Weather: The amount of rain this year, as measured at the Michigan State University Enviroweather station at Applewood Orchards in Deerfield from March 1 to July 5 has been 9.32 inches this year. This compares to almost 11 inches last year and a six-year average of 12.44 inches of rain. From May 1 through July 5 this year, the station has recorded only 3.13 inches from May 1 to July 5. This compares to 7.28 inches last year and a previous five-year average of 7.49 inches. The near-term weather forecast is for more seasonal rainfall. Better news is the growing degree day (GDD base 50º F) number of 1233 GDD since March 1 and a six-year average of 1292 GDD. Both Eric Snodgrass of Nutrien and Jeff Andresen of MSU are calling for more seasonal temperatures.
Smoke haze from the Canadian wildfires should not affect crop growth, even though smoke does reduce light availability and photosynthesis in crops. Studies involving sustained shading of crops showed a yield reduction when light was reduced by 30% to 50%.
Soybeans should still be scouted for insects, mites, manganese deficiency and soybean cyst nematodes. Soybean plants can tolerate a fair amount of leaf defoliation before economic injury levels are met. Bean leaf beetles and Japanese beetles are two common leaf feeding insects in soybeans. Farmers can Google “soybean leaf defoliation” and get a chart showing various levels of soybean leaf defoliation. It is very easy to overestimate the amount of defoliation, and people tend to only focus of the worst leaves and not an average of several leaves. Remember to scout several areas of a field and not rely on field margins or pickup truck observations.
Wheat straw value: What is the value of wheat straw? Calculating the nutrient removal value is easier than other values. The actual amounts of nitrogen, phosphorus and potassium contained in a ton of wheat straw are 13, 3.3 and 23 pounds respectively. Depending on the current market value of these nutrients, a ton of straw will contain about $15 to $60 worth of nutrients. Calculating the value on a “per ton” basis rather than a “per acre” basis helps take the guess work out of determining actual yield. Many wheat fields could yield over two tons of wheat straw per acre, depending on the yield and cut height of the wheat stubble. There is also value in the organic matter, which is difficult to put a specific dollar value on. Removing the organic material will diminish the carbon content and can result in a negative impact on soil health and on the physical, chemical and biological properties of the soil.
Straw is an important part of growing wheat, but a delay in baling straw due to excessive rainfall could cause the quality of the straw to deteriorate as a result of mold growth. Under warm, wet conditions, fungi can result in a dark moldy cast, particularly in lodged fields. Some of the molds may produce mycotoxins such as vomitoxin, so look for a pinkish-white mold as an indication that the straw could be contaminated with vomitoxin. Even when straw is used for bedding, a small portion of it may be consumed by livestock. The MSU Plant Pathology Laboratory does not test for mycotoxins, but they suggested farmers could email Marty Chilvers at firstname.lastname@example.org who might know where straw samples could be sent.
Weeds in wheat: Now that wheat harvest is wrapping up, weed control becomes an issue. Two traditional methods of weed control include chemical control (herbicides) and mechanical control (mowing). A third option is tillage using an “aggressive” tillage tool, which could also stir up new weed seeds to germinate. Post-harvest herbicides depend on the following crop or cover crop and any crop rotation restrictions. Visit the MSU Weed Control website at www.msuweeds.com.
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Starting vegetables in summer heat depends on the vegetable. Beets and carrots do not mind warmer soils. Lettuce, spinach and cole crops generally require cooler soil temperatures. Many people like a “summer” garden, but planting spring and fall gardens can better utilize a smaller garden space and still provide a variety of nutritious vegetables. Untreated grass clippings provides a great mulch for tomatoes and peppers and straw will help hold moisture and weed control in pumpkins, squash and melons. Water gardens early enough in the day so leaves dry out before evening and overnight dew to help prevent diseases.
Ned Birkey is an MSU Extension educator emeritus and a regular contributor to The Monroe News.