Location: Commodity Utilization ResearchTitle: Differential accumulation of heavy metals in soil profile and corn and soybean grains after 15-year poultry litter application under no-tillage
|XIAO, JINGXIU - University Of Tennessee|
|YIN, XINHUA - University Of Tennessee|
|SYKES, VIRGINIA - University Of Tennessee|
Submitted to: Journal of Soils and Sediments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2021
Publication Date: 2/7/2022
Citation: Xiao, J., Yin, X., Sykes, V.R., He, Z. 2022. Differential accumulation of heavy metals in soil profile and corn and soybean grains after 15-year poultry litter application under no-tillage. Journal of Soils and Sediments. 22:844-858. https://doi.org/10.1007/s11368-021-03087-7.
Interpretive Summary: Application of poultry litter (PL) is typically based on crop N requirement, but PL also contains substantial amounts of heavy elements including As, Cu, Zn, Cd, and Pb. Understanding their concentrations in soil and crop grains from a long-term PL application could help identify sustainable PL application strategy for regional crop production with low environmental risk potential. Thus, we conducted experiments to identify heavy metal contents in soil profile based on long-term field trials with or without PL application under major corn and soybean cropping systems. While the potential soil heavy metal contamination risk was observed due to elevated total Cu and Zn in the surface soil, soil total and available Cu and Zn concentrations were still within the WHO/FAO permissible limits. In conclusion, long-term application of PL to no-tillage corn and soybean systems does not pose risk of As, Pb, Cd, or Cr contamination to soil or crop grains but enhanced total and available contents of Zn and Cu in surface soil and total Zn content in crop grains. Enhanced total Zn content in corn and soybean grains is beneficial for animal and human health. Overall, long-term PL application as a N source via surface broadcast without any incorporation into the soil is generally safe for the environment and human and animal health in the southeastern USA. The contents of heavy metals especially Cu in PL should be taken into account when a guideline for PL application is developed for the southeastern USA and similar regions.
Technical Abstract: Application of poultry litter (PL) is a good practice to elevate soil fertility and crop production and for disposal of poultry waste. Long-term field experiments initiated in 2002 with or without PL application as a N source (annually rate at 4.4 Mg ha-1) involving monocultures of corn and soybean under no-tillage at Milan and Spring Hill in Tennessee, USA were selected for this study in 2017. The tcontents of As, Cd, Cr, Cu, Pb, and Zn in soil, corn and soybean grains were determined. Contamination indices including the contamination factor (CF), degree of contamination (DC), pollution load index (PLI), and geo-accumulation index (Igeo) were calculated to evaluate soil contamination risk by heavy metals after long-term application of PL. The results showed that long-term application of PL did not increase the total content of As, Cd, Cr, or Pb in the surface soil of 0-15 cm relative to no PL application. However, total and available contents of Zn were increased by 11-17% and 2.2-5.6 times respectively, in the surface soil due to PL application. In addition, 1.7 times of total Cu and 1.7-2.1 times of available Cu were accumulated in surface soil after long-term PL application compared to no PL. Only total Zn content was increased by 7-17% in corn and soybean grains due to PL application. Overall, long-term PL application as a N source is generally safe for the environment and human and animal health in the southeastern USA.