Location: Crop Genetics and Breeding Research
Title: Winter legume cover effects on yields of biomass-sorghum and cotton in GeorgiaAuthor
Anderson, William - Bill | |
Knoll, Joseph - Joe | |
Olson, Dawn | |
Scully, Brian | |
Strickland, Timothy | |
Webster, Theodore |
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/19/2022 Publication Date: 3/7/2022 Citation: Anderson, W.F., Knoll, J.E., Olson, D.M., Scully, B.T., Strickland, T.C., Webster, T.M. 2022. Winter legume cover effects on yields of biomass-sorghum and cotton in Georgia. Agronomy Journal. 114(2):1298-1310. https://doi.org/10.1002/agj2.21018. DOI: https://doi.org/10.1002/agj2.21018 Interpretive Summary: For growers of commercial row crops in Southern United States, winter cover crops can help improve the soil and reduce inputs for subsequent crops in the rotation. Winter legumes have the advantage over winter grain crops by fixing nitrogen that is used for the cover crop and supply nitrogen to the following summer row crops. For Georgia, there are several winter legumes that could be used but research is needed to determine the best species. It is also not known if removing the crop for forage or use for bioenergy production has an effect on the subsequent summer crop yield. A 5-year study was conducted to compare biomass yields of several leguminous winter cover crops, and determine the effects of these winter crops, either harvested or left on the soil, on subsequent biomass sorghum and cotton yields at two field locations in Georgia. Austrian winter pea, fava bean, narrow-leaf lupin, white vetch, crimson clover, and winter rye, were grown during the winter. Three control treatments were included (fallow with standard fertilizer; fallow with an organic fertilizer; and fallow with no fertilizer). Narrow-leaf lupin produced between 4.16 and 9.54 Mg ha-1 biomass, approximately two to four times more than any other cover at both locations every year. Lupin, followed by vetch and winter pea had the greatest positive effect on biomass sorghum yields, from both the plots with covers left on the soil and those where cover biomass was removed. Seed cotton yields were higher after lupin and vetch winter covers. Significantly higher sorghum and cotton yields occurred for rolled covers but only with crimson clover, winter pea and fava bean as the covers. Averaged over the five years and two locations, lupin biomass contained approximately 143 kg ha-1 N, more than any other cover. The study suggests that harvested or grazed lupin or vetch covers could give similar benefits to summer row crops as with traditional cover management. Technical Abstract: Winter cover crops can provide many economic and ecosystem services to growers. Winter legumes can have an advantage over winter grain covers by fixing nitrogen that may be used by subsequent crops. The amount of biomass of winter crops can vary depending on the climate and soil conditions. A 5-year study was conducted to compare biomass yields of several leguminous winter cover crops, and determine the effects of these winter crops, either harvested or left on the soil, on subsequent biomass sorghum and cotton yields at two field locations in Georgia. Austrian winter pea, fava bean, narrow-leaf lupin, white vetch, crimson clover, and winter rye, were grown during the winter. Three control treatments were included (fallow with standard fertilizer; fallow with an organic fertilizer; and fallow with no fertilizer). Narrow-leaf lupin produced between 4.16 and 9.54 Mg ha-1 biomass, approximately two to four times more than any other cover at both locations every year. Lupin, followed by vetch and winter pea had the greatest positive effect on biomass sorghum yields, from both cover residue treatments: retained on the soil by rolling and removed cover biomass. Seed cotton yields were higher after lupin and vetch winter covers. Significantly higher sorghum and cotton yields occurred for rolled covers with only crimson clover, winter pea and fava bean. Averaged over the five years and two locations, lupin biomass contained approximately 143 kg ha-1 N, more than any other cover. The study suggests that harvested or grazed lupin or vetch covers could give similar benefits to summer row crops as with traditional cover management. |