Increasing Farm Sustainability through the Use of Cover Crops for Weed Suppression in Non-Transgenic Conventional Cotton
To demonstrate if a Black Oats cover crop can be used and how effective the cover is in suppressing weed pressure in a conservation tillage system. Additionally the research will compare yield and quality differences in non-GMO modified and GMO cotton.
February 2005 – Helped sponsor the 2005 Conservation Tillage Conference held in Perry, GA by sending 5 farmers and assisting with other parts of the conference. The project also helped in the same way with the 2006 Conservation Tillage Conference (Feb 7-8, 2006) held in Tifton, GA.
April – May 2005 — Killed cover crop in April prior to the planting of non-GMO and GMO cotton to determined any differences as stated above. The winter cover crop, Black Oats, were severely damaged by the cold span (approximately 1 week of sub 15 F days) and did not provide the biomass as expected. Cotton was planted at normal times (Approximately May 1, 2005).
May – August 2005 — During the growing season, weed counts were taken in a randomized pattern in all treatments on an every other week basis. Data can be seen on Figure 1. The legend for all graphs is (BCT1 – weed as cover crop – non-GMO cotton, BCT2, normal spray f herbicide – non-GMO cotton, BCT3, herbicide spray at threshold level – non-GMO cotton, BMT4 – herbicide spray at threshold level – non-GMO cotton, BMT5 – normal spray of herbicide – non-GMO cotton, HFT6 – herbicide spray at threshold level – GMO cotton, HFT7 – normal spray of herbicide – GMO cotton, WF – these were some plots that used Black oats outside our research and had great growth of cover crop – GMO cotton).[Since Figures can not be added to the reporting method, if you are interested in a copy of the graphs referenced here feel free to e-mail me for a copy.]
October 2005 — A Field Day was held in the field of the growers involved in the study on October 25, 2005 with 15 persons present. The discussions centered around the planting, the use of cover, the weed data collected and the build-up of soil organic matter (SOM) to suppress weeds during the growing season in non-GMO and GMO cotton. Interest was shown in the costs associated with the use of the cover, SOM and planting non-GMO cotton seed.
November 2005 — The cotton from 4 of the treatments was harvested between November 2 and Nov 9, 2005. Due to some uncontrollable circumstances, three of the treatments were destroyed and no cotton was harvested. Yield and quality were measured in replicates on each treatment and the relative differences can be seen on Figures 2, 3 and 4.
November 2005 — Black Oat cover crop for the 2006 growing season was planted on November 25, 2005. As of the date of this report the cover was growing well and a comment from one of the participating growers was “We have some cover this year, I hope we can manage that much cover.” This statement suggests that we will have a good thick cover crop for the 2006 growing year (barring any hard freezes of the cover). If the cover continues to grow as expected, then we will get an opposite view this year of how this cover crop suppresses weeds verses the low biomass associated with the cover remaining after the hard freeze of 2005.
Impacts and Contributions/Outcomes
As seen on the graphs (Figure 2), the use of non-GMO cotton on conservation tillage soil (9+ years) and a regular regimen of herbicide sprays to control weeds provided the highest yield. As can be seen in Figures 3 and 4, there was no difference in the quality of the non-GMO and the GMO cotton. [Since Figures can not be added to the reporting method, if you are interested in a copy of the graphs referenced here feel free to e-mail me for a copy.]
No economics have been run on this data, but conversations with the farmers and general calculations of the variable costs suggest that the use of non-GMO cotton in a conservation tillage system (9+ years) has economic benefits that will help this system become more sustainable.
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University of Georgia
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