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Dedicated Bioenergy Crops and Water Erosion
Author(s) -
Acharya Bharat Sharma,
BlancoCanqui Humberto,
Mitchell Robert B.,
Cruse Richard,
Laird David
Publication year - 2019
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2018.10.0380
Subject(s) - panicum virgatum , environmental science , surface runoff , agronomy , soil water , water quality , nutrient , erosion , hydrology (agriculture) , erosion control , bioenergy , soil science , biology , geology , biofuel , ecology , geotechnical engineering , paleontology
Information on the water quality impact of perennial warm‐season grasses (WSGs) when grown in marginal lands as dedicated energy crops is limited. We studied how WSGs affected runoff, sediment, and nutrient losses and related near‐surface soil properties to those of no‐till corn ( Zea mays L.) on an eroded soil in southwestern Iowa and a center pivot corner in east‐central Nebraska. The experiment at the eroded soil was established in 2012, and treatments included ‘Liberty’ switchgrass ( Panicum virgatum L.) and no‐till continuous corn. The experiment at the pivot corner was established in 2013 with ‘Liberty’ switchgrass, ‘Shawnee’ switchgrass, low‐diversity grass mixture, and corn. We simulated rainfall at 63.5 ± 2.8 mm h −1 for 1 h to portray 5‐yr return periods and measured water erosion in spring 2017. Time to runoff start and runoff depth did not differ between WSGs and corn. On the eroded soil, sediment and nutrient losses did not differ between treatments. At the pivot corner, sediment (0.71 vs. 0.15 Mg ha −1 ) and PO 4 –P (0.037 vs. 0.006 kg ha −1 ) losses were five times higher in corn than in WSGs. Near‐surface soil properties did not differ on the eroded soil, but at the pivot corner, wet aggregate stability was four times higher and residue cover was 34% higher in WSGs than in corn. Water‐stable aggregates were negatively correlated with NO 3 –N and PO 4 –P losses. Overall, WSGs can improve water quality in marginally productive croplands, but their effectiveness appears to be site specific. Core Ideas Warm‐season grasses did not reduce runoff depth compared with corn. Warm‐season grasses on a center pivot corner reduced sediment and nutrient loss compared with corn. Sediment loss between corn and switchgrass grown in an eroded soil did not differ. Warm‐season grass effectiveness to reduce water erosion can be site specific.