Mid-season applications of Quadris with and without Warrior insecticide were evaluated in 2004 and 2005, and Headline, Folicur, Domark, or Headline plus Folicur were evaluated in 2006, 2007, and 2008 in 37 farm scale studies in Ohio. Producer cooperators selected fields, applied treatments at growth stage R3 and harvested fields. Each trial was rated at growth stage R5 or R6 for incidence and severity of brown spot and frogeye leaf spot. Aphids and foliar disease incidence was low in 2004. Soybean aphids were counted at stage R5 in 2005. Brown spot severity was reduced significantly by Headline in seven of the 13 locations. In the absence of soybean aphid, a single application of fungicide(s) increased yield significantly in only six of the 28 locations, of which only three had yield increases greater than 4.2 bu/acre. Populations of soybean aphids were high during 2005 at nine locations, and an insecticide application increased yield significantly at eight locations. These data indicated that foliar diseases and aphids contribute to yield loss in soybeans. However, more studies are required to determine action thresholds for brown spot and frogeye leaf spot. Accepted for publication 14 October 2010. Published 22 January 2010.
Increasing C sequestration through no-till (NT) can reduce agricultural COj emissions. However, for long-term NT, information is lacking on the effect of biophysical C pools and processes on C sequestration. Composite soil samples taken at 7.5-cm increments to a 30-cm depth from conventionally tilled (CT) and 2 (NTj), 23 (NTj,), and 44 yr (NT^) of NT corn [Zea mays L.) plots in northwest Ohio were analyzed. The microbial biomass (SMB) was 13,83, and 86% higher in NTj, NTj,, and NT^, respectively, than in CT. No-till had slightly higher basal respiration rates but significandy lower specific maintenance respiration rates and SMB loss than CT. Aggregate stability in NT was 35 to 45% higher than in CT. Macroaggregate-protected C (Cj^^^) was 24, 80, and 92% higher in NTj, NT,j, and NT^, respectively, than in CT. For all tillage treatments, these properties decreased with depth. The C sequestration rates for SMB were 22,13,7, and 3 kg ha"' yr"' at the 0-to 7. 5-, 7.5-to 15-, 15-to 22.5-, and 22.5-to 30-cm depths, respectively for the first 10 yr of NT. During the same time, the C^^j^^ sequestration rates were 92,63,47, and 37 kg ha" ' yr" ' at the four depths, and macroaggregate (MaA) formation rates were 3170, 350, 170, and 70 kg ha"' yr"', respectively However, these rates decreased over the 44 yr of NT. By 20 yr of NT, at all depths the C sequestered in SMB reached a plateau. Similarly, C,^(^^ sequestration plateaued at the surface by 20 yr and MaA formation at the surface leveled out by 10 yr.
whose help in the field and in the office made my projects possible and fun. Many thanks to the OARDC farm staff for their help with our projects and helping me get the truck out of the mud hole on West Badger.
Increased fuels costs have prompted many producers to consider conservation tillage techniques and single pass applications of nitrogen (N) fertilizer and herbicide to reduce fuel expenses. The objective of this study was to determine the impacts of tillage and nitrogen application methodology on corn grain yield. The experiment was conducted from 2002-2005 at the Northwest Research Station of the Ohio Agricultural Research and Development Center (OARDC) near Hoytville, OH. Six different tillage regimes were established as main plots: no-till, fall disc-field cultivator, Aerway tool tillage, early planted strip-till, late planted strip-till, and zone deep-till. Subplots consisted of either a single-pass application of broadcast, surface applied urea-ammonoium nitrate (UAN) representing a weed 'n' feed application, a split application of nitrogen between planter applied and sidedress N (subsurface injected N), or an unfertilized control. The rate of N for the different application methodologies was 168 kg ha −1 . Dry conditions during the 2002 growing season resulted in very poor corn yield and thus little response to tillage or N application. In 2003, the split treatment maximized corn yield likely due to minimized ammonia volatilization independent of tillage regime. Surface broadcast applications of UAN resulted in lower grain yields in conservation tillage treatments compared to split nitrogen applications in 2004. No statistical differences were noted between the two application methods in the conventional tillage treatments. In 2005, no yield differences could be attributed to N application methodology across tillage treatments. From this study it was concluded that surface broadcast application of UAN can result in yield loss, especially in conservation tillage systems.
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