Included: Double crop soybeans, weed control strategies, soil nitrogen status, wheat insect update and more.
Synopsis: Rainfall has been very sparse. A few isolated showers brought relief to a few areas Sunday but much of the region has had less than one inch of rain since March. Weather innovations data show that rainfall is down by 60% in some areas (see Figure 1).
Figure 1. 2011 (left) and 2012 (right) rainfall from April 1 to May 24 across Ontario as compared to the 30 year average. Source: www.weathercentral.ca
Wind erosion is excessive this year and moisture is disappearing fast. Growers should work fields at night to help conserve moisture and soil. Corn and soybean planting is finished and edible bean planting is estimated at 50% complete. The balance of edible bean growers are waiting for a rain before they plant. Moisture is deeper than edible beans can be seeded. In some cases there is no moisture until you dig over 3-4 inches down. Soybeans and corn look good with a few stand problems here and there. Corn is starting to show moisture stress. There are problems with pre-emergent weed control programs. Wheat looks variable. It has really starting to suffer from the dry conditions over the last week. Some think yields could be disappointing while others feel it may yield better than it looks today. Straw prices will be very high this year with supplies low. There is great hope that the forecasted rain on Friday will be enough to significantly change the situation. Keep in mind it’s still very early in the year. Last year at this time many corn fields were still not planted. First cut hay has been disappointing. One third to one half of normal yields have been reported.
Corn: Corn planting has been finished for some time with a few replants already completed. Most fields look good. There were germination problems, mostly in fields that were planted just before the extremely cold temperatures April 26/27. It appears that parts of the field that got the coldest have the worst germination. Although it’s hard to explain why some of the corn did not germinate properly it does not seem to be strictly a seed quality issue. It could be imbibitional chilling injury or even freeze injury. One report was given that some fields that were deep ripped looked the toughest. Another report was given of the opposite response. The ripped part of the field had better emergence, but was also worked finer that may have given higher insulation value when the frost hit. Jack Legg reported that soil nitrate levels are higher than normal, due to a warm start and very little rain. Nitrate tests are best used as a guide when making recommendations, rather than for absolute rates. A few tests in manured fields have been so high no further nitrogen should be necessary. Some nitrogen fertilizer could be applied even if the soil numbers come back high, with zero strips to verify yield impact. The annual OMAFRA soil nitrate survey will be done late this week and report numbers next week.
Wheat: It’s estimated there are about 650 000 acres of wheat in Ontario this year. The Statistics Canada number is significantly higher (>800,000). Winter wheat is 7 to 10 days ahead of normal development. Spring cereals are well ahead of schedule as well. On dry knolls the wheat is really suffering from lack of moisture. Yields could be disappointing but there was optimism that many of these fields will yield better than they look right now. Fusarium fungicides are being applied, with a small decrease in the % of acres treated expected. “Pigtail” wheat leaves are the result of weather stress. These symptoms have been misdiagnosed as copper deficiency. Yield impact of these deformations will be minimal. Snagged heads are also more prevalent this year especially in some varieties. Yield losses due to snagged heads are very low. Barley yellow dwarf virus (BYDV) is evident in some fields and some growers are confusing this with septoria. Septoria starts at the bottom of the canopy and works its way up while BYDV starts at the top of the canopy. Mn deficient fields are more prone to frost damage. Cereal leaf beetle is above threshold in the Clinton area.
Armyworms: High levels of small armyworm have been found in the wheat crop across a wide area of the province. 5 larvae under 1” per square foot is the threshold. 19” of row equals 1 square foot. SCOUT! Early control is essential to achieve best possible efficacy and least yield loss.
Soybeans: Soybean planting finished last week. Stands are exceptional if seed was placed into moisture. Plants emerged in less than a week. Planter units have provided better stands than drills this year because they do a superior job of seed placement. Plant stands are less than expected where seed was not placed into moisture. There may need to be some “patching” in the toughest parts of fields. In some cases no-till drills were not able to penetrate properly especially on top of corn rows.
If the seed remains dry and doesn’t have enough moisture to swell it can remain in the soil for up to six weeks and still emerge once moisture arrives. However, if the seed starts to swell and then runs out of moisture before it can complete the germination process it has a limited time before it will die. The exact length of time depends on temperature and how far along the germination process the seed developed. These half germinated beans are sometimes called “jelly” beans. They can survive 5 to 7 days before receiving additional moisture. After that time they will start to rot even if it does rain. There were crusting issues with early planted beans although many of these fields did eventually emerge. One trial planted on the 19th of April in the Arthur area crusted over heavily in early May. It took until last week before the beans finally emerged. (5 weeks) As long as seedlings remain healthy and the hypocotyl is not broken off it’s surprising the push soybean seed has. Soybeans are highly adaptive and can yield very well with low populations if fields are kept weed free. Do not consider replanting unless stands are below 100 000 plants/acre on lighter textured soils and 120 000 plants/acre on clay soils.
There will be pre-emergent herbicide problems in dry areas. A few millimeters of rainfall are not sufficient to activate pre-emergent herbicides. These herbicides will work on weeds that have not emerged once rain comes so don’t give up on them yet. Fortunately weeds have not been aggressive yet due to the dry conditions. Foxtails like dry hot weather and are one of the more prevalent weed escapes. It’s probably best at this point to wait and see the weed spectrum before making post-emergent decisions in those fields that had pre-emergent herbicides. Assess fields to see what the worst escapes are. Ideally grass and broadleaf herbicides should be split in fields with tough to kill weeds. Fortunately this year many fields had pre herbicides incorporated, less dependent on rainfall. If conditions remain dry it could become very hard to kill emerged weeds since they are not growing actively. The challenge may be between waiting to see what weeds will escape and early escapes getting too big or hardened off. Do not wait past the critical weed free period of the first trifoliate if heavy weed pressure exists.
Double Cropping Soybeans: There is tremendous interest in double cropping soybeans after wheat this year. Since wheat looks like it will be ready a week early and soybean prices are high this might be the year to try it. In the last two years there has been some success in Ontario with double cropping beans largely because of adequate moisture in July for emergence and an open fall allowing beans to finish in time. Double cropping is risky and experience has shown in Ontario that it only works occasionally. Crop Insurance does not cover double cropped beans. If a grower is going to plant beans after wheat plant high populations (250 000 seeds/acre) in narrow rows. Glyposate tolerant varieties are preferred because moisture can be very limiting in mid summer so other weed control programs can be challenging. Keep expectations realistic. Although some growers did harvest over 40 bu/ac from double cropped beans in 2011 a 25 bu/ac crop is more realistic. General rule of thumb would be 30 bu/ac yield potential on July 1st, with a 1 bu/ac/day yield reduction after that. Consistency of results is poor so keep input costs as low as possible. If wheat does come off early this would be a good year to experiment with cover crops. Tillage radish are an option but can go into tiles so do not plant them too early.
Chair for this meeting was Jim Morlock. Thanks for keeping us on time. Chair for next meeting will be Art DeVos.
Crop Insurance deadlines:
June 15: Last day to report unseeded acreage.
June 30: Spring seeded final acreage reports due.
July 10: Premiums due.
Publications:
Publication 812 – Field Crop Protection Guide is available at any resource center, or by calling ServiceOntario Publications, 1-800-668-9938 or 416-326-5300.
CropLine – 1-888-449-0937
CropPest Website – http://www.omafra.gov.on.ca/english/crops/field/news/news_croppest.html
Stratford Crop Technology Contacts:
Horst Bohner, 519-271-5858 or horst.bohner@ontario.ca
Peter Johnson, 519-271-8180 or peter.johnson@ontario.ca