Title: Application of the precision agricultural landscape modeling system in semiarid environments Authors
|Nelson, John -|
|Booker, Jon -|
Submitted to: Western Society of Soil Science
Publication Type: Abstract Only
Publication Acceptance Date: June 22, 2009
Publication Date: June 24, 2009
Citation: Nelson, J.R., Lascano, R.J., Booker, J.D. 2009. Application of the precision agricultural landscape modeling system in semiarid environments[abstract]. Western Society of Soil Science Branch Meeting. June 22-24, 2009. Fort Collins, Colorado. Technical Abstract: The Precision Agricultural Landscape Modeling System (PALMS) is a terrain and weather driven, distributed parameter hydrological-biophysical model primarily used in the Midwestern United States. Recently, research was started to evaluate the effectiveness of PALMS on irrigated and on dryland cropping systems in the semiarid Southern High Plains (SHP) of Texas. However, the accuracy of PALMS in semiarid climates due to the contrasting nature of climate and soil type in the Midwest and SHP needs to be evaluated. Two characteristic soils in the SHP are the Amarillo series (fine-loamy, mixed, superactive, thermic aridic paleustalfs) and the Pullman series (fine, mixed, superactive, thermic Torrertic Paleustolls). The hydraulic properties of these soil series are different than those previously used and tested in PALMS, and thus calculated values of the soil water balance need to be verified for the region of interest.Volumetric water content measurements were taken by neutron attenuation from 1998 to 2001 on irrigated cotton and corn fields in Lamesa, TX and in Halfway, TX. PALMS simulations were run for the respective growing seasons using maps of topography, soil texture, irrigation, and crop type, as well as local atmospheric and rainfall data. Simulated values of volumetric water content were compared with measured ones at 0.3-m soil depth increments to 1.8-m.Initial results indicate that PALMS overestimates soil volumetric water content in the semiarid SHP. Several options for correcting this problem are being explored, including modification of the soil water solver to more reliably represent aridic soil types, accounting for tillage pattern under center pivot irrigation, and modification of current crop models to include cotton.