CHATHAM: The Great Lakes Grain Crop Assessment Tour has concluded now in its 13th year. The tour spans all of Ontario from Windsor to Ottawa. Great Lakes Grain staff, including their FS System partners from across Ontario, have assessed over 900 corn and soybean fields.
The Tour assesses the size of the Ontario crop as well as gives growers a better understanding of how their crop is performing compared to others in the province. It allows growers with their agronomists and grain marketers an opportunity to refine their management plans for future improvements in production and marketing.
Crops for most of the province were planted in the seasonal time frame. However, heavy rains following planting in many areas caused some replanting and lower population stands. This was followed by a drier than normal period through June and July, with some areas barely having any measurable rainfall. Overall, we expect the Ontario corn and soybean crops to be about average.
The dry weather limited some nitrogen and potassium uptake on corn. This is confirmed with deficiency symptoms on the lower leaves expressed as chlorosis and later followed by necrotic tissue. Nitrogen starts at the tip and moves down the center of the leaf mid-rib, whereas potassium also starts on the leaf tip but moves down the margin of the leaf. The symptoms are, of course, more severe when the nutrients are limited due to low soil test levels and or inadequate application of nutrients. The moisture stress on crops serves to amplify other issues apart from a nutrient supply, such as soil compaction.
Foliar leaf disease in terms of incidence and severity was relatively minor in a majority of the fields. Tar Spot did start to develop after R5, which has a minor impact, if any, on yields at this growth stage. Most corn fields will black layer in the next week, so any impact on loss of green leaves at this point will not likely impact much on kernel weights. If conditions stay favourable for disease progression, we will see a rapid loss of green tissue. It remains to be seen what impact it may have on grain dry down rates, stalk integrity and standability. Certainly, it will add to the inoculum load in the fields going forward.
The soybean crop seems to offer more yield stability within fields and between fields with more consistent pod counts, the average number of beans per pod is still 2.5 beans. The difference between this year and last year is a slightly lower pod count and smaller bean size in 2022. This will lower the yield estimate but still produce respectable yields.
We did observe a difference in planting dates on yields. It seems soybeans planted before May 15th may have been impacted more at R1 by heat and lack of moisture. Soybeans planted after May 15th to May 20th may have found that sweet spot for pod retention. Of course, the later planted beans yield less regardless of the year. Full-season beans seemed to take advantage of any August moisture to fill pods at the top nodes.
The drier weather influenced nutrient uptake. Widespread Manganese deficiency, along with some potassium deficiency symptoms, were readily observed. Manganese deficiency was alleviated by a foliar application and some fields required two applications to relieve the symptoms. Yield response in the past to a foliar application averaged from a typical 5 bushel to 20 bushels per acre when severe.
Some potassium deficiencies were observed further up in the canopy when late-season pods were filling and drawing potassium from the nearest trifoliate.
Root rots in some clay farms were a bit of a surprise to see during dryer weather. There must have been enough moisture early on for infection and the dry weather was the tipping point of added stress to increase the severity. White mould was very isolated; in thinner stands Septoria Brown Spot was further up the canopy than normal.
Japanese Beetle feeding appears to be on the increase but still well below action thresholds.
Perhaps the most troubling development is the increase in multiple modes of resistant water hemp populations in soybeans. Either an escape, miss or an ineffective herbicide choice. Regardless this weed will need a diligent effort over several seasons to lower the seed weed bank to get it under control.
Don Kabbes, Great Lakes Grain General Manager, states, “the tour allows us to observe crop performance on the farms of our customer and gain valuable insight into what is working and where the opportunities are for improvement.”
Visit us at www.greatlakesgrain.com for more information.