JACKSON, Tenn. – The University of Tennessee Institute of Agriculture will host the annual Weed Tour on Wednesday, June 16 at the West Tennessee AgResearch and Education Center. The guided tour will feature 60 weed management research tests in corn, soybean and cotton as well as a demonstration of herbicide symptomology. Continue reading
JACKSON, Tenn. – The University of Tennessee Institute of Agriculture will host the annual Weed Tour on Wednesday, June 16 at the West Tennessee AgResearch and Education Center. The guided tour will feature 50 weed management research tests in corn, soybean and cotton as well as a demonstration of herbicide symptomology. Continue reading
This is the third article in a series of blog articles that will focus on some fundamental information on UT fertilizer recommendations for corn, with a different nutrient featured in each article. Commonly recommended nutrients for use in corn production in TN include nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and zinc (Zn). Each nutrient will be discussed in terms of the relevant soil test that may be used or used in recommendation; recommended preplant, starter, sidedress, and foliar fertilizer applications; and plant/tissue analysis. Today’s blog will focus on UT potassium recommendations for optimal corn productivity under conditions in TN. Potassium is a macronutrient that plays important functions in the plant including protein and starch formation in the grain, movement of water, nutrients, and carbohydrate within the plant, stomata closure, cell wall and stalk strength. Thus, corn plants with inadequate K are susceptible to drought stress, diseases and insects, and greater risk of lodging after maturity. Additionally, K-deficient corn plants may have shorter ear length and narrower ear diameter.
Soil test for potassium
Potassium fertilizer application rate should be based on soil test. In TN, K fertilizer recommendations are based on Mehlich I extraction procedure because it correlates well with the soils in Tennessee. Detailed information on how UT recommendations were developed is addressed in UT Publication W795, University of Tennessee Fertilizer Recommendation Development. Recently, a calibration for Mehlich III was established for west TN soils and ranges of sufficiency for soil K using Mehlich III testing are described in the UT Publication, UT Fertility Recommendations for Tennessee Row Crops.
This has ,clearly, been the worst year for ryegrass in the state in both corn and wheat. There are a good many corn fields that are clean where the burndown was glyphosate + clethodim. Fields where dicamba was added in the burndown are, in most cases, the most infested with ryegrass. As mentioned in a previous blog, other than just going out and spraying the typical POST corn application and hoping that pushes the ryegrass on to maturity there is no real solution to controlling it. Continue reading
This is part one of a series of blog articles that will focus on some fundamental information on UT fertilizer recommendations for corn. Commonly recommended nutrients for use in corn production in TN include nitrogen (N), phosphorus (P), potassium (K), sulfur (S), and zinc (Zn). Each nutrient will be discussed in terms of the relevant soil test that maybe used or used in recommendation; recommended preplant, starter, sidedress, and foliar fertilizer applications; and plant/tissue analysis. To ensure simplicity and better assimilation of the voluminous information, each nutrient will be featured on a different day of this week. Today’s focus will be on nitrogen (N).
UT nitrogen (N) fertilizer recommendations for optimal corn productivity
Today’s blog will focus on UT nitrogen recommendations for optimal corn productivity under conditions in TN. Nitrogen is a major component of chlorophyll (the green pigment), that is essential for photosynthesis. Hence, its deficiency tends to cause chlorosis. In addition, inadequate supply of N at critical growth stage can reduce ear size and lead to yield loss.
Soil test for nitrogen
Plants use N in the nitrate (NO3–) and ammonium (NH4+) forms. However, ammonium levels are generally very low in upland soils so soil nitrate tests are used to measure plant available N and adjust N fertilizer applications for corn. There are two commonly used soil nitrate tests used in the US, the Pre-Plant Nitrate Test (PPNT) and Pre-Sidedress Nitrate Test (PSNT). Soil samples for PPNT is collected prior to preplant N application while PSNT are collected prior to pre-sidedress application.
In TN, only the Pre-sidedress Soil Nitrate Test (PSNT) is recommended for corn production, particularly for producers using animal manure such as poultry litter. Detailed information on sample collection and processing procedure are described in the UT Publication, The Pre-Sidedress Nitrate-N Soil Test (PSNT) For Nitrogen Management in Corn Production Systems of Tennessee. Interpretation of the PSNT in Tennessee is made based on yield potential of the field, soil test level, and field history.
In TN, current N application rate for corn production is based on yield goal. However, adjustment can be made based on past production records and PSNT if applicable. Another tool available for estimating corn N rate is the Nitrogen Rate Calculator at www.utcrops.com.
As of May 9th, corn producers were reported to be about 75% planted which is actually on track with Tennessee’s 5-year average for corn planting progress. Continue reading
As we wait out this latest round of wet weather, just wanted to remind those who have not had the opportunity to view our grain conference videos for continuing education credits, that points will be available for just a few more weeks. Continue reading
The call of the week is how to control ryegrass and, in a few other cases, fine fescue in emerged corn (Video of ryegrass and fescue in corn). Several have reported these grasses recovering from glyphosate + dicamba or in a few instances, glyphosate + rimsulfuron burndown. The questions that follow are why did they recover and what is the best way to control them now that the corn is up? Continue reading