Browsing by Author "Brye, Kristofor R"

Now showing 1 - 2 of 2

Soil property and soybean yield trends in response to alternative wheat residue management practices in a wheat-soybean, double-crop production system in eastern Arkansas
(Electronic Journal of Integrative Biosciences, 2008) Amuri, Nyambilila; Brye, Kristofor R; Gbur, Edward E; Popp, Jennie; Chen, Pengyin
Growing concerns over the long-term sustainability of agricultural systems require investigation of agricultural management practices that may improve and sustain soil quality and crop productivity over time. Over 20% of the soybean [Glycine max (L.) Merr.] area in the highly productive Mississippi River Delta region of the mid southern United States is in a double-crop rotation with wheat [Triticum aestivum (L.)]. Currently, much of the resulting wheat residue is managed by burning followed by conventional tillage, but this combination may not be environmentally sustainable. Therefore, the objective of this study was to determine the long term effects of tillage [conventional (CT) and no-tillage (NT)], wheat-residue burning (burn and no burn), wheat-residue level (low and high, achieved with differential N fertilization), and irrigation (irrigated and dry-land) on soybean yield, net economic returns, and soil properties in the top 10 cm of a wheat -soybean, double-crop production system. A field experiment was conducted from 2001 through 2007 in the Mississippi River Delta region of eastern Arkansas on a Calloway silt loam (fine silty, mixed, active, thermic Glossaquic Fraglossudalf). Soil bulk density increased in both CT and NT during the first three years, but at a greater rate under NT (0.12 g cm-3 yr-1) than CT (0.08 g cm-3 yr-1), followed by a decline at a similar rate in both tillage treatments. Soil pH and Mehlich-3 extractable soil Ca and Mg contents increased, while electrical conductivity decreased linearly over time when all treatments were combined. Soil organic matter (SOM) increased over time in all treatment combinations. Total C (TC) increased at a greater rate in the no burn (0.08 kg C m-2 yr-1) and high-residue level (0.07 kg C m-2 yr-1) than in the burn (0.05 kg C m-2 yr-1) and low-residue-level (0.05 kg C m-2 yr-1) treatments. Extractable soil P content declined linearly over time at greater rate under NT (3.3 kg P ha-1 yr-1) and high-residue-level (3.4 kg P ha-1 yr-1) than under CT (2.6 kg P ha-1 yr-1) and low-residue-level (2.4 kg P ha-1 yr-1) treatments. Soybean yield declined at a similar rate in the first three years, but increased at a similar rate over the subsequent three years in all tillage-treatment combinations. Increasing SOM and TC over time indicated that the silt-loam soils of the Mississippi River Delta region have the potential to accumulate C in the top 10 cm at increasing rates beyond six years from initial conversion to alternative residue management practices. Implementation of the appropriate residue management practices has the potential to improve soil quality and maintain long-term productivity of silt-loam soils in the Mississippi River Delta region of the mid-southern United States.
Weed populations as affected by residue management practices in a wheat-soybean double-crop production system
(Cambridge University Press, 2010) Amuri, Nyambilila; Brye, Kristofor R; Gbur, dward E; Dick, Oliver; Jason, kelly
Management practices and cropping systems that serve as integrated weed management practices, and at the same time can contribute to improved soil quality, will be important for the sustainability of agricultural production systems. The objective of this study was to assess weed species population density under contrasting tillage (conventional tillage [CT] and no tillage [NT]), residue burning (burn and no burn), and residue level (low and high) treatments after 5 and 6 yr of consistent management in a wheat-soybean double-crop production system. A field experiment was conducted from fall 2001 to fall 2007 in the Mississippi River Delta region of eastern Arkansas on a Calloway silt-loam. Weed assessments were conducted twice during the soybean growing season, before (early season) and after herbicide application (late season) in 2006 and 2007. Total weed density was greater under CT (513 plants m ) than under NT (340 plants m ) early in the growing season in 2006, but was greater under NT than CT late in the season in 2007, suggesting that the effectiveness of glyphosate on total weeds differs between CT and NT. Averaged across residue levels, grass species density was greatest in the NT-burn (68 to 167 plants m ) combination and lowest in the NT-no-burn (41 to 63 plants m ) early in the growing season in both years. Broadleaf density was greater early (200 to 349 plants m ) than late (18 to 20 plants m ) in the growing season under both CT and NT in 2006, but in 2007 broadleaf density did not differ by tillage treatment between seasons. Perennial weed density was greater in the burn (99 plants m ) than in the no-burn (59 plants m ) treatment in 2006. No tillage, no burning, and a high residue level appeared to contribute to the suppression of most weed species without reducing herbicide efficiency. Nomenclature: Soybean, Glycine max Merr.; wheat, Triticum aestivum