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The Cropwalker - Volume 2 Issue 18

Always read and follow label directions.

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Crop Conditions

Winter wheat is at second node in earliest fields in the south, to starting first node in later fields in lower CHU areas. About 75% of nitrogen is applied. Applying nitrogen on wheat will be a priority once weather is fit. Corn and soybeans – other than some light ground, less than 10% is planted. This is fairly consistent across the province. (One grower in Courtland area has 1400 acres of sand planted, with first plants emerging.) Ground conditions trumps soil temperature and future rains. If the soil is fit, plant! Don’t worry about cold soil, or, cold rain. It is now May 13, and soil will warm quickly with longer days. The research looking at planting into cold soil was done in late April, early May. Those conditions do not apply now since the soil will warm quickly. Switch hybrid dates, 3200 CHU areas the switch date is May 31, for 2800—3200 CHU switch date is May 25th, for lower CHU areas switch date is May 15-20. US Corn planting is at 29% up slightly from last weeks 23%. Soybeans are at 11%. Some concern in the US about emergence being affected by wet soils.

Forages some planting and touching up of damaged stands. Established stands are a few days behind normal but can catch up with heat.

In 2014 on May 12 we were later planting than the previous 5 years. About 10% of N was still to be applied to wheat. Corn about 5-10% planted. Soybeans none planted. That year wheat averaged 77.3 bu/ac, corn 160 and soybeans 45.5. Right now, if you are estimating yield, look at your 2014 yields.


Can I Drop Dry Starter from My Corn Planter?

Looking for a way to speed up planting? Dropping dry 2x2 starter would cost you about 10 bu/ac on even the highest testing soils based on OMAFRA trials. See table below as you try to develop your strategy. On average, dry 2x2 starter P has 3 times greater response than broadcast P (9.7 bu/ac vs 3.5 bu/ac)

Table 1 - Corn Starter Response

Spraying Weeds in Cool Weather

Weeds must be actively growing to be controlled. You like to have air temperature above 5 o C the night before and 10 o C the day of and after spraying. The warmer the weather the better the weed control. And most herbicides have a 1-4-hour rain free period. (table below has some products, check Pub 75, or a label for specifics) HOWEVER, you will still get some weed control if the temperature is not ideal. Probably better to have reduced weed control by spraying when temperature is cooler as opposed to not controlling weeds. If you delay spraying, bigger weeds are harder to kill, and bigger crop is easier to damage.  Sunshine and heat while spraying is more critical than a cool night. After a cool night plant metabolism is slowed down. Once it warms up and the sun starts to shine plants start to grow again. Thus, if cool nights spray in the middle of the day as opposed to mornings or evenings. Watch winds. Winds can stress plants and cause off target movement. You probably saw the video of off target spray movement when being cautioned about spraying dicamba. The same type of off target movement occurs with all herbicides resulting in uneven spray applications. I have seen this happen when a pre-emerge herbicide was applied while too windy. Do not spray if a frost is forecasted and wait at least 24 hours after a frost before spraying post emergent. (on a positive note with all the rain, not apt to have frost). Surfactants either already in the herbicide or added will increase herbicide activity, but, can also increase crop damage.

Table 2 - Rainfast of Selected Herbicides

How Long Must Glyphosate be on Before Tillage?

For perennials it is nice to have 48 hours and 24 hours for annuals. Reality is if applying glyphosate as part of a burn down probably 1-2 hours between spraying and planting will be adequate to control annuals. Nice to have longer but you will get significant activity from glyphosate if it is only on for a couple of hours. The compromise is less weed control vs. getting planting done.

Is Weather Too Uncertain to Apply a Herbicide to Wheat

Then just spray your fungicide. Weed control in wheat seldom gives an increase in yield. It can make harvest easier and reduce weed seed bank. If you do not control weeds now, you can use a pre-harvest.

Antagonism Between Metribuzin and Glyphosate

Clay based products like metribuzin can tie up glyphosate. The table below indicates that 1.0 L/ acre of a 356 gm/L glyphosate loses some activity on perennial weeds, such as, dandelion and perennial sow thistle. Annual weeds like mustard, and lamb’s quarters, are not affected. This antagonism is over come by increasing the rate of glyphosate. In this research 0.25 L/ac of glyphosate (356 gm/L) were needed to over come antagonism for perennial weed control.

Table 3 - Glyphosate Rate/Herbicide Effectiveness

How deep am I working in my fertilizer?

The rule of thumb is that half the distance that your tillage tool is engaging the soil, your fertilizer is being worked in.

Sulphur Deficiency in Winter Wheat

Symptoms of S deficiency in the field resemble N deficiency with a light yellowing of the leaves. However, unlike N deficiency, where symptoms are predominantly on the younger leaves. S deficiency differs from N deficiency, in that the whole plant is pale, with a greater degree of chlorosis in the young leaves. The reason is S is not mobile in the plant, like N, so the lower leaves do not “fire” and show more severe deficiency symptoms than the upper leaves as is the case with N deficiency. The uniform nature of the yellowing on the plants is one means of diagnosing S deficiency in wheat. Another common difference compared to N deficiency is the pattern in the fields. Sulfur deficiency often occurs first on slopes, eroded areas, on coarser soils, or wherever organic matter levels are lowest. Therefore, deficiencies are usually limited to only certain areas of the field.

Picture 1 - Sulphur Deficiency in Wheat (Source: IPNI)

Fungicides Increase Straw Yield

Data forwarded by BASF shows that spraying spring wheat with Caramba increased the straw yield by 303 lbs/ac and the grain yield by 7.8 bu/ac. But, if you also sprayed Headline AMP at growth stage 32 (2nd node), the straw yield was 644 lbs/ac vs. check. This also increased grain yield by 10 bu/ac vs check. This data was from spring wheat. BASF suggests that you should expect equal or higher yield response from winter wheat.

Reducing Sidewall Compaction

(Notes from Michael Staton, MSU Extension)

1)Reduce the down pressure on both the gauge wheels and the closing wheels. This is one of the most important adjustments you can make to avoid sidewall compaction. 2) Level the planter from front to rear or possibly operate it slightly tail down to improve seed-to-soil contact and seed furrow closing. The closing wheel arm must be level for angled closing wheels to function properly. 3) Use a seed firmer to improve seed-to-soil contact when using two spiked closing wheels per row to breakup sidewall compaction. 4) Various types of spiked closing wheels are available. In general, closing wheels having long straight tines are more aggressive than those having short or curved tines. The aggressive closing wheels tend to dry the soil and may require a seed firmer to improve seed-to-soil contact and a drag chain to level the soil. 5) Consider adding just one spiked closing wheel per row. This will break up the sidewall compaction on one side of the furrow and close the seed furrow more effectively in a wide range of conditions. 6) Staggering the closing wheels will reduce the potential for the seed furrow to open up as the soil dries. If using one spiked wheel and one standard rubber wheel, place the spiked wheel in front.

Which modes of action do you use?

This year could be the 3rd year of soybeans for some growers on some acres. As you get ready to put your third crop of beans, take a good look at the last 3-4 years and check to see which herbicides modes of action you have used. It is important to look at modes and not brand names, as one mode could be sold as multiple brand names. A good integrated weed management practice is to keep track of which crop (including herbicide tolerance), weed history, and which modes of action were used from year to year. Once you have selected for resistance, the resistant population will always be in that field.

Herbicide Timing Terminology

Burndown – Herbicide is applied to remove weeds and create a stale seed bed, usually without tillage, prior to planting/drilling,

Pre-Plant Incorporate (PPI)– Herbicide is applied prior to the last shallow tillage pass.

Pre-Plant (PP) – Herbicide is applied after the final tillage pass, but prior to planting/drilling the field.

Pre-Emerge (PRE) – Herbicide is applied after planting, but prior to crop and weed emergence. In warm weather conditions, can be as short as 1-3 days, depending on the crop.

Early Post (EP)– Herbicide is applied in-crop at 1-4 leaves to control small annual weeds. .

Late Post (LP) – Herbicide is applied in-crop at 4- to 8 leaves (at the tail end of the herbicide window). Usually a rescue treatment, unless attempting to controlling perennial weeds.

Pre-Harvest (PH) – Crop has reached maturity, but not yet harvestable. Herbicide is applied to improve harvestability, and/or, to control perennial weeds.

Post-Harvest – Crop has been removed from the field, herbicide is applied to reduce weed/volunteer crop population prior to tillage or the next crop.

Growth Regulators to Control Lodging in Winter Wheat

Currently only two registered in Ontario; Manipulator, which inhibits gibberellin production and, Ethrel, which blocks auxin transport within the plant. Manipulator reduces the distance between internodes on the lower stem. Manipulator should be applied between Zadok’s 30-32 (stem elongation to 2nd node on the main stem). Ethrel, reduces plant height by 2 to 15 cm, and causes a thicker stem to be produced at the top of the plant. Ethrel should be applied between Zadok’s 37-45 – (flag leaf visible, but rolled up, to swollen boot, but head not visible). Do not apply either product to a crop under stress (i.e. Frost/Heat). For a wheat staging guide, visit Bayer CropScience below by clicking "Cereal Staging Guide".

Cereal Staging Guide

Bayer CropScience

"Showing up is the first step. Every. Single. Day." - Shane Parrish