Location: Natural Resource Management ResearchTitle: Soil response to perennial herbaceous biofeedstocks under rainfed conditions in the northern Great Plains, USA Author
Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2016
Publication Date: 3/1/2017
Citation: Liebig, M.A., Wang, G.J., Aberle, E., Eriksmoen, E., Nyren, P., Staricka, J., Nichols, K. 2017. Soil response to perennial herbaceous biofeedstocks under rainfed conditions in the northern Great Plains, USA. Geoderma. 290:10-18. Interpretive Summary: Understanding how perennial herbaceous biofeedstocks (PHB) alter soil properties, and in turn, how such alterations affect ecosystem services is essential for the development and adoption of improved management practices to promote multifunctional agricultural landscapes. A study was undertaken to quantify potential changes to soil properties resulting from different PHB at five sites in central and western North Dakota over a 5-yr period. Soil properties investigated in the study were selected for their association with water regulation (soil bulk density), salinity mitigation (electrical conductivity), buffering capacity (soil pH), nutrient cycling (available P), and climate regulation (soil organic C). Perennial herbaceous biofeedstock treatments with multiple plant species were hypothesized to induce greater improvements in soil condition compared to monocultures. Outcomes from the study did not support this hypothesis, as PHB mixtures failed to improve soil condition compared to monocultures. Perennial herbaceous biofeedstocks, however, induced changes in soil properties over the 5-yr study, with substantial declines in available P at sites with high initial P and modest increases in SOC at sites with low initial SOC. Results highlighted the value of PHB to remediate nutrient-laden and/or degraded soils. In contrast to observed changes in available P and SOC, other soil properties changed minimally (electrical conductivity) or not at all (soil pH). Such resistance to change can have important implications for continued soil function, and can confer a period of stability against a backdrop of increased salinity and acidification for rainfed cropping systems in the northern Great Plains.
Technical Abstract: Perennial herbaceous biofeedstocks (PHB) have been proposed to confer multiple ecosystem services to agricultural lands. However, the role of PHBs to affect change in soil condition is not well documented, particularly for treatments with multiple species. The objective of this study was to quantify potential changes to soil properties resulting from PHB treatments in central and western North Dakota over a 5-yr period. Treatments with multiple perennial plant species were hypothesized to induce greater improvements in soil condition compared to monocultures. Soil properties were evaluated in seven PHB treatments (four monocultures, three mixtures) at five sites with sampling occurring immediately prior to treatment establishment in 2006 and again in 2011 across a 0 to 1.2 m depth. Perennial herbaceous biofeedstocks had minor and inconsistent effects on soil bulk density, electrical conductivity, and soil pH, and no effect on available P and soil organic C (SOC). However, PHB treatments did induce significant changes in soil properties between 2006 and 2011, with substantial declines in available P (>10 kg P/ha/yr) at sites with high initial P and modest increases in SOC (0.9-5.7 Mg C/ha/yr) at sites with low initial SOC. Electrical conductivity decreased at two sites, though changes were minor (-0.08 to -0.18 dS/m). Soil pH did not change over the 5-yr study. Results from this study underscore the value of PHBs to remediate nutrient-laden and/or degraded soils, while concurrently resisting increased salinity and fertilizer-induced acidification.