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Organic amendment is a traditional practice for rehabilitating saline patches in north-east Thailand, but organic matter is known to enhance methane emission. However, a high degree of salinity might mitigate methane emission. The objective of the present study was to quantify the effects of salinity and organic amendments on methane emission from rain-fed paddy fields exposed to increasing salinity. A paddy field on a salt-affected Typic Natraqualfs was selected. Eighteen experimental plots were located in two randomized complete block designs placed inside and outside a saline patch. Each design of nine plots presented three replicates of two different organic amendments and a control treatment without organic amendment. During the rainy season the soil electrical conductivity, measured with an electromagnetic conductivity meter (ECEM), was greater than 300 mS m−1 inside the saline patch, whereas outside the saline patch the values were lower than 200 mS m−1. Rice straw (6.25 t ha−1) and cow manure (8.99 t ha−1), representing similar amounts of carbon, were incorporated. Methane emission from the soil, EC1:5 and soil redox potential (Eh) were monitored during the rice-growing season. High methane emission was mostly associated with low Eh, 48% of the Eh measurements were between −100 mV and −200 mV. In the saline patch, the average methane emission ranged from 251 to 334 mg CH4 m−2 day−1; outside the saline patch the values had a wider range from 209 to 544 mg CH4 m−2 day−1. The addition of rice straw or cow manure significantly enhanced methane emission by an approximate factor of 2.5 outside the saline patch, but did not significantly increase methane emission inside the saline patch. The attenuating effect of salinity on methane emission was particularly strong at the beginning of flooding during the first 20 days after transplanting and at the end of flooding (from 54 days after transplanting). When applied to saline patches, organic amendment did not significantly enhance methane emission in the first year. [ABSTRACT FROM AUTHOR]

Economic growth in recent years has induced a labor shortage for agriculture in north-east Thailand. Labor-saving techniques, such as the replacement of transplanting with direct seeding, have become widespread. Direct seeding methods have advantages over transplanting regarding labor savings and reductions in production risks, but may cause weed problems. Therefore, rice yield reduction by competition with weeds becomes a potential problem in this region. In the present research, the extent of weed competition in rice production from the viewpoint of resource level and disturbance intensity was studied. A large number of paddy fields from a wide range of climatic, topographical, soil and hydrological conditions were analyzed. The survey was conducted every 3 weeks, and data on paddy cultivation, weeds and water conditions were recorded. Average yield of direct seeded rice was significantly lower than that of transplanted rice. The yield decreased with resource decreases in both direct seeded (DSF) and transplanted paddy fields (TF). Although the yield was not different under resource-rich conditions, the yield of direct seeded rice was lower than that of transplanted rice under resource-medium and -poor conditions. Competition intensity was not different among resource levels or between DSF and TF. Competition intensity in all fields was between 0.02 and 0.09 on average, indicating 2–9% yield losses caused by competition with weeds regardless of resource level and disturbance intensity. This suggests that low yield of direct seeded rice under resource-medium and -poor conditions was not mainly caused by competition with weeds, whereas yield losses by weeds were observed in all field types. However, from an economical viewpoint, weeding should be applied only to limited parts of this region with stable and relatively high rice yields. [ABSTRACT FROM AUTHOR]

In north-east Thailand where rainfed paddy cultivation is commonplace, direct dry seeding is replacing transplanting to increase the frequency of successful plantings and to save labor. The present study shows the impact of this change on paddy vegetation from agricultural and ecological viewpoints. One hundred and seventy-nine paddy fields from a wide range of climatic, topography, soil and hydrological conditions were used in this study. Authors visited these fields every 3 weeks during the rainy seasons of 1996–1998 to collect data about water conditions, rice growth, progress of cultivation, paddy vegetation and roughness (unevenness) of the soil surface. Analysis of this data revealed that direct dry seeded fields are resource-poor and have a wider range of water conditions within a field than transplanted fields due to a rougher soil surface. This results in lower productivity of total vegetation for rice growing in direct dry seeded fields. However, weed productivity was not significantly different between the direct dry seeding and transplanted fields. Direct dry seeded fields have more species-rich vegetation and greater diversity than the transplanted fields. Previous planting methods for particular fields did not influence productivity and diversity of paddy vegetation. It is concluded that the use of direct dry seeding increases biomass production of rice and the diversity of the paddy vegetation. The present results also suggest that an analytical framework be used to integrate agricultural and ecological studies of paddy vegetation in order to harmonize agricultural productivity with biological diversity. [ABSTRACT FROM AUTHOR]

Rainfed paddy cultivation predominates in north-east Thailand. Direct dry seeding is replacing transplanting rice cultivation to increase the frequency of successful plantings and to save labor. The present study clarified differences in weed vegetation of direct dry-seeded and transplanted paddy fields under rich, medium and poor water conditions from agricultural and ecological viewpoints. A large number of paddy fields from a wide range of climatic, topographic, soil and hydrological conditions were used. A survey was conducted every three weeks, and data regarding paddy cultivation, weeds and water conditions were collected. Expansion of direct dry seeding may increase species with in-between water adaptability to hygrophytes and mesophytes, and decrease hydrophytes and mesophytes. This characteristic was remarkable under poor water conditions. Rice cover was similar in either planting method under rich water conditions. However, cover of direct-seeded rice was significantly smaller than that of transplanted rice under medium and poor water conditions. Species diversity was higher in direct dry-seeded paddy fields than in transplanted paddy fields under medium and poor water conditions. Impact of direct dry seeding in the fields with rich water conditions on the vegetation is small in the context of maintaining rice production by transplanting and species diversity. However, direct dry seeding is mainly adopted in fields with poor water conditions. Impact of the changes in cultivating methods is large on rice productivity, species composition and species diversity under such conditions. Therefore, how to best use resource-poor fields may be the key to maintaining rice production and regional-level species diversity. [ABSTRACT FROM AUTHOR]

This paper uses a linear programming model to examine the economic viability of four fish production strategies in the context of rainfed farming systems in the north‐eastern region of Thailand. The four systems are rice bran feeding system, pond fertilization using buffalo manure, fish production recommendations developed by the Asian Institute of Technology (AIT) Recommendations and an integrated duck/fish production system. These systems have been introduced into North‐eastern Thailand where the main obstacles to fish production are the lack of indigenous knowledge offish culture and a shortage of water. While technical feasibility studies are needed to evaluate the practical viability of aquaculture technologies, economic assessment is required to assess their commercial viability. The objective of this paper is to examine whether or not these fish production systems can contribute to, and integrate with, the prevailing farm system in the North‐east of Thailand. The linear programming model is used to determine the optimum on farm product mix that maximizes net returns under each of the four production systems. Among different resources, labour requirement in the fish‐stocking month appeared to be the first binding resource, while capital requirement was not a constraint for an average farming household of the region. A sensitivity analysis is presented to show how each of the fish production systems operates with different levels of pond size, labour and capital availability. The results of the study show that these aquaculture systems are economically attractive and can contribute significantly to the livelihood of the small‐scale farmers of North‐east Thailand. [ABSTRACT FROM PUBLISHER]

Background: In implementation research, it is essential to involve all stakeholders in the development of complex interventions to ensure that the proposed intervention strategy is relevant and acceptable to the target area and group. The aim of this study was to involve stakeholders in conceptualising, developing, and prioritising a feasible intervention strategy to improve the 6‐month exclusive breastfeeding rate in North‐east Thailand. Concept mapping was used in a purposive sample including health care volunteers, health care professionals, and community leaders. During the first meeting, stakeholders (n = 22) expressed the generation of feasible interventions. During the second meeting, participants (n = 21) were asked to individually rate the feasibility of each intervention and to group them into relevant categories to enable multidimensional scaling and hierarchical cluster analysis. The outputs of analysis included the intervention list, cluster list, point map, point rating map, cluster map, and cluster rating map. All of these were shared with stakeholders (n = 17) during the third meeting to reach consensus on an intervention model. The final proposed intervention strategy included 15 feasible interventions in five clusters: health care services, community services, and education packages for parents, family members, and communities. These interventions were prioritised for implementation over a 3‐year period. Once the feasibility of each intervention is established, the proposed model could be implemented and incorporated into local health policy. After assessing intervention effectiveness, each intervention could be scaled up to other middle‐income countries to help improve overall maternal and child survival. [ABSTRACT FROM AUTHOR]