Cassava is one of the most important annual crops in Southeast Asia, and faces increasing seed borne pest and disease pressures. Despite this, cassava seed systems have received scant research attention. In a first analysis of Vietnamese and Cambodian cassava seed systems, we characterized existing cassava seed systems in 2016-2017 through a farmer survey based approach at both national and community scales, with particular focus on identifying seed system actors, planting material management, exchange mechanisms, geographies, and variety use, and performed a network analysis of detected seed movement at the provincial level. Despite their status as self-organized "informal" networks, the cassava seed systems used by farmers in Vietnam and Cambodia are complex, connected over multiple scales, and include links between geographically distant sites. Cassava planting material was exchanged through farmer seed systems, in which re-use of farm-saved supply and community-level exchanges dominated. At the national level, use of self-saved seed occurred in 47 and 64% of seed use cases in Cambodia and Vietnam, respectively. Movement within communes was prevalent, with 82 and 78% of seed provided to others being exchanged between family and acquaintances within the commune in Cambodia and Vietnam, respectively. Yet, meaningful proportions of seed flows, mediated mostly by traders, also formed inter-provincial and international exchange networks, with 20% of Cambodia's seed acquisitions imported from abroad, especially neighboring Vietnam and Thailand. Dedicated seed traders and local cassava collection points played important roles in the planting material distribution network at particular sites. Sales of planting material were important means of both acquiring and providing seed in both countries, and commercial sale was more prevalent in high-intensity than in low-intensity production sites. Considerable variability existed in local seed networks, depending on the intensity of production and integration with trader networks. Adapted innovations are needed to Delaquis et al. Cassava Seed-Vietnam and Cambodia upgrade cassava seed systems in the face of emerging pests and diseases, taking into account and building on the strengths of the existing systems; including their social nature and ability to quickly and efficiently distribute planting materials at the regional level.
Smart-grid rooftop solar electricity (SG rooftop PV) is an alternative sustainable energy resource. This research was conducted in the Central Highlands of Vietnam (CHV) in light of the different levels of retail electricity pricing, the sunshine duration, and the implementation of a feed-in-tariff system, in order to calculate the financial indicators (FIs) of SG rooftop PV, which would supply investors, companies supplying SG rooftop PV, and policymakers with useful information. The FI values were calculated based on the net present value, the payback period, and the internal return rate. The results show that the electricity retail price level affects the FI of SG rooftop PV. SG rooftop PV is installed to satisfy higher electricity consumption levels, which attracts a higher retail electricity price. As a result of the greater benefits, especially if SG rooftop PV is installed and the highest level of electricity (exceeds 400 kWh) is used to satisfy domestic consumption, users will recoup their investment in only four years and after that will enjoy free electricity. All the FI values derived from this research show that people in the CHV can derive benefits from installing SG rooftop PV.
Dak Lak province, Central Highlands, Vietnam presents an interesting case in perennial crop systems, of which coffee and black pepper are the two premier commodities and contribute a large part to economic growth provincially and at the national level. In recent years, in addition to mono-cropping systems, intercropping systems for diversification have developed quickly. This paper focuses on (1) comparing the economic efficiency of mono-coffee systems (MCSes), mono-pepper systems (MPSes), and coffee and pepper intercropping (CPI) by analyzing startup cost, annual cost, and profits; and (2) identifying the main factors affecting farmers’ decisions to convert their crop systems. The study was carried out by investigating 90 perennial crop samples using the three perennial crop systems (MCSes, MPSes, and CPI) in 2017–2018. Additionally, in-depth interviews and focus group discussion (FGD) methods were applied to collect more information about the operations of each system. Another survey with 37 samples (new plantations) was carried out to compute the startup cost. The findings showed evidence that MCSes had the lowest startup and annual costs, whereas MPSes had the highest costs of the three perennial crop systems. MCSes used less manure or compost in the initial setup and overused chemical fertilizer in annual production. Similarly, MPSes had high pesticide-stimulant costs in the production process to sustain crop development. The study indicated that CPI not only had the highest economic efficiency, but also created the best family employment opportunities of the three systems. Additionally, the study found some social factors that strongly influenced farmers’ decisions to shift their cropping system: These included ethnicity, education, training, and crop failure, in addition to economic factors (profits).
This study focuses on the impact of preference diversity and relative country size on intra-industry trade (IIT) in an industry with a vertically differentiated product. By adopting a two-stage game model, we find that the IIT share is higher between countries with a similar preference for quality and that the impact of country size on the IIT index is asymmetric depending on the relative size of the exports and imports of the country. The results of the model can be empirically tested, since preference diversity and country size are related to per capita income and population, respectively.
This paper provides a simple theoretical model to investigate determinants of the vertical IIT based on Bertrand price competition. We find that the volume of trade is higher among countries where R&D investments are larger. In addition, the vertical IIT share increases with the similarity between two countries in terms of technology and per-capita income. Our theoretical findings are consistent with recent empirical findings
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