The first half of April was dry and warm in Illinois, and 159 growing degree days accumulated, compared to the average of 99. The second half of April was also dry in most areas, but only 92 GDD accumulated, compared to the average of 132. Some producers who would normally plant as fast as possible during the second half of April decided to delay planting due to low temperatures. That’s very unusual when soils are in good working condition,…
Dry soil conditions across many areas of Illinois have contributed to accelerated crop planting. It is a bit unusual at this point in the season that such a high percentage of corn and soybean acres already have been planted. Soon, postemergence herbicide applications will begin. However, one potentially adverse consequence of very dry soil is the often large amount of dust propelled into the air by either application equipment or high winds.
Airborne dust has been shown to reduce the activity of some foliar-applied herbicides,…
While conditions during much of April were conducive for planting, these same conditions were NOT conducive for good performance of soil-residual herbicides. Many surface-applied herbicides received neither timely precipitation nor mechanical incorporation to move the applied herbicide into the soil solution. Herbicide effectiveness can be significantly reduced when a soil-applied herbicide is sprayed on a dry soil surface with no incorporation (mechanical or by precipitation) for several days following application. The amount of precipitation required to move the herbicide into the soil and how soon after application the precipitation is needed are difficult to define and can vary by herbicide,…
Soil-residual herbicides are important components of integrated weed management programs. Reducing the number of weeds exposed to foliar-applied herbicides helps reduce the selection intensity for weeds to evolve resistance to foliar-applied herbicides. Residual herbicides applied with postemergence soybean herbicides also can reduce the need for a second postemergence application. However, simply applying a soil-residual herbicide does not guarantee the product will provide the desired level or duration of weed control. Many edaphic and environmental factors influence the level of weed control achieved by soil-residual herbicides.…
A potential scenario encountered each growing season is corn planted in fields where no soil-residual herbicide was applied. If the corn has not yet emerged, the soil-residual herbicide can be applied as originally planned. But, what if the corn has emerged and the soil-residual herbicide has not been applied? Can the application proceed as planned, or will a different product need to be selected? The answer depends on the respective herbicide.
Most, but not all, soil residual herbicides can be applied after corn has emerged.…
The weed science program at the University of Illinois invites all weed management practitioners to our annual weed science field tour on Wednesday, June 28 at the Department of Crop Sciences field research location known as the Clem Farm, located at 1114 County Road 1200 East, Champaign. Registration begins at 7:30 a.m. and the tour will start at 9:00 a.m. Preregistration is not required, but please let us know in advance if you will be bringing a large group of participants so we can plan accordingly for meals.…
By April 16, 10 percent of the Illinois corn crop and 4 percent of soybeans had been planted. Rainfall across Illinois is below normal so far in April, with an unprecedented 10 (of 20) days with no rainfall recorded anywhere in the state. Topsoil moisture ranges from slightly above to slightly below normal across Illinois; there are no areas of really wet or of really dry soils. Some rain fell over the last 24 hours, but little rain is forecast for the next week.…
Hundreds of full-rate N trials run over the past decade in Illinois have been used to develop the N rate calculator that generates Maximum Return to Nitrogen (MRTN) N rates. While using the MRTN rate maximizes the dollar return to N, it is a lower N rate than many producers use currently. Reluctance to lower rates following years of high yields with high N rates is understandable, given that the yield-goal-based N rates used into the early 2000s called for raising N rates as yields increased.…
March was a wet month across much of Illinois. Statewide precipitation averaged 4.48 inches, 1.27 inches above normal. The wet trend continued throughout the first week of April, especially in northern Illinois: more than 1.5 inches of rain fell in some places. NASS reported 1.7 and 2.5 days suitable for fieldwork for the weeks ending April 2 and April 9, respectively.
March temperature averaged 40.5 degrees compared to the 30-yr average of 41.1 degrees, but with wild swings.…
March rainfall ranged from about normal to an inch above normal in the northern half of Illinois to twice normal in the southern end of the state. NASS reported 1.7 days suitable for fieldwork for the week ending on April 2, and soil moisture is rated as adequate or surplus in more than 95% of the state. Up to an inch of rain fell in the first week of April, but dry weather is in the forecast,…