ARS | Publication request: Availability of triazine herbicides in aged soils amended with olive oil mill waste

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2008
Publication Date: May 20, 2008
Citation: Cabrera, A., Cox, L., Koskinen, W.C., Sadowsky, M.J. 2008. Availability of triazine herbicides in aged soils amended with olive oil mill waste. Journal of Agricultural and Food Chemistry. 56(11):4112-4119.

Interpretive Summary: Olive oil extraction generates a lot of organic waste, which can potentially cause adverse environmental impacts. Application of olive oil mill waste to the land could be an effective way to dispose of the waste. However, addition of olive oil mill wastes can modify the binding capacity of sandy soils for herbicides and subsequently their availability in soil for degradation and leaching. Our results show that olive oil mill waste amendments in soil can increase the binding to soil of terbuthylazine and atrazine, herbicides widely used in olive production. The increased binding will decrease potential offsite movement of these herbicides. Although there was also decreased degradation of the herbicides in amended soil, it was not sufficient to adversely affect the dissipation of the herbicides; they will degrade before they can appreciably leach through soil. The application of olive oil mill waste to the land would appear be an extremely effective contribution to maintaining or improving soil fertility if properly mixed and incorporated at acceptable loading rates. Producers now have a practice that has been shown to be able to mitigate a large potential environmental problem associated with olive oil production wastes.

Technical Abstract: Olive oil extraction generates a lot of organic waste, which can potentially cause adverse environmental impacts. Application of olive oil mill waste, alperujo, to the land could be an effective way to dispose of the waste. However, addition of olive oil mill wastes can modify the binding capacity of sandy soils for herbicides and subsequently their availability in soil for degradation and leaching. In this work we have determined the effect of addition of alperujo to a sandy soil from an olive grove on availability of terbuthylazine and atrazine, triazine herbicides widely used in olive tree cultures, for transport and degrdation. Effects on terbuthylazine and atrazine sorption and mineralization were determined in freshly treated and aged soils, which were either unamended or amended with alperujo. Two sandy soils used in this study, one from Spain and the other from Minnesota. The soils were amended in the laboratory with fresh alperujo, which increased the % OC of the soils by ~3%. Availability of both herbicides for transport decreased in amended soils, as compared to unamended soils, as evidenced by increased sorption coefficients. Sorption Kd increased by as much as a factor of 8. Sorption also increased with herbicide aging in soil for both herbicides in both unamended and amended soils. Amending the soil with alperujo also decreased the availability of both herbicides for degradation as evidenced by decreased mineralization of the herbicides by a specific triazine degrading microorganism. Although aperujo addition to soil has been shown to affect terbuthylazine and atraizne availability in soil, it appears that adding alperujo to soil would not adversely impact the behavior of the herbicides in olive production.