All posts by Avat Shekoofa, Crop Physiologist

Cover crop residues impact on cotton germination and seedling growth at different termination timings

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Authors: A. Shekoofa, S. Safikhan, T. Raper, and S. Butler

 For those that have cover crops, you’re likely contemplating when to terminate.  While delayed termination can increase the amount of biomass produced and prolong the length of time that biomass remains in the system, delayed termination can also bring a few challenges- one of which is allelopathic impacts on our cash crop.  This article highlights recent research at the University of Tennessee examining how termination timing might allow us to harness these chemicals for weed suppression while minimizing the impacts on our cash crop (Fig. 1).

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Inhibitions of cotton germination and early seedling growth by cover crop residues

Authors: Avat Shekoofa, Sara Safikhan, Tyson Raper, and Shawn Butler

 Cover crops have been used to suppress weeds, reduce erosion, and increase water infiltration for many years. While cover crops can improve soil quality and physical properties, integration of cover crops into row crop production-specifically cotton- remains challenging. One potential negative impact on cotton growth may come from allelopathy.  Allelopathy is defined as the direct or indirect harmful or beneficial effects of one plant on another through the production of chemical compounds that escape into the environment (Fig. 1). Although allelopathic toxicity of cover crops can suppress weeds and therefore assist in weed control, they may also suppress cotton germination and reduce stand. Little is currently known about the actual allelopathic effects of cover crops on germination and seedling growth of cotton. Proper selection of cover crop species and termination timing could potentially reduce the allelopathic toxicity which negatively impacts cotton germination and early seedling growth.

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TOO MUCH TOO SOON

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Soybeans lose gallons of water daily during hot, dry conditions through transpiration. Plants transpire, or lose more than 98% of water taken up by the roots, through leaf tissue. Evapotranspiration (ET) describes the movement of water through evaporation from the soil and transpiration through plant surfaces, which is the movement of water from the soil into plant roots, through plant stems and leaves, and back out into the atmosphere. The rate of ET depends upon the soybean growth stage and the time of the year (Fig 1.) Both transpiration and evaporation need to be Continue reading


Rain-out Shelters

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For farmers including Tennessee’s farmers to grow crops, they need good – or at least decent  weather, including nourishing rain. But sometimes producers must deal with water deficit and drought (especially in West Tennessee, approximately 95% of soybean production is rainfed). If so why not go for a variety that still can survive, still can give you the benefits of growth and yield compared to the one that after a while is gone, the one cannot handle the drought conditions.


Heat stress on its way

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The three-month outlook for July, August, and September currently depicts enhanced odds of warmer than normal temperatures. Meanwhile, the precipitation outlook for the same three-month time period places the region in an area of equal chances of above, near, or below normal precipitation totals (see the map). Continue reading