Western Kansas Agricultural Research Centers
Weed Science


Weed Science - Hays, KS

Project Description


The goal is to improve current or develop new safe and efficient weed management strategies in dry land cropping systems including ways to reduce risks of soil erosion and crop failure through plant residue and soil water management. Basic and applied studies in weed ecology, weed-crop competition, herbicide efficacy, environmental fate, crop tolerance, and cultural agronomics are conducted to assess the impact of weed interference, determine critical weed density thresholds, discover ways to optimize herbicide performance and crop safety, and integrate cultural and chemical control methods. Experimental and non-labeled herbicides are evaluated to assess their fit and potential usefulness in semi-arid dry land cropping systems.

Current Projects

Phillip W. Stahlman honored with Weed Science Society of America Fellow Award

The Weed Science Society of America (WSSA) honored more than two dozen individuals for their outstanding contributions to the field of weed science. The awards were presented during the organization’s annual meeting, held this year in Waikoloa, Hawaii.  The organization presented Phillip Stahlman with its highest recognition of Fellow.  Read more...

 

Corn Research 

The Weed Science group at the Ag Research Center in Hays has the equipment for not only dryland corn systems, but also irrigated programs.  We have land located on the east side of the experiment station that is set up for linear, overhead irrigation.  The area is split into two areas so half can be cropped while the other is fallowed. 

Therefore, corn herbicide research at the station is devoted to development of new and maintenance of existing herbicide technology in dryland and limited-irrigation production systems. New technologies, such as herbicide-resistant hybrids (Roundup-Ready®, Liberty-Link®, and Clearfield®) as well as new herbicides such as Balance Pro®, Callisto®, and Option®, are evaluated for weed control efficacy and crop response. These new technologies are compared with existing herbicide programs to determine strengths and weakness on weeds common in the western Great Plains. Specific weed problems, such as Palmer amaranth and longspine sandbur, are evaluated for competitiveness with the crop and to determine which management practices best control these weeds. All of these areas of research are integrated to determine the weed management programs that are most cost effective for the producers of our area.

  • Poster-Efficacy of Mesotrione (Callisto) in Kansas
  • KIH-485 and S-metolachlor Efficacy Comparisons in Conventional and No-Tillage Corn

    Grain Sorghum Research

    Grain sorghum (milo) herbicide research under the direction of Dr. Phil Stahlman is devoted to the development of new and maintenance of existing weed management programs in the western Great Plains. New herbicide technologies such as Paramount®, Aim®, and Starane® are compared to existing herbicides to determine weed control efficacy and crop response. These comparisons are made under various management systems to determine the most economical weed control programs for local producers.

    Mark Lubbers, graduate student, worked on the development of fluroxypyr in grain sorghum during 2001-02.  Mark has evaluated the effects of herbicide application timing, crop response, tank mix partners, and adjuvant effects on fluroxypyr activity in grain sorghum.

    Since grain sorghum is a popular crop in Western Kansas, research will continue on weed control programs as well as other biological aspects of sorghum production.

    Grain sorghum (milo) herbicide research under the direction of Dr. Phil Stahlman is devoted to the development of new and maintenance of existing weed management programs in the western Great Plains. New herbicide technologies such as Paramount®, Aim®, and Starane® are compared to existing herbicides to determine weed control efficacy and crop response. These comparisons are made under various management systems to determine the most economical weed control programs for local producers.

    Mark Lubbers, graduate student, worked on the development of fluroxypyr in grain sorghum during 2001-02.  Mark has evaluated the effects of herbicide application timing, crop response, tank mix partners, and adjuvant effects on fluroxypyr activity in grain sorghum.

    Since grain sorghum is a popular crop in Western Kansas, research will continue on weed control programs as well as other biological aspects of sorghum production.

    Soybean Research

    Typically soybean production in Western Kansas is not popular because of the lack of rainfall.  Dryland soybeans usually suffer from the combination of heat and drought and are not as profitable as other more tolerant crops.

    Despite these downfalls, research on soybeans continues.  The ARCH Weed Science group has a study evaluating the environmental effects of using Roundup technology.  This study includes using Roundup Ready soybeans in the cropping system and is scheduled to be completed in a few years.

    Other research in soybeans has included evaluating treatments to control volunteer corn from Roundup Ready corn the previous year.  Lack of rainfall or adequate irrigation equipment prevents further research on soybeans in this part of Kansas.

    Sunflower Research

    Sunflower production in Kansas is growing and so is sunflower research conducted by the ARCH Weed Science group. 

    Weed control in sunflower is a challenge.  Grass control is typically not too difficult due to the availability of several graminicides (grass herbicides).  Broadleaf weeds, on the other hand, are quite a challenge.  Most herbicides that control common broadleaf weeds found in sunflowers also control the crop itself!  Therefore, many studies are geared towards evaluating crop tolerance and weed control for various herbicide combinations.

    A great deal of effort has been focused on evaluating the crop tolerance and weed control effects of sulfentrazone.  Past studies have shown excellent crop safety and weed efficacy when applied at the correct time.  Continued research is being conducted on this herbicide and possible tankmix partners.

    Other research in sunflower includes the use of Clearfield sunflower.  The expected release of limited seed in 2003 by BASF is well accepted by many growers.  This new technology would couple herbicide resistant sunflower varieties with Beyond herbicide to provide weed control.  Dr. Stahlman has conducted numerous studies on this technology and is currently evaluating the performance of different varieties.  More information on Clearfield sunflower will be available soon.

    Wheat Research

    Wheat research with the ARCH Weed Science group is king!  Along with several long-term jointed goatgrass projects in wheat and recropping studies, the group conducts countless herbicide performance trials each season.

    Herbicide performance trials include old and new herbicide technology and how each perform in a weed control program in wheat.  The first publications of Maverick Pro and Olympus in wheat were written by Pat Geier and Phil Stahlman from work conducted at ARCH. 

    The recent introduction of Clearfield winter wheat in the central Great Plains has established the importance of ongoing research on this technology.  Currently, several studies containing Clearfield wheat are being conducted on station and at outlying locations.  Trials include the effects of proper application timing for weed control of many broadleaf weeds and winter annual grasses.  Much attention is being put on the proper timing for feral rye control and the most appropriate adjuvant selection for maximum weed control and minimal crop injury.

    Wheat research at the Ag Research Center will continue to expand as more advanced technology becomes available. 

    Recropping Studies

    Managing winter wheat can be a challenge in Western Kansas.  Some years drought or other natural phenomenon occur that destroys a wheat crop.  The remedy for this is either to replant wheat or revert to a summer crop.

    Usually replanting winter wheat is not possible because the extent of the damage is not seen until spring.  By that time winter wheat planting is not possible since an overwintering period is necessary for flowering.  The other alternative is to plant a spring crop in the given field.  This practice is ideal if no herbicides have been applied to the wheat crop that may affect a summer crop planted so soon after application.

    Recent studies conducted by the Weed Science group at the Ag Research Center in Hays has evaluated the effects of recropping to crops such as soybean, corn, grain sorghum, forage sorghum, and alfalfa after varying application rates of Maverick Pro or Olympus herbicides.  These studies are essential in determining the minimum time required to allow planting a summer crop after a failed wheat crop. 

    Biology Research

    Although research on herbicide performance is important, it is not the only thing involved in Weed Science.  Researchers need to know the fundamentals on how crops grow, what they require for proper growth, how they interact with weeds in the field and how cultural practices influence the way crops function.

    Dr. Phil Stahlman has put together a strong research program on crop-weed interference, weed thresholds, and the effects of cultural practices in various cropping systems.  We currently have several studies looking as various aspects of weed biology in multiple cropping systems.

    Our crop rotation study was established to evaluate the effects of crop rotation in a dryland environment.  Specific crop rotations were established to evaluate the effects of yield due only to a rotation component.

    A study looking at the ecological benefits of Roundup Ready cropping systems was established to evaluate what effects the use of Roundup technology has on the environment.  Soil infiltration, insect, nematode, and other valuable data is being collected to evaluate if benefits are seen with Roundup systems over conventional cropping systems.  This study is being conducted in cooperation with Dr. Kassim Al-Khatib, KSU Weed Scientist in Manhattan.

    Jointed Goatgrass

    The Weed Science group at the KSU Ag Research Center-Hays is heavily involved in jointed goatgrass research.  They are currently conducting three long-term experiments.  Projects are funded by the National Jointed Goatgrass Research Program, Kansas Wheat Commission and BASF.
     

    • "Controlling Jointed Goatgrass in Winter Wheat Rotations Using Cultural Practices"

    This study, located at the KSU Ag Research Center in Hays, was initiated in the fall of 1996.  The study is based on the hypothesis that integrating winter wheat cultivars, limited tillage during fallow periods as compared to no tillage, and multi-year crop rotations will hasten control and reduce the impact of jointed goatgrass more than any of the component practices alone.

    What we have seen since the initiation of the study is that wheat cultivar and fallow weed management systems have very little effect on jointed goatgrass populations.  However, a three or four year crop rotation has reduced populations 10 to 30% compared to a wheat-fallow rotation.

    Grain sorghum yield has been higher in 4 of 5 years when grown in the GS-F-W compared to the GS-SF-F-W rotation.  Inadequate soil moisture or depleted soil minerals may be the result of adding sunflower into the rotation.  Further testing is being proposed to validate this hypothesis.

    •  "Clearfield Winter Wheat Risk Assessment"

    The risk assessment study, located at the Sandyland Research Center in St. John, KS, was established in August 2001.  The study is based on the hypothesis that the prolonged use of Clearfield winter wheat will increase the risk of transferring herbicide resistance to jointed goatgrass and hasten selection of herbicide resistant biotypes in other winter annual grass weed species.

    The first wheat crop was seeded in October 2001 and the jointed goatgrass population, averaging only 2 to 5 plants/square meter, were determined in late November.  Low populations in the fall and carrying on through harvest were believed to be related to extremely low moisture.

    •  "Prolonging Clearfield Technology with Certified Seed and Crop Rotation"

    This study, located at the KSU Ag Research Center in Hays, was initiated in the fall of 2001.  The study is based on the hypothesis that using certified versus bin-run Clearfield wheat and restricting the use of Clearfield technology in any given field to not more than once every other year.  More frequent use will limit development of resistant weed biotypes and prolong the utility of Clearfield technology for the management of jointed goatgrass.

    Although conditions were dry during the early part of the 2002-03 wheat growing season, the wheat yields were well above average and jointed goatgrass was able to grow and set seed.  As expected, JGG counts indicated major differences between plots sprayed with Beyond (Clearfield) and those sprayed with Rave.

    •  "Characterization of Post Dispersal Jointed Goatgrass Seed Predation"

    Currently, little information is available regarding jointed goatgrass predation and disappearance.  To address this data gap in the biology of jointed goatgrass, an experiment has been initiated to evaluate the level of disappearance of post-dispersal jointed goatgrass spikelets.  One field study will provide information regarding the level of predation, identity of potential bird and rodent jointed goatgrass seed predators, and the effects tillage systems have on seed disappearance.  A second study will evaluate and identify potential insect predators that feed on jointed goatgrass spikelets.

    A study was initiated in cooperation with Dr. Anita Dille, Weed Ecologist in Manhattan, to evaluate Palmer amaranth growth and interference in corn.  Crop biomass and plant height was measured for both the crop and weed to evaluate the growth rate of each during the growing season.  The crop and Palmer amaranth was grown in monoculture and together to evaluate the effects of not only the effect of weeds on corn, but also to see what competitive effect the crop can have on weeds.

    A study was initiated in cooperation with Dr. Dille to evaluate the effects of variable rate technology in a large production field situation.  With the assistance of Dave Braun, ARCH Farm Manager, and Spencer Casey, ARCH Administrative Assistant and GPS Technician, the group was able to apply herbicide at different rates with a specially equipped sprayer.  Locations where rates changed were mapped using GPS.  Results of this study will be interesting.