|Baumhardt, Roland - Louis|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/22/2003
Publication Date: 11/3/2003
Citation: AMBATI, S., PAYNE, W.B., BAUMHARDT, R.L., BRONSON, K., STEWART, B.A. 2003. RESPONSE OF DRYLAND GRAIN SORGHUM TO LABELED NITROGEN PLACED AT DIFFERENT SOIL DEPTHS. ANNUAL MEETING ABSTRACTS 2003. ASA-CSSA-SSSA, DENVER, CO. 2003 CDROM.
Technical Abstract: The purpose of study was to determine the response of dryland sorghum to nitrogen fertilizer injected in soil in Texas High Plains. The research was conducted in 2m X 1.5m microplots at USDA-ARS, Bushland, Texas. Sorghum hybrid, Pioneer-8699, was used in an annually cropped site at a seed rate of 80,000 seeds/ha and plant spacing of 0.75m between rows. Labeled 15N Urea Ammonium Nitrate was applied at a rate of 45 kg/ha at depths of 0.1, 0.3 and 0.55m below the soil surface to determine nitrate uptake into the plant system. A solution containing 24.5 percent N labeled fertilizer enriched at 3 atom percent was applied at 0.3m intervals in the microplots using a point injector. Soil moisture measurements were taken at 15-day intervals using a neutron moisture gauge. Plant height, tiller count, grain yields and harvest index were used to determine the differences between depths of placement. Soil nitrate content was determined before fertilization and at harvest. Soil samples were taken at 0.3m intervals to a depth of 1.2m to determine the residual 15N. Plants in the middle 1.2m in two rows were harvested to analyze total N and 15N in grain and stover. Preliminary results show little differences within the treatments and control even though it was a dry year in the area. However, statistical analysis is not completed as some of the laboratory data are awaited.