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The Cropwalker - Volume 3 Issue 3

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There are numerous conferences we will be sharing content from this month. SWAC will denote Southwest Ag Conference, held in Ridgetown, ON. CCA will denote the Certified Crop Advisor Conference held later this week, and FS will denote FarmSmart or CerealSmart.


Question from a reader “I loved your “SWAC - Organic Matter (OM) With Various Crops” article. I am curious, if a livestock farmer grows grain corn but bales the stalks for bedding, is corn still a net increaser of OM? How does silage corn compare, in terms of net organic matter left in the soil, annually?”

Answer; I put that chart in as a summary of Dale Cowan's (of Agris Wanstead Co-op) presentation. The calculation presumes 1) stover mass equals grain mass. 2) Root mass will be the same whether grain or silage or baled. 3) The soil is 3% OM. Presumption is annual 2% loss of OM. Soils with less OM have smaller losses. 4) There is an annual retention of 15% OM. (Higher yields mean higher OM retention from residue) 5) Bottom line is that corn will still be positive OM addition but not as much if stalks are removed. Silage removes the most OM. Thus, planting a cover crop after corn silage is advantageous. Baling stover removes some OM but typically you cannot harvest 100% of the stalks. (40-80% of residue is typical). On your farm, you can check the OM by a soil sample and compare it to OM in an uncropped area such as fence row. Or check your county soil map for OM levels in certain soils in the 1950’s.

Furthering the case for cash crop growers to plant more forages

Last week we showed you a decrease in forage acres in Ontario, a guesstimate of ruminant numbers, and predicted a continued demand for good forages. Some of the fields/areas you should consider are 1) areas of fields which do not produce good corn and wheat yields, such as outside of fields and headlands and along open waterways. If you normally lose yield to deer, I think planting forages should decrease your field loss. 2) Consider hiring someone to harvest the forage as “baled wrapped forages”. And you will need your own market. There is export markets, but they tend to come and go. Better to have your own market. I know there is forages from Ontario being shipped to US dairy farms. There are also responsible local hay dealers, or local hay auctions. This is currently a growth market. You should expect to harvest a minimum of 4 tonnes/ac of forages as dry hay. The real benefit to forages is the yield increase in the following crops, as well as the reduction in purchased nitrogen.

Question from a non-reader. How are farmers adapting to climate change?

I explained that farmers in Canada are doing OK. As temperatures increase it means we have more heat and a longer season to get higher yields. More frost-free days means more days to collect sunlight to produce yields. Another aspect of climate change is higher CO2 levels. Plants utilize CO2 to make carbohydrates. Higher CO2 levels means higher yields. The big challenge is the swings in weather as we have seen the last couple of years. Wetter and drier periods and possibly hotter days in the summer. The one big thing is to have a plan that you can adapt to changes. It starts with being ready in the spring to plant as soon as you can. Then as the season unfurls, to make good changes such as switching to a shorter season hybrid or soybean variety. And speaking of changes, probably the biggest change in crop production is the rapid spread of resistant weeds. In the 70’s we had triazine resistant lamb’s quarters, and in the 90’s group 2 resistant pigweed. But these weeds spread relatively slow compared to the speed that resistant fleabane and water hemp are spreading. This means you need to switch herbicide groups or use a combination of groups. And watch for escapes in your fields and your neighbours.

SWAC - Your Soybean Yields Were Good, but Could they have been better?

Dr. Peter Sikkema presented research at SWAC showing the yield loss when you delay spraying weeds in soybeans post emergent. Peter suggested that often growers wait to be sure all weeds are up. However, if you have applied a pre-emerge residual herbicide that should control the next flush of weeds. His research shows a significant dollar loss by waiting. He just re-enforces the idea that “if you can see weeds dead or alive from the road”, you have lost yield.

Figure 1 - Weed Height and Yield Loss

SWAC - Crop loss with no weed control

Dr. Peter Sikkema put together the table on % yield loss if there was no weed control. He summarized yields from his various weed research trials over the years. His summary shows how crucial it is to get good weed control in corn, beans, and spring cereals. Weed control in winter wheat is not as critical to maintain yield. Remember this next spring when you are agonizing about mixing a fungicide with an herbicide. (The timing of the fungicide is more critical than the timing of the herbicide.)

Figure 2 - Yield loss due to weed pressure by Crop

SWAC - How Soon Before Planting Soybeans Can I spray 2,4-D Ester?

Research presented by Dr Petr Sikkema at SWAC summarized spraying 2,4-D ester 700 at 0.427 L/ac at 14, 7, and 1 day before planting and 7 days after planting. In his research there was a 4% increase in visual symptoms spraying 1 day before planting vs. virtually no symptoms spray 7 or 14 days before planting. When yield was taken 1 day before planting had a small decrease in yield that was not statistically different that spraying 7 or 14 days before planting.

Where should soil test P and K be?

Research presented at SWAC consistently showed the value of having certain soil test levels of P and K to get top yields. The research suggested that P should be at least 20 ppm using Sodium Bicarb (Olsen) and K should be at least 120 ppm, with Ammonium Acetate. This is from soils with CEC’s around 12-18. The CEC can be used as an indication of how heavy as soil is. Typically, sands are below 10, clays are above 20 and silt and clay loams in Ontario typically are 12-18. Research from the tri-states of Michigan Ohio and Purdue suggest a different way to make fertilizer recommendations based on soil test levels and CEC. For P they recommend that you should have a P level of 15 for corn and soybeans and 25 for wheat. (I like to have P levels around 25), For K they recommend that K levels should be based on CEC. For CEC of 20 they recommend soil test levels should be 125. For soils with a CEC of 30 they recommend that soil test should be 150. One way to indicate if your soil test is reaching maximum yield potential based on soil P and K levels is whether your soil tests are dropping or rising. If your P level is below 20 and still rising, P is probably not limiting since there is more P available than is being used. Same goes with K levels. You need to track them over 6-10 years to get a good handle as to whether your soils are building or being depleted. If tracking, you should use the same lab, and georeference the areas you are sampling.

Which grass species should I include in my forage mix?

Reader asked, what should I be doing to bulk up my alfalfa/timothy mix or my next new seeding? Rather than come up with the exact answer on what to include, I would look at the following characteristics. 1) Will the grass mature at the same time as the rest of the forage crop (alfalfa)? 2) Will the grass meet the nutritional/volume requirements of my livestock? 3) What will survive/establish with my soil conditions/management? i.e. soil type, tile vs no-tile, fertility levels, number of cuttings etc. 4) What will dry down of the grass be like, if trying to make dry hay? 5) Will the grass recover to provide feed for more than 1 cut?

Thoughts on Lodging

Lodging is thought of as an issue to due to poor root anchoring, poor genetics, or excessive plants. When I look at a field and see lodging, especially on headlands, I see most limiting factors removed (seeding rate/nutrient application), and that the plants are suffering from lack of sunlight. Sunlight? Yes, because water and nutrients are not the limiting factors, seeding rate isn’t the limiting factor. In my opinion, the plants are trying to out compete each other for sunlight.

Strip-till vs No-till Soybeans

Speaking with a Huron County grower this week that has both strip-till and no-till 30” soybeans, their comments were; 1) They get better populations with the strip-till soybeans, enough to justify running the strip tiller, compared to no-tilling (by being able to reduce seed rate). 2) They like using the strip tiller to place phosphate and potash, not necessarily for that year’s soybeans, but also the following corn crop. 3) They have seen very little yield difference between strip till and no-till soybeans.

Soybean Seeding Rates

Last week I attended a meeting where data was presented that suggested regardless of management zone, growers are planting too many soybeans. If you have the capability, run a soybean population trial in 2020. Aside from the risk of giving up weed control, most growers maybe planting too many plants with today’s planting technology and genetics. The strip till grower above commented, that they have reduced their population from 200,000 to sub 160,000 or less on some fields, partially due to getting better plant stands with better equipment.

“If it weren't for the last minute, nothing would get done.”

- Rita Mae Brown