Dry field conditions prevail, corn, soy planting nearly complete

Conditions

Some thunderstorms through Essex provided some moisture, but most areas of the province received less than 5 mm over the long weekend and conditions throughout the province remain dry. Temperatures have transitioned from colder than normal to summer-like, and double-digit night-time temperatures have helped newly planted crops to emerge quickly.

Cereals

Early planted wheat fields are starting to head. T3 fungicide applications are being planned for control of fusarium, but also to help the plant stay green longer during grainfill. Each day the grainfill period is extended by staying green, there can be up to a 3 bu/ac/day yield increase. Dry conditions can shorten the grainfill period, in which case fungicides have less impact on yield. The current DONcast modeling (May 25) suggests low level risk for fusarium, however that risk increases moving east across the province.  Unknown impact of potential moisture and humidity combined with strong wheat prices helps sway the decision to apply T3 fungicide.

Wheat samples with symptoms that look like that of cereal viruses (e.g. barley yellow dwarf virus) have so far come back negative. The symptoms may be associated to rarely seen magnesium deficiency. Tissue sampling is suggesting that magnesium levels in the plant are low. While manganese deficiency has been visible in many fields this year, it is relatively easy to correct with foliar applications. Magnesium levels in the soil may be adequate, but magnesium deficiency symptoms occur when soils are dry.  Magnesium in dry soil conditions is converted to the oxidized form which is less soluble and has limited ability to move with mass-flow into the plant roots. Rainfall will help correct the problem.

Corn and soybeans

Corn and soybean planting are all but complete, except where planting will occur after forage harvest. Planting into moisture is important, but beyond 2.5 inch depth in some soils, if moisture is down too deep, it may be better to plant into a dry seed bed and wait for rain rather than to plant into a transition zone where the seed can take on moisture and start to emerge before running out of moisture a few days later.

Crop emergence has been excellent for the most part, with fields planted during warm conditions emerging in as quickly as 4 days. Some fields planted before soil conditions were ideal are experiencing some stand reduction, but even fields planted during the cool conditions have uniform stands.

Forages

Forage harvest will start in earnest during the last week of May for dairy producers.  Orchard and Italian ryegrass are heading. With current soybean crop prices, protein is expensive for livestock producers. Some beef and sheep producers plan to harvest legume forages earlier than usual to increase the protein content of the hay. Earlier harvest comes at the cost of yield; however, straw may help stretch feed.

Older stands of alfalfa and fields with cereal rye for ryelage are being harvested with plans to plant a crop of corn or soybeans as soon after harvest as possible (Figure 1.). Cereal rye yield and quality were excellent where there were good fertility levels.

Concerns about lack of moisture in these fields is resulting in some no-till planting of corn and soybeans. Forage and rye root mass are difficult to plant into without some tillage. Too much tillage will dry soils, but no-till into alfalfa crowns makes uniform seed depth and consistently seeding into moisture difficult. Application of high-liquid manure can help add some moisture. Un-agitated manure will provide the highest liquid content and a 10,000-imperial gallon (12,000 US gal) provides just under a half inch of moisture.  It is important to be aware of salts in manure, especially with finisher hog manure. The ammonium and potassium and sodium salts can be high and if applied and followed immediately with planting, it can increase the risk of seed burn, especially in sandy soils and when soil moisture conditions are dry.

Manure application after forage harvest has been shown to improve yields and alfalfa quality, however it is important to apply manure as quickly after harvest as possible before regrowth occurs. Application on regrowth damages the new stems and results in lower yield in the tracked areas of the field. Application rates should be set to apply no more than 50 lbs/ac as ammonium-N – which is usually around 3,500 – 4,000 imperial gallons/ac with dairy manure – to prevent leaf burn or salt injury. A manure analysis will provide the phosphorus and potassium that was applied. Potassium applied with manure on alfalfa is often lower than crop requirements.

Insects

With warmer soil temps, grubs and wireworms have been very active at the soil surface. Warm conditions have led to rapid emergence of crops and have limited insect damage so far. Scouting for cereal leaf beetle in wheat and spring cereals and for alfalfa weevil in legume fields, especially older stands, should continue. If there is 40% leaf-tip feeding, with 2 or 3 active weevils per stem, and there are more than 7–10 days to preferred harvest date, consider applying an insecticide. Registered insecticides can be found in Chapter 3 of Publication 812.

Weed Control

Dry conditions are leading to concerns about weed escapes from pre-emerge herbicides not being activated, although the emergence of weeds is also limited by dry conditions. Rainfall is required to activate weed control however there is still reasonable herbicide activity (50 to 80%) of control which will reduce the number and pressure of weeds to control with post emerge herbicides. Rainfall will also bring on a flush of weeds, so scouting at 7, 14, and 21 days after herbicide application to evaluate weed pressure and weed stage is important for best application timing of post treatments.  With dry conditions the weeds will be physically smaller, but at a more advanced stage of growth.

Read the full Ontario Field Crop Report for May 26 at fieldcropnews.com.