title: Evaluating the impacts of landscape positions and nitrogen fertilizer rates on dissolved organic carbon on switchgrass land seeded on marginally yielding cropland.
abstract: Dissolved organic carbon (DOC) through leaching into the soils is another mechanism of net C loss. It plays an important role in impacting the environment and impacted by soil and crop management practices. However, little is known about the impacts of landscape positions and nitrogen (N) fertilizer rates on DOC leaching in switchgrass (Panicum virgatum L.). This experimental design included three N fertilizer rates [0 (low); 56 (medium); 112 (high) kg N ha(-1)] and three landscape positions (shoulder, backslope and footslope). Daily average DOC contents at backslope were significantly lower than that at shoulder and footslope. The DOC contents from the plots that received medium N rate were also significantly lower than the plots that received low N rates. The interactions of landscape and N rates on DOC contents were different in every year from 2009 to 2014, however, no significant consistent trend of DOC contents was observed over time. Annual average DOC contents from the plots managed with low N rate were higher than those with high N rate. These contents at the footslope were higher than that at the shoulder position. Data show that there is a moderate positive relationship between the total average DOC contents and the total average switchgrass biomass yields. Overall, the DOC contents from leachate in the switchgrass land were significantly influenced by landscape positions and N rates. The N fertilization reduced DOC leaching contents in switchgrass field. The switchgrass could retain soil and environment sustainability to some extent. These findings will assist in understanding the mechanism of changes in DOC contents with various parameters in the natural environment and crop management systems. However, use of long-term data might help to better assess the effects of above factors on DOC leaching contents and loss in the switchgrass field in the future.
authors: Department of Plant Science, South Dakota State University, Brookings, SD 57007, USA.
authors: Liming
authors: L
authors: Lai
authors: Department of Plant Science, South Dakota State University, Brookings, SD 57007, USA. Electronic address: Sandeep.Kumar@sdstate.edu.
authors: Sandeep
authors: S
authors: Kumar
authors: Department of Systems Engineering and Management, Air Force Institute of Technology, WPAFB, OH 45433, USA.
authors: Eric G
authors: EG
authors: Mbonimpa
authors: Department of Life Science and Environmental Biochemistry, Pusan National University, Miryang 50463, South Korea.
authors: Chang Oh
authors: CO
authors: Hong
authors: North Central Sun Grant Center, South Dakota State University, Brookings, SD 57007, USA.
authors: Vance N
authors: VN
authors: Owens
authors: Department of Plant Science, South Dakota State University, Brookings, SD 57007, USA.
authors: Ram P
authors: RP
authors: Neupane
mesh_terms: D018533:Biomass; D018556:Crops, Agricultural / Q000254:growth & development*; D017753:Ecosystem; D005308:Fertilizers / Q000032:analysis*; D006838:Hydrocarbons / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D008897:Panicum / Q000254:growth & development*; D012639:Seeds / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012995:Solubility
chemical_list: D005308:Fertilizers; D006838:Hydrocarbons; D012987:Soil; D009584:Nitrogen
keywords: Dissolved organic carbon (DOC); Landscape positions; Nitrogen management; Switchgrass