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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #300598
Title: A modeling approach to soil type and precipitation seasonality interactions on bioenergy crop production

Author
item REICHMANN, LARA - University Of Texas
item Behrman, Kathrine
item Kiniry, James
item Polley, Herbert
item Fay, Philip

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/20/2013
Publication Date: 9/10/2013
Citation: Reichmann, L.G., Behrman, K.D., Kiniry, J.R., Polley, H.W., Fay, P.A. 2013. A modeling approach to soil type and precipitation seasonality interactions on bioenergy crop production. Switchgrass II Conference, September 10-12, 2013, Madison, Wisconsin. 2013.

Interpretive Summary:

Technical Abstract: Precipitation limits primary production by affecting soil moisture, and soil type interacts with soil moisture to determine soil water availability to plants. We used ALMANAC, a process-based model, to simulate switchgrass (Panicum virgatum var. Alamo) biomass production in Central Texas under three different precipitation scenarios and two nitrogen inputs (100 or 200 kg-N/ha/year) on two soil types (silty-clay and clay soils). Precipitation scenarios were: 1) wetter-spring, shifting 25% of winter precipitation to spring, 2) wetter-winter, shifting 25% of spring precipitation to winter, or 3) mean precipitation seasonality, based on historical weather. With high nitrogen inputs, silty-clay soils were 1.13 tons/ha/year more productive than clay soils, but the opposite occurred at low N, where clay soils produced on average 4 tons more than silty-clay soils, because silty-clay soils experienced between 104-112 N-stress days per year, compared to 5-13 N-stress days per year on the clay soils. The wetter-spring was the most productive scenario at high N, and more so on the silty-clay than clay soil because plant available water varied less on the silty-clay than clay soil. Precipitation scenarios at lower nitrogen inputs had no effect on production, suggesting that nitrogen limitation may have outweighed effects of precipitation seasonality, especially on the silty-clay soils. Modeled switchgrass productivity thus varied with soil type, because soils differed in frequency of water versus N limitation. Climate variability effects on switchgrass biomass production and its temporal stability will likely vary spatially across the landscape because of soil-texture related changes in limitation by water versus nitrogen.