Title: SOIL PRODUCTIVITY AT TWO NORTH DAKOTA SITES DIFFERING IN TOPSOIL QUALITY AND PROFILE STRUCTURE Authors
|Merrill, Stephen - RETIRED ARS SCIENTIST|
Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 13, 2007
Publication Date: November 4, 2007
Citation: Merrill, S.D., Tanaka, D.L., Liebig, M.A., Krupinsky, J.M., Hanson, J.D. 2007. Soil productivity at two North Dakota sites differing in topsoil quality and profile structure. IN: ASA-CSSA-SSSA Annual Meeting Abstracts (CDROM), 4-8 November 2007. New Orleans, LA. ASA-CSSA-SSSA, Madison, WI. Technical Abstract: Soil and land productivity depends on the interaction of topsoil quality, profile structure, and landform character. Crop sequence experiments were performed under no-tillage at two sites by growing crops in strips one year, and in perpendicular strips the following year. The two sites (hereafter referred to as SL and SiL), differed in genetic origins (alluvial-derived vs. glacial-till derived with loess cap), predominant soil texture (sandy loam vs. silt loam) and topsoil quality at 0 – 0.3 m (10 g/kg soil organic carbon (SOC) for SL vs. 17 g/kg SOC for SiL). The SL site had shelterbelts and previous grass cover; SiL had no shelterbelts and had been previously long-term cropped. Crops extracted water deeper in the profile on SL: 49% of soil water depletion on SL under corn (CN, Zea mays) and spring wheat (SW, Triticum aestivum) was below 0.9 m depth compared with 20% on SiL. In drier 2004 (20% below seasonal average), seed yields (SYld) of dry pea (DP, Pisum sativum) and SW following DP and SW crops were 8% lower on SL soil than on SiL. However DP and SW SYlds in 2004 following CN were 36% higher on SL than on SiL, and CN following DP and SW was 41% higher on SL than SiL. Under average precipitation 2005, SW SYld following SW and DP was 30% lower on SL than on SiL; SW after CN was 24% lower on SL. Under lower precipitation combined with their higher water-use of CN, relative soil productivity of SL was increased by crop extraction of water deeper in the profile and by probably better land quality factors. Under average precipitation, superior topsoil quality of SiL set productivity with SW higher than that of SL.