Do Switchgrass Barriers Improve Water Infiltration Compared to Row Crops?.

Switchgrass (Panicum virgatum) barriers have been shown to be an effective conservation practice in sloping fields to pond runoff and reduce erosion. Limited research information is, however, available on the impact of switchgrass barriers on water infiltration that is crucial in croplands, particularly in water-limited region. The objective of this study was to compare infiltration in switchgrass barriers and row crops. We hypothesized that switchgrass barriers may improve water infiltration compared to row crops because of their ability to increase macroporosity and pore continuity. We studied an experiment established at the Rogers Memorial Farm in 1998 about 16 km east of Lincoln, NE. The experiment had five 1.4 m wide-switchgrass barriers established in parallel rows (38-m intervals) in soybean-sorghum-corn rotation. The design was split plot with no-till and conventional till as main plots and soybean and switchgrass as sub-plots. We measured infiltration rate, cumulative infiltration, runoff volume, soil water content, and total porosity during the soybean phase in mid-July, 2017. Cornell infiltrometer and single ring infiltrometer methods were used to measure water infiltration parameters. Grass barriers showed about 30 % higher infiltration rate relative to soybean using the Cornell infiltrometer, but not with the single ring infiltrometer. Grass barriers and tillage had no effect on cumulative infiltration and infiltration rate measured with the single ring infiltrometer. Based on our results, we can conclude that switchgrass barriers can improve infiltration compared to row crops. Future research should determine the most efficient way to manage grass barriers to expand the use of this conservation practice.