Cover crops Can they be used for weed management JOSH LOFTON CROPPING SYSTEM SPECIALIST 12/20/2016

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Arron Farmer
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1 Cover crops Can they be used for weed management JOSH LOFTON CROPPING SYSTEM SPECIALIST 12/20/2016

2 Thanks for the help Jason Warren Worked with a lot of these crops before I came

3 Cover crops in Oklahoma systems Cover crops are being pushed on our systems Integrated in several system Theorized benefits Soil health Crop performance Water and nutrient dynamics Prevention of nutrient and sediment loss Pest problems

4 Cover crops in Oklahoma systems Photo attributed to Laloy and Bielders

5 How does this actually relate Work in Oklahoma systems Yield benefits Highly variable Loss Even Marginal benefit Showed benefit for one crop but not for system (neutral) Benefits in winter crop systems a lot harder to come by

6 1Cowpea, Sunn Hemp 2Cowpea, Sunn Hemp, Buckwheat, G. Millet, Laredo Soybean 3Cowpea 4Cowpea, Mungbean, Laredo Soybean, Sterile Sudan, P. Millet 5Cowpea, Mungbean, Sunn Hemp, Laredo Soybean 6Cowpea, Sunn Hemp, Radish, G. Millet 7P. Millet, Sterile Sudan, G. Millet 8Cowpea, Sunn Hemp, Sterile Corn, Sterile Sudan, Sunflower 9Inorganic 40 Wheat

7 1 Cowpea, Sunn Hemp 2 Cowpea, Sunn Hemp, Buckwheat, G. Millet, Laredo Soybean 3 Cowpea 4 Cowpea, Mungbean, Laredo Soybean, Sterile Sudan, P. Millet 5 Cowpea, Mungbean, Sunn Hemp, Laredo Soybean 6 Cowpea, Sunn Hemp, Radish, G. Millet 7 P. Millet, Sterile Sudan, G. Millet 8 Cowpea, Sunn Hemp, Sterile Corn, Sterile Sudan, Sunflower 9 Inorganic Wheat

8 1Cowpea, Sunn Hemp 2Cowpea, Sunn Hemp, Buckwheat, G. Millet, Laredo Soybean 3Cowpea 4Cowpea, Mungbean, Laredo Soybean, Sterile Sudan, P. Millet 5Cowpea, Mungbean, Sunn Hemp, Laredo Soybean 6Cowpea, Sunn Hemp, Radish, G. Millet 7P. Millet, Sterile Sudan, G. Millet 8Cowpea, Sunn Hemp, Sterile Corn, Sterile Sudan, Sunflower 9Inorganic Grain Sorghum

9 1 Cowpea, Sunn Hemp 2 Cowpea, Sunn Hemp, Buckwheat, G. Millet, Laredo Soybean 3 Cowpea 4 Cowpea, Mungbean, Laredo Soybean, Sterile Sudan, P. Millet 5 Cowpea, Mungbean, Sunn Hemp, Laredo Soybean 6 Cowpea, Sunn Hemp, Radish, G. Millet 7 P. Millet, Sterile Sudan, G. Millet 8 Cowpea, Sunn Hemp, Sterile Corn, Sterile Sudan, Sunflower 9 Inorganic Return on system

10 Where is the fit Integration of cover crops without a yield benefit Cost of production Cost of set up and continual input cost Need some secondary benefit of cover crops Soil organic matter/soil C Soil health Is this enough? How do you measure benefit? What about something we can not only measure but put a value on Weed management

11 Cover crops benefits Weed control Not a new topic 70BC 1960s and 1980s A decrease weed populations needed when planting into cover crop residue Vegetable crops Small scale

12 Weed control using covers Have to ask the question What are the cover crops doing for weed control Not all cover crops are created equal There are many mechanisms that can help control weeds These have varying degrees of success Depending on weed community

13 Methods for weed control Shading Minimizing weeds at planting Herbicide to terminate cover crop This would make on par with traditional practices Some covers can be easier to control than fallow weeds Some will be more challenging Some weed will be easier to control following cover than fallow Mixes can increase the herbicide need

14 Methods for weed control Minimizing weeds at planting Shading Herbicide to terminate cover crop This would make on par with traditional practices Some covers can be easier to control than fallow weeds Some will be more challenging Mixes can increase the herbicide need

15 Methods for weed control Minimizing weeds at planting Shading Herbicide to terminate cover crop This would make on par with traditional practices Some covers can be easier to control than fallow weeds Some will be more challenging Some weed will be easier to control following cover than fallow Mixes can increase the herbicide need

19 Methods for weed control Control in season Altering soil conditions in season Shading, moisture, etc. What is the difference this and no till Worth with low residue crops Chemical inhabitation Plants release a chemical that inhibit other growth All plants will have allelopathy to a degree Matching what allelopathy a plant has with a weed issue

20 How does this relate to Oklahoma systems? Weed Counts at Burndown (m2)

22 How does this relate to Oklahoma systems? Weed Counts at V2 (m2)

23 How does this relate to Oklahoma systems? Weed Counts at V

24 How does this relate to Oklahoma systems? Weed Counts at R2 R

25 Check Tillage Radish Cereal Rye

26 Is this universal? Yes and no Covers can help Complexity in weed management programs Have to do it right Example Cereal rye Can control marestail, lambsquarter, purslane, and crabgrass Very weak ragweeds, sicklepods, and morning glories Mixed results pigweed, Bermuda grass

27 Summary Cover crops can provide some degree of secondary benefits through weed control Not for all systems Find the right system Will probably not be universal Will take proper management

28 Questions? Josh Lofton Cropping Systems Blog: osucrops.com

Cover Crops (Section 6.3)

Cover Crops (Section 6.3) Conceptually they are meant to provide cover to prevent erosion during fallow periods between cash crops. They can provide a variety of benefits to the crop rotation. The intended