Quantifying Hydrologic and Water Quality Responses to Bioenergy Crops in Town Creek Watershed in Mississippi

摘要

Bioenergy crops are considered as a feedstock source, which can be grown in marginal soils. However, these crops may have different levels of crop yield potential and environmental benefits. The objectives of this study were to model and compare the effects of four bioenergy crops (corn—Zea mays, soybean—Glycine max (L.) Merr., miscanthus—Miscanthus-giganteus, and switchgrass—Panicum virgatum) in the Town Creek watershed (TCW) in northeast Mississippi using the Soil and Water Assessment Tool (SWAT) model. The calibrated SWAT model for TCW was used to quantify impacts to streamflow, crop yield, and sediment yield. The SWAT model reasonably (3·s-1) from the TCW when compared with the USGS observed stream flow (29.34 m3·s-1. In addition, model reasonably predicted (±6%) average annual corn yield (4.66 Mg·ha-1) and soybean yield (1.42 Mg·ha-1) as compared to National Agricultural Statistics Service (NASS) reported average annual corn (4.96 Mg·ha-1) and soybean yield (1.34 Mg·ha-1) from the watershed. Further, the model simulated results from this study determined that long-term average annual feedstock yield from TCW is the greatest when growing miscanthus grass (817,732 Mg) followed by switchgrass (477,317 Mg), corn (236,132 Mg), and soybeans (65,235 Mg). The SWAT model predicted the greatest annual average sediment yield (6.62 Mg·ha-1) from continuous corn crop scenario while the perennial grasses (switchgrass and miscanthus) had the lowest sediment yield (2.91 Mg·ha-1 and 3.20 Mg·ha-1 respectively). Overall, producing a perennial grass in the TCW would provide the largest biomass feedstock source with the least environmental impact. The results of this study will help to lang="EN-US" style="font-family:Verdana