Browsing by Author "Mulvaney, Michael J."

Now showing 1 - 20 of 27
  • Biomass shifts and suppresses weed populations under conservation agriculture
    Mulvaney, Michael J.; Wood, C. Wesley; Price, A. J. (2011)
    Shifting tillage practices to Conservation Agriculture has numerous effects on both the soil and weed populations found in productive areas. The purpose of this research is to "quantify weed suppression of a summer cover crop and organic mulches under no-till collard (Brassica oleracea L.) production during conversion to CA" (authors). The authors examined weed populations, SOC, and collard yield over the course of three years.
  • Can conservation agriculture improve soil quality and sequester carbon in the short term for dryland smallholders in the developing world?
    Mulvaney, Michael J. (2011)
    The United States Agency for International Development (USAID)-funded Sustainable Agriculture and Natural Resources Management (SANREM) Collaborative Research Support Program (CRSP) seeks to determine the effects of conservation agriculture (CA) on soil fertility and carbon (C) sequestration in the developing world. Time 0 and Year 3 soil samples at 0 – 5 and 5 – 10 cm depths will be compared to determine the effects of CA on soil fertility and soil C. (Author's abstract).
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    Can conservation agriculture improve soil quality and sequester carbon in the short term for dryland smallholders in the developing world?
    Mulvaney, Michael J. (Australian Centre for International Agricultural Research, 2011)
    This article provides an overview of the Soils Cross-Cutting Research Activity (CCRA) within the Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program (SANREM CRSP). Through the Soils CCRA, a soil library compiling soil test results from all SANREM CRSP project sites (Haiti, Bolivia, Ecuador, Ghana, Mali, Lesotho, Mozambique, Uganda, Kenya, India, Nepal, Cambodia, and the Philippines) will be created. Samples will be tested on the basis of soil fertility, soil organic carbon content (SOC), and particulate organic matter (POM).
  • Carbon and nitrogen mineralization and persistence of organic residues under conservation and conventional tillage
    Mulvaney, Michael J.; Wood, C. Wesley; Balkcom, Kipling S.; Shannon, D. A.; Kemble, J. M. (Madison, WI: American Society of Agronomy, 2010)
    Combining high biomass cover crops with in situ organic mulches may achieve adequate weed control for no-till production, but the persistence and nutrient release rates from cover crops and mulches is unknown. This article describes carbon and nitrogen mineralization rates from three organic mulches (mimosa (Albizia julibrissin Durazz.), lespedeza (Lespedeza cuneata (Dum. Cours.) G. Don)), and oat (Avena sativa L.) straw) and one summer cover crop (soybean (Glycine max (L.) Merr.)). The experiment used litterbag methodology on a Wickham fine sandy loam in Tallassee, AL, USA. Litterbags containing the equivalent of 6.7 Mg ha-1 were placed on the soil surface (to represent conservation tillage) or buried at 10 cm depth (to represent conventional tillage) in October 2007 and retrieved periodically up to a year later. Soybean residue mineralized N at similar rates regardless of placement, but more N was potentially available from surface-placed residues than buried residues, showing that surface placed residues may act as a slow-release N fertilizer. Likewise, C was mineralized more rapidly from buried residues than surface-placed residues. The results quantify the increased amount of C that is sequestered when these residues are used in conservation tillage compared to conventional tillage. This research implies that the use of biomass cover crops and in situ organic mulches could have a measurable impact on carbon retention rates, which will reduce the amount of carbon being released into the atmosphere.
  • Conservation Agriculture in Southeast Asia and Beyond
    Mulvaney, Michael J.; Reyes, Manuel R.; Chan-Halbrendt, Catherine; Boulakia, Stephane; Jumpa, K.; Sukvibool, C.; Sombatpanit, Samran (Bangkok, Thailand: Funny Publishing, 2012)
    Conservation agriculture (CA) provides a tool with the potential for smallholder farmers to improve soil fertility and increase production. These proceedings, from the 2nd International Agriculture Workshop and Conference in Southeast Asia, in Phnom Penh, Cambodia July 4-7, 2011, addresses biophysical and socioeconomic questions related to locally-adapted CA practices throughout Southeast Asia and in the rest of the world. The papers and abstracts cover various facets of conservation agriculture, including economic impacts, process of dissemination and adoption, effects on soil quality and yields, and farmer preferences.
  • Cover crop residue and organic mulches provide weed control during limited-input no-till collard production
    Mulvaney, Michael J.; Price, A. J.; Wood, C. Wesley (Taylor & Francis Group, LLC, 2011)
    Conservation tillage is an effective means to suppress weeds, improve soil quality, and thus enhance food security. However, limited-input producers are reluctant to adopt these practices because of inadequate weed suppression without herbicide use. The purpose of this study was to demonstrate that effective weed control and stable collard yields can be achieved through high-biomass producing cover crops with organic mulches. This system was employed for three consecutive years (2005 - 2008) using forage soybean summer cover crop and mimosa, lespedeza, wheat straw, and a no-mulch control. Mulch use was successful in suppressing broadleaf and sedge weeds over the course of the experiment and demonstrated grass weed suppression after three years. Collard yields were not affected by mulch use and averaged 17,863 kg/ha. The results of this study strongly suggest that limited-input producers may incorporate mulch use in conservation tillage systems without affecting crop yields.
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    Decomposition, nitrogen and carbon mineralization from food and cover crop residues in the central plateau of Haiti
    Lynch, M. J.; Mulvaney, Michael J.; Hodges, Steven C.; Thompson, Thomas L.; Thomason, Wade E. (Springer, 2016-07-04)
  • Development of a new dual-chamber microlysimeter model for residue decomposition measures
    Lynch, M. J.; Thomason, Wade E.; Thompson, Thomas L.; Mulvaney, Michael J. (2013)
    This is an abstract from the 2013 American Society of Agronomy Annual Meetings, presented in the second session on General Soil Fertility and Plant Nutrition.
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    Does density fractionation of SOC represent chemically different carbon pools?
    Mulvaney, Michael J.; Graham, M.; Xia, K.; Barrera, Victor H.; Botello, Rubén C.; Saavedra, Ana Karina; Mamani, Pablo (2012)
    Organic matter stabilization is thought to be a process of physical protection and chemical recalcitrance. The determination of recalcitrant soil organic carbon (SOC) often relies on operational definitions provided by various fractionation techniques, usually particle size or density fractionation. However, it is unknown if these operational definitions represent true chemical recalcitrance.
  • Effects of high biomass cover crops and organic mulches on soil properties and collard yield three years after conversion to no-till
    Mulvaney, Michael J.; Wood, C. Wesley; Balkcom, Kipling S.; Shannon, Dennis; Kemble, Joseph (ASA-CSSA-SSSA, 2010)
    Organic producers interested in the adoption of conservation tillage continue to face considerable challenges, particularly with regard to weed control. Previous work demonstrated that high biomass cover crops in conjunction with organic mulches can provide adequate weed control in a no-till system, but the effects of high biomass cover crops and mulches on soil quality during no-till vegetable production has not been investigated. The objective of this study was to determine the effects of organic mulches and forage soybean (Glycine max (L.) Merr. cv. Derry) as a summer cover crop on soil organic carbon (SOC), carbon (C) mineralization, total soil nitrogen (N), aggregate stability, and yield in a no-till system without the use of herbicides during limited-input fall collard (Brassica oleracea L. cv. Champion) production in central eastern Alabama. All treatments, including controls, increased SOC in the 0-5 cm soil depth, indicating that high biomass no-till was more influential on SOC accumulation than the inclusion of summer cover crops or organic mulches. Treatments did not affect collard yield, which averaged 17,863 kg ha-1 yr-1. Mulches applied at 6.7 Mg ha-1 yr-1 did not mineralize nutrients in sufficient quantities to meet collard demands after three years, although the crop appeared healthy. This research highlights the need for careful nutrient management under limited-input no-till vegetable production.
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    Food security through conservation agriculture
    Mulvaney, Michael J.; Dillaha, Theo A. III; Moore, Keith M. (ASA-CSSA-SSSA, 2010)
    This poster describes SANREM CRSP Phase IV activities. "The research theme of the SANREM CRSP's current phase is developing conservation agriculture production systems (CAPS). Our research is aimed at increasing smallholders' agricultural productivity and food security through improved cropping systems that contribute to and take advantage of improved soil quality and fertility."
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    Gender and Soil Knowledge: Linking Farmers' Perceptions of Soils with Fertility Analysis in the Philippines
    Christie, Maria Elisa; Mulvaney, Michael J.; Harman, Mary (2013)
    This presentation discusses the integration of gendered soil knowledge and scientific soil knowledge based on fieldwork in the Philippines. Qualitative methods were used to understand men's and women's soil knowledge as part of a soils conservation project. Quantitative methods such as soil sampling and analysis, and ANOVA were used in combination with the local information to determine statistical differences in the soil fertility between the men's and women's 'best' and 'worst' soils. We found that men and women did choose 'best' soils that had greater fertility than the 'worst' soils. However,there were no significant differences in fertility between the men's and women's chosen soil regarding gender. In other words, mens' soils were not more fertile than womens' and vice verse. This is significant since women were perceived to not have any knowledge of soil and fertility. The authors argue that while men's and women's knowledge of soil fertility was supported by the fertility analysis, men and women chose their soils using different experiences and knowledge of soil interactions. Men based much of their soil knowledge on direct interactions such as tilling while women based their soil knowledge from indirect interactions such as harvesting and marketing. This has important, gendered implications for how extension agents communicate soil conservation management. The authors recommend a closing of the gap between the soil sampling and the ethnographic methods when it comes to collaboration between soils scientists, extension agents, and farmers.
  • High biomass cover crops and organic mulch effects on yields, soil carbon, and weed populations during no-till herbicide-free collard production
    Mulvaney, Michael J. (Blacksburg, VA: Office of International Research Education and Development, Virginia Tech, 2009)
    This presentation describes dissertation work focusing on conservation agriculture production systems for smallholders and limited input farmers. The research design focuses on the conversion of previously conventionally tilled fields to a no till system and subsequently compares different mulch applications including straw and leguminous plants. The main objective of the research was to study whether herbicide free systems could be productive. Such findings may also have promising impacts for organic farmers.
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    Initial Environmental Evaluations and PERSUAPs
    Mulvaney, Michael J. (SANREM CRSP, 2010)
    This presentation describes Initial Environmental Evaluations and PERSUAPs. It begins with a history of the developments that led to the creation of these requirements and then gives detailed logistical information on how SANREM partners can comply with the regulations.
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    Integrating economics, technology networks, soils and gender to remove constraints to conservation agriculture in the developing world
    Mulvaney, Michael J.; Moore, Keith M.; Christie, Maria Elisa; Norton, George W.; Bertelsen, Michael; Sutphin, L. K. (2011)
    The following poster provides an overview of the multidisciplinary approach of the Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program (SANREM CRSP) in promoting the expansion of Conservation Agriculture (CA) practices in the developing world. The program currently pulls experts and ideologies from agricultural economics, technology networks/knowledge dissemination, soils, and gender fields within its CA research projects.
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    Integrating economics, technology networks, soils and gender to remove constraints to Conservation Agriculture in the developing world
    Mulvaney, Michael J.; Moore, Keith M.; Christie, Maria Elisa; Norton, George W.; Bertelsen, Michael; Sutphin, L. K. (Australian Centre for International Agricultural Research, 2011)
    The following paper presented provides an overview of the multidisciplinary approach of the Sustainable Agriculture and Natural Resource Management Collaborative Research Support Program (SANREM CRSP) in promoting the expansion of Conservation Agriculture (CA) practices in the developing world. The program currently pulls experts and ideologies from agricultural economics, technology networks/knowledge dissemination, soils, and gender fields within its CA research projects.
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    A Measurement of Conservation Agriculture’s Effect on Nitrogen and Carbon Mineralization Rates for Agricultural Recommendations in Haiti’s Central Plateau
    Lynch, Madalyn Josephine (Virginia Tech, 2015-03-16)
    Much of Haitian agriculture is characterized by subsistence farming systems on eroded and nutrient-poor soils. Implementation of Conservation Agriculture systems has proven effective at improving soil quality and crop yield in many areas of the world, including areas similar to those in Haiti. While most Haitian smallholder farmers are highly resource-limited and adoption of new technologies is limited, these farmers are known to adopt new crops and practices if benefits that outweigh risks are demonstrated. Cover crops that help provide soil cover and increase nutrient mineralization are one of the most potentially beneficial changes that could be made on most smallholder farms. However, before specific cover crop recommendations can be made, their potential benefits need to be quantified. One field experiment in the summer of 2013 assessed decomposition rates and nutrient mineralization from common cash crops and two potential cover crops either on the soil surface or buried at 15 cm. The relative difficulty and expense of conducting these types of field trials led to the development and assessment of a laboratory-based system that could be used to simulate plant residue decomposition and nutrient release under controlled conditions. Additional benefits of a laboratory-based study include the ability to test significantly more treatment combinations than would likely be possible under field conditions and to control nearly all other experimental variables, other than the desired treatment comparisons.
  • Nitrogen and Carbon Mineralization from Peanut Residues under Conservation and Conventional Tillage at Two Locations
    Mulvaney, Michael J.; Wood, C. Wesley; Balkcom, Kipling S.; Meso, Bernard (2011)
    Residue management is an important aspect of crop production systems. Availability of plant residue nitrogen (N) to succeeding crops is dependent on N mineralization rates and therefore on rates of N release during decomposition. Much of the information available on N release rates from peanut (Arachis hypogaea L.) residue is based on controlled-environment studies. The objective of this study was to assess N release rates in the field from the residues of three peanut varieties (NC V-11, GA 02-C and ANorden) at two placements (surface and 10 cm deep) and two locations (Upper Coastal Plain Experiment Station in Edgecombe County, North Carolina and Wiregrass Experiment Station in Henry County, Alabama), representing the northern and southern limits of commercial peanut production in the US. Litterbags containing the equivalent of 3.5 Mg ha-1 were placed in a completely randomized design, blocked by location, with four replications and retrieved periodically up to 335 days after application. Results showed a statistical difference for placement by time (within location) interactions and fit single or double exponential decay models. Buried residues mineralized N at higher rates than surface residues in North Carolina during the initial 50 days of decomposition. After the initial rapid phase of decomposition, there was no difference in rates of N release at either experiment station. Apart from time, no treatment differences were found at the Wiregrass Experiment Station. The data show that N is released quickly after peanut harvest if residue is left in the field.
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    Physical and Chemical Parameters of Common Soils in the Central Plateau Region of Haiti
    Stewart, Ryan E. (Virginia Tech, 2012-04-20)
    Soil degradation is a common occurrence in Haiti that is mainly caused by the cultivation of marginal lands and deforestation, which both contribute to the excessive erosion rate seen in the country today. The Central Plateau of Haiti is a mountainous region in which a majority of the population is rural and practices subsistence agriculture on hillsides and steeply-sloping land. Essential plant nutrients, such as nitrogen (N) and phosphorus (P), are commonly a limiting factor in crop production, yet fertilizer is unavailable or is too expensive for smallholder farmers to purchase. This study was conducted to a) evaluate organic matter and nutrient stocks of various soils in the Central Plateau region, along with other chemical and physical characteristics and b) to evaluate the phosphorus-scavenging ability of commonly-grown crops to isolate those that may benefit subsequent smallholder yields. Soils from four locations in the Central Plateau were assessed for organic matter in labile and non-labile fractions as well as for cation exchange capacity (CEC), total organic carbon (C) and N, pH, texture, and other characteristics. Results indicated that most of the soil (92%) was contained within aggregates, and organic matter was mainly present in stable, slowly-decomposing fractions. Seven species were evaluated in a controlled-environment pot experiment for bulk and rhizosphere soil P and pH, plant dry weight, and above- and below-ground P tissue content as indicators of the species' ability to solubilize P from the soil. Velvet bean (Mucuna pruriens (L.) DC) produced the most biomass and was able to take up the most P, though lablab (Lablab purpureous (L.) Sweet), took up comparable amounts of P.
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    Research strategy report
    Ares, Adrian; Moore, Keith M.; Kelly, Michael D.; Mulvaney, Michael J. (SANREM CRSP, OIRED, Virginia Tech, 2011)
    The SANREM CRSP is sponsored by the U.S. Agency for International Development (USAID) and host countries around the world. The SANREM vision is to support sustainable agriculture and natural resource management decision makers in developing countries by providing access to appropriate data, knowledge tools, and methods of analysis in addition to enhancing their capacity to make better decisions to improve the livelihoods and the sustainability of natural resources. The research theme of the SANREM CRSP’s current phase is to develop conservation agriculture production systems (CAPS). Our research engages stakeholders of all levels to develop sustainable, localized farming practices. Increasing smallholder’s agricultural productivity and local food security through improved cropping systems that contribute to and take advantage of improves soil quality and fertility is our ultimate goal. Also, implementing CAPS farming systems will maintain a year-round soil cover, minimize soil disturbance by tillage, and utilize crop rotation systems. This multi-country program is also comparative, with research identifying common elements that affect CAPS adoption.