Simulating and evaluating best management practices for integrated landscape management scenarios in biofuel feedstock production

Abstract

Sound crop and land management strategies can maintain land productivity and improve the environmental sustainability of agricultural crop and feedstock production. This study evaluates a strategy of incorporating landscape design and management concepts into bioenergy feedstock production. It examines the effect of land conversion and agricultural best management practices (BMPs) on water quality (nutrients and suspended sediments) and hydrology. The strategy was applied to the watershed of the South Fork Iowa River in Iowa, where the focus was on converting low-productivity land to provide cellulosic biomass and implementing riparian buffers. The Soil and Water Assessment Tool (SWAT) was employed to simulate the impact at watershed and sub-basin scales. The study compared the representation of buffers by using trapping effi ciency and area ratio methods in SWAT. Landscape design and management scenarios were developed to quantify water quality under (i) current land use, (ii) partial land conversion to switchgrass, and (iii) riparian buffer implementation. Results show that implementation of vegetative barriers and riparian buffer can trap the loss of total nitrogen, total phosphorus, and sediment signifi cantly. The effect increases with the increase of buffer area coverage. Implementing riparian buffer at 30 m width is able to produce 4 million liters of biofuels. When low-productivity land (15.2% of total watershed land area) is converted to grow switchgrass, suspended sediment, total nitrogen, total phosphorus, and nitrate loadings are reduced by 69.3%, 55.5%, 46.1%, and 13.4%, respectively. Results highlight the signifi cant role of lower-productivity land and buffers in cellulosic biomass and provide insights into the design of an integrated landscape with a conservation buffer for future bioenergy feedstock production. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Biofuels, Bioproducts and Biorefi ning published by Society of Industrial Chemistry and John Wiley & Sons Ltd. Supporting information may be found in the online version of this article.Keywords: riparian buffer; vegetative barrier; landscape design and management; bioenergy production; switchgrass; sediment; nutrient; nitrogen; phosphorus; South Fork Iowa River growth, and agricultural inputs and management practices. SWAT simulates buff ers by using two methods. Th e fi rst, the trapping effi ciency method, uses the width of buff ers as a key parameter, where trapping effi ciency is calculated by the reduction of sediment and nutrient loadings transported by in-surface runoff through buff ers. 27Th e second method, vegetative fi lter strip (VFS), which was developed by Munoz-Carpena, 28 was derived from 22 published studies. Th e VFS calculates buff er effi ciency on the basis of the ratio of total land area to buff er area (area ratio method). 21 Th e trapping effi ciency method allows for convenient application with only one parameter (buff er width), whereas users have more fl exib...

Recognizing economic value in multifunctional buffers in the lower Mississippi river basin

“…According to USDA NRCS, the width of the riparian herbaceous buffer should range from about 9 to 37 m . Thirty‐meter buffers were selected because previous studies found that a 30 m buffer is more effective than a narrower one, but reduction rates remain flat when the buffer width increased beyond 30 m . The SWAT uses the vegetative filter strip (VFS) model to simulate the effect of riparian buffers on hydrology and nutrient loads .…”

“…In particular, perennial grasses, such as switchgrass, are seen as promising cellulosic biofuel feedstock . Switchgrass has also been demonstrated to be a good choice for riparian buffers because of its relatively highly effective nutrient removal …”

“…Recent developments have focused on integrating agricultural conservation practices and cellulosic biomass production through a landscape‐management approach . While conservation practices like riparian buffers, constructed wetlands, and bioreactors are effective at reducing nutrient lost through surface runoff, the costs associated with conservation practices are typically viewed implicitly as a financial burden to the public sector .…”

“…When integrated with biomass production, the intercepted nutrients may be reused by energy crops, like switchgrass, to generate economic returns . In recent years, integrated landscape management strategies, such as using riparian buffers with perennial grasses or woody biomass crops have been gaining increased attention because they can take advantage of both the effectiveness of conservation practices in reducing nutrient loss and the economic potential of cellulosic biomass as bioenergy feedstock.…”

Progress and Challenges in Quantifying Water Quality and Ecosystem Responses from Agricultural, Forestry, and Bioenergy Landscapes

“…These buffers could reduce surface runoff into streams, increase water quality, and provide corridors that allow wildlife to move between patches of forest. Ha and Wu [32] recently examined the effect of implementing riparian buffers and converting lowproductivity land to switchgrass on nutrients and suspended sediments and hydrology in the watershed of the South Fork Iowa River in Iowa by using a SWAT model. The study found that SWAT represents field buffer and riparian buffer well with its respective sub-modules.…”