Evaluating the water quality impacts and soil moisture dynamics of biomass production systems is essential to assessing their environmental impacts. The objective of this study is to determine potential water quality and soil moisture impacts of various production systems across different landscape positions. Five production systems are being evaluated: (1) continuous corn, (2) corn-soy/triticale-soy, (3) switchgrass, (4) triticale/sorghum, and (5) triticale/trees, at five landscape locations: (1) summit, (2) shoulder, (3) backslope, (4) toeslope, and (5) floodplain. Each production system is randomly assigned within three replicates at each landscape location. Soil water samples are taken monthly during the growing season from two suction lysimeters per plot at a depth of 60cm. Volumetric soil moisture measurements were taken monthly during the 2010 and 2011 growing seasons from two access tubes at 20 cm intervals to a depth of 120 cm. Significant differences among the cropping systems’ NO3-N concentrations in the root zone were observed with a likely association between nitrogen (N) fertilizer inputs to the systems containing corn. The triticale/sorghum system showed consistently lower NO 3-N concentrations in the root zone than the corn systems, although they received only slightly lower total N fertilizer. Higher NO3-N concentration in the root zone was also not observed in the switchgrass plots following a significant N input from fertilization. The triticale/trees system had lower moisture and soil water storage in the upper 60 cm of the soil profile than the other systems in April, May, and October 2011, which may indicate increased evapotranspirative demand. The relatively larger amount of stubble and residue in the switchgrass plots may account for the higher moisture levels at the surface in April, May and September 2011. Quantifying environmental impacts of biomass production systems will aid in optimizing deployment as producers gear up to meet biomass production demand.
|Advisor:||Helmers, Matthew J.|
|Commitee:||Isenhart, Thomas M., Schulte-Moore, Lisa A.|
|School:||Iowa State University|
|Department:||Agricultural and Biosystems Engineering|
|School Location:||United States -- Iowa|
|Source:||MAI 50/06M, Masters Abstracts International|
|Subjects:||Agronomy, Hydrologic sciences, Sustainability, Environmental science|
|Keywords:||Biomass, Landscape position, Nitrate, Soil moisture, Soil water storage, Water quality|
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