Bicksler A.J.,Urbana University |
Bicksler A.J.,International Sustainable Development Studies Institute |
Masiunas J.B.,Urbana University |
Davis A.,Urbana University |
Davis A.,Global Change and Photosynthesis Research Unit
Weed Science | Year: 2012
Canada thistle is difficult to manage in organic farming systems and others with reduced reliance on herbicides. Previous field studies found that defoliation or sudangrass interference suppressed Canada thistle. Our objective was to understand the factors causing suppression of Canada thistle observed in the field. Three greenhouse studies were conducted utilizing frequency of defoliation, sudangrass interference and defoliation, and interspecific phytotoxicity to discern mechanisms of Canada thistle suppression. Increased defoliation frequency (up to four defoliations) decreased Canada thistle shoot height, shoot and root mass, and root-to-shoot ratio. Plants with larger root mass had greater shoot mass and number (r = 0.87 and 0.73, respectively), indicating a probable interdependence of root size (carbohydrate reserves), bud density, and subsequent shoot growth. In the sudangrass interference and defoliation study, Canada thistle shoot dry mass was 38.7, 2.76, and 0.39 g pot -1 in the defoliation only, sudangrass interference only, and defoliation + interference + surface mulch treatments, respectively. Sudangrass interference by itself was effective in suppressing thistle growth; combining interference with defoliation did not further reduce growth (2.76 and 2.83 g pot -1, respectively). In the experiment minimizing interspecific competition, we found no evidence of sudangrass having a phytotoxic effect on Canada thistle. Overall results indicate that sudangrass competition or frequent shoot removal suppresses growth of Canada thistle. © 2012 Weed Science Society of America.
Bates R.,United International University Dhanmondi |
Gill T.,United International University Dhanmondi |
Bicksler A.,International Sustainable Development Studies Institute |
Meitzner Yoder L.,International Sustainable Development Studies Institute |
And 2 more authors.
Acta Horticulturae | Year: 2013
Informal seed systems, such as farmer-to-farmer exchanges and farmer self-saved seed, are critical components of resource poor farming systems. This local seed production and distribution facilitates maintenance of crop bio-diversity by preserving in situ locally adapted cultivars and by broadening the genetic base of production with multiple cultivars adapted to specific production systems and micro-climates. They also enhance seed and food security during periods of instability or natural disaster, including changing environmental conditions. A rich diversity of underutilized crop species function within these informal seed systems in Southeast Asia, yet current efforts to conserve, improve, and disseminate indigenous species are failing. A strategy was developed and tested linking an innovative seed bank, local farmers and non-commercial seed traders, with developing markets, supported by accessible information made available through a local outreach network. Impacts included identification of key seed traders and farmers functioning within targeted regions of high species diversity, inventories of important indigenous crop species, documentation of specific indigenous knowledge surrounding the culture of key crops, and expanded exchange and distribution of locally adapted underutilized species. This project paves the way for potential longer term benefits including formation of seed bank-farmer linkages that allow noncommercial seed producers to access new cultivars, hybrids and high-value seed resources not available from traditional sources, development of value chains around key indigenous species, and regional distribution of important seed resources to less developed neighbor nations.
Bicksler A.,International Sustainable Development Studies Institute |
Bates R.,Pennsylvania State University |
Burnette R.,Asia Impact Center |
Gill T.,Pennsylvania State University |
And 3 more authors.
Acta Horticulturae | Year: 2012
Informal seed systems provide access to locally-adapted indigenous crops and constitute an essential component of sustainable production for resource-poor farmers in Southeast Asia. Research conducted with five ethno-linguistic groups in 12 villages in northern Thailand and Cambodia focuses on strengthening the indigenous informal vegetable seed system, including the conservation of knowledge surrounding that system. Through targeted village surveys and using photo card sorts to standardize responses across languages, our methodology documents and characterizes seed system species, pathways, and "germplasm gatekeepers" for indigenous annual and perennial vegetable crops important to northern Thailand hilltribe and Khmer communities. Additionally, farmer-innovated seed preservation and storage methodologies are documented, and farmer-saved seeds are tested using a village-based photovoltaic-powered growth chamber to determine baseline seed viability and vigor under local conditions. At the culmination of research in village clusters, seed and information exchange events occur that facilitate the inter-village exchange, preservation and dissemination of important genetic resources and best practices for seed saving and storage methodologies identified during the farmer community surveys. This research, which was completed in eight northern Thai villages and in four Cambodian villages, helped to build important linkages between under-represented Southeast Asia farmers of diverse ethnicities, a local innovative seed bank (ECHO Asia Impact Center), and a local university extension training system.
Yoder L.S.M.,International Sustainable Development Studies Institute
Journal of Political Ecology | Year: 2011
The enclave of Oecusse-Ambeno, Timor Leste, was formed in part through struggles over controlling trade in sandalwood and beeswax, two forest products that continue to influence political and ritual allegiances, and the political history of Oecusse. These products are interwoven with the region's contacts with outsiders, influencing local political hierarchies and roles of kings, village heads, and ritual authorities. While wood and wax are recognized to be of Timorese origin, local myths posit that their use and value was unrecognized before the arrival of Chinese traders and Portuguese missionaries. Several narratives of the origins of trade in sandalwood, and the kings' annual beeswax candle tributes, illustrate the enduring connections among local authorities, forest resource control, religious symbolism, and ritual obligations surrounding harvests of sandalwood and beeswax. Customary practices contribute to forest conservation through local protection of beeswax-producing forests, and by circumscribing the harvest. While both beehives and sandalwood impede intensive agricultural land uses, farmers welcome beeswax as a profitable product that supports ritual. But they resent sandalwood's growth in their fields since it involves more regulation and increased labor requirements. The two products' different ecologies of disturbance and incidence contributed over time to distinct ownership norms and forms of control by customary authorities. This is the "political ecology of wood and wax" in Oecusse.