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The Cropwalker - Volume 3 Issue 12

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Crop Conditions

Weather Little snow left. Fields are wet so no crop activity. General consensus is that we are 2 weeks ahead of many years. Wheat is greening up. Some areas of fields with brown leaves. This may be followed by purple leaves on heavy soils when it turns wet. But overall Ontario’s wheat crop is doing good. Some heaving on heavy soils in Niagara area (Haldimand) but overall a small acreage is suffering heaving. The wheat planted in September and first 4-6 days of October is good. The later planted wheat is behind. Forages so far little talk of winter kill. If you have a thin stand consider no tilling annual rye grass or broadcast red clover. There is significant experiences and research to show you cannot thicken an alfalfa stand by broadcasting more alfalfa. There is a shortage of forage feed in Ontario. Central Ontario has the greatest shortage. Indications are that farmers will plant more than normal forages acres this year.


Wheat Stand and Yield

The table below is based on research done by Dr Arend Smid at RCAT between 1986 and 1990. While the research is old, I can’t find any that is more relevant. Normally you drop 20-25 seeds per foot of row at seeding. It is interesting that even at 7 plants per foot you have potential for 90% yield. Some later planted fields (after Oct 5-10) are looking poorer than fields that were planted in September. But at current wheat prices even 7 GOOD plants per foot of row should be profitable. If you have some later planted fields put N on them first. Phil Needham recently spoke at CerealSmart on heads per square meter or square yard. You can see quickly why he had the target number of heads per square meter that he did, more in a future issue. Not all varieties will respond the same way, but it provides an indication on what you can expect. Also, late planted wheat will be unlikely to have 100% yield potential at the same stand count as earlier planted wheat, assumption for yield percentage is at optimal planting date.

Figure 1 - Winter Wheat Plant Stand by Yield

Q. Will early N increase lodging?

No. Not from my experience. Lodging is influenced by variety first, residual N and P from manure, and weather during stem elongation. Cool overcast weather during this period can increase lodging by making the stems longer with less lignin. Hot sunny weather during this period reduces chances of lodging. High phosphorus fields with many tillers are more prone to lodging. Phosphorus encourages fall tiller initiation. When you have more than enough plants or tillers in the field, and adequate moisture, the plants are starving for sunlight, and try to outgrow each other, increasing the risk of lodging. This is less of an issue now that most producers grow semi-dwarf wheat.

Question: Can I under seed alfalfa into winter wheat?

Answer: NO! I know this is being suggested. But it doesn’t work. You end up with a poor stand that you wonder about keeping or destroying. Either way you lose. I have seen it tried many times, but never successfully. You can under seed winter wheat with red clover or seed alfalfa after wheat harvest. Crop Insurance will not insure alfalfa underseeded to winter wheat.

Question: Should I apply nitrogen to a cereal rye crop that will be harvested for forage this spring?

Answer Yes. You need at least 40 lbs/ac actual N. If you applied manure last summer when you seeded your cereal rye, some of that nitrogen will be available. But not sure if it will be available for early spring growth. Suggest you apply some nitrogen this spring if you applied a low rate of manure last year. You can apply it at same time as you are applying your first split on winter wheat. Any nitrogen that is not used by the cereal rye can be used by the corn crop that is planted after you harvest the cereal rye.

Question: I would like more information on basing fertilizer recommendations based on yield potential and CEC

Answer: In the TriState area, just across the border from us, phosphate recommendations are based on soil test levels and yield. These results are based on calibration trials. It makes sense that since higher yields remove more nutrients you need to take that into account. The table below is part of the TriState Recommendations. To view them the recommendations  https://soil.msu.edu/wp-content/uploads/2014/06/Tri-State-Fertilizer-Recs-E-2567.pdf

Question: Is it too early to apply first split of N on wheat.

Answer It is not too early. Your first split should be 30-50 actual N along with sulfur. Every year we have a few hours now that we could apply early N. Some wait for another 7-10 days and then it starts to rain and cannot get there until late April. By then there are so many other things to do that you wished you had have spread some N earlier. Will early N lead to more tillers? If it does this will make no difference to final yield. If there are extra tillers, they will not be detrimental to yield. Will early N increase lodging? No. Biggest factor determining lodging is variety. Most soft red wheat varieties have good lodging scores. Factors that affect lodging are variety, N rate including residual N from manure, and weather during stem elongation. Typically, we do not have a lodging issue with winter wheat.

Question: I would like more information on basing fertilizer recommendations based on yield potential and CEC

Answer: In the TriState area, just across the border from us, phosphate recommendations are based on soil test levels and yield. These results are based on calibration trials. It makes sense that since higher yields remove more nutrients you need to take that into account. The table below is part of the TriState Recommendations. To view them the recommendations  https://soil.msu.edu/wp-content/uploads/2014/06/Tri-State-Fertilizer-Recs-E-2567.pdf

Figure 2 - Phosphorus Recommendations for Corn/Wheat from Tri-State

Potash recommendations are more complicated. They recommend different rates of potassium based on yield level and CEC. The reasoning being that the potassium that is measured is different at different CEC levels. At higher CEC levels less is plant available compared to lower CEC levels. For instance, at CEC of 10 and yield level of 160 bushels per acre they recommend 65 lbs/ac K20 at soil test level of 100-130, but if CEC is 20, they recommend 65 lbs/ac for soils testing 125-155. What TriState does do is recommend more than the official Ontario recommendations, so that soil test levels do not drop.

Omitting residual herbicides in soybeans – really - we have to have this argument again? This is an article written by Mark Loux in the OHIO Crop newsletter

The gist is that now that we have soybeans that you can spray post emergent with dicamba or 2,4-D you still should use a pre emerge herbicide. He goes through the trouble we got into by counting on post emergent herbicides only first programs like CleanSweep which resulted in group 2 weeds that we could not control post emergent, then spraying Roundup resulting in weeds that could not be controlled post emergent, and now the same can happen if we count on dicamba or 2,4-D post as the only herbicide program. You must use a pre and post program in soybeans.   https://agcrops.osu.edu/newsletter/corn-newsletter/2020-05/omitting-residual-herbicides-soybeans-%E2%80%93-really-we-have-have

Chronic vs Acute Cropping Problems and Short Term vs Long Term Solutions

Which problems should I avoid? I would avoid acute problems that require long term solutions to correct them. The big one off the top of my head is soil compaction. An even bigger one is allowing weeds like Canada Fleabane to get out of control. Chronic problems, like excess water that needs to be solved with tile drainage, are a long-term priority, but have less upside than address a weed control issue like Canada Fleabane, which would impact crop yields regardless of field drainage.

Acute problems are ones cause by a single event. Chronic problems develop over time. Each of these will then have solutions that can be categorized into short term and long-term solutions. You should try and prevent acute problems that require long term solutions and address chronic problems that only require short term solutions. I did not consider available resources or payback period for simplicity sake.

Figure 3 - Chronic vs Acute Problems

Strip Till Safe Rates

I’m going to go out on a limb after speaking with various industry professionals that no one really knows what the safe rates are. When fertilizer is mixed in a strip till operation, some go by the safe broadcast rate related back to the strip. i.e. if the safe rate is 200 lbs/ac N (as urea)+ K broadcast and you are working a 10” band then the safe rate is 1/3 the broadcast rate. In some situations, you may burn the crop slightly, and still have a better response if the fertilizer application is more responsive than the crop injury. In non-response environments, this maybe the opposite. A soil test provides a good indication if it’s worth the risk. Another factor to consider is fertilizer placement, if it is banding product at a 2” depth, vs. those that mix with the soil, you will want to adjust the safety factor. A good product to visual this in the soil is ESN, due to the colour contrast, and there is not be a single product you can apply that will have better flowability, so this will be the best case scenario as far as soil mixing goes.

What we do have good data on is starter fertilizer, at a bare minimum we can apply that in a band if it’s away from the seed (get out and check!). But keep in mind, if a dry starter on planter is properly set up, it won’t have any contact with the seed. If it’s mixed into the soil, especially around the seed, maybe try using the broadcast safe rate, which is actually lower than the band rate when using urea, it’s listed in the bottom section of the chart (see arrows). The chart is sourced from data in OMAFRA Publication 611 – Soil Fertility Handbook

Figure 4 - Corn Strip-till Safe Rates (OMAFRA Data)

Another option is to use laboratory data from South Dakota State, here are few of their calculations. You can source the calculator from the www.ipni.net/toolbox website. The assumption with this model is that the nutrients are applied individually and not in a blend, so at a minimum you have an idea on the maximum rate for a single nutrient for that soil type. They also have data ranging from dry to moist soil, so if you are trying to VR a dry clay knoll vs a low spot, you have an indication what the maximum spring applied rate should be for that management zone.

Keep in mind this chart is based on laboratory data, it is broken out into two soil types, and it assumes than the product was applied in a 8” band, but could be in contact with the corn seed, and the rates are for a single product application.

Figure 5 - Corn Strip-till Safe Rates (SDSU Ext)

Nutrient Cycling and Crop Response

I had a call recently with another agronomist around adding new fertilizer ingredients to a field, and how over time the effect will become dulled. Let’s take sulphur for example. If you have never applied sulphur in your crop rotation, and then you start applying it, you are in a situation that you get a significant response. If you continue to apply it, provided there isn’t other limiting nutrients, that is likely the highest response you will ever get. After the big response, plant nutrients that were once limiting will be added back to that element’s nutrient cycle. If you are greatly deficient, expect to see big response the first year, and likely require higher rates to address a build up period. After a period, you will only need to replace what is being lost from the system, to keep those deficiencies from showing up.

Sulphur Release from Manure

Does sulphur release from manure? Yes, eventually. But it is in the elemental form and requires the right weather conditions to release. Don’t get caught being short on sulphur on cool season crops if you are depending on manure releasing sulphur.

Fertilizer Test vs. Manure Test

A fertilizer test checks for plant available forms of P2O5 and soluble K2O. A manure test has a total elemental P and K ran, not just the portions available that year to the plant. Generally, we count on 40% of the total manure P being plant available in the year of application. Potassium is about 90% plant available in year of application. The % N available from manure depends on the amount in the ammonia form as well as incorporation timing/time of year (temperature).

Should I put sulphur on soybeans?

Responsiveness to sulphur on soybeans has been variable. In most situations I would not do a separate trip to just add sulphur. If you are a grower with average soybean yield expectations, and use sulphur on other crops, likely not worth adding it. If you are a grower that does not add sulphur on other crops, or are seeking additional yield, consider adding it to your cropping plans. If you farm on sandy soils, strongly consider adding sulphur to your soybean program. One grower has seen a 5 bu/ac yield response to side-dressing sulphur on soybeans on his sandy knolls. I don’t know if he has been applying it on his other crops in the rotation.

The Value of Organic Amendments in the Crop Rotation – Why we can’t just rely on commercial fertilizer.

This isn’t an article about improving soil health, yada, yada, yada, it’s about finding ways to improve soil productivity and net income per dollar spent. And I’m talking about it now, so that you can have this in place for summer spreading on wheat stubble. There are two camps in understanding the value of organic amendments (by that I mean manures, compost, biosolids, digestate, etc.). One camp that purely looks at the NPK portion relative to today’s fertilizer value and hauling costs. And another that looks at the NPK portion as a way to reduce the fertilizer bill but is also looking for the hidden benefits that cannot be purchased at the local fertilizer plant (unless they retail compost). Frankly, if retails were incentivized to work with their clients in getting the organic amendments into their fertility plan, there would be more of them used. And less of these products would end up in landfills, or on farms where they provide limited benefit. Are these products the holy grail of crop production? No, I do not believe that, but I can think of numerous situations where they would go a long way to improving soil productivity.

What are the benefits? One study side by side study ran with OMAFRA and continued on by a grower (who may be one of our readers), found that there was never a yield lag for using compost. In years of stress the benefits showed more significantly. My understanding is that he farms some fairly responsive soils. (All slides courtesy of Chris Brown, CCA-ON – OMAFRA Field Crop Sustainability Specialist)

Figure 6 - Compost Response Study

Another study found that the use of organic amendments improved both yields and soil bulk density. Soil bulk density is a measurement of how much soil weight is in a given volume and can provide an indication if fine root growth is being restricted. If you are seeing a range of fertilizer response to low fertility tests, it could be a combination of water availability (low water availability increases response to fertilizer), topsoil depth and bulk density.

Figure 7 - Yield Response to Various Organic Amendments
Figure 8 - Soil Bulk Density by Organic Amendment

"If you haven’t done something 3 times before, successfully, don’t assume you know how to do it. "

- Ray Dalio - Founder of Bridgewater Associates