.

“Last year we had 150 farmers testing in those four states. We had maybe 25 farmers in Indiana that actually ground truthed this for us last year, and the whole objective was to have them test it and kind of debug the system for us so we could come back and take some learnings from their experiences and make a better product so when we launched it we had a better product for the farmers who would buy in 2014.”

FieldScripts effectively diagnoses individual and unique farm field conditions to maximize that field’s yield potential.

“It’s the best hybrid match for that particular field and then we write a variable seeding rate that will change every ten meters in a field if it requires, by up to 500 seeds. The objective is to not overplant the poor areas of the field, put the right amount of seed on that area and then redistribute that seed to other areas of the field that should actually be planted at a higher population than what the farmer could today.”

One thing Monsanto has learned through testing and debugging is that farmers will need to accumulate 3 years of data to plug into FieldScripts.

“When we started this last year with these farmers in Indiana we only asked them for 2 years of yield data,” Rhylander said. “What we learned from this is we cannot use just 2 years. We need to have 3 years of data, so that was a significant learning for us. the other thing that we learned, you set your yield target for the fieldscript based upon how you’re going to fertilize the field.”

If you’re thinking about FieldScripts for the future, Rhylander says start saving the data. You’ll need the 3 years total and 2 years of corn, plus 3 acre grid samples, not 4 acre grid samples. And the Monsanto approach to data is, if you create it, it’s yours.

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Practices That Help Reduce Soil Compaction

By Sjoerd Duiker

April 8, 2014 — The pressure is on with a short time window to do field work before planting season begins. However, soil moisture conditions may be suboptimal for field work and the danger of causing soil compaction is very high right now.

Ball Test: Grab a handful of soil, mold it in your hand — if it sticks together as a ball, the soil is too wet for field operations.

The effects of soil compaction caused now may haunt us the rest of the season, and even in years to come.

Research has shown that surface soil compaction effects can linger for up to five years, and subsoil compaction effects can last for 10 years or more.

The ‘ball test’ is an easy way to figure out if soil is too wet to get into the field: grab a handful of soil, mold it in your hand — if it sticks together as a ball, the soil is too wet for field operations. Don’t only take soil from the surface — also take some soil from a foot deep or so. It may be impractical to wait until all of the field is fit, but at least check that 80-90% of the field is ready before starting field work. 

In addition to no-till, here are some other practices that can help mitigate the effects of field traffic.

Cover crops — a vigorous cover crop with a massive, fibrous root system acts like a living ‘geotextile,' providing protection against compaction.Organic matter — a soil with high organic matter (‘humus’) content has a better ability to withstand compaction.Drainage — artificial drainage helps remove free water from the subsoil allowing faster field access in the spring. It is only effective where you have a shallow water table either year-round or during parts of the year.Low tire pressure — low tire pressure helps reduce surface compaction. Tire pressure should be below 35 psi, but it would be much better if run at lower pressures (new tires are available that can be run at 10-12 psi). Check loading charts to make sure the tire can handle the load it is carrying.Radial tires instead of bias-ply tires — radials have a much bigger footprint and more even distribution of stress than bias ply tires so they cause less surface compaction.Tracks — tracks have the same effect as low pressure in tires. It is important to have many rollers as stress is concentrated under the rollers and axles supporting the tracks.Low axle load — keep axle load as low as possible, but at least below 10 tons per axle. Don’t assume weight is distributed evenly over all axles but check each axle on a loaded vehicle or implement. Axle load determines depth of stress penetration in the soil, so it controls subsoil compaction.Avoid random traffic — if there is repeated traffic it is better to concentrate it in certain paths which can be ‘sacrificed’ or signaled for compaction alleviation later on.Reduce number of passes — Use no-tillage and wide equipment, which reduces the proportion of the field trafficked (for example a wide-swath manure spreader causes less compaction than a narrow-swath spreader).

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Corn-on-Corn Planting Yields 25 Bushels Per Acre Less Than Rotation

Corn-on-Corn Planting Yields 25 Bushels Per Acre Less Than Rotation | Corn Yield |

Continuous corn can take a toll on crop yield. That’s true even in intensively managed corn-on-corn fields, according to a six-year study conducted in Illinois by DuPont Pioneer agronomists.

The report found continuous corn yielded 25 bushels per acre less than corn planted following soybeans. Nitrogen (N) was the most important factor in explaining the loss. The continuous corn yield penalty decreased as soil nitrogen supply increased.


The number of years the field was planted to corn was the second-most important component of the yield penalty, according to the study.


Weather proved to be the third yield driver. The continuous corn yield penalty increased as weather conditions limited N. While also a factor in corn/soybean rotations, the study pointed to a more profound influence in continuous corn.

DuPont Pioneer agronomists concluded that the two important management practices for achieving high continuous corn yields were planting continuous corn on highly productive soils and managing corn residues.

University of Illinois soil scientist Laura Gentry and crop physiologist Fred Below have also coauthored a study on corn-after-corn challenges. That study found stover accumulation in continuous corn to be one of the greatest factors in reducing yields, Gentry told DTN.


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vidéo du CRAAQ sur la Fusariose de l'épi (part 1)

Cette vidéo destinée aux conseillers agricoles et aux producteurs de céréales présente l'infection par le champignon Fusarium, agent responsable de la fusariose de l'épi. Les facteurs de risque, le développement de l'infection et les différences entre les espèces cultivées (avoine, blé et orge), les moyens de lutte selon une approche intégrée, l'intervention avec un fongicide et les bonnes pratiques de récolte y sont expliqués.

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Nutrient deficiency symptoms in soybeans

Nutrient deficiency symptoms in soybeans | Corn Yield |

This time of year, soybeans may begin showing signs of chlorosis or other leaf discoloration in all or parts of the field. There may be many causes of discoloration. Nutrient deficiencies are one possibility.

The following is a brief description of the symptoms of some of the most common nutrient deficiencies in soybeans.

Nutrient deficiency symptoms

Nitrogen. Lower leaves are chlorotic or pale green. Within the plant, any available nitrogen (N) from the soil or from nitrogen fixation within nodules on the roots goes to the new growth first. Soybeans prefer to take up N from the soil solution as much as possible, since this requires less energy than the nitrogen fixation process. Both sources of N are important for soybeans since they are a big user of N.

Iron. Iron chlorosis, occurs in calcareous soils with high soil pH. The classic symptom is chlorosis (yellowing) between the veins of young leaves. Iron is not mobile within the plant. A side effect of iron deficiency can be N deficiency, since iron is necessary for nodule formation and function. If iron is deficient, N fixation rates may be reduced. Iron deficiency occurs on calcareous soils because at high levels of calcium, iron molecules become tightly bound to the soil particle and unavailable for plant uptake. In addition to high pH, plant stress can favor the development of iron chlorosis, and therefore the severity can vary significantly from year to year in the same field.

Magnesium. Lower leaves will be pale green, with yellow mottling between the veins. At later stages, leaves may appear to be speckled bronze. This deficiency may occur on very sandy soils.

Manganese. Stunted plants with interveinal chlorosis. Can be a problem in soils with high pH (>7), or on soils that are sandy or with a high organic matter content. Manganese activates enzymes which are important in photosynthesis, as well as nitrogen metabolism and synthesis. Symptoms are hard to distinguish from iron chlorosis.

Molybdenum. Plants turn a light green color due to lack of nitrogen fixation. This deficiency is not common, but can occur on acidic, highly weathered soils.

Phosphorus. Phosphorus deficiency may cause stunted growth, dark green coloration of the leaves, necrotic spots on the leaves, a purple color to the leaves, and leaf cupping. These symptoms occur first on older leaves. Phosphorus deficiency can also delay blooming and maturity. This deficiency may be noticeable when soils are cool and wet, due to decrease in phosphorus uptake.

Potassium. Soybean typically requires large amounts of potassium. Like phosphorus deficiency, potassium deficiency occurs first on older leaves. Symptoms are chlorosis at the leaf margins and between the veins. In severe cases, all but the very youngest leaves may show symptoms.

Sulfur. Stunted plants, pale green color, similar to nitrogen deficiency except chlorosis may be more apparent on upper leaves. Plant-available sulfur is released from organic matter. Deficiency is most likely during cool wet conditions or on sandy soils with low organic matter content.

General considerations

Mobile Nutrients: These nutrients can be transfer from older tissues to youngest tissues within the plant. Symptoms are noticeable first on lower, oldest leaves.


Immobile Nutrients: These nutrients are not easily transfer within the plant. Therefore, symptoms occur first on upper, youngest leaves.


Possible causes of nutrient deficiencies:

  1. Low soil levels of the nutrient. 
  2. Poor inoculation (in the case of nitrogen deficiency).
  3. Unusually low or high soil pH levels.
  4. Roots are unable to access sufficient amounts of the nutrients. This can be due to poor growing conditions, excessively wet or dry soils, cold weather, or soil compaction.
  5. Root injury due to mechanical, insect, disease, or herbicide injury.
  6. Genetics of the plant.

For more information, see K-State Research and Extension publication MF-3028, Diagnosing Nutrient Deficiencies in the Field at:

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Where is the soil N?

With the high rainfall amounts received in southeast South Dakota during the first half of June, questions about soil N in corn fields are justified.

First of all, the N cycle is very complex! Nitrogen occurs in many forms and is influenced by soil microbiology. The majority of plant available N in the soil is nitrate-N (NO3-N) and therefore used to measure availability to plants. Nitrate-N is mobile in soil water because of its negative charge and is also vulnerable to denitrification.

Water moving through the soil profile will leach or move it to lower soil depths. Saturated soil conditions provide the set-up for denitrification. We know that large precipitation events occurred. Some areas in Lincoln County received up to 15 inches with some private reports being even higher. The rainfall intensity was extremely high as some records show rates of 6.1, 4.2, and 3.1 inches per hour in Sioux Falls, 3.9 inches per hour at Baltic, 4.3 inches per hour at Parkston, and 2.4 inches per hour at Beresford.

The un-answerable question is how much water actually went into the soil and what was run-off? This fact will greatly influence the extent of nitrate-N movement in the soil profile. After extreme rainfall events, we recommend soil sampling as deep as possible and analyzing the samples for nitrate-N. Sample a few fields, or locations in fields to get an impression of where the N might be. The degree or extent of nitrate-N leaching will be hard to determine. However, if there are higher amounts of N in the top two feet compared to deeper depths, leaching was probably low. If there are lower amounts then leaching probably occurred. The question is can some of the N in the 2 to 4 foot soil layer be extracted by corn roots?

If the growing season remains wet, plant roots might not go deep enough and some water from lower depths could be drawn upward with heavy crop water uptake and therefore provide N to the corn plants. A soil sample survey was taken at the end of last week to help determine the status of soil nitrate-N in the high rainfall areas. Four sites in Minnehaha and three in Lincoln County were sampled as deep as possible for nitrate-N analysis.

Samples were obtained from one foot increments to the four foot depth except for two sites in Lincoln County where only three foot samples could be obtained. Areas sampled were not flooded or saturated, and represented corn that had good yield potential. The objective of this sampling project was to show the amount of soil nitrate-N in the upper root zone (0 – 2 feet) and estimate if leaching had occurred, irrespective of the amount of N that was originally applied by the grower. Nitrate-N ranged from 82 to 423 lbs/a (Table 1). Percent of nitrate-N in the 0-2 ft soil layer compared with the 0-4 ft total were 61 to 74%.

Lincoln County site 2 may not have received a planned side-dress application and that could explain the lower 0-2 ft. nitrate-N. Past experience has shown when soil nitrate-N leaching has not occurred that 2-4 ft. background nitrate-N is 30-40 lbs/a. Comparing the 2-4 ft nitrate-N values to these typical background levels, these samples show that 30-50 lbs/a nitrate-N could have leached from the 0-2 ft layer into the 2-4 ft. layer. Except for the Lincoln County 2 site, all sites should have adequate N for good corn grain yields, given that the remaining growing season doesn’t result in continued above average precipitation.

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Nitrogen is a grain growers priority

Nitrogen is a grain growers priority | Corn Yield |

GRAIN growers across the Wheatbelt have been urged to monitor their crops for nitrogen deficiency, as they face a different soil nitrogen scenario this year compared with recent seasons.

Last season's high grain yields and a dry summer combined to reduce soil nitrogen and may result in some crops running short of nitrogen this year.

Department of Agriculture and Food research officer Craig Scanlan said with a drier-than-normal winter and spring forecasted, growers would be wise to monitor the nitrogen status of their crops.

Dr Scanlan said there were several tools available to assist growers to make informed decisions about their nitrogen regime for the rest of the season.

"Tissue testing is an effective way to assess whether the soil supply of nitrogen is keeping up with crop demand, though the weather conditions prior to taking the tissue sample needs to be taken into account," he said.

There are several commercial and online applications available to assist growers, while most fertiliser companies have their own recommendation models.

Growers can also access valuable information from local Yield Prophet sites, which is supported by the department.

"Yield Prophet is probably the best model we have for dealing with unusual seasons, because it uses daily rainfall and temperatures to model wheat growth for different nitrogen scenarios," Dr Scanlan said.

Data from the widespread Farm Focus Paddock project, supported by the department and the Grains Research and Development Corporation, have confirmed that plant available nitrogen in the soil profile is lower across the Grainbelt this year compared with the previous four years.

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Lightning: Nature's Fertilizer

Lightning: Nature's Fertilizer | Corn Yield |
Lightning: Nature's Way Of Converting Atmospheric Nitrogen Into Fertilizer.

The powerful bursts of electrical energy from the flashes of lightning ionize the air and produce nitrogen oxide. This ionization process converts the free nitrogen of the air into its water soluble state which all plants need. Just ask WSAZ home and garden expert, John Marra, nitrogen is an essential part of fertilizer. Lightning also help generate new growth in forest areas that are burned by fires triggered by lightning by clearing dead trees so that seedlings have the space and soil to germinate. 

The following list taken from an old newspaper describes the ionization of nitrogen in the atmosphere when lightning strikes:

  • Lightning barrage our earth about 100 times per second.
  •  Lightning is a violent explosion due to the sudden and extremely rapid equalization of electric charges which were formerly forced apart.
  •  Lightning takes place in a thunderstorm cloud wherein the electric charges are forced to separate.
  • The (+) particles gather at the top of the cloud and the (-) particles go to the bottom of the cloud.
  • On earth – directly below the cloud, + charges are attracted. These follow the cloud wherever it drifts.
  •  Lightning happens when the (-) charges in the cloud finally meet the (+) charges on the ground --wham . . . lightning is produced.
  •  These charges meet by traveling through a channel formed by a gaseous arm leaping up from the ground.
  •  Lightning is not produced in one big burst of power. Equalization of electric charges occur in a series or in spurts so that lightning is actually a series of powerful sparks.
  •  Lightning last about one second.
  •  Lightning doesn’t strike down. It is actually going up. It starts from point of contact and it jets up to the cloud along the path established by the gaseous arm.
  •  Lightning appears to be going down because it is an optical illusion. Its speed is actually too fast for the eye to follow.
  • All lightning bolts have no connection on the ground but lightning can be produced between clouds.
  • It is different from St. Elmo’s light in that the latter is really an electric overload becoming visible in the form of light.
  •  Thunder is the sound created by air rushing away at supersonic speed after it has been superheated by the lightning bolt.
  • Below is a great illustration from the NWS on how lightning does this.
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Mixing corn hybrids to increase yield

Mixing corn hybrids to increase yield | Corn Yield |

There are advantages to mixing hybrids, such as lengthening the period of pollen availability to potentially decrease the risk of poor pollination from moisture stress during flowering and promoting cross pollination toward larger kernels and higher grain protein. However, it has not yet been determined whether or not planting them across neighbouring fields offers similar advantages.

As with any practice, there are challenges that need to be met through advances in precision agricultural technologies, but many believe that, one day, mixing hybrids within fields will could become common practice.

Crop stress

According to Dr. Bao-Luo Ma, a crop physiologist with Agriculture and Agri-Food Canada’s Eastern Cereal and Oilseed Research Centre in Ottawa, within every growing season, crops are inevitably exposed to stress, both biotic (stress caused by living creatures like fungus or insects) and abiotic (stress caused by the environment, like cold, heat, crowding, weeds or water or nutrient deficiencies.)

Bao-Luo Ma’s research focuses mainly on corn crop responses to abiotic stress. Theoretically, Bao-Luo Ma sees mixing corn hybrids within a field increasing the diversity and adaptability to both types of stress. “Slightly early or delayed growth stages of one hybrid could help it avoid insect damage, pathogen infestation, effects of drought, flooding, nutrient deficiency, shading, etc. at critical stages of crop development, compared to other hybrids in a mixed-culture or monoculture field,” says Bao-Luo Ma.

“This would result in overall greater grain yields of mixed culture fields than those of the monoculture fields.”

But mixing corn hybrids will not always produce greater yields than would mixing monocultures. “Mixing corn hybrids could often result in the same or even lower yields than monocultures if the conditions weren’t right for mixing cultures or if the wrong hybrids were chosen,” said Bao-Luo Ma.

Bao-Luo Ma advised, first and foremost, knowing your field. Mixing hybrids could be more profitable where there are more differences within the field. “Mixed culture may be more promising in fields with expected large spatial variability, coarse-textured soil, and continuous rain-fed monoculture with a history of higher risk of diseases and insect damages.”

“As well, all hybrids should have high productivity potential with similar plant height, but should have different specific traits.” Some hybrids may be more tolerant to drought, nutrient, crowding or resistant to root or foliar diseases. In a mix, some hybrids may be more suitable for heavy textured soil, have stronger root/stalk strength, or fast dry-down rates — a variety of traits can make mixing hybrids more profitable.

Precision agriculture

As new hybrids become available, it is important to conduct frequent tests to optimize agronomic measures. Testing small areas in many locations before implementing change over the whole farm is very important.

According to Dr. Jiali Shang, who conducts research in remote sensing at AAFC, since the 1950’s, several studies conducted in the U.S. and Canada to evaluate the potential increase in yields of hybrid mixing have shown little or no yield benefit — but, with advances in precision agricultural technologies, mixing hybrids within fields is receiving more attention. “Under the control of precision farming, we’re able to alter the variables of many factors influencing the crop yield and obtain different yield results,” said Shang.

With precision agriculture, it is important that varying hybrid plantings and seeding rates within a field are in accordance with varying soil conditions and properties. “Precision seeding technology, for example, allows for the planting of ‘defensive hybrids’ and ‘high yielding’ hybrids at varying seeding rates, according to the differences in yield potential across a field,” said Dr. Bao-Luo Ma.

By measuring the yield results of mixing crop hybrids using precision farming technologies, farmers and researchers can know what affects the productivity of mixed crop hybrids and ultimately improve the mix.

“Growers should pay attention to kernel shape and maturity of the selected hybrids for mixing culture,” said Bao-Luo Ma. “Planter setting of seeding rates for round shape kernel is different from that of long grain shape hybrids at the same seeding rates.

“Keep in mind that if the difference in anthesis (flower blooming time) or physiological maturity between hybrids in the field is five days or more, kernel moisture content in the mixing could be exceeding the desirable range (below 20 per cent) for combine harvest. This could influence the quality of kernels (broken kernels) and cost of drying.”

More improvements of corn hybrids and the development of agri-technology will help improve productivity, reduce production costs and increase environmental sustainability.

Mixing in Manitoba

Morgan Cott, field agronomist with the Manitoba Corn Growers Association atCarman, Man., is not aware of any farmers in Manitoba who mix hybrids — besides those planting both Bt and non-Bt varieties (which help combat European Corn Borer infestations).

“Mixing varieties would get really tricky, as many have different points of maturity,” said Cott. “Even if you have two varieties with the same specification for corn heat units required, they may not ripen evenly.” This could be especially true for farmers using hybrids from different companies.

Cott advises farmers not to mix varieties that need different heat units, due to the risk of varying maturity.

“At planting, if you have different varieties of different CHUs or not, you may have different types of seed — round versus flat,” says Cott. “At pollination, different varieties may pollinate at different times. At harvest, you’ll find the biggest struggle. A producer following this practice will have to wait until the later variety matures. If he begins harvest when the early variety finishes, the later variety will be too wet and he’ll run into higher drying times and costs.

Assuming the two varieties are the same maturity, there will still likely be different moistures at the same time of harvest. It all depends on the hybrids chosen and how fast/slow they each dry down.”

According to Cott, much work is still needed to improve corn on the Canadian prairies, by way of shortening their maturity times while increasing yields in these varieties.

“We’re extremely lucky here, in Manitoba, to be able to take advantage of all of the advances in corn in the recent past — enabling us to grow a successful crop in the Red River Valley and surrounding areas, pushing outwards in all directions. It won’t be long before you should be able to grow a grain corn crop in southern Manitoba and not run the risk of it being frozen before maturity.”

In 2012, Manitoba had 273,000 acres of grain corn and 75,000 acres of silage corn. In 2013, provincial corn acreage increased to about 342,000 acres of grain corn and 86,000 acres of silage corn. The majority of harvested grain corn is sold toMinnedosa’s Husky Energy plant for ethanol and feed.

This article first appeared in the March 11 issue of Grainews.

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Tips for sidedressing nitrogen on corn | Fertilizer content from Corn and Soybean Digest

Tips for sidedressing nitrogen on corn | Fertilizer content from Corn and Soybean Digest | Corn Yield |
Here is what you need to know for peak nitrogen and financial efficiency.

Spoon-feeding nitrogen makes agronomic and economic sense. These guidelines will help you get the best return on your nitrogen investment.

Sidedress corn at the V5 to V6 corn stage (five or six collared leaves), when the plants are about 20 inches tall, says University of Minnesota Corn Specialist Jeff Coulter.

Heavy spring rainfall does not automatically indicate a heavy nitrogen loss if soils are below 50° F, according to University of Minnesota research.

Skip-row sidedressing works because a relatively small portion of corn roots can absorb all the nutrients, according to the University of Illinois. Because the method supplies nitrogen on one side of each row, injecting nitrogen between every other row maintains yields while reducing power requirements, and increasing maneuverability between rows can cut compaction.


Nitrogen rate

It’s important to calculate how much nitrogen your soil has before applying more. Below are several ways to do this:

One tool is a University of Minnesota in-season corn nitrogen calculator (pdf) can help you determine whether to sidedress nitrogen at corn’s V5 growth stage or beyond.

Another way to determine supplemental nitrogen rates is by calculating the crop’s nitrogen-removal rate comes from Dupont Pioneer: Calculate residual soil-nitrogen levels by multiplying 0.66 (average pounds of nitrogen removed by 1 bushel of corn) by the number of bushels produced per acre. Then subtract that from the amount of nitrogen applied per acre.

A University of Illinois nitrogen-rate calculator is another tool to estimate the amount of residual nitrogen and determine how much you need to adjust for this year’s application.

A spring soil sample is another way to assess the need of the growing crop to calculate an efficient nitrogen application.


Nitrogen form

“Banding with incorporation is obviously the best alternative, but even with 28% or 32% UAN,” Kaiser says. “Only half the nitrogen is in the urea form, which is most susceptible to volatilization.”

Since UAN solutions contain about 50% of their N as urea, expect some losses from surface UAN application without incorporation. Agrotain is the only product that’s consistently proven to reduce nitrogen volatilization loss in university tests. There’s not a product that has proven effective to reduce N volatilization from liquid solutions, says the University of Minnesota Extension.

Surface-applied urea fertilizers are at risk for nitrogen volatilization; even more so at higher soil-pH levels. Rainfall of 0.25 in. or more is generally adequate to sufficiently incorporate urea into the soil.

Injecting UAN at least 4 inches deep insures that corn roots will reach the nitrogen and is preferred to broadcast and surface-dribbling UAN solutions, according to the University of Illinois Extension.

Anhydrous ammonia is another preferred nirogen form for sidedressing, says the University of Illinois Extension.  The ideal application depth for it hinges on soil type, because its ability to move from application site depends on soil structure. The more clay or organic matter, the more tightly the positive NH4+ ion binds to the negative clay soil ions. Therefore, knife at these depths:

6-8 inches for silt-loams

8-10 inches deep for sandy soils

Spraying UAN solutions directly on corn foliage will reduce yields at high rates, Kaiser says.



Sulfur-supplementing decisions can be more challenging, says John Shanahan, DuPont Pioneer agronomy research manager. If you applied sulfur preplant, you may not need to sidedress it except on fields receiving elemental sulfur for the first time this year. Some striping may occur, even when sulfur was applied as elemental sulfur, he says. Sulfur-deficiency symptoms could be caused by rapid plant growth and possible limited sulfur uptake. The corn will grow out of this without affecting yields. If S was not applied this spring, research results indicate that early season applications (V3-V4) of S responded the same as those made at planting.

Surface-applying ammonium thiosulfate between the rows or coulter injected is best, according to University of Minnesota recommendations. Post-application with ammonium sulfate in 2009 and 2010 showed little effect on grain yields at 10 or 20 lbs. sulfur/acre or 42 or 84 lbs. of AMS/acre.

Sulfur can still be applied around the V5 growth stage, according to the University of Minnesota Extension. In most instances, 10 lbs. of sulfur per acre should be adequate for an in-season application. 

Some leaf burning may occur, but that generally has not been found to reduce yields. Spraying liquid sources containing thiosulfate over the top of growing corn can severely injure corn.

Gypsum (broadcast) is another sulfur source.

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Dr. Dan Talks Agronomy : Chill Out: Wait a Few Days to Assess Frost Damage

Dr. Dan Talks Agronomy : Chill Out: Wait a Few Days to Assess Frost Damage | Corn Yield |

Cold weather covered the Corn Belt this week and some farmers, especially in low-lying areas of the northern reaches, had frost. So what damage may it have caused, and will replanting be required?


It has been a long, cold spring for certain, but no one expected to see mid-April weather during mid-May with temperatures dropping into the 30s and 20s with a layer of frost covering the ground at sun-up. With today's large planters and multiple planters per farm, a lot of acres get sown quickly. The seed seemed to come up quickly with the soil in good condition this spring.

So what are the prospects for a crop that experienced frost after it emerged? It all depends on the crop and its height, landscape, temperature and duration of the frost. Don't rush to judgment. Wait a few days to see how the crop responds. If a hard frost hit, you can see permanent symptoms of damage after four days. For soybeans, just look at the top of the seedling to see if its growing point has turned dark. For corn, cut open the growing point and see if it is necrotic or brown.


Soybeans are more vulnerable than corn because of the location of the growing point. Corn's growing point is located below the surface until V6 when it begins to elongate. Corn that has emerged is small, probably just spiking or at V1 or V2. Sure, leaves will be frost-damaged and appear water-soaked, but the seedling will recover and grow back with no impact on yield at this young stage.

Soybeans are another story. Their growing point is located at the top of the plant and is vulnerable to frost. Once the growing point dies at this young stage, there is no recovery.


As we saw in northeast Nebraska this week, heavy frost hit low-lying areas while hills were not affected. This limits the number of acres affected in a field in hilly terrain. Another factor is crop height and residue cover. Air temperature is warmer near the soil surface and residue helps trap a little heat. Smaller seedlings nearer to the ground and protected by residue's insulation may have been unaffected. However, temperatures near the soil surface can be colder than a few feet above because air movement mixes warm and cold air -- or they can be warmer if the soil contained a lot of heat energy built up during previous warm days.


Frost damage depends on how cold it got and how long it lasts. Frost can occur when air temperatures fall to 30 to 32 F, but that probably is not cold enough to create ice crystals and damage cells in a plant near the soil surface. However, if air temperatures drop to 26 to 28 F, that is cold enough to form ice crystals within cells, causing damage.

The other factor is duration. A light 30 to 32 F frost that occurs before sunrise and lasts for an hour is less likely to cause damage than one that lasts four hours. The greater the duration, the more time to form ice crystals. Corn can survive short-duration, light frosts even though leaf tissue is damaged. Cold temperatures below 28 F can be lethal even if the growing point is below ground and the frost lasts for several hours.


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Don't rush to replant without due consideration. Soybeans are easy to replant because they can be seeded over the top, and any new seedling will not necessarily compete because of soybeans' compensatory nature. However, replanting corn means disking out the damaged crop first or replanting over the top with early and late-planted corn seedlings competing with each other.


Before replanting, consider the yield potential of the existing crop compared to replanting costs and yield of a replanted crop. Replant costs include time, fuel, seed costs, and penalties associated with hybrid selection when the best genetics are no longer available. Yield potential of a replanted crop will also be influenced by planting date.

Read more about corn and soybean replanting decisions here:…;…;

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Cool, wet soils promote the growth of one of the major seed and seedling pathogens of corn and soybean, Pythium.

Temperatures are Still Cool


Authors: Anne Dorrance

Soil temperatures from around the state are highly variable still on the cool side.  


Cool, wet soils promote the growth of one of the major seed and seedling pathogens of corn and soybean, Pythium.  Some or the more than 25 different species of Pythium are particularly favored by these cooler temperatures.  Since the soil is moist, oospores which overwinter, are germinating.  When the soils become saturated, they will form a structure called a sporangium which forms the zoospores.  What is unique about this group of pathogens compared to watermolds is that these spores will then swim to the roots, they are actually attracted to germinating seeds and growing roots.  When seeds are planted into cool soils, and we have some low temperature nights, the seeds themselves can be injured.  This then serves to attract more zoospores – quite a system all in favor of these cool, wet loving pathogens.

I think Peter Thomison said it best in last week’s article.  Plant in as close to optimum conditions as possible.  Don’t try to beat a major storm front – in Ohio that is a classic set up for replant conditions.  Keep monitoring those soil temperatures to ensure the best jump start for this seed.  If in doubt, go back and look at the receipt for that seed, this is a huge investment for the overall farming inputs.  You only want to plant once.

Well drained soil, and seed treatments with one or more of the following:  metalaxyl/mefenoxam, strobilurin, or the new fungicide ethaboxam will all protect young seeds/seedlings, but to a point.  Too much cold, long periods below 50 F and extensive saturated soils can overwhelm the system.  Resistance to Phytophthora sojae (warmer temperature oomycete) is well studies and well known for all of the varieties that you purchase.  It is not known how resistant the varieties are to Pythium spp.  There are just too many to test.

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6 Tips for a good corn crop

Help your corn crop get off to a good start this year with these tips from Ohio State University. From planting timing and tillage to seeding depth and rates, these tips will help alleviate mistakes during crop establishment and increase corn yield potential.

Perform tillage operations only when necessary and under the proper soil conditions. Avoid working wet soil and reduce secondary tillage passes. Perform secondary tillage operations only when necessary to prepare an adequate seedbed.

Complete corn planting by early May. During the two to three weeks of optimal corn planting time, there is, on average, only one out of three days when field work can occur. Avoid early planting on poorly drained soils or those prone to ponding. Yield reductions resulting from "mudding the seed in" are often much greater than those resulting from a slight planting delay.

Adjust seeding depth according to soil conditions. Plant between 1 1/2 and 2 inches deep to allow for frost protection and adequate root development. Seeding depth should be monitored regularly during the planting operation and adjusted for varying weather and soil conditions.

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Adjust seeding rates on a field-by-field basis. Adjust planting rates using the yield potential of a site as a major criterion for determining the appropriate plant populations. Lower seeding rates are usually preferable when droughty or marginal soils limit yield potential. Most research suggests that planting a hybrid at suboptimal seeding rates is more likely to cause yield loss than planting above recommended rates. Follow seed company recommendations with regard to optimal seeding rates for different hybrids.

Plant a mix of hybrid maturities. Planting a mix of hybrids with different maturities reduces damage from diseases and environmental stress at different growth stages (improving the odds of successful pollination) and spreads out harvest time and workload.

Plant full‑season hybrids first. Planting a full‑season hybrid first, then alternately planting early‑season and mid‑season hybrids, allows the grower to take full advantage of maturity ranges and gives the late‑season hybrids the benefit of maximum heat unit accumulation.

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Northwest Iowa research explores nitrate runoff from farm fields

Northwest Iowa research explores nitrate runoff from farm fields | Corn Yield |

SIOUX CENTER, Iowa | Matt Schuiteman farms land around all but two of the city of Sioux Center's 12 shallow wells.

Worried about the threat the nitrogen-based fertilizer applied to his corn acres posed to the underground aquifer, the Northwest Iowa farmer agreed five years ago to take part in a comprehensive study aimed at controlling the runoff, while still allowing him to grow crops on the valuable soil.

"The nitrates in the city wells were coming up a bit," Schuiteman said. "We wanted to make sure we could keep farming. We didn't want to see a lot of land going to (the Conservation Reserve Program) if we could help it."

As commodity prices have soared to historic highs in recent years, the federal CRP has become less attractive economically to farmers around the country.

At the same time, public health officials have expressed growing concerns about runoff of nitrogen, not only from fertilizer but also from livestock manure spread on fields.

The Environmental Protection Agency requires nitrates in drinking water be kept at less than 10 milligrams per liter. Levels above that can be deadly to infants six months or younger because the chemical can reduce the amount of oxygen carried in their blood.

The Sioux Center research project, which brought together the city, state and federal environmental agencies and Dordt College, examined five alternative cropping systems on a 40-acre tract of Schuiteman's land, above a bank of shallow wells that provide more than 50 percent of the drinking water for Sioux Center, pop. 7,210.

"The idea was to use perennial crops and cover crops to keep the nitrogen in the upper layers of the soil and available for next season, and apply just what the crops need when they need it," Dordt environmental studies professor Robb De Hann said.

De Haan was awarded a $90,000 grant for the research, which was funded by the Leopold Center for Sustainable Agriculture on the campus of Iowa State University and the Iowa Department of Natural Resources' Source water Protection Program for Targeted Community Water Supplies. Findings of the study were presented at a public meeting last month in Sioux Center.

The alternative cropping systems the researchers designed for standard farm equipment ranged from continuous corn on corn with a winter rye cover crop to perennial grass. The latter is common for wellheads but generally a low-income choice for farmers.

Three other systems used various rotations of corn, soybeans, wheat, oats, alfalfa and red clover. No commercial nitrogen was applied to the perennial grass or alfalfa crops.

After collecting six-foot-deep soil samples each fall, the researchers used the data to construct nitrate profiles for each plot and track nitrate movement over time.

As expected, the findings showed the continuous corn with rye left high levels of residual nitrate in the top two feet of soil.

The grass or hay acres averaged five-fold fewer residuals for every year and at every depth, proving to be the most effective system for reducing nitrate escape into local water supplies. However, wheat with a soybean and corn rotation performed better than continuous corn with rye.

Adding a tap-rooted legume, such as red clover or alfalfa, to corn dramatically lowered residual nitrate levels, De Haan said.

Schuiteman, who started farming his family farm after graduating from college in 1997, said he was surprised at how effective alfalfa was in managing both the amount and distribution of nitrates. But he was disappointed that wheat and oats were less effective in cleaning up nitrages at the lowest depths.

Based on the results, he is planning to implement a four-year rotation of two years of alfalfa, followed by two years of corn. Oats may be included for weed and erosion management to help establish the alfalfa stand.

"We've been using cover crops more and more for four or five years," said Schuiteman, who also has a cow-calf herd. "Some of the things we've learned are really effective at keeping the nitrates out of the water."

De Haan said the research show a potential for raising more alfalfa acres in Sioux County, where demand for forage is greater than some other rural areas due to a large concentration of beef and dairy herds.

De Haan's colleague at Dordt College, agriculture professor Ron Vos, will analyze profitability of the systems using Iowa State University annual custom rates and prices. Based on a preliminary comparison, continuous corn with a winter rye cover crop has a higher average profit per acre than an oat-alfalfa-corn rotation.

De Haan said he hopes the research can be applied to other areas of the state, particularly cities that are prone to escalated nitrate levels in their drinking water. The problem, he said, is more acute in a wet year followed by several drier years.

During an usually dry year, such as the drought of 2012, crops don't do as well so they use less nitrogen, which accumulates in the soil. After heavy rains, he said, the water soluble chemical can break down and wash away into tiles, creeks, rivers and underwater aquifers.

After an abnormally wet spring last year, the Des Moines Water Works, for example, was forced to spend $500,000 removing nitrates, De Haan said. The city typically draws water from the Raccoon and Des Moines rivers and mixes it with water from a reservoir to keep nitrate levels in check.

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Corn-on-Corn Penalty

Corn-on-Corn Penalty | Corn Yield |

DECATUR, Ill. (DTN) -- Continuous corn can take a toll on crop yield. That's true even in intensively managed corn-on-corn fields, according to a six-year study conducted in Illinois by DuPont Pioneer agronomists.


The report found continuous corn yielded 25 bushels per acre less than corn planted following soybeans. Nitrogen (N) was the most important factor in explaining the loss. The continuous corn yield penalty decreased as soil nitrogen supply increased.

The number of years the field was planted to corn was the second-most important component of the yield penalty, according to the study.

Weather proved to be the third yield driver. The continuous corn yield penalty increased as weather conditions limited N. While also a factor in corn/soybean rotations, the study pointed to a more profound influence in continuous corn.

DuPont Pioneer agronomists concluded that the two important management practices for achieving high continuous corn yields were planting continuous corn on highly productive soils and managing corn residues.

University of Illinois soil scientist Laura Gentry and crop physiologist Fred Below have also coauthored a study on corn-after-corn challenges. That study found stover accumulation in continuous corn to be one of the greatest factors in reducing yields, Gentry told DTN.

For more on the University of Illinois study and managing corn on corn, go to:…;

For more information on Pioneer's continuous corn studies go to:…and…;

Pamela Smith can be reached at

Follow Pamela Smith on Twitter @PamSmithDTN

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vidéo du CRAAQ sur la Fusariose de l'épi (part 2)

Cette deuxième partie de la vidéo sur la fusariose de l'épi porte sur la période critique pour l'infection par le champignon Fusarium, agent responsable de la fusariose de l'épi des céréales. Les stades de développement de la culture au cours de cette période sont présentés et expliqués pour déterminer le moment d'une éventuelle intervention avec un fongicide.

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